CLOSED-LOOP CONTROL DEVICE FOR CLOSED-LOOP CONTROL OF A POWER ASSEMBLY INCLUDING AN INTERNAL COMBUSTION ENGINE AND A GENERATOR HAVING AN OPERATIVE DRIVE CONNECTION TO THE INTERNAL COMBUSTION ENGINE, CLOSED-LOOP CONTROL ARRANGEMENT HAVING SUCH A CLOSED-LOOP CONTROL DEVICE, POWER ASSEMBLY AND METHOD FOR CLOSED-LOOP CONTROL OF A POWER ASSEMBLY

Abstract

A closed-loop control device includes: a power controller; a frequency controller for: detecting a generator frequency (f.sub.G) as a controlled variable; determining a frequency control deviation (e.sub.f) as a difference between the detected generator frequency (f.sub.G) and a target generator frequency (f.sub.soll); determining a second preset variable as a manipulated variable for controlling an internal combustion engine as a function of the frequency control deviation (e.sub.f); and a switchover module for: using, in a first functional state, a first preset variable as a control preset variable for controlling the internal combustion engine; using, in a second functional state, the second preset variable as a control preset variable for controlling the internal combustion engine; wherein the power controller and the frequency controller can calculate a controller component for a respectively assigned preset variable during operation of the closed-loop control device, independently of a current functional state of the switchover module.

Claims

1. A closed-loop control device for closed-loop control of a power assembly including an internal combustion engine and a generator having an operative drive connection to the internal combustion engine, the closed-loop control device comprising: a power controller which is configured for: detecting a generator power (P.sub.G) of the generator as a controlled variable; determining a power control deviation (e.sub.P) as a difference between the generator power (P.sub.G) which is detected and a target generator power (P.sub.soll); and determining a first preset variable as a manipulated variable for controlling the internal combustion engine as a function of the power control deviation (e.sub.P); a frequency controller which is configured for: detecting a generator frequency (f.sub.G) of the generator as a controlled variable; determining a frequency control deviation (e.sub.f) as a difference between the generator frequency (f.sub.G) which is detected and a target generator frequency (f.sub.soll); determining a second preset variable as a manipulated variable for controlling the internal combustion engine as a function of the frequency control deviation (e.sub.f); and a switchover module which is configured for: using, in a first functional state of the switchover module, the first preset variable as a control preset variable for controlling the internal combustion engine; using, in a second functional state of the switchover module, the second preset variable as a control preset variable for controlling the internal combustion engine; wherein the power controller and the frequency controller are configured for calculating at least one controller component for a respectively assigned preset variable during operation of the closed-loop control device, independently of a current functional state of the switchover module.

2. The closed-loop control device according to claim 1, wherein the at least one controller component is selected from a group consisting of a proportional component and a differential component.

3. The closed-loop control device according to claim 1, wherein the closed-loop control device is configured for transferring the respectively assigned preset variable determined by a controlling controllerselected from the power controller and the frequency controllerto a non-controlling controllerselected from the power controller and the frequency controllerfor an initialization before the switchover module switches over.

4. The closed-loop control device according to claim 3, wherein the closed-loop control device is configured for calculating an initialization variable for the initialization of the non-controlling controller from the respectively assigned preset variablewhich is transferredbased on the at least one controller component calculated by the non-controlling controller.

5. The closed-loop control device according to claim 4, wherein the closed-loop control device is configured for initializing an integral component of the non-controlling controller with the initialization variable.

6. The closed-loop control device according to claim 1, wherein the closed-loop control device is configured for determining, as the first preset variable and as the second preset variable respectively, a target torque (M.sub.soll) or a target speed (n.sub.soll).

7. The closed-loop control device according to claim 1, wherein the closed-loop control device is formed as: (a) an open-loop control device for directly controlling the internal combustion engine; or (b) a generator controller.

8. The closed-loop control device according to claim 7, wherein the closed-loop control device is formed as the generator controller with an interface to an open-loop control device of the internal combustion engine.

9. The closed-loop control device according to claim 1, wherein the switchover module is configured for switching between the first functional state and the second functional state parameter-dependently, alternately, or according to a predetermined sequence.

10. The closed-loop control device according to claim 9, wherein the switchover module is configured for switching between the first functional state and the second functional state alternately and thereby cyclically.

11. The closed-loop control device according to claim 1, wherein the closed-loop control device is configured for: calculating a preset variable additional term from the target generator power (P.sub.soll) by way of a calculation element having a differential transfer behavior; and offsetting the preset variable additional term against a precursor preset variable calculated by the power controller in order to obtain the first preset variable.

12. The closed-loop control device according to claim 11, wherein the closed-loop control device is configured for: calculating a preset variable additional term from the target generator power (P.sub.soll) by way of a calculation element having a differential transfer behavior; and offsetting the preset variable additional term against a precursor preset variable calculated by the power controllerin order to add the preset variable additional term to the precursor preset variablein order to obtain the first preset variable.

13. A closed-loop control arrangement for closed-loop control of a power assembly including an internal combustion engine and a generator having an operative drive connection to the internal combustion engine, the closed-loop control arrangement comprising: a closed-loop control device which is formed as a general controller, is for closed-loop control of the power assembly, and includes: a power controller which is configured for: detecting a generator power (P.sub.G) of the generator as a controlled variable; determining a power control deviation (e.sub.P) as a difference between the generator power (P.sub.G) which is detected and a target generator power (P.sub.soll); and determining a first preset variable as a manipulated variable for controlling the internal combustion engine as a function of the power control deviation (e.sub.P); a frequency controller which is configured for: detecting a generator frequency (f.sub.G) of the generator as a controlled variable; determining a frequency control deviation (e.sub.f) as a difference between the generator frequency (f.sub.G) which is detected and a target generator frequency (f.sub.soll); determining a second preset variable as a manipulated variable for controlling the internal combustion engine as a function of the frequency control deviation (e.sub.f); and a switchover module which is configured for: using, in a first functional state of the switchover module, the first preset variable as a control preset variable for controlling the internal combustion engine; using, in a second functional state of the switchover module, the second preset variable as the control preset variable for controlling the internal combustion engine; wherein the power controller and the frequency controller are configured for calculating at least one controller component for a respectively assigned preset variable during operation of the closed-loop control device, independently of a current functional state of the switchover module; and an open-loop control device operatively connected to the closed-loop control device for direct control of the internal combustion engine, the closed-loop control device being configured for transmitting the control preset variable to the open-loop control device.

14. A power assembly, comprising: an internal combustion engine; a generator including an operative drive connection to the internal combustion engine; and one of: (a) a closed-loop control device for closed-loop control of the power assembly, the closed-loop control device including: a power controller which is configured for: detecting a generator power (P.sub.G) of the generator as a controlled variable; determining a power control deviation (e.sub.P) as a difference between the generator power (P.sub.G) which is detected and a target generator power (P.sub.soll); and determining a first preset variable as a manipulated variable for controlling the internal combustion engine as a function of the power control deviation (e.sub.P); a frequency controller which is configured for: detecting a generator frequency (f.sub.G) of the generator as a controlled variable; determining a frequency control deviation (e.sub.f) as a difference between the generator frequency (f.sub.G) which is detected and a target generator frequency (f.sub.soll); determining a second preset variable as a manipulated variable for controlling the internal combustion engine as a function of the frequency control deviation (e.sub.f); and a switchover module which is configured for: using, in a first functional state of the switchover module, the first preset variable (16) as a control preset variable for controlling the internal combustion engine; using, in a second functional state of the switchover module, the second preset variable as the control preset variable for controlling the internal combustion engine; wherein the power controller and the frequency controller are configured for calculating at least one controller component for a respectively assigned preset variable during operation of the closed-loop control device, independently of a current functional state of the switchover module; and (b) a closed-loop control arrangement for closed-loop control of the power assembly, the closed-loop control arrangement including: a closed-loop control device which is formed as a general controller, is for closed-loop control of the power assembly, and includes: a power controller which is configured for: detecting a generator power (P.sub.G) of the generator as a controlled variable; determining a power control deviation (e.sub.P) as a difference between the generator power (P.sub.G) which is detected and a target generator power (P.sub.soll); and determining a first preset variable as a manipulated variable for controlling the internal combustion engine as a function of the power control deviation (e.sub.P); a frequency controller which is configured for: detecting a generator frequency (f.sub.G) of the generator as a controlled variable; determining a frequency control deviation (e.sub.f) as a difference between the generator frequency (f.sub.G) which is detected and a target generator frequency (f.sub.soll); determining a second preset variable as a manipulated variable for controlling the internal combustion engine as a function of the frequency control deviation (e.sub.f); a switchover module which is configured for: using, in a first functional state of the switchover module, the first preset variable as a control preset variable for controlling the internal combustion engine; using, in a second functional state of the switchover module, the second preset variable as the control preset variable for controlling the internal combustion engine; wherein the power controller and the frequency controller are configured for calculating at least one controller component for a respectively assigned preset variable during operation of the closed-loop control device, independently of a current functional state of the switchover module; and an open-loop control device operatively connected to the closed-loop control device for direct control of the internal combustion engine, the closed-loop control device being configured for transmitting the control preset variable to the open-loop control device; wherein the closed-loop control device or the closed-loop control arrangement is operatively connected to the internal combustion engine and the generator of the power assembly.

15. A method for closed-loop control of a power assembly including an internal combustion engine and a generator having an operative drive connection to the internal combustion engine, the method comprising the steps of: detecting a generator power (P.sub.G) of the generator as a controlled variable; determining a power control deviation (e.sub.P) as a difference between the generator power (P.sub.G) which is detected and a target generator power (P.sub.soll); determining a first preset variable as a manipulated variable for controlling the internal combustion engine as a function of the power control deviation (e.sub.P); detecting a generator frequency (f.sub.G) of the generator as a controlled variable; determining a frequency control deviation (e.sub.f) as a difference between the generator frequency (f.sub.G) which is detected and a target generator frequency (f.sub.soll); determining a second preset variable as a manipulated variable for controlling the internal combustion engine as a function of the frequency control deviation (e.sub.f); using, in a first functional state, the first preset variable as a control preset variable for controlling the internal combustion engine; using, in a second functional state, the second preset variable as a control preset variable for controlling the internal combustion engine; calculating at least one controller component for the first preset variable and for the second preset variable, independently of the current functional state.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0050] The invention will be explained in more detail below with reference to the drawing, in which: The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein:

[0051] FIG. 1 shows a schematic representation of a first exemplary embodiment of a power assembly with a first exemplary embodiment of a closed-loop control arrangement and a first exemplary embodiment of a closed-loop control device;

[0052] FIG. 2 shows a schematic representation of a second exemplary embodiment of a power assembly with a second exemplary embodiment of a closed-loop control arrangement and a second exemplary embodiment of a closed-loop control device;

[0053] FIG. 3 shows a schematic representation of a third exemplary embodiment of a power assembly with a third exemplary embodiment of a closed-loop control device;

[0054] FIG. 4 shows a first schematic detailed representation of the first exemplary embodiment of the power assembly;

[0055] FIG. 5 shows a second schematic detailed representation of the exemplary embodiment of the power assembly in a first functional state;

[0056] FIG. 6 shows a third schematic detailed representation of the first exemplary embodiment of the power assembly in a second functional state, and

[0057] FIG. 7 shows a schematic representation of a fourth exemplary embodiment of a power assembly with a third exemplary embodiment of a closed-loop control arrangement and a fourth exemplary embodiment of a closed-loop control device.

[0058] Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate embodiments of the invention, and such exemplifications are not to be construed as limiting the scope of the invention in any manner.

DETAILED DESCRIPTION OF THE INVENTION

[0059] FIG. 1 shows a schematic representation of a first exemplary embodiment of a power assembly 1 with a first exemplary embodiment of a closed-loop control arrangement 13 and a first exemplary embodiment of a closed-loop control device 3. The power assembly 1 in this exemplary embodiment is part of a higher-level network of a multiplicity of power assemblies, of which only the one power assembly 1 considered in greater detail here is shown. In particular, the power assembly 1 is electrically connected to a power grid 4, here specifically to a busbar 6. In particular, the power assembly 1 can be operated in island parallel operation or in grid parallel operation; in particular, the power grid 4 can be a local power grid, in particular an on-board electrical system of a vehicle, for example a ship, or a supra-regional power grid. An external open-loop control unit 8 is assigned to the power grid 4 and distributes a total power P.sub.Schiene requested at the busbar 6, which is also referred to as the total load, across the individual power assemblies 1, in particular by calculating a separate target generator power P.sub.soll.sup.1, P.sub.soll.sup.2, P.sub.soll.sup.3, etc. for each power assembly 1. A first target generator power P.sub.soll.sup.1 assigned to the power assembly 1 specifically shown here is referred to in the following as the target generator power P.sub.soll for short for the sake of simplicity.

[0060] However, the power assembly 1 can also be operated in isolation.

[0061] It is also possible that the power distribution is not carried out in an external open-loop control unit 8, but in the closed-loop control device 3 itself, in particular in a master closed-loop control device of one of the power assemblies 1, wherein the other closed-loop control devices 3 of the other power assemblies 1 are then optionally operated as slave closed-loop control devices, which receive their respective target generator power from the master closed-loop control device.

[0062] The power assembly 1 has an internal combustion engine 5 and a generator 9 which has an operative drive connection to the internal combustion engine 5 via a shaft 7 shown schematically. The closed-loop control device 3 is operatively connected to the internal combustion engine 5 on the one hand and to the generator 9 on the other. In particular, the generator 9 is electrically connected to the busbar 6 in a manner not presented explicitly here.

[0063] In particular, the closed-loop control device 3 is set up (compare also FIG. 4 in this regard) for closed-loop control of the power assembly 1, wherein it has a power controller 14 which is set up to detect a generator power P.sub.G of the generator 9 as a first controlled variable, to determine a power control deviation e.sub.P as the difference between the detected generator power P.sub.G and the target generator power P.sub.soll, and to determine a preset variable 16 as a manipulated variable for controlling the internal combustion engine 5 as a function of the power control deviation e.sub.P. In addition, the closed-loop control device 3 has a frequency controller 18, which is set up to detect a generator frequency f.sub.G of the generator 9 as a second controlled variable, to determine a frequency control deviation e.sub.f as the difference between the detected generator frequency f.sub.G and the target generator frequency f.sub.soll, and to determine a second preset variable 20 as a manipulated variable for controlling the internal combustion engine 5 as a function of the frequency control deviation e.sub.f. The closed-loop control device 3 also has a switchover module 22, which is set up to use the first preset variable 16 as a control preset variable 24 for controlling the internal combustion engine 5 in a first functional state of the switchover module 22, and to use the second preset variable 20 as the control preset variable 24 for controlling the internal combustion engine 5 in a second functional state of the switchover module 22. The power controller 14 and the frequency controller 18 are set up to always calculate at least one controller component for the respectively assigned preset variable 16, 20 during operation of the closed-loop control device 3, independently of the current functional state of the switchover module 22.

[0064] The closed-loop control device 3 enables a defined, clear and robust control strategy for the closed-loop control of both the generator frequency and the generator power. The switchover module 22 is used here to decide at any time whether the frequency controller 18 or the power controller 14 takes over control of the internal combustion engine 5 as the currently controlling controller. The switchover module 22 also allows the hierarchy of the controllers to be clearly specified. Advantageously, at least one variable to be transferred between the controllers immediately before the switchover can be determined, by way of which undesirable jumps in the control of the internal combustion engine 5 can be avoided during the switchover. This can be advantageously designed in such a way that the controller currently controlling immediately after the switchover calculates the preset variable 16, 20 assigned to it in the sampling step immediately following the switchoverin the case of discrete-time samplingas if it had also been the controller currently controlling in the immediately preceding sampling step, that is to say immediately before the switchover.

[0065] In the first exemplary embodiment shown here, the control preset variable 24and correspondingly also each of the preset variables 16, 20is in particular a target speed n.sub.soll.

[0066] The closed-loop control device 3 is designed as a generator controller 12 according to the first exemplary embodiment shown here and is operatively connected to an open-loop control device 11 of the internal combustion engine 5 in such a way that the target preset variable 24 can be transmitted from the closed-loop control device 3 to the open-loop control device 11. This also enables, at the same time, particularly robust power control and versatile use of the closed-loop control device 3, in particular with a multiplicity of power assemblies 1.

[0067] The closed-loop control device 3 and the open-loop control device 11 together form the closed-loop control arrangement 13 for control of the power assembly 1. The open-loop control device 11 is optionally designed as an engine controller, in particular as an engine control unit (ECU).

[0068] The open-loop control device 11 also has the target speed n.sub.soll and a detected speed n.sub.ist as input variables. From this, the open-loop control device 11 calculates a speed control deviation. Lastly, the open-loop control device 11 uses this speed control deviation to calculate an energization duration BD for controlling the fuel injection valves of the internal combustion engine 5. Optionally, the open-loop control device 11 first calculates a target torque M.sub.soll from the speed control deviation and, from this, in turn, the energization duration BD.

[0069] A speed controller is optionally activated in the open-loop control device 11 if the target speed n.sub.soll is calculated as the control preset variable 24.

[0070] FIG. 2 shows a schematic representation of a second exemplary embodiment of a power assembly 1 with a second exemplary embodiment of a closed-loop control arrangement 13 and a second exemplary embodiment of a closed-loop control device 3.

[0071] Like and functionally similar elements are provided with the same reference signs in all figures, and therefore reference is made to the previous description in each case.

[0072] This second exemplary embodiment differs from the first exemplary embodiment according to FIG. 1 in particular in that the control preset variable 24 here is not a target speed n.sub.soll, but rather a target torque M.sub.soll is calculated and transferred to the open-loop control device 11.

[0073] A speed controller of the open-loop control device 11 is optionally deactivated in this case. Optionally, a final idling speed controller of the open-loop control device 11 is activated. This is used to control the speed of the internal combustion engine 5 if the detected speed n.sub.ist falls below a lower speed limit n.sub.Leer or exceeds an upper speed limit n.sub.End. Between these speed limits, a target torque calculated in the open-loop control device 11 is equal to the target torque M.sub.soll specified by the closed-loop control device 3. In particular, a torque specification is activated in the open-loop control device 11.

[0074] FIG. 3 shows a schematic representation of a third exemplary embodiment of a power assembly 1 with a third exemplary embodiment of a closed-loop control device 3. In this exemplary embodiment the closed-loop control device 3 is designed as an open-loop control device 11, here specifically an engine controller 15, for direct, in particular immediate control of the internal combustion engine 5. In particular, the closed-loop control device 3 is set up to calculate an energization duration BD for controlling the injectors of the internal combustion engine 5 from the control preset variable 24, in particular the target speed n.sub.soll or the target torque M.sub.soll.

[0075] FIG. 4 shows a first schematic detailed representation of the first exemplary embodiment of the power assembly 1 according to FIG. 1.

[0076] In this respect, the further mode of operation of the closed-loop control device 3 in particular is explained in conjunction with the first exemplary embodiment according to FIG. 1. However, the mode of operation explained below is equally applicable to the other exemplary embodiments according to FIGS. 2 and 3. In this respect, the target speed n.sub.soll is also used in the following, in particular by way of example, as the control preset variable 24. However, the logic and functionality explained for calculating the control preset variable 24 can also be used if the target torque M.sub.soll is used as the control preset variable 24.

[0077] The switchover module 22 is shown here as the first switch 17, wherein the first functional state of the switchover module 22 corresponds to the upper switch position of the first switch 17, and wherein the second functional state corresponds to the lower switch position of the first switch 17.

[0078] The switchover module 22 is optionally set up to switch between the first functional state and the second functional state parameter-dependently, or alternately, in particular cyclically, or according to a predetermined sequence. In particular, the switchover can take place equidistantly in time, optionally after each sampling step, or according to a predetermined prioritization of one of the controllers, optionally the power controller 14. For example, switching from the power controller 14 to the frequency controller 18, i.e., from the first functional state to the second functional state, only takes place after two sampling steps, wherein switching from the second functional state back to the first functional state, i.e., from the frequency controller 18 to the power controller 14, already takes place after one sampling step.

[0079] The closed-loop control device 3 is optionally set up to filter an instantaneous actual power P.sub.ist of the generator 9 in a power filter 19 and to use the filtered actual power P.sub.ist as the detected generator power P.sub.G. According to an optional embodiment, the power filter 19 is a PT.sub.1 filter or a mean value filter.

[0080] The closed-loop control device 3 is additionally set up to filter an instantaneous actual frequency f.sub.ist of the generator 9 in a frequency filter 21 and to use the filtered actual frequency f.sub.ist as the detected generator frequency f.sub.G. According to an optional embodiment, the frequency filter 21 is a PT.sub.1 filter or a mean value filter.

[0081] FIG. 5 shows a second schematic detailed representation of the first exemplary embodiment of the power assembly 1 in the first functional state in a discrete-time representation, wherein the sampling steps are denoted by a running index. In both FIGS. 5 and 6, the index value of the running index indicated by k corresponds to a sampling step immediately before switching from the power controller 14, i.e., from the first functional state, to the frequency controller 18, i.e., to the second functional state. This means that the index value k corresponds to the last sampling step in the first functional state. Accordingly, the index value indicated by k+1 denotes the sampling step that immediately follows the switchover, i.e., the first sampling step in the second functional state. Accordingly, the index value indicated by k?1 denotes the sampling step immediately before the sampling step denoted by k. In particular, FIG. 5 shows the closed-loop control device 3 in its state at the time indicated by k.

[0082] The control algorithms for the power controller 14 and the frequency controller 18 are designed as PI controllers in both FIGS. 5 and 6. Alternatively, however, it is also possible that at least one of the controllers, selected from the power controller 14 and the frequency controller 18, is designed as a PID controller or as a PI(DT.sub.1) controller.

[0083] The power controller 14 calculates the power control deviation e.sub.P(k) from the target generator power P.sub.soll(k) and the detected generator power P.sub.G(k) in the current sampling step k, and, from this, a power proportional component n.sub.soll.sup.P,p(k), by multiplying the power control deviation e.sub.P(k) by a first power constant r.sub.1.sup.P. The first power constant r.sub.1.sup.P is optionally equal to an optionally parameterizable, i.e., predeterminable power proportional coefficient k.sub.p.sup.P. The power controller 14 also calculates a power integral component n.sub.soll.sup.P,i(k) at least in the first functional state, using the trapezoidal rule for integration by adding the power control deviation e.sub.P(k) of the current sampling step k to the power control deviation e.sub.P(k?1) of the previous sampling step k?1, wherein the sum thus formed is multiplied by a second power constant r.sub.2.sup.P, wherein the product thus formed is added to the preceding power integral component n.sub.soll.sup.P,i(k?1) delayed by one sampling step ?.sub.a, and wherein the sum formed in this way is delimited upward to a first, optionally parameterizable maximum value n.sub.soll.sup.P,i,max and downward to a first, optionally parameterizable minimum value n.sub.soll.sup.P,i,min. The power integral component n.sub.soll.sup.P,i(k) calculated in this way is added to the power proportional component n.sub.soll.sup.P,p(k) at least in the first functional state, wherein the sum formed in this way is in turn limited upward to a second maximum value, optionally to the first maximum value n.sub.soll.sup.P,i,max, and downward to a second minimum value, optionally to the first minimum value n.sub.soll.sup.P,i,min. This results in the first preset variable 16, in this case the target speed n.sub.soll.sup.P(k) of the power controller 14. In the first functional state, the first preset variable 16 is output by the switchover module 22 as a control preset variable 24.

[0084] The second power constant r.sub.2.sup.P is optionally given by:

[00001]$\begin{array}{cc}{r}_2^P=\frac{k_p^P{?}_a}{2{?}_N},& \left(1\right)\end{array}$

with the parameterizable power proportional coefficient k.sub.p.sup.P, the time width ?.sub.a of a sampling step, and the parameterizable reset time ?.sub.N. The first maximum value n.sub.soll.sup.P,i,max is optionally given by a nominal speed for the internal combustion engine 5 plus 200 min.sup.?1. The first minimum value n.sub.soll.sup.P,i,min optionally given by the nominal speed minus 200 min.sup.?1.

[0085] The frequency controller 18 calculates the frequency control deviation e.sub.f(k) from the target generator frequency f.sub.soll(k) and the detected generator frequency f.sub.G(k) in the current sampling step k, and, from this, a frequency proportional component n.sub.soll.sup.f,p(k), by multiplying the frequency control deviation e.sub.f(k) by a first frequency constant r.sub.1.sup.f. The first frequency constant r.sub.1.sup.f is optionally equal to an optionally parameterizable, i.e., predeterminable frequency proportional coefficient k.sub.p.sup.f. The frequency controller 18 also calculatesnot necessarily in the first functional state, but at least in the second functional statea frequency integral component n.sub.soll.sup.f,i(k), using the trapezoidal rule for integration by adding the frequency control deviation e.sub.f(k) of the current sampling step k to the frequency control deviation e.sub.f(k?1) of the previous sampling step k?1, wherein the sum thus formed is multiplied by a second frequency constant r.sub.2.sup.f, wherein the product thus formed is added to the preceding frequency integral component n.sub.soll.sup.f,i(k?1) delayed by one sampling step ?.sub.a, and wherein the sum formed in this way is delimited upward to a third, optionally parameterizable maximum value n.sub.soll.sup.f,i,max and downward to a third, optionally parameterizable minimum value n.sub.soll.sup.f,i,min.

[0086] The frequency controller 18 is set up so that, at least in the second functional state, the thus calculated frequency integral component n.sub.soll.sup.f,i(k) is added to the frequency proportional component n.sub.soll.sup.f,p(k) and the sum thus formed is in turn limited upward to a fourth maximum value, optionally to the third maximum value n.sub.soll.sup.f,i,max, and downward to a fourth minimum value, optionally to the third minimum value n.sub.soll.sup.f,i,min. This then results in the second preset variable 20, in this case the target speed n.sub.soll.sup.f(k) of the frequency controller 18.

[0087] The second frequency constant r.sub.2.sup.f is optionally given by:

[00002]$\begin{array}{cc}{r}_2^f=\frac{k_p^f{?}_a}{2{?}_N},& \left(2\right)\end{array}$

with the parameterizable frequency proportional coefficient k.sub.p.sup.f, the time width ?.sub.a of a sampling step, and the parameterizable reset time ?.sub.N. The third maximum value n.sub.soll.sup.f,i,max is optionally given by the nominal speed plus 200 min.sup.?1. The third minimum value n.sub.soll.sup.f,i,min is optionally given by the nominal speed minus 200 min.sup.?1.

[0088] In the first functional state, the power controller 14 calculates at least the power proportional component n.sub.soll.sup.P,p(k) and the power integral component n.sub.soll.sup.P,i(k) if it is designed as a PI controller, as shown here. If the power controller 14 is designed as a PID controller, it additionally calculates a power differential component in the first functional state. In the second functional statecompare FIG. 6 in this regardthe power controller 14 calculates at least the power proportional component n.sub.soll.sup.P,p(k), especially if the power controller 14 is designed as a PI controller. If the power controller 14 is designed as a PID controller, it optionally calculates at least the power proportional component n.sub.soll.sup.P,p(k) and the power differential component in the second functional state. It is possible that the power controller 14 does not calculate the power integral component n.sub.soll.sup.P,i(k) in the second functional state. However, it is also possible that the power controller 14 also calculates the power integral component n.sub.soll.sup.P,i(k) in the second functional state, wherein the power integral component n.sub.soll.sup.P,i(k) is not used in the second functional state. In particular, it is possible that the power controller 14 does not calculate the first preset variable 16 in the second functional state, or that this is calculated butat least due to the functional position of the switchover module 22is not used, in particular is not forwarded as a control preset variable 24.

[0089] In the second functional statecompare FIG. 6 in this regardthe frequency controller 18 calculates at least the frequency proportional component n.sub.soll.sup.f,p(k) and the frequency integral component n.sub.soll.sup.f,i(k) if it is designed as a PI controller, as shown here. If the frequency controller 18 is designed as a PID controller, it additionally calculates a frequency differential component in the second functional state. In the first functional statesee FIG. 5 in this regardthe frequency controller 18 calculates at least the frequency proportional component n.sub.soll.sup.f,p(k), especially if the frequency controller 18 is designed as a PI controller. If the frequency controller 18 is designed as a PID controller, it optionally calculates at least the frequency proportional component n.sub.soll.sup.f,p(k) and the frequency differential component in the first functional state. It is possible that the frequency controller 18 does not calculate the frequency integral component n.sub.soll.sup.f,i(k) in the first functional state. However, it is also possible that the frequency controller 18 also calculates the frequency integral component n.sub.soll.sup.f,i(k) in the first functional state, wherein the frequency integral component n.sub.soll.sup.f,i(k) is not used in the first functional state. In particular, it is possible that the frequency controller 18 does not calculate the second preset variable 20 in the first functional state, or that this is calculated butat least due to the functional position of the switchover module 22is not used, in particular is not forwarded as a control preset variable 24.

[0090] The closed-loop control device 3 is set up to transfer the preset variable 16, 20 calculated by the controlling controller, selected from the frequency controller 18 and the power controller 14, to a non-controlling controller, selected from the power controller 14 and the frequency controller 18, of which the assigned preset variable 16, 20 is not used as a control preset variable in a current functional state of the switchover module 22, for initialization before the switchover module 22 switches to a subsequent functional state. Specifically, the power controller 14 controlling in the sampling step denoted by the index value k in the first functional state transfers the first preset variable 16 to the non-controlling frequency controller 18 for initialization immediately before the switchover.

[0091] The closed-loop control device 3 is further set up to calculate an initialization variable 32 for the initialization of the non-controlling controller from the transferred preset variable 16, 20 on the basis of the at least one controller component calculated by the non-controlling controller. Specifically, the frequency proportional component n.sub.soll.sup.f,p(k) calculated by the non-controlling frequency controller 18 is subtracted from the first preset variable 16, and the difference thus formed is used as the initialization variable 32 for initializing the frequency controller 18.

[0092] In particular, the closed-loop control device 3 is set up to initialize the integral component of the non-controlling controller with the initialization variable 32. The difference between the first preset variable 16 and the frequency proportional component n.sub.soll.sup.f,p(k) is thus used in the first functional state to initialize the frequency controller 18, which is symbolically represented here by a second switch 25.

[0093] If the frequency controller 18 is designed as a PID controller, the frequency differential component is optionally subtracted from the first preset variable 16 in addition to the frequency proportional component n.sub.soll.sup.f,p(k) in order to calculate the initialization variable 32.

[0094] In this procedure, a hypothetical second preset variable 20 calculated in the sampling step denoted by the index value k, which is the sum of the initialization variable 32 and the frequency proportional component n.sub.soll.sup.f,p(k)and possibly also the frequency differential componentcorresponds to the value that would have resulted if the second preset variable 20 had been calculated regularly by the frequency controller 18 at the same point in time. In particular, this hypothetical second preset variable 20 would optionally have the same value as the first preset variable 16 actually calculated by the power controller 14 in the sampling step denoted by the index value k. Starting from the initialization variable 32, the actual second preset variable 20 and thus also the control preset variable 24 is then calculated in the next sampling step designated by the index value k+1 (compare FIG. 6).

[0095] FIG. 6 shows a third schematic detailed representation of the first exemplary embodiment of the power assembly 1 according to FIG. 5, but now in the second functional state, again in the discrete-time representation. The index value of the running index indicated by k+1 now denotes the sampling step shown in FIG. 6 immediately after switching from the power controller 14, i.e., from the first functional state, to the frequency controller 18, i.e., to the second functional state. This means that the index value k+1 corresponds to the first sampling step in the second functional state.

[0096] The second preset variable 20 is now forwarded by the switchover module 22 as the control preset variable 24, i.e., the frequency controller 18 is now the controlling controller. The preceding frequency integral component n.sub.soll.sup.f,i(k), which is delayed by one sampling step ?.sub.a, used to calculate the frequency integral component n.sub.soll.sup.f,i(k+1) is now the initialization variable 32 from the previous sampling step denoted by the index value k, i.e., in this case specifically the difference between the preset variable 16 in sampling step k and the frequency proportional component n.sub.soll.sup.f,p(k). This advantageously enables a smooth transition from power control to frequency control.

[0097] At the same time, the frequency controller 18 controlling in the sampling step, denoted by the index value k+1, in the second functional state now transfers the second preset variable 20 to the non-controlling power controller 14 for initialization. The power proportional component n.sub.soll.sup.P,p(k+1) calculated by the non-controlling power controller 14 is subtracted from the second preset variable 20, and the difference thus formed is now used as the initialization variable 32 for initializing the power controller 14. In particular, the integral component of the non-controlling power controller 14 is initialized with the initialization variable 32. The difference between the second preset variable 20 and the power proportional component n.sub.soll.sup.P,p(k+1) is thus used in the second functional state to initialize the power controller 14, which is symbolically represented here by a third switch 27.

[0098] If the power controller 14 is designed as a PID controller, the power differential component is optionally subtracted from the second preset variable 20 in addition to the power proportional component n.sub.soll.sup.P,p(k+1) in order to calculate the initialization variable 32.

[0099] In this procedure, a hypothetical first preset variable 16 calculated in the sampling step denoted by the index value k+1, which is the sum of the initialization variable 32 and the power proportional component n.sub.soll.sup.P,p(k+1)and possibly also the power differential componentcorresponds to the value that would have resulted if the first preset variable 16 had been calculated regularly by the power controller 14 at the same point in time. In particular, this hypothetical first preset variable 16 would optionally have the same value as the second preset variable 20 actually calculated by the frequency controller 18 in the sampling step denoted by the index value k+1. Starting from the initialization variable 32, the actual first preset variable 16 and thus also the control preset variable 24 is then calculated again in a next sampling step denoted by the index value k+2 according to one embodiment. In this way, an interference-free transition from frequency control to power control is also made possible.

[0100] Otherwise, the power controller 14 and the frequency controller 18 operate as explained in conjunction with FIG. 5.

[0101] Overall, the initialization strategy proposed here for the respective integral components of the frequency controller 18 on the one hand and the power controller 14 on the other enables a smooth transition between the two control modes.

[0102] The procedure shown in FIGS. 5 and 6 is optionally continued iteratively.

[0103] FIG. 7 shows a schematic representation of a fourth exemplary embodiment of a power assembly 1 with a third exemplary embodiment of the closed-loop control arrangement 13 and a fourth exemplary embodiment of the closed-loop control device 3. The closed-loop control device 3 is shown here by way of example as a higher-level generator controller 12; however, the embodiment explained in conjunction with FIG. 7 can also be implemented in a closed-loop control device 3 designed as an engine controller 15 in another embodiment of the present invention.

[0104] The power controller 14 does not directly calculate the first preset variable 16 here, but instead calculates a precursor preset variable 28. The closed-loop control device 3 is set up to calculate a preset variable additional term 30 from the target generator power Paoli by way of a calculation element 29, which has a differential transmission behavior, and to offset the preset variable additional term 30 with the precursor preset variable 28 calculated by the power controller 14 in order to obtain the first preset variable 16. In particular, the closed-loop control device 3 is set up to add the preset variable additional term 30 to the precursor preset variable 28 in order to obtain the first preset variable 16. In the exemplary embodiment shown here, the calculation element 29 is a DT.sub.1 element. Alternatively, however, it is also possible for the calculation element 29 to be designed as a D-element in another exemplary embodiment.

[0105] The target power P.sub.soll is thus amplified by the calculation element 29 andin the exemplary embodiment shown heresuperimposed additively on the output of the power controller 14, i.e., the precursor preset variable 28. In this way, the closed-loop control device 3 has an improved, in particular more dynamic load switching behavior.

[0106] The embodiment shown here has the advantageover an embodiment in which the power controller 14 would have an overall PI(DT.sub.1) characteristicthat only the target power P.sub.soll is amplified and not the power control deviation e.sub.P. If instead a power controller 14 were used that has an overall PI(DT.sub.1) characteristic, the dynamics of the power control would depend on the design of the power filter 19. If, for example, a PT.sub.1 power filter with a small time constant T.sub.1 were selected, this, in combination with the PI(DT.sub.1) characteristic of the power controller 14, would lead to a delayed adaptation to a sudden change in the target generator power P.sub.soll. Specifically, the detected generator power P.sub.G is subtracted from this, and then also changes rapidly when the load changes, in particular fed from the reserve of kinetic energy, in particular rotational energy, of the system consisting of the generator 9, the coupling 7 and the internal combustion engine 5. In particular, the actual generator power P.sub.ist follows an electrical load change almost instantaneously. This means that the target generator power P.sub.soll and the detected generator power P.sub.G change in the same effective direction, so that the power change is only attenuated in the power control deviation e.sub.P. The resulting delay is advantageously avoided ifas shown in FIG. 7the target generator power P.sub.soll is fed directly to the calculation element 29.

[0107] The calculation element 29 optionally has the following transfer function:

[00003]$\begin{array}{cc}{G}_{D{T}_1}\left(s\right)=K_1\frac{T_{V}s}{1+T_{1}s},& \left(3\right)\end{array}$

with a factor K.sub.1, the lead time T.sub.V and the delay time T.sub.1. The calculation element 29 is only effective transiently, i.e., only in the event of a load change. The preset variable additional term 30 also changes abruptly in the event of a sudden load change and then finally decays to zero. In a steady state, the preset variable additional term 30 is zero. How quickly the preset variable additional term 30 decays depends on the delay time T.sub.1. The factor K.sub.1 is used in particular to convert the physical unit of the input variable, i.e., the target generator power P.sub.soll, into the physical unit of the power variable, i.e., of the preset variable additional term 30, in particular a target speed or a target torque.

[0108] While this invention has been described with respect to at least one embodiment, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.