METHOD FOR CONTROLLING A COMPRESSOR SYSTEM, COMPRESSOR FOR COMPRESSING A WORKING MEDIUM, COMPRESSOR SYSTEM AND REFRIGERATION CIRCUIT SYSTEM FOR CARRYING OUT A REFRIGERATION CYCLE PROCESS

Abstract

A method for controlling a compressor system includes an electrically operated compressor for compressing a working medium, and a further electrical load. The compressor includes an electric motor for compressing the working medium, an inverter supplying the electric motor with single- or multi-phase alternating current, a power factor correction filter (PFC) supplying the inverter with direct current and whose current input for supplying power to the compressor connects to a grid current source providing alternating current. For supplying power thereto the further electrical load connects to the same grid connection point as the power factor correction filter. The method includes operating the compressor system with electrical current from the grid current source, determining at least one current characteristic value of the further load, and controlling the power factor correction filter of the compressor at least in dependence of the determined at least one current characteristic value of the further load.

Claims

1. A method for controlling a compressor system, and which comprises an electrically operated compressor, which is configured for compressing a working medium, and a further electrical load, wherein the compressor in turn comprises: an electric motor for providing a mechanical movement for compressing the working medium; an inverter, which supplies the electric motor with single- or multi-phase alternating current; and a power factor correction filter, which supplies the inverter with direct current and whose current input for supplying power to the compressor is connected to a grid connection point of a grid current source providing alternating current; and, for supplying power to the further electrical load, the further electrical load is connected to the same grid connection point as the power factor correction filter, wherein the method comprises: operating the compressor system with electrical current from the grid current source; determining at least one current characteristic value of the further load, which describes a current consumption of the further load; and controlling the power factor correction filter of the compressor at least in dependence of the determined at least one current characteristic value of the further load.

2. The method according to claim 1, wherein the controlling of the power factor correction filter comprises: setting an operating parameter of the power factor correction filter, which determines the direct current output by the power factor correction filter and/or which influences the alternating current tapped from the grid current source by the compressor, at least in dependence of the determined at least one current characteristic value of the further load.

3. The method according to claim 2, wherein the power factor correction filter comprises at least one transistor unit, and the setting of the operating parameter of the power factor correction filter for controlling the power factor correction filter in turn comprises: setting a control signal of the at least one transistor unit at least in dependence of the determined at least one current characteristic value of the further load.

4. The method according to claim 1, wherein the determined at least one current characteristic value is an electrical current strength or an electrical power.

5. The method according to claim 1, wherein the further load and the compressor are connected parallel to one another at the grid connection point.

6. The method according to claim 1, wherein the determining of the at least one current characteristic value of the further load comprises: detecting a current variable of an electrical current present at a current input of the further load; determining the at least one current characteristic value on the basis of the detected current variable.

7. The method according to claim 1, wherein the determining of the at least one current characteristic value of the further load comprises: providing a calculation model, which describes the electrical structure of the further load, comprising one or more electrical characteristic variables of the further load; calculating the at least one current characteristic value on the basis of the provided calculation model; outputting the calculated at least one current characteristic value as a determined current characteristic value of the further load.

8. The method according to claim 1, wherein the power factor correction filter comprises a rectifier with an input for alternating current and an output current.

9. The method according to claim 8, wherein the method further comprises: detecting a current variable of an output current of the rectifier at the output of the rectifier; wherein the controlling of the power factor correction filter of the compressor takes place in additional dependence on the detected current variable of the output current of the rectifier.

10. The method according to claim 1, wherein the power factor correction filter comprises a totem-pole PFC converter.

11. The method according to claim 10, wherein the method further comprises: detecting a current variable of an input current of the totem-pole PFC converter, wherein the controlling of the power factor correction filter of the compressor takes place in additional dependence on the detected current variable of the input current of the totem-pole PFC converter.

12. The method according to claim 1, wherein the method further comprises: detecting a current variable of an electrical current present at the current input of the power factor correction filter; wherein the controlling of the power factor correction filter of the compressor takes place in additional dependence on the detected current variable of the electrical current present at the current input of the power factor correction filter.

13. The method according to claim 1, wherein the controlling of the power factor correction filter takes place under the provision that one or more characteristic values of an electrical current tapped from the compressor system at the grid connection point lie below a respectively predetermined limit value.

14. The method according to claim 1, wherein the compressor system is designed as part of a refrigeration circuit system.

15. A compressor for compressing a working medium, comprising: an electric motor for providing a mechanical movement for compressing the working medium; an inverter, which supplies the electric motor with single- or multi-phase alternating current; a power factor correction filter, which supplies the inverter with direct current and whose current input for supplying power to the compressor is connectable to a grid connection point of a grid current source providing alternating current; a control device, which at least configured to control the power factor correction filter; wherein the compressor is operated electrically and, in the event that the compressor and a further electrical load are connected to the same grid connection point of a grid current source providing alternating current, the control device is configured to determine at least one current characteristic value of the further load, which describes a current consumption of the further load, and to control the power factor correction filter at least in dependence of the determined at least one current characteristic value of the further load.

16. A compressor system comprising: an electrically operated compressor for compressing a working medium according to claim 15; and a further electrical load; wherein the compressor and the further load are provided to be connected to a same grid connection point of a grid current source providing alternating current, wherein for this case the control device of the compressor is configured to determine at least one current characteristic value of the further load, which describes a current consumption of the further load, and to control the power factor correction filter at least in dependence of the determined at least one current characteristic value of the further load.

17. A refrigeration circuit system for carrying out a refrigeration circuit process on the basis of a working medium, wherein the refrigeration circuit system comprises a compressor system according to claim 16, the compressor of which is configured to compress a working medium of the refrigeration circuit system.

Description

[0095] Further aspects and the advantages thereof as well as more specific exemplary embodiments of the aforementioned aspects and embodiments will be described in the following with the aid of the drawings shown in the attached figures.

[0096] FIG. 1 schematically shows a flow diagram of a first exemplary embodiment of the method according to the invention.

[0097] FIG. 2 schematically shows the structure of a first exemplary embodiment of the compressor system according to the invention.

[0098] FIG. 3 schematically shows the structure of a second exemplary embodiment of the compressor system according to the invention.

[0099] FIG. 4 schematically shows the structure of a third exemplary embodiment of the compressor system according to the invention.

[0100] FIG. 5 schematically shows the structure of a control device of a fourth exemplary embodiment of the compressor system according to the invention.

[0101] It is emphasized that the present invention is in no way limited to the exemplary embodiments described in the following and their exemplary features. The invention further comprises modifications of the specified exemplary embodiments, in particular those which result from modifications and/or combinations of individual or a plurality of features of the described exemplary embodiments within the scope of protection of the independent claims.

DETAILED DESCRIPTION OF THE FIGURES

[0102] FIG. 1 schematically shows a flow diagram of a first exemplary embodiment of the method according to the invention.

[0103] The method is carried out on a compressor system, which comprises an electrically operated compressor, which is configured for compressing a working medium, and a further electrical load. The compressor in turn comprises an electric motor for providing a mechanical movement for compressing the working medium, an inverter, which supplies the electric motor with single- or multi-phase alternating current, a power factor correction filter, which supplies the inverter with direct current and whose current input for supplying power to the compressor is connected to a grid connection point of a grid current source providing alternating current. For supplying power, the further electrical load is connected to the same grid connection point as the power factor correction filter.

[0104] In step S1, the compressor system is operated with electrical current from the grid current source.

[0105] In step S2, at least one current characteristic value of the further load, which describes a current consumption of the further load, is determined; and

[0106] For this purpose, step S2 preferably comprises the substeps S2.1 to S2.3.

[0107] In step S2.1, a calculation model is provided, which describes the electrical structure of the further load, comprising one or more electrical characteristic variables of the further load.

[0108] In step S2.2, the at least one current characteristic value is calculated on the basis of the calculation model provided in step S2.1.

[0109] In step S2.3, the at least one current characteristic value calculated in step S2.2 is output as a determined current characteristic value of the further load.

[0110] In step S3, the power factor correction filter of the compressor is controlled at least in dependence of the at least one current characteristic value of the further load determined in step S2.

[0111] The method permits harmonics generated by the further load to be compensated in an advantageous manner by taking into account the at least one current characteristic value at the further load during the controlling of the power factor correction filter of the compressor.

[0112] In this way, the described compressor system can maintain normative specifications during the tapping of the electrical current from the grid current source without the further load having to be structurally modified or supplemented by additional components, such as, for example, dissipative elements.

[0113] In this respect, the method permits an efficient operation of a compressor system, in which in particular energy losses are kept low.

[0114] FIG. 2 schematically shows the structure of a first exemplary embodiment of the compressor system 1000 according to the invention.

[0115] The compressor system comprises a compressor 1 and a further electrical load 2, which are connected to the same grid connection point 2000 of a grid current source providing alternating current, in particular in the form of a parallel circuit.

[0116] The further load 2 preferably comprises a rectifier 21, in particular a passive rectifier, and a DC load 22 supplied with direct current by the latter. Optionally and not necessarily, the further load 2 can also comprise an inductance 24 connected upstream of the rectifier 21.

[0117] The compressor 1 is an electrically operated compressor 1 for compressing a working medium, which comprises an electric motor 11 for providing a mechanical movement for compressing the working medium, an inverter 12, a power factor correction filter 13 and a control device 14.

[0118] The inverter 12 supplies the electric motor 11 with single- or multi-phase alternating current, in this case with 3-phase alternating current.

[0119] The power factor correction filter 13 in turn supplies the inverter 12 with direct current, wherein a current input of the power factor correction filter 13 for supplying power to the compressor 1 is connectable to the grid connection point 2000 or is connected in the exemplary embodiment shown.

[0120] The control device 14 is configured at least to control the power factor correction filter 13.

[0121] The control device 14 is configured to determine at least one current characteristic value of the further load 2, which describes a current consumption of the further load 2, and to control the power factor correction filter 13 at least in dependence of the determined at least one current characteristic value.

[0122] The illustrated compressor system 1000 permits harmonics generated by the further load 2 to be compensated in an advantageous manner by taking into account the at least one current characteristic value at the further load 2 during the controlling of the power factor correction filter 13 of the compressor 1 by the control device 14.

[0123] In this way, the compressor system 1000 can maintain normative specifications during the tapping of the electrical current from the grid current source without the further load 2 having to be structurally modified or supplemented by additional components, such as, for example, dissipative elements.

[0124] In this respect, an efficiently operable compressor system 1000 is provided, in which in particular energy losses are kept low.

[0125] FIG. 3 schematically shows the structure of a second exemplary embodiment of the compressor system according to the invention.

[0126] The compressor system 1000 comprises a compressor 1 and a further electrical load 2, which are connected to the same grid connection point 2000 of a grid current source providing alternating current, in particular in the form of a parallel circuit.

[0127] The further load 2 preferably comprises a rectifier 21, in particular a passive rectifier, which in the exemplary embodiment shown is configured as a bridge rectifier based on diodes 301, and a DC load 22 supplied with direct current by the latter.

[0128] The compressor 1 is an electrically operated compressor 1 for compressing a working medium, which comprises an electric motor 11 for providing a mechanical movement for compressing the working medium, an inverter 12, a power factor correction filter 13 and a control device not illustrated here.

[0129] The inverter 12 supplies the electric motor 11 with single- or multi-phase alternating current, in this case with 3-phase alternating current.

[0130] The inverter 12 is preferably constructed from a plurality of transistor units, particularly preferably from a plurality of MOSFETs 302 or IGBTs.

[0131] The power factor correction filter 13 in turn supplies the inverter 12 with direct current, wherein a current input of the power factor correction filter 13 for supplying power to the compressor 1 is connectable to the grid connection point 2000 or is connected in the exemplary embodiment shown.

[0132] The power factor correction filter 13 preferably comprises a rectifier 131, in particular a passive rectifier, which in the exemplary embodiment shown is configured as a bridge rectifier based on diodes 301.

[0133] Furthermore, the power factor correction filter 13 comprises a step-up converter 132 connected downstream of the rectifier 131, which step-up converter, as active power factor correction filter, has at least one transistor unit which can be configured as a MOSFET 302 or as an IGBT.

[0134] In FIG. 3, the voltage present at the current input of the power factor correction filter 13 is specified by u_ac, the current strength in the interface between rectifier 131 and step-up converter 132 is specified by i_pfc, the voltage in the interface between power factor correction filter 13 and inverter 12 is specified by u_dc, the current strength at the input of the further load 2 is specified by i_load and the current strength at the grid connection point 2000 is specified by i_grid.

[0135] Said designations are used later with respect to the exemplary embodiment in FIG. 5.

[0136] The control device is configured at least to control the power factor correction filter 13.

[0137] The control device is configured to determine at least one current characteristic value of the further load 2, which describes a current consumption of the further load 2, and to control the power factor correction filter 13 at least in dependence of the determined at least one current characteristic value.

[0138] The illustrated compressor system 1000 permits harmonics generated by the further load 2 to be compensated in an advantageous manner by taking into account the at least one current characteristic value at the further load 2 during the controlling of the power factor correction filter 13 of the compressor 1 by the control device 14.

[0139] In this way, the compressor system 1000 can maintain normative specifications during the tapping of the electrical current from the grid current source without the further load 2 having to be structurally modified or supplemented by additional components, such as, for example, dissipative elements.

[0140] In this respect, an efficiently operable compressor system 1000 is provided, in which in particular energy losses are kept low.

[0141] FIG. 4 schematically shows the structure of a third exemplary embodiment of the compressor system 1000 according to the invention.

[0142] The compressor system 1000 according to the third exemplary embodiment differs here from the second exemplary embodiment merely in the configuration of the power factor correction filter 13, which in the present case has a totem-pole topology.

[0143] For this purpose, the power factor correction filter 13 preferably comprises a totem-pole PFC converter 135, whose current input is connected to the grid connection point 2000 and whose output is connected to the inverter 12, here for example via an interposed capacitance (see FIG. 4).

[0144] The totem-pole PFC converter 135 can be formed via a plurality of MOSFETs 302 or IGBTs, which can be arranged, for example and without limitation, in accordance with the electrical circuit diagram in FIG. 4.

[0145] An inductance 24 can preferably be connected upstream of the totem-pole PFC converter 135 with respect to an energy flow direction from the grid connection point 2000 to the electric motor 11.

[0146] The remaining structure substantially corresponds to that from FIG. 3 and will not be explained again at this point.

[0147] FIG. 5 schematically shows the structure of a control device 14 of a fourth exemplary embodiment of the compressor system according to the invention.

[0148] The compressor system comprises a compressor for compressing a working medium, which comprises an electric motor for providing a mechanical movement for compressing the working medium, an inverter, which supplies the electric motor with single- or multi-phase alternating current, a power factor correction filter 13, which supplies the inverter with direct current and whose current input for supplying power to the compressor is connectable to a grid connection point of a grid current source providing alternating current, and a control device 14, which is configured at least to control the power factor correction filter 13.

[0149] In addition to the compressor, the compressor system comprises at least one further electrical load. The compressor and the further load are provided to be connected to a same grid connection point of a grid current source providing alternating current, wherein for this case the control device 14 of the compressor is configured to determine at least one current characteristic value of the further load, which describes a current consumption of the further load, and to control the power factor correction filter 13 at least in dependence of the determined at least one current characteristic value of the further load.

[0150] The power factor correction filter of this exemplary embodiment preferably comprises a rectifier, in particular a passive rectifier, and a step-up converter connected downstream thereof, which comprises at least one transistor unit.

[0151] The further load and the compressor are connected in parallel at the grid connection point.

[0152] Except for the power factor correction filter 13 and the control device 14, the components of the compressor mentioned otherwise above are not illustrated in FIG. 5.

[0153] In the following, an explanation of the design of the control device 14 takes place to illustrate the sequences for controlling the power factor correction filter 13 taking place therein.

[0154] The control device 14 according to FIG. 5 can be used, for example, in the compressor system from FIG. 2 or from FIG. 3, but is not restricted to the use therein.

[0155] To explain the sequences, reference is made in part to the current variables u_dc, u_ac, i_pfc etc. from FIG. 3, which does not mean, however, that the control device 14 shown in FIG. 5 is intended to be restricted to the use in a compressor system according to FIG. 3. The reference to FIG. 3 is produced merely for better explanation of the sequences in the control device.

[0156] The control device 14 preferably comprises a voltage regulator 141, a current intensity regulator 142, a calculation model unit 143, a compensation unit 144 and a PWM calculation unit 145.

[0157] Furthermore, the compressor system comprises a current measuring means 15, preferably a voltage measuring means, at the grid connection point, a first current measuring means 133 of the power factor correction filter 13, a second current measuring means 134 of the power factor correction filter 13 and an operating data provision unit 23.

[0158] The first current measuring means 133 is arranged at an output of the rectifier of the power factor correction filter and in particular configured to measure a current strength of the output current of the rectifier there. In the case of the exemplary embodiment from FIG. 3, this current strength would correspond to the current strength i_pfc there.

[0159] The second current measuring means 134 is arranged at an interface between power factor correction filter and inverter and in particular configured to measure a voltage there. In the case of the exemplary embodiment from FIG. 3, this voltage would correspond to the voltage u_dc there.

[0160] The current measuring means 15 at the grid connection point is in particular configured to measure a voltage there. In the case of the exemplary embodiment from FIG. 3, this voltage would correspond to the voltage u_ac there.

[0161] The operating data provision unit 23 contains operating data of the further load, in particular data relating to its rated operation, such as for example a rated power or a rated current strength. In the exemplary case in which the further load is a DC fan unit or a DC circulation pump, the operating data can be data relating to a rotational speed of the fan unit or a DC circulation pump, which describe either an absolute rotational speed or a ratio of the rotational speed to a rated rotational speed value.

[0162] Although the components 133, 134 in FIG. 5 are not drawn within the rectangle denoted by 13, they are nevertheless components of the power factor correction filter 13 in the exemplary embodiment shown. The second current measuring means 134 can alternatively also be configured as a component of the inverter.

[0163] The voltage regulator 141 is coupled to the second current measuring means 134 and receives its voltage measurement value as an input variable. Based on the received voltage measurement value and a correspondingly predetermined voltage setpoint value, the voltage regulator 141 is configured to determine a setpoint value for the current strength of the output current of the rectifier of the power factor correction filter.

[0164] The current intensity regulator 142 is coupled to the voltage regulator 141 and receives the setpoint value for the current strength determined by the latter as an input variable. Furthermore, the current intensity regulator 142 is coupled to the first measuring means 133 and receives its current intensity measurement value as a further input variable. Based on the received current intensity measurement value (as an actual value) and the received setpoint value for the current strength from the voltage regulator 141, the current intensity regulator 142 is configured to determine a first control signal for the power factor correction filter, so that the voltage in the interface between power correction factor and inverter follows the predetermined voltage setpoint value as far as possible.

[0165] The calculation model unit 143 is coupled to the operating data provision unit 23 and receives operating data of the further load from the latter as an input variable. The calculation model unit 143 provides a calculation model, which describes the electrical structure of the further load, comprising one or more electrical characteristic variables of the further load. The calculation model unit 143 is configured to determine the at least one current characteristic value of the further load on the basis of the provided calculation model and the input variable from the operating data provision unit 23, in particular in the form of a current strength, preferably in the form of amplitudes and phase angles of individual harmonics of the current, and to transmit these to the compensation unit 144. In the case of the exemplary embodiment from FIG. 3, the determined current strength would correspond to the current strength i_load there or would be an estimation thereof.

[0166] The compensation unit 144 is coupled to the calculation model unit 143 and receives the at least one current characteristic value determined by the latter, in this case the current strength, as an input variable. Furthermore, the compensation unit 142 is coupled to the first measuring means 133 and receives its current intensity measurement value as a further input variable. Based on the received current intensity measurement value and the determined at least one current characteristic value, the compensation unit 144 is configured to determine a current strength at the mains connection point. In the case of the exemplary embodiment from FIG. 3, the determined current strength would correspond to the current strength i_grid there or would be an estimation thereof.

[0167] Preferably, the respective variables described above are detected as time profiles or the variables determined therefrom are determined as time profiles.

[0168] Based on the determined current strength at the grid connection point, the compensation unit 144 is in turn configured to determine a compensation signal and to transmit this to the PWM calculation unit 145.

[0169] In this case, the compensation signal is determined under the provision of reducing the harmonic content of the current at the grid connection point.

[0170] The PWM calculation unit 145 now receives the first control signal from the current intensity regulator 142, the compensation signal from the compensation unit 144 and the voltage measurement value of the current measuring means 15 at the grid connection point and determines on the basis thereof a PWM control signal for the transistor unit of the power factor correction filter 13, which is transmitted from the PWM calculation unit to the transistor unit.

[0171] The transistor actuated in this manner permits harmonics generated by the further load to be compensated in an advantageous manner by the controlling of the power factor correction filter of the compressor.

[0172] In this way, the compressor system can maintain normative specifications during the tapping of the electrical current from the grid current source without the further load having to be structurally modified or supplemented by additional components, such as, for example, dissipative elements.

[0173] In this respect, an efficiently operable compressor system is provided, in which in particular energy losses can be kept low.

[0174] Exemplary embodiments of the present invention and the advantages thereof have been described in detail above with reference to the attached figures.

[0175] It is emphasized again that the present invention is in no way limited to the exemplary embodiments described above and their exemplary features. The invention further comprises modifications of the specified exemplary embodiments, in particular those which result from modifications and/or combinations of individual or a plurality of features of the described exemplary embodiments within the scope of protection of the independent claims.

LIST OF REFERENCE SIGNS

[0176] 1 compressor [0177] 2 further Load [0178] 11 electric motor [0179] 12 inverter [0180] 13 power factor correction filter [0181] 14 control device [0182] 15 current measuring means at the grid connection point (voltage measuring means) [0183] 21 rectifier of the further load [0184] 22 DC load [0185] 23 operating data provision unit [0186] 24 inductance [0187] 131 rectifier [0188] 132 step-up converter [0189] 133 first current measuring means of the power factor correction filter [0190] 134 second current measuring means of the power factor correction filter (voltage measuring means) [0191] 135 totem-pole PFC converter [0192] 141 voltage regulator [0193] 142 current intensity regulator [0194] 143 calculation model unit [0195] 144 compensation unit [0196] 145 PWM calculation unit [0197] 301 diode [0198] 302 transistor (MOSFET) [0199] 1000 compressor system [0200] 2000 grid connection point