Method for distributing a limited amount of electrical power from an energy source

Abstract

A method for distributing a limited amount of electrical power from an energy source to a plurality of electrical loads includes sensing and/or encoding the available electrical power of the energy source, monitoring a power balance of the loads by sensing and/or encoding the drawn power in the individual loads, and reducing the drawn power in the loads if the available power is not sufficient for supplying all the loads with the required power.

Claims

1. A method for distributing a limited amount of electrical power from an energy source among a plurality of loads, the method comprising: at least one of measuring and coding available electrical power of the energy source; monitoring a power balance of the plurality of loads by at least one of measuring and coding drawn electrical power in individual loads of the plurality of loads; reducing the drawn electrical power in the plurality of loads to operate the plurality of loads at reduced power if the available electrical power is not sufficient to supply all of the plurality of loads with a required electrical power, wherein the plurality of loads are connected to a data bus via which the drawn electrical power to the respective load is transmitted to a control unit and a division of the available electrical power among all of the plurality of loads is calculated, wherein the available electrical power is coded via digital signals between the energy source and at least one of the plurality of loads.

2. The method as claimed in claim 1, wherein the available electrical power of the energy source is coded via a voltage characteristic, a resistance, or an analog voltage signal.

3. The method as claimed in claim 1, wherein a maximum required electrical power of at least one of the plurality of loads is determined and coded via an electrical resistance.

4. The method as claimed in claim 1, wherein the reduction is performed uniformly in all of the plurality of loads or is adapted individually to a respective one of the plurality of loads depending on the requirement.

5. The method as claimed in claim 1, wherein the available electrical power is coded via analog signals.

6. The method as claimed in claim 1, wherein the available electrical power is coded via a pull-up resistance in a power supply unit and a maximum electrical power to be drawn is coded via at least one pull-down resistance in at least one of the plurality of loads.

7. The method as claimed in claim 1, wherein, if an analog and digital coding are applied, the digital coding is prioritized.

8. The method as claimed in claim 1, wherein the available electrical power is coded via an optical medium or wirelessly.

9. The method as claimed in claim 1, wherein the available electrical power is coded in a plug-in connector which connects one or more of the plurality of loads to the energy source.

10. The method as claimed in claim 1, wherein an identifier is assigned to the plurality of loads and all of the plurality of loads of the system provided with an identifier are identified and authenticated.

11. The method as claimed in claim 10, wherein each identified and authenticated load of the plurality of loads is granted a power release which is assigned to it.

12. The method as claimed in claim 1, wherein the available electrical power is coded in the energy source.

13. A method for distributing a limited amount of electrical power from an energy source in an orthopedic system among a plurality of loads in the orthopedic system, the method comprising: at least one of measuring and coding available electrical power of the energy source in the orthopedic system; monitoring a power balance of the plurality of loads by at least one of measuring and coding drawn electrical power in individual loads of the plurality of loads in the orthopedic system; reducing the drawn electrical power in the plurality of loads to operate the plurality of loads at reduced power if the available electrical power is not sufficient to supply all of the plurality of loads with a required electrical power for operation of the orthopedic system, wherein the plurality of loads are connected to a data bus via which the drawn electrical power to the respective load is transmitted to a control unit and a division of the available electrical power among all of the plurality of loads is calculated, wherein the available electrical power is coded via digital signals between the energy source and at least one of the plurality of loads.

14. The method as claimed in claim 13, wherein the available electrical power of the energy source is coded via at least one of a voltage characteristic, a resistance, or an analog voltage signal.

15. The method as claimed in claim 13, wherein a maximum required electrical power of at least one of the plurality of loads is determined and coded via an electrical resistance.

16. The method as claimed in claim 13, wherein the reduction is performed uniformly in all of the plurality of loads or is adapted individually to a respective one of the plurality of loads depending on the requirement.

17. The method as claimed in claim 13, wherein the available electrical power is coded via analog signals.

18. The method as claimed in claim 13, wherein the available electrical power is coded via a pull-up resistance in a power supply unit and a maximum electrical power to be drawn is coded via at least one pull-down resistance in at least one of the plurality of loads.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) An example embodiment of the invention is explained in detail below with reference to the attached figures, in which:

(2) FIG. 1—shows a schematic view of a system with an energy source and two loads;

(3) FIG. 2—shows a variant of FIG. 1 with two optional energy sources;

(4) FIG. 3—shows a variant of FIG. 1 with a digital bus as a connection between two loads;

(5) FIG. 4—shows a variant of FIG. 3 with different power supply units;

(6) FIG. 5—shows an example dimensioning of a pull-up resistance in a power supply unit;

(7) FIG. 6—shows an example dimensioning of a pull-down resistance in loads; and

(8) FIG. 7—shows an example calculation of a power factor.

DETAILED DESCRIPTION

(9) FIG. 1 shows a schematic view of a power supply unit as the sole energy source 1 to supply a plurality of electrical loads 2 and 3. The power supply unit is connected via a device connector 4 to the first load 2. The second electrical load 3 is similarly connected to the plug-in power supply unit 1 via a cable connection which can similarly be implemented via a plug-in connector 5. The cable connection can also be implemented via the device connector 4 or a further cable connection on the load 2. In the case of a conventional coupling of a power supply unit 1 to a plurality of loads 2, 3, it is problematic to monitor the power P.sub.SUP available for charging which can be delivered by the power supply unit 1. Due to installation space restrictions, it may be necessary to provide only one plug-in connection 4 for a power supply unit 1 in a system with a plurality of loads 2, 3. Installation space restrictions apply, for example, in orthopedic systems such as orthoses, prostheses or wheelchairs. In addition, due to a modular design, different device combinations with different loads or energy stores may have to be provided, for example in order to enable an adaptation to the respective customer requirement or to carry out an adaptation to a user through installation of different loads. In addition, an increasing energy and power requirement which was not foreseeable in the original design can occur in the event of developments or in the event of a module exchange. Different electrical energy sources or power supply units with different power classes which are usable for a system may similarly be present. With a rigid definition of available power or maximum power to be delivered, can not possible with a conventional power supply unit and with conventional loads which are supplied with DC voltage via two conductors. It is desirable to provide a system which permits flexibility in terms of modifications both in the hardware and in terms of conditions of use. It is therefore provided according to the invention that, along with the ground and the conductor to the positive pole, a control line 6 via which the power can be coded is provided in both the power supply unit 1 or the energy supply 1 and in the loads 2, 3. The control line 6 or energy distribution line is routed to all plug-in connections 4, 5. The control line 6 indicates the ratio of the power P.sub.SUP available for charging to the respectively required power P.sub.LOAD1, P.sub.LOAD2 via an analog DC voltage U.sub.EDC. The voltage value U.sub.EDC is therefore the quotient from the power P.sub.SUP available for charging and the power P.sub.LOAD required in each case on the load 2, 3.

(10) In order to guarantee continuing functional capability for possible extensions or modifications in the system with additional electrical loads or with modified electrical loads or in the event of a combination with other power supply units, it is initially advantageous for the design of the system that a standard power supply unit or a standard energy source with an associated pull-up resistance is defined. All further and future power supply units 1 must be designed as compatible with this standard power supply unit.

(11) It is furthermore advantageous that a voltage value is defined for the DC voltage U.sub.EDC with which a full utilization of the respectively connected power supply unit 1 is signaled for all connected devices. If lower voltages U.sub.EDC are determined, this means that the respective power intake in the loads 2, 3 must be reduced. The value for the voltage U.sub.EDC is measurable in all connected loads 2, 3.

(12) The supply voltage is first defined for the energy distribution control with a uniform charging voltage. If modified charging voltages are required in future, this must be adjusted on the power supply unit side to the respectively defined level.

(13) FIG. 2 shows a variant of FIG. 1 in which two different power supply units 1, 1′ with different pull-up resistances for different powers are present. The power supply unit 1 has the pull-up resistance R.sub.SUP1, the second power supply unit 1′ has a different pull-up resistance R.sub.SUP1′ which may, for example, be 50% higher than the pull-up resistance R.sub.SUP.

(14) In one example embodiment according to FIG. 3, the available power is coded via digital signals by means of a signal bus, similar to the example embodiments according to FIGS. 1 and 2, but only to a load 2. In addition, a signal exchange takes place between the loads 2, 3. The signal bus is installed between the loads 2, 3. The first load 2 determines how much energy is distributed among the downstream loads 3 and takes over the distribution of the energy within the system, for example an orthosis or prosthesis. It uses the signal bus for this purpose. The pull-down resistances R.sub.LOAD in the loads are identical in this example embodiment.

(15) In FIG. 4, two power supply units 1, 1′ are connected in each case to a connection 4 of the respective load 2, 3. When both power supply units 1, 1′ are connected, an internal alignment is performed between the loads, 2, 3 in order to determine how the energy from the power supply units 1, 1′ is to be distributed among the respective loads.

(16) FIG. 5 shows an example dimensioning of the resistances depending on the available power P.sub.SUP. All power supply units 1, 1′ must implement a pull-up resistance R.sub.SUP from the supply voltage U.sub.SUP which is present on the control line 6 in order to code the available electrical power P.sub.SUP therewith. The necessary minimum value of the respective pull-up resistance is calculated from

(17) $R_{{\sup }_{\min }}=R_{\mathrm{Ref}}\frac{P_{\mathrm{Ref}}}{P_{\mathrm{Sub}}},$
where P.sub.Ref is the power of a reference power supply unit and R.sub.Ref is the pull-up resistance at a reference power. A possible progression of the ratio of the available power P.sub.SUP to the minimum pull-up resistance is plotted in the diagram shown in FIG. 5.

(18) All loads 2, 3 must implement a pull-down resistance R.sub.LOAD from the control line 6 to ground in order to code their respective maximum electrical power intake. If the load is not currently being supplied with energy, the pull-down resistance R.sub.LOAD can be deactivated, which is indicated by the switch in FIG. 1 and FIG. 2.

(19) The necessary maximum resistance value for the respective pull-down resistance R.sub.LOAD is calculated from

(20) $\frac{R_{\mathrm{Ref}}{P}_{\mathrm{Ref}}}{P_{\mathrm{LOAD}}}\times \frac{U_{100\%}}{U_{\mathrm{SUP}}-U_{100\%}}.$
An example curve progression of the ratio between the required power P.sub.LOAD and the pull-down resistance R.sub.LOAD is shown in the diagram in FIG. 6.

(21) All loads 2, 3 must evaluate the control voltage U.sub.EDC. If the reference voltage U.sub.100% is not attained, the available electrical power P.sub.SUP is less than the required power, so that the respective power intake in the loads 2, 3 must be reduced. The available relative power k is derived from the quotient of the available power P.sub.SUP and the sum of the required powers P.sub.LOAD. If the relative power is above 1, sufficient power is available from the power supply unit 1 or the power supply units 1. If the value for the available relative power k is below 1, too little power is available. A load is permitted to consume at most the proportion of power P.sub.max available to it, the maximum available power P.sub.max being calculated from the product of the available relative power k and the required power P.sub.LOAD. The ratio of the measuring voltage U.sub.EDC to the power factor k is shown in FIG. 7. In the example calculation, the threshold value for the measuring voltage U.sub.EDC is 2.5V in order to ensure that all loads 2, 3 are supplied with sufficient energy.

(22) A status indicator for the available power can be fitted to the respective power supply unit 1, 1′. A coding can be defined for this purpose, for example in three stages corresponding to the power factors. Above the power factor of 1, a green status indicator can signal that sufficient power is available, below the power factor of 0.5, a red status indicator can signal insufficient power, and between them, for example, an amber power indicator can signal that the charging procedure is being extended.