Converter system, method, and converter

• US 7,786,694 B2
• Filed: 03/11/2003
• Issued: 08/31/2010
• Est. Priority Date: 04/10/2002
• Status: Expired due to Term

• Current Assignee: Sew-Eurodrive GmbH & Company KG (BV Beteiligung GmbH & Company KG)
• Original Assignee: Sew-Eurodrive GmbH & Company KG (BV Beteiligung GmbH & Company KG)
• Inventors: Kneller, Klaus
• Primary Examiner(s): Ro; Bentsu
• Assistant Examiner(s): Paul; Antony M
• Application Number:
  US10/510,562
• Publication Number:
  US 20050146305A1
• Time in Patent Office: 2,730 Days
• Field of Search: 318/700, 318/703, 318/727, 318/729, 318/730, 318/757, 318/759, 318/762, 318/795, 318/798, 318/800, 318/254.1, 318/273, 318/375, 318/376, 318/430
• US Class Current: 318/800
• CPC Class Codes: H02M 1/0006 Arrangements for supplying an adequate voltage to the control circuit of converters
• CPC Class Codes: H02M 1/008 Plural converter units for generating at two or more independent and non-parallel outputs, e.g. systems with plural point of load switching regulators
• CPC Class Codes: H02M 1/34 Snubber circuits
• CPC Class Codes: H02M 1/348 Passive dissipative snubbers
• CPC Class Codes: H02M 7/537 using semiconductor devices only, e.g. single switched pulse inverters
• CPC Class Codes: H02P 5/74 controlling two or more ac dynamo-electric motors H02P5/46, H02P5/60 take precedence

Abstract

A converter system and method, including: at least one supply module, which provides a unipolar, intermediate circuit voltage; one or more drive modules, which may be powered from the intermediate circuit voltage and each include at least one inverter for powering at least one electric motor; and at least one buffer module for storing energy.

Claims

1. A converter system, comprising:

at least one supply module configured to provide a unipolar, intermediate circuit voltage;

at least one drive module powerable by the intermediate circuit voltage, each drive module including at least one inverter configured to power at least one electric motor;

at least one buffer module configured to store energy; and

a power cable electrically connecting the supply module to the buffer module;

wherein the buffer module is configured to be supplied with energy for periods of time when the intermediate circuit voltage exceeds a first critical value and an overall regenerative power of a first drive module exceeds a motive power of a second drive module to store the supplied energy, and to supply the stored energy to at least one drive module when a total motive power of the at least one drive module exceeds the regenerative power to power the corresponding electric motor;

wherein the buffer module includes a capacitor and a diode, and a cathode of the diode is directly connected to a negative plate of the capacitor.

2. The converter system according to claim 1, wherein the electric motor includes one of (a) a synchronous motor and (b) an asynchronous motor.

3. The converter system according to claim 1, wherein the buffer module is configured to be supplied with energy for periods of time and to subsequently release stored energy to at least the drive module.

4. The converter system according to claim 1, wherein the buffer module is configured to be supplied with energy for periods of time during regenerative operation of at least one drive module and to subsequently release stored energy to at least the drive module.

5. The converter system according to claim 1, wherein at least one supply module includes a rectifier configured to generate a d.c. voltage from an a.c. voltage.

6. The converter system according to claim 1, wherein at least one supply module includes a rectifier configured to generate a d.c. voltage from an a.c. voltage from a three-phase a.c. network voltage.

7. The converter system according to claim 1, wherein one of:

(a) at least one supply module includes a feedback unit; and

(b) the converter system further comprises a feedback unit connected to the intermediate circuit voltage and an a.c. voltage.

8. The converter system according to claim 1, wherein one of:

(a) at least one supply module includes a feedback unit; and

(b) the converter system further comprises a feedback unit connected to the intermediate circuit voltage and a three-phase a.c. network voltage.

9. The converter system according to claim 1, wherein at least one supply module includes an electronic circuit breaker configured to allow passage of and to block, as a function of activation of the electronic circuit breaker, current induced by the intermediate circuit voltage and in a direction of a device connected to an output of the supply module.

10. The converter system according to claim 9, wherein a drive circuit of the electronic circuit breaker is connected to a device configured to measure the intermediate circuit voltage.

11. The converter system according to claim 1, wherein a capacitance of the capacitor is greater than a sum of capacitance of all other capacitors to which the intermediate circuit voltage is directly applied.

12. The converter system according to claim 1, wherein the buffer module is arranged as a device connected to an output of the supply module, the buffer module including a capacitor having a charging current,

wherein the charging current is at least one of:

(a) influenceable by at least an electronic circuit breaker; and

(b) controllable by at least an electronic circuit breaker.

13. The converter system according to claim 1, wherein the buffer module includes at least one electrolytic capacitor.

14. The converter system according to claim 1, wherein the buffer module and the supply module are manufactured separately, each of the buffer module and the supply module including a respective housing.

15. The converter system according to claim 1, wherein the buffer module and the supply module are integrated into a buffer/supply module and arranged in a single housing.

16. The converter system according to claim 15, wherein the buffer/supply module includes an electronic circuit breaker configured to allow passage of and block, as a function of activation of the electronic circuit breaker, current induced by the intermediate circuit voltage and in a direction of a device.

17. The converter system according to claim 16, wherein a drive circuit of the electronic circuit breaker is connected to a device configured to measure the intermediate circuit voltage.

18. The converter system according to claim 16, wherein a drive circuit of the electronic circuit breaker is connected to a device configured to measure an intermediate circuit current.

19. The converter system according to claim 1, wherein the buffer module includes an electronic circuit breaker and a corresponding drive circuit at least connected to a device configured to measure voltage, the electronic circuit breaker configured to influence supply of current to a braking resistor.

20. A converter system, comprising:

at least one supply module configured to provide a unipolar, intermediate circuit voltage;

at least one drive module powerable by the intermediate circuit voltage, each drive module including at least one inverter configured to power at least one electric motor; and

at least one buffer module configured to store energy,

wherein a capacitor of the supply module directly connected to the intermediate circuit voltage and a capacitor included in the buffer module are configured so that during motive operation at a nominal load, with the capacitor of the buffer module directly connected to the intermediate circuit voltage, an a.c. voltage component of the intermediate circuit voltage is less than half an a.c. voltage component with the buffer module removed together with the capacitor of the buffer module.

21. A converter system, comprising:

at least one supply module configured to provide a unipolar, intermediate circuit voltage;

at least one drive module powerable by the intermediate circuit voltage, each drive module including at least one inverter configured to power at least one electric motor;

at least one buffer module configured to store energy; and

a bus system configured to electrically connect the supply module, the drive module and the buffer module, the bus system including at least two power cables configured to carry the intermediate circuit voltage and a power cable configured to electrically connect the supply module to the buffer module,

wherein the buffer module is configured to be supplied with energy for periods of time when the intermediate circuit voltage exceeds a first critical value and an overall regenerative power of a first drive module exceeds a motive power of a second drive module to store the supplied energy, and to supply the stored energy to at least one of the drive modules when a total motive power of the drive modules exceeds the regenerative power to power the corresponding electric motor;

wherein the buffer module includes a capacitor and a diode, and a cathode of the diode is directly connected to a negative plate of the capacitor.

22. The converter system according to claim 21, wherein the electric motor includes one of (a) a synchronous motor and (b) an asynchronous motor.

23. The converter system according to claim 21, wherein the buffer module, the drive module and the supply module include an interface configured to electrically and mechanically connect to the bus system.

24. The converter system according to claim 23, further comprising at least one further module including an interface configured to electrically and mechanically connect to the bus system.

25. The converter system according to claim 23, wherein the interface of each of the buffer module, the drive module and the supply module is the same.

26. A method for operating a buffer module in a converter system, the converter system including at least one supply module configured to provide a unipolar, intermediate circuit voltage, at least one drive module powerable from the intermediate circuit voltage and including at least one inverter configured to power at least one electric motor, at least one buffer module configured to store energy, and a power cable electrically connecting the supply module to the buffer module, comprising:

measuring the intermediate circuit voltage;

in response to the intermediate circuit voltage exceeding a first critical value, supplying the buffer module with energy when an overall regenerative power of a first drive module exceeds a motive power of a second drive module to store the supplied energy; and

supplying the stored energy by the buffer module to at least one of the drive modules powered by the intermediate circuit voltage when a total motive power of the drive modules exceeds the regenerative power to power the corresponding electric motor;

wherein the buffer module includes a capacitor and a diode, and a cathode of the diode is directly connected to a negative plate of the capacitor.

27. The method according to claim 26, further comprising, in response to the intermediate circuit voltage exceeding a second critical value, flowing current through a braking resistor to dissipate energy when a total regenerative power of first drive modules exceeds the motive power of second drive modules.

28. The method according to claim 27, wherein the first critical value and the second critical value are equal.

29. A converter, comprising:

a rectifier configured to generate an intermediate circuit voltage;

an inverter configured to be powered by the intermediate circuit voltage;

a first capacitor not directly connected to the intermediate circuit voltage configured to be energized by an electronic circuit breaker in a controlled manner as a function of the intermediate circuit voltage, the first capacitor configured to release energy to an intermediate circuit; and

a second capacitor directly connected to the intermediate circuit voltage, a capacitance of the first capacitor and a capacitance of the second capacitor configured so that during motive operation at nominal load, with the capacitor directly connected to the intermediate circuit, an a.c. voltage component of the intermediate circuit voltage is less than half an a.c. voltage component with the first capacitor removed.