Combined power inverter and auxilliary power supply using null vector modulation

• US 6,208,540 B1
• Filed: 05/23/2000
• Issued: 03/27/2001
• Est. Priority Date: 05/23/2000
• Status: Expired due to Term

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: General Motors Corporation (General Motors Company)
• Inventors: Stancu, Constantin C., OʼMeara, Thomas P.
• Primary Examiner(s): NGUYEN, MATTHEW VAN
• Application Number:
  US09/575,523
• Time in Patent Office: 308 Days
• Field of Search: 363/16, 363/17, 363/56.02, 363/56.05, 363/56.12, 363/97, 363/98, 363/131, 363/132, 318/254, 318/800-803, 318/812, 318/813
• US Class Current: 363/98
• CPC Class Codes: H02M 1/0006 Arrangements for supplying an adequate voltage to the control circuit of converters
• CPC Class Codes: H02M 1/009 having two or more independently controlled outputs for DC-DC converter with intermediate AC H02M3/33561
• CPC Class Codes: H02M 7/53875 with analogue control of three-phase output

Abstract

Power-generating apparatus and a voltage generation method employing null vector modulation for use with an electric vehicle. A DC power supply voltage is provided or generated from a power source and is inverted by a three-phase inverter to generate three phase AC that is supplied to an AC motor or load. One phase of the three phase AC is filtered and transformed by a DC rejection capacitor and single phase transformer of an auxiliary power supply to generate an AC voltage. The AC voltage is rectified and filtered by a rectifier and low pass filter of the auxiliary power supply to produce a DC output voltage. The one phase of the three phase AC and the DC output voltage are processed by a controller to control frequencies of null line-to-line zero voltage vectors during inversion so that the transformed AC voltage does not affect or is not seen by the AC motor or load. This allows for independent control of the voltage at the output of the auxiliary power supply.

Claims

1. Power generating apparatus comprising:

a DC power source;

a three-phase voltage source power inverter coupled to the power source;

a load coupled to outputs of the three-phase voltage source power inverter;

an auxiliary power supply coupled to one output of the three-phase voltage source power inverter for producing a DC output voltage; and

a controller coupled to an input and output of the auxiliary power supply for controlling frequencies of null line-to-line zero voltage vectors of the three-phase voltage source power inverter so that an AC voltage is generated by the auxiliary power supply that is not seen by the load.

2. The apparatus recited in claim 1 wherein the power-generating apparatus is disposed in a vehicle and the load comprises an AC motor.

3. The apparatus recited in claim 1 wherein the auxiliary power supply comprises:

a single-phase transformer coupled by way of a DC rejection capacitor to one output of the three-phase voltage source power inverter;

a rectifier coupled to the single-phase transformer; and

a low pass filter coupled across the rectifier that produces a DC output voltage.

4. A voltage generation method comprising the steps of:

generating a DC power supply voltage;

inverting the DC power supply voltage to generate three phase AC;

supplying the three phase AC to a load;

processing one phase of the three phase AC to produce a predetermined DC output voltage; and

processing the one phase of the three phase AC and the predetermined DC output voltage to control frequencies of null line-to-line zero voltage vectors during the inversion step such that the transformed AC voltage does not affect the load.

5. The method recited in claim 4 wherein the step of processing the one phase of the three phase AC comprises the steps of:

transforming the one phase of the three phase AC to produce a transformed AC voltage; and

rectifying and filtering the transformed AC voltage to produce a predetermined DC output voltage.

6. The method recited in claim 5 further comprising the step of filtering the one phase of the three phase AC prior to the transforming step.

7. The method recited in claim 4 wherein the load comprises an AC motor.

8. A voltage generation method comprising the steps of:

generating a DC power supply voltage;

inverting the DC power supply voltage to generate three phase AC;

supplying the three phase AC to a load;

filtering and transforming one phase of the three phase AC to produce a transformed AC voltage;

rectifying and filtering the transformed AC voltage to produce a predetermined DC output voltage; and

processing the one phase of the three phase AC and the predetermined DC output voltage to control frequencies of null line-to-line zero voltage vectors during the inversion step so that the transformed AC voltage does not affect the load.