POWER INVERTER AND METHOD

• US 20090237968A1
• Filed: 03/20/2008
• Published: 09/24/2009
• Est. Priority Date: 03/20/2008
• Status: Active Grant

• Current Assignee: Pratt & Whitney Canada Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Original Assignee: Pratt & Whitney Canada Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: DOOLEY, Kevin Allan
• Granted Patent: US 8,279,648 B2
• Time in Patent Office: Days
• US Class Current: 363/97
• CPC Class Codes: H02M 7/4807 having a high frequency intermediate AC stage
• CPC Class Codes: H02M 7/538 in a push-pull configuration H02M7/5375 takes precedence ; with oscillating arrangements H02M7/53832, H02M7/53846
• CPC Class Codes: H02M 7/53832 in a push-pull arrangement
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

An apparatus and method for converting an input signal to an output AC signal in which the input voltage signal is inverted and modulated to provide an intermediate AC signal having twice the desired output frequency. The intermediate signal is then full-wave rectified and then the polarity of the rectified signal is switched every second cycle to produce the output AC signal of a desired frequency and voltage.

Claims

1. A method for conditioning a power signal, the method comprising the steps of:

providing an input voltage signal;

providing an input modulation signal;

inverting the input signal to an intermediate AC signal, including a step of using the input modulation signal to impart a desired a voltage-time function to the intermediate AC signal;

full-wave rectifying the intermediate AC signal to provide a rectified DC signal, the rectified DC signal having a periodic cyclical voltage-time function;

reversing a polarity of the rectified DC signal every second cycle to thereby produce an output AC signal.

2. The method of claim 1 further comprising the step of transforming the intermediate AC signal to a desired voltage level.

3. The method of claim 1 wherein the desired voltage-time function is sinusoidal in nature.

4. The method of claim 1 wherein the input modulation signal is sinusoidal in nature.

5. The method of claim 4 wherein the input modulation signal is a full-wave rectified sine wave.

6. The method of claim 1 wherein the step of reversing the polarity of the rectified DC signal comprises the steps of:

supplying the rectified DC signal to a commutator;

supplying an appropriate switching signal to the commutator;

switching the commutator to reverse the polarity of the rectified DC signal every second cycle.

7. The method of claim 1 wherein the step of inverting the input signal to the intermediate AC signal is performed with a push/pull switching circuit.

8. The method of claim 7 wherein the appropriate switching signal is a sinusoidal signal.

9. The method of claim 1, wherein the step of providing the input modulation signal comprises:

generating a sine wave; and

rectifying said sine wave to provide a rectified sine wave input modulation signal.

10. The method of claim 1 further comprising the step of filtering the rectified DC signal to remove noise from the rectified DC signal.

11. A power inverter having an output, the power inverter comprising:

a push-pull switching circuit having a DC input and an intermediate AC output;

a modulator for modulating the push-pull switching circuit;

a full-wave rectifier having the intermediate AC output as an input and having a full-wave rectified DC output;

a commutator having the full-wave rectified DC output as an input, the commutator being connected to the power inverter output; and

a controller configured to cause the commutator to intermittently switch a polarity of the full-wave rectified DC output to thereby provide AC power to the power inverter output.

12. The power inverter of claim 11, the switching circuit includes a transformer connected between the modulator and the full-wave rectifier, the transformer configured to step-up transform a voltage of the intermediate AC output.

13. The power inverter of claim 11, wherein said transformer is a high frequency torroidal transformer.

14. The power inverter of claim 11, wherein the modulator comprises a pulse width modulator, a sine wave generator, and a second full-wave rectifier.

15. The power inverter of claim 11, wherein the full-wave rectified DC output delivers a signal having a cycle, and wherein the commutator is driven to switch the polarity every other cycle.

16. The power inverter of claim 15, wherein the commutator is a H-bridge commutator.

17. The power inverter of claim 15, wherein the commutator is a SCR commutator.

18. An inverter comprising:

means for providing an input voltage signal;

means for providing a modulation signal;

means for inverting the input signal to an AC intermediate signal having a desired a voltage-time function;

means for rectifying the intermediate AC signal to provide a rectified DC signal having a periodic cyclical voltage-time function; and

means for reversing polarity of the rectified DC signal every other cycle to thereby produce an output AC signal.