Auxiliary power generation in a motor transformer
View Patent ↗A power supply generates alternating current and direct current from a constant-voltage source. A multi-phase pulse width modulation voltage source inverter is connected across the source to output multi-phase alternating current. At least one waveform generator is bridged in parallel with the inverter, with each waveform generator outputting zero-sequence waveform current compensated to maintain the multi-phase current within a predetermined tolerance from a desired set point. A rectifier receives the waveform current and generates direct current.
1. A power supply that generates alternating current (AC) and direct current (DC) from a DC voltage source, comprising:
an inverter that supplies a first phase current and a second phase current to a traction motor, wherein said inverter comprises:
a first phase half bridQe connected across said DC voltage source to provide said first phase current;
a second phase half bridge connected across said DC voltage source to provide said first phase current;
a third chase half bridge connected across said DC voltage source to provide a third phase current to said traction motor;
a first auxiliary half bridge connected across said DC voltage source to provide a first auxiliary current; and
a second auxiliary half bridge connected across said DC voltage source to provide a second auxiliary current; and
a controller that determines a first adjusted phase current based on said first phase current, determines a second adjusted phase current based on said second phase current, calculates an available current based on said first and second adjusted phase currents and generates a voltage control signal based on said available current, wherein said controller controls said inverter based on said voltage control signal.
2. The power supply of claim 1 further comprising:
a first auxiliary transformer supplied with a first auxiliary current from said inverter and having a first voltage output;
a second auxiliary transformer supplied with a second auxiliary current from said inverter and having a second voltage output; and
wherein said controller determines said first and second adjusted phase currents based on said first and second auxiliary currents.
3. The power supply of claim 1 wherein said first adjusted phase current is determined by subtracting a first phase magnetized current and a total auxiliary current from said first phase current.
4. The power supply of claim 3 wherein said first magnetized current is determined based on a first phase voltage and a frequency.
5. The power supply of claim 1 wherein said second adjusted phase current is determined by subtracting a second phase magnetized current and a total auxiliary current from said second phase current.
6. The power supply of claim 5 wherein said second magnetized current is determined based on a second phase voltage and a frequency.
7. A method of controlling an alternating current (AC) and direct current (DC) power supply, comprising:
determining a first adjusted phase current for a first phase current supplied to a traction motor;
determining a second adjusted phase current for a second phase current supplied to said traction motor;
calculating an available current based on said first and second adjusted phase currents;
generating a voltage control signal based on said available current; and
controlling said AC and DC power supply based on said voltage control signal.
8. The method of claim 7 wherein said step of determining a first adjusted phase current comprises subtracting a first phase magnetized current and a total auxiliary current from said first phase current.
9. The method of claim 8 wherein said first magnetized current is determined based on a first phase voltage and a frequency.
10. The method of claim 7 wherein said step of determining a second adjusted phase current comprises subtracting a second phase magnetized current and a total auxiliary current from said second phase current.
11. The method of claim 10 wherein said second magnetized current is determined based on a second phase voltage and a frequency.
12. The method of claim 7 wherein said first adjusted phase current is equivalent to said first phase current.
13. The method of claim 7 wherein said second adjusted phase current is equivalent to said second phase current.
14. The method of claim 7 further comprising:
generating a first auxiliary voltage signal;
generating a first auxiliary current signal; and
determining said voltage control signal based on said first auxiliary voltage signal, said first auxiliary current signal and said available current signal.
15. The method of claim 14 further comprising:
generating a second auxiliary voltage signal;
generating a second auxiliary current signal; and
determining said voltage control signal based on said second auxiliary voltage signal, said second auxiliary current signal and said available current signal.
16. A method of regulating an alternating current (AC) and direct current (DC) power supply having a DC source, an inverter and first and second auxiliary transformers, comprising:
determining a first adjusted phase current for a first phase current supplied from said inverter to a traction motor by subtracting a first phase magnetized current and a total auxiliary current from said first phase current;
determining a second adjusted phase current for a second phase current supplied from said inverter to said traction motor;
calculating an available current based on said first and second adjusted phase currents;
generating a voltage control signal based on said available current; and
controlling said inverter based on said voltage control signal to adjust DC voltage outputs of said first and second auxiliary transformers.
17. The method of claim 16 wherein said first magnetized current is determined based on a first phase voltage and a frequency.
18. The method of claim 16 wherein said step of determining a second adjusted phase current comprises subtracting a second phase magnetized current and a total auxiliary current from said second phase current.
19. The method of claim 18 wherein said second magnetized current is determined based on a second phase voltage and a frequency.
20. The method of claim 16 wherein said first adjusted phase current is equivalent to said first phase current.
21. The method of claim 16 wherein said second adjusted phase current is equivalent to said second phase current.
22. The method of claim 16 further comprising:
generating a first auxiliary voltage signal;
generating a first auxiliary current signal; and
determining said voltage control signal based on said first auxiliary voltage signal, said first auxiliary current signal and said available current signal.
23. The method of claim 22 further comprising:
generating a second auxiliary voltage signal;
generating a second auxiliary current signal; and
determining said voltage control signal based on said second auxiliary voltage signal, said second auxiliary current signal and said available current signal.