Method and system for converting DC power to AC power
View Patent ↗Methods and systems for converting direct current (DC) power to alternating current (AC) power are provided. A first phase of the AC power is generated based on a first carrier signal. A second phase of the AC power is generated based on a second carrier signal.
1. A method for operating an electric motor comprising a first winding and a second winding, the method comprising:
generating a first phase of alternating current (AC) power based on a first carrier signal, wherein the generating of the first phase of AC power comprises operating a first set of switches in a power inverter based on the first carrier signal, and said operating of the first set of switches causes current to flow through the first winding within the electric motor; and
generating a second phase of the AC power based on a second carrier signal, wherein the generating of the second phase of AC power comprises operating a second set of switches in the power inverter based on the second carrier signal, and said operating of the second set of switches causes current to flow through the second winding within the electric motor.
2. The method of claim 1 , wherein the first set of switches is connected in series by a first node and the second set of switches is connected in series by a second node, the first winding of the electric motor is connected to the first node, and the second winding of the electric motor is connected to the second node.
3. The method of claim 2 , further comprising:
generating the first and second carrier signals;
generating a first modulation signal, and wherein the operation of the first set of switches is further based on the first modulation signal; and
generating a second modulation signal, and wherein the operation of the second set of switches is further based on the second modulation signal.
4. The method of claim 3 , wherein the first carrier signal and the first modulation signal jointly determine a first waveform, and wherein the operation of the first set of switches is further based on the first waveform.
5. The method of claim 4 , wherein the second carrier signal and the second modulation signal jointly determine a second waveform, and wherein the operation of the second set of switches is further based on the second waveform.
6. The method of claim 2 , further comprising:
generating a third carrier signal; and
generating a third phase of the AC power based on the third carrier signal.
7. The method of claim 6 , wherein the generating of the third phase comprises operating a third set of switches in the power inverter based on the third carrier signal, and said operating of the second set of switches causes current to flow through a second winding within the electric motor.
8. The method of claim 7 , further comprising generating a third modulation signal, the third carrier signal and the third modulation signal jointly determining a third waveform, and wherein the operation of the third set of switches is further based on the third waveform.
9. A method for operating a multi-phase motor through a power inverter having a pair of switches for each phase of the motor, the method comprising:
generating a first carrier signal;
generating a first modulation signal, the first carrier signal and the first modulation signal jointly determining a first waveform;
operating a first pair of the switches in the power inverter based on the first waveform, wherein the first pair of switches is connected to a first winding in the motor such that the operating of the first pair of switches causes current to flow through the first winding;
generating a second carrier signal;
generating a second modulation signal, the second carrier signal and the first modulation signal jointly determining a second waveform; and
operating a second pair of the switches in the power inverter based on the second waveform, wherein the second pair of switches is connected to a second winding in the motor such that the operating of the second pair of switches causes current to flow through the second winding.
10. The method of claim 9 , further comprising:
generating a third carrier signal;
generating a third modulation signal, the third carrier signal and the third modulation signal jointly determining a third waveform; and
operating a third pair of the switches in the power inverter based on the third waveform, wherein the third pair of switches is connected to a third winding in the motor such that the operating of the third pair of switches causes current to flow through the third winding.
11. An automotive drive system comprising:
an electric motor comprising a first winding and a second winding;
a direct current (DC) power supply coupled to the electric motor;
a power inverter comprising first and second pairs of switches and being coupled to the electric motor and the DC power supply to receive DC power from the DC power supply and provide alternating current (AC) power to the electric motor, wherein the first pair of switches is connected in series by a first node and the second pair of switches is connected in series by a second node, and further wherein the first winding of the electric motor is connected to the first node, and the second winding of the electric motor is connected to the second node; and
a processor in operable communication with the electric motor, the DC power supply, and the power inverter, the processor being configured to:
generate a first carrier signal;
operate the first pair of switches in the power inverter based on the first carrier signal;
generate a second carrier signal; and
operate the second pair of switches in the power inverter based on the second carrier signal.
12. The automotive drive system of claim 11 , wherein the processor is further configured to:
generate a first modulation signal, the first carrier signal and the first modulation signal jointly determining a first waveform and the operation of the first pair of switches being further based on the first waveform; and
generate a second modulation signal, the second carrier signal and the second modulation signal jointly determining a second waveform and the operation of the second pair of switches being further based on the second waveform.
13. The automotive drive system of claim 12 , wherein the DC power supply comprises a battery, a fuel cell, or a combination thereof.
14. The automotive drive system of claim 13 , wherein the electric motor comprises a third winding, and wherein the power inverter further comprises a third pair of switches connected in series by a third node, and the third winding of the electric motor is connected to the third node.
15. The automotive drive system of claim 14 , wherein the processor is further configured to:
generate a third carrier signal; and
operate the third pair of switches based on the third carrier signal.
16. The automotive drive system of claim 15 , wherein the processor is further configured to generate a third modulation signal, the third carrier signal and the third modulation signal jointly determining a third waveform and the operation of the third pair of switches being further based on the third waveform.
17. The automotive drive system of claim 16 , wherein the power inverter further comprises an impedance source coupled between the DC power source and the first, second, and third pairs of switches.
18. The automotive drive system of claim 17 , wherein the impedance source comprises at least one inductor and at least one capacitor.
19. The automotive drive system of claim 18 , wherein the at least one inductor comprises a split inductor having first and second inductive portions with first and second sides and the at least one capacitor comprises first and second capacitors, the first capacitor having a first terminal connected to the first side of the first inductive portion and a second terminal connected to the second side of the second inductive portion and the second capacitor having a first terminal connected to the second side of the first inductive portion and a second terminal connected to the first side of the second inductive portion.
20. The automotive drive system of claim 19 , wherein the first, second, and third pairs of switches comprise a plurality of transistors.