Power supply system with multiphase motor and multiphase inverter
In a power supply system, a controller is electrically connected with a plurality of switching elements of a multiphase inverter. The controller switches the plurality of switching elements on and off during a multiphase motor being activated. This converts a voltage of a first power storage device into a multiphase AC voltage so as to supply the multiphase AC voltage to the multiphase motor. This also boosts a voltage of a second power storage device to charge the first power storage device by the boosted voltage via multiphase windings of the motor. The controller switches the plurality of switching elements on and off during the multiphase motor being inactivated to thereby boost the voltage of the second power storage device to charge the first power storage device by the boosted voltage.
1. A power supply system comprising:
a chargeable and dischargeable first power storage device having one potential terminal, an other potential terminal, and a first chargeable voltage range;
a chargeable and dischargeable second power storage device having one potential terminal, an other potential terminal, and a second chargeable voltage range lower than the first chargeable voltage range;
a multiphase motor having a star-connected multiphase stator windings with a neutral point, the multiphase motor working to generate torque when the star-connected multiphase stator windings are energized, the neutral point being electrically connected with the one potential terminal of the second power storage device;
a multiphase inverter including a plurality of switching elements connected with each other in bridge configuration to provide a high-side direct-current (DC) terminal and a low-side direct-current (DC) terminal, the high-side DC terminal being electrically connected with the one potential terminal of the first power storage device, the low-side DC terminal being electrically connected with the other potential terminal of the first power storage device, any one of the high-side and low-side DC terminals being electrically connected with the other potential terminal of the second power storage device; and
a controller electrically connected with the plurality of switching elements, the controller working to switch the plurality of switching elements on and off during the multiphase motor being activated to thereby:
convert a voltage of the first power storage device into a multiphase alternating-current (AC) voltage so as to supply the multiphase AC voltage to the multiphase motor; and
boost the voltage of the second power storage device to charge the first power storage device by the boosted voltage,
the controller working to switch the plurality of switching elements on and off during the multiphase motor being inactivated to thereby boost the voltage of the second power storage device to charge the first power storage device by the boosted voltage.
2. The power supply system according to claim 1 , wherein the voltage charged in the first power storage device during the multiphase motor being inactivated is greater than that charged in the first power storage device during the multiphase motor being activated.
3. The power supply system according to claim 1 , wherein the power supply system is installed in a motor vehicle, further comprising:
a power generator driven by torque created in the motor vehicle to intermittently generate power, the power generated by the power generator charging the second power storage device,
the controller working to switch the plurality of switching elements on and off during the multiphase motor being inactivated and the power generator generating the power to thereby boost the voltage of the second power storage device and charge the first power storage device by the boosted voltage.
4. The power supply system according to claim 1 , wherein the controller works to switch the plurality of switching elements on and off during the multiphase motor being activated to thereby cause multiphase alternating currents to flow through the corresponding multiphase stator windings, each of the multiphase alternating currents being DC offset, and the controller works to switch the plurality of switching elements on and off during the multiphase motor being inactivated to thereby cause a direct current to flow through each of the multiphase stator windings.
5. The power supply system according to claim 3 , wherein the power generator operates in a power generation mode to generate the power during the motor vehicle being decelerated, and operates in a power-generation inhibiting mode to inhibit generation of the power during the motor vehicle being driven at least except when being decelerated, and
wherein, during the power generator operating in the power-generation inhibiting mode, when the voltage of the second power storage device is less than a predetermined threshold, the power generator works to stop the power-generation inhibiting mode to thereby charge the second power storage device.
6. The power supply system according to claim 3 , wherein the power generator works to charge the first and second power storage devices, and the controller works to, even though the multiphase motor being inactivated, switch the plurality of switching elements on and off to thereby step down the voltage of the first power storage device to charge the second power storage device by the stepped-down voltage when the voltage of the second power storage device is less than a predetermined threshold.
7. The power supply system according to claim 1 , wherein the power supply system is installed in a motor vehicle, further comprising:
a power generator driven by torque created in the motor vehicle to intermittently generate power, the power generated by the power generator charging the second power storage device, the power generator including an excitation circuit,
wherein the controller works to supply the boosted voltage to the excitation circuit of the power generator.
8. The power supply system according to claim 1 , wherein the power supply system is installed in a motor vehicle, further comprising:
a power generator driven by torque created in the motor vehicle to intermittently generate power, the power generated by the power generator charging the second power storage device, the power generator including an excitation circuit,
wherein the first power storage device works to supply the voltage thereof to the excitation circuit of the power generator.
9. The power supply system according to claim 1 , wherein the controller works to stop the boosting of the voltage of the second power storage device when the voltage of the first power storage device is equal to or greater than a predetermined threshold.
10. The power supply system according to claim 1 , wherein the controller works to switch the plurality of switching elements on and off at least during the multiphase motor being inactivated to thereby boost the voltage of the second power storage device so that the boosted voltage is equal to or greater twice the voltage of the second power storage device.
11. A power supply system comprising:
a chargeable and dischargeable first power storage device having one potential terminal, an other potential terminal, and a first chargeable voltage range;
a chargeable and dischargeable second power storage device having one potential terminal, an other potential terminal, and a second chargeable voltage range lower than the first chargeable voltage range;
a multiphase motor having a star-connected multiphase stator windings with a neutral point, the multiphase motor working to generate torque when the star-connected multiphase stator windings are energized, the neutral point being electrically connected with the one potential terminal of the second power storage device;
a multiphase inverter including a plurality of switching elements connected with each other in bridge configuration to provide a high-side direct-current (DC) terminal and a low-side direct-current (DC) terminal, the high-side DC terminal being electrically connected with the one potential terminal of the first power storage device, the low-side DC terminal being electrically connected with the other potential terminal of the first power storage device, any one of the high-side and low-side DC terminals being electrically connected with the other potential terminal of the second power storage device; and
a controller electrically connected with the plurality of switching elements, the controller working to switch the plurality of switching elements on and off during the multiphase motor being activated to thereby:
convert a voltage of the first power storage device into a multiphase alternating-current (AC) voltage so as to supply the multiphase AC voltage to the multiphase motor; and
step down the voltage of the first power storage device to charge the second power storage device by the stepped-down voltage,
the controller working to switch the plurality of switching elements on and off during the multiphase motor being inactivated to thereby step down the voltage of the first power storage device to charge the second power storage device by the stepped-down voltage.
12. The power supply system according to claim 11 , wherein the power supply system is installed in a motor vehicle, further comprising:
a power generator driven by torque created in the motor vehicle to intermittently generate power, the power generated by the power generator charging the first power storage device,
the controller working to switch the plurality of switching elements on and off during the multiphase motor being inactivated and the power generator generating the power to thereby step down the voltage of the first power storage device and charge the second power storage device by the stepped-down voltage.
13. The power supply system according to claim 12 , wherein the power generator operates in a power generation mode to generate the power during the motor vehicle being decelerated, and operates in a power-generation inhibiting mode to inhibit generation of the power during the motor vehicle being driven at least except when being decelerated, and
wherein, during the power generator operating in the power-generation inhibiting mode, when the voltage of the first power storage device is less than a predetermined threshold, the power generator works to stop the power-generation inhibiting mode to thereby charge the first power storage device.
14. The power supply system according to claim 11 , wherein the power generator works to charge the first and second power storage devices, and the controller works to, even though the multiphase motor being inactivated, switch the plurality of switching elements on and off to thereby boost the voltage of the second power storage device to charge the first power storage device by the boosted voltage when the voltage of the first power storage device is less than a predetermined threshold.
15. The power supply system according to claim 11 , wherein the controller works to stop the stepping-down of the voltage of the first power storage device when the voltage of the second power storage device is equal to or greater than a predetermined threshold.
16. The power supply system according to claim 11 , wherein the controller works to switch the plurality of switching elements on and off to thereby step down the voltage of the first power storage device so that the stepped-down voltage is equal to or lower than the half of the voltage of the first power storage device.
17. The power supply system according to claim 1 , further comprising a switching circuit electrically connected between the neutral point of the multiphase stator windings and the first power storage device, the switching circuit being electrically connected with the controller so as to be turned on or off under control of the controller,
wherein, when boosting the voltage of the second power storage device, the controller drives the switching circuit on to thereby electrically connect between the neutral point of the multiphase stator windings and the first power storage device.
18. The power supply system according to claim 11 , further comprising a switching circuit electrically connected between the neutral point of the multiphase stator windings and the second power storage device, the switching circuit being electrically connected with the controller so as to be turned on or off under control of the controller,
wherein, when stepping down the voltage of the first power storage device, the controller drives the switching circuit on to thereby electrically connect between the neutral point of the multiphase stator windings and the second power storage device.
19. The power supply system according to claim 1 , wherein at least one of the first and second power storage devices is composed of a capacitor.
20. The power supply system according to claim 11 , wherein at least one of the first and second power storage devices is composed of a capacitor.
21. The power supply system according to claim 1 , wherein the multiphase motor is one of: a motor for a starter system that causes an engine to start running, a motor for an electric power steering system that assists a driver's operation of a steering wheel of a vehicle a motor for a stabilizer system that keeps a state of a vehicle controllable, and a motor for a compressor of an air-conditioning system.
22. The power supply system according to claim 11 , wherein the multiphase motor is one of: a motor for a starter system that causes an engine to start running, a motor for an electric power steering system that assists a driver's operation of a steering wheel of a vehicle, a motor for a stabilizer system that keeps a state of a vehicle controllable, and a motor for a compressor of an air-conditioning system.