Shared-leg voltage source inverter
A system includes a first motor, a second motor, and a third motor, each respective motor comprising three phases. The system further includes a voltage source inverter circuit comprising multiple respective inverter legs. Each respective inverter leg coupled to drive at least one phase of at least one of the respective motors, with a first shared inverter leg coupled to drive a third phase of the first motor and drive a first phase of the second motor. A second shared inverter leg is coupled to drive a third phase of the second motor and a first phase of the third motor.
1 . A system comprising:
a first motor, a second motor, and a third motor, each respective motor comprising three phases; and
a voltage source inverter circuit comprising multiple respective inverter legs;
each respective inverter leg coupled to drive at least one phase of at least one of the respective motors;
wherein multiple respective inverter legs comprise at least a first shared inverter leg and a second shared inverter leg;
wherein the first shared inverter leg is coupled to drive a third phase of the first motor and drive a first phase of the second motor; and
wherein the second shared inverter leg is coupled to drive a third phase of the second motor and a first phase of the third motor.
2 . The system of claim 1 further comprising:
a fourth motor comprising three phases;
wherein a third shared inverter leg is coupled to drive a third phase of the third motor and drive a first phase of the fourth motor.
3 . The system of claim 2 further comprising:
a fifth motor comprising three phases;
wherein a fourth shared inverter leg is coupled to drive a third phase of the fourth motor and drive a first phase of the fifth motor.
4 . The system of claim 3 ,
wherein a first exclusive inverter leg is coupled to drive a first phase of the first motor;
wherein a second exclusive inverter leg is coupled to drive a second phase of the first motor;
wherein a third exclusive inverter leg is coupled to drive a second phase of the second motor;
wherein a fourth exclusive inverter leg is coupled to drive a second phase of the third motor;
wherein a fifth exclusive inverter leg is coupled to drive a second phase of the fourth motor;
wherein a sixth exclusive inverter leg is coupled to drive a second phase of the fifth motor; and
wherein a seventh exclusive inverter leg is coupled to drive a third phase of the fifth motor.
5 . The system of claim 2 ,
wherein a first exclusive inverter leg is coupled to drive a first phase of the first motor;
wherein a second exclusive inverter leg is coupled to drive a second phase of the first motor;
wherein a third exclusive inverter leg is coupled to drive a second phase of the second motor;
wherein a fourth exclusive inverter leg is coupled to drive a second phase of the third motor; and
wherein a fifth exclusive inverter leg is coupled to drive a second phase of the fourth motor.
6 . The system of claim 1 ,
wherein a first exclusive inverter leg is coupled to drive a first phase of the first motor;
wherein a second exclusive inverter leg is coupled to drive a second phase of the first motor;
wherein a third exclusive inverter leg is coupled to drive a second phase of the second motor; and
wherein a fourth exclusive inverter leg is coupled to drive a second phase of the third motor.
7 . The system of claim 1 ,
wherein the first, second, and third motors each includes a permanent magnet synchronous motor.
8 . The system of claim 1 ,
wherein the first, second, and third motors each includes a brushless direct current motor.
9 . The system of claim 1 ,
wherein the first, second, and third motors each includes an induction motor.
10 . The system of claim 1 ,
wherein each respective inverter leg includes a respective first switch coupled as a voltage pull-up switch between a respective center tap voltage node and a bus voltage and a respective second switch coupled as a voltage pull-down switch to between the respective center tap voltage node and a ground voltage.
11 . The system of claim 10 ,
wherein the third phase of the first motor is coupled between a neutral node of the first motor and a respective center tap node of the first shared inverter leg and the first phase of the second motor is coupled between a neutral node of the second motor and the respective center tap node of the first shared inverter leg; and
wherein the third phase of the second motor is coupled between the neutral node of the second motor and a respective center tap node of the second shared inverter leg and the first phase of the third motor is coupled between the neutral node of the third motor and the respective center tap node of the second shared inverter leg.
12 . The system of claim 11 ,
wherein a second phase of the first motor is coupled between the neutral node of the first motor and a respective center tap node of a second exclusive leg;
wherein a second phase of the second motor is coupled between the neutral node of the second motor and a respective center tap node of a third exclusive leg; and
wherein a second phase of the third motor is coupled between a neutral node of the third motor and a respective center tap node of a fourth exclusive leg.
13 . The system of claim 12 ,
wherein a third phase of the third motor is coupled between a neutral node of the third motor and a respective center tap node of a third shared inverter leg.
14 . The system of claim 1 ,
wherein each respective inverter leg includes a respective first transistor switch coupled as a voltage pull-up switch between a respective center tap voltage node and a bus voltage and a respective second transistor switch coupled as a voltage pull-down switch between the respective center tap voltage node and a ground voltage.
15 . The system of claim 1 , further including:
a commutation control circuit including,
a first voltage transformation block to transform first, second and third sets of space vector voltage signals, corresponding to the first, second, and third motors, to multiple phase voltage signals that include a first shared phase voltage signal and a second shared phase voltage signal; and
a duty cycle block to modulate the first shared phase voltage signal and the second shared phase voltage signals and add a common mode voltage value to the first and second shared phase voltage signals to produce corresponding first and second input control signals;
wherein the first shared inverter leg imparts a first shared excitation signal to the third phase of the first motor and the first phase of the second motor, in response to the first input control signal; and
wherein the second shared inverter leg imparts a second shared excitation signal to the third phase of the second motor and the first phase of the third motor, in response to the second input control signal.
16 . The system of claim 15 ,
wherein the multiple phase voltage signals include a first exclusive phase signal;
wherein the duty cycle block modulates the first exclusive phase signal and adds the common mode voltage value to the first exclusive phase signals to produce a corresponding third input control signal; and
wherein a first exclusive inverter leg imparts a first exclusive excitation signal in response to the third input control signal.
17 . The system of claim 15 further comprising:
one or more second voltage transform blocks that for each of one of the respective first, second, and third motors,
transforms a respective rotating two-axis coordinate system of the respective motor, based upon respective angular position of a respective rotor of the respective motor, to a respective set of space vector voltage signals in a respective stationary two-axis space vector coordinate system of a respective stationary stator of the respective motor;
whereby the one or more second voltage transform blocks produce the first, second, and third sets of space vector voltage signals.
18 . A system comprising:
a first motor, a second motor, and a third motor, each respective motor comprising three phases;
a voltage source inverter circuit comprising multiple respective inverter legs;
a commutation control circuit including,
a first voltage transformation block to transform first, second and third sets of space vector voltage signals, corresponding to the first, second, and third motors, to multiple phase voltage signals that include a first shared phase voltage signal and a second shared phase voltage signal, and
a duty cycle block to modulate the first and second shared phase voltage signals and add a common mode voltage value to the first and second shared phase voltage signals to produce corresponding first and second input control signals;
wherein a first inverter leg of the voltage source inverter circuit is coupled to impart a first shared excitation signal to a third phase of the first motor and to a first phase of the second motor, in response to the first input control signal; and
wherein a second inverter leg of the voltage source inverter circuit is coupled to impart a second shared excitation signal to a third phase of the second motor and to a first phase of the third motor, in response to the second input control signal.
19 . The system of claim 18 ,
wherein the multiple phase voltage signals include a first exclusive phase voltage signal;
wherein the duty cycle block modulates the first exclusive phase voltage signal and adds the common mode voltage value to the first exclusive phase voltage signal to produce a corresponding third input control signal; and
wherein a third inverter leg of the voltage source inverter circuit is coupled to impart a first exclusive excitation signal to only one phase of one motor, in response to the third input control signal.
20 . The system of claim 18 further comprising:
one or more second voltage transform blocks that for each of one of the respective first, second, and third motors,
transforms a respective rotating two-axis coordinate system of the respective motor, based upon respective angular position of a respective rotor of the respective motor, to a respective set of space vector voltage signals in a respective stationary two-axis space vector coordinate system of a respective stationary stator of the respective motor;
whereby the one or more second voltage transform blocks produce the first, second, and third sets of space vector voltage signals.