INVERTER CIRCUITS AND ELECTRICAL PROPULSION SYSTEMS FOR EVTOL AIRCRAFT
An electrical propulsion system includes an electrical motor configured to drive one or more propellers of the aircraft, a capacitor configured to stabilize a direct current (DC) bus voltage, a first inverter circuit coupled to the capacitor and configured to convert the DC bus voltage to alternate current (AC) voltages to drive a first set of stator windings of the electrical motor, in response to a first pulse width modulation (PWM) vector, and a second inverter circuit coupled to the capacitor and configured to convert the DC bus voltage to AC voltages to drive a second set of stator windings of the electrical motor, in response to a second PWM vector. The first PWM vector and the second PWM vector are substantially equal and opposite vectors.
1 . A propulsion system, comprising:
an electrical motor configured to drive an output shaft; and
a capacitor configured to stabilize a direct current (DC) bus voltage;
a first inverter circuit coupled to the capacitor and configured to convert the DC bus voltage on a first bus of the first inverter circuit to alternate current (AC) voltages to drive a first set of stator windings of the electrical motor, based on a first pulse width modulation (PWM) vector; and
a second inverter circuit coupled to the capacitor and configured to convert the DC bus voltage on a second bus of the second inverter circuit to AC voltages to drive a second set of stator windings of the electrical motor, based on a second PWM vector, wherein the first PWM vector and the second PWM vector are substantially equal and opposite vectors.
2 . The propulsion system of claim 1 , wherein the first set of stator windings and the second set of stator winding are shifted by substantially 180 degrees.
3 . The propulsion system of claim 1 , wherein the first inverter circuit is controlled using a center aligned space vector modulation.
4 . The propulsion system of claim 3 , wherein the second inverter circuit is controlled using an inverted center aligned space vector modulation.
5 . The propulsion system of claim 1 , wherein the first inverter circuit is configured to output a first set of three-phase AC voltages and the second inverter circuit is configured to output a second set of three-phase AC voltages.
6 . The propulsion system of claim 5 , wherein a phase of the first set of three-phase AC voltages and a corresponding phase of the second set of three-phase AC voltages are two interleaved phases with a phase-shift of substantially 180 degrees.
7 . The propulsion system of claim 1 , further comprising:
a DC common-mode filter coupled to the capacitor and configured to reduce common mode signals at a DC-side of the first inverter circuit and the second inverter circuit.
8 . The propulsion system of claim 1 , further comprising:
one or more AC common-mode chokes coupled to an AC-side of the first inverter circuit or the second inverter circuit to reduce common mode signals.
9 . A method for controlling a propulsion system, comprising:
stabilizing, by a capacitor, a direct current (DC) bus voltage;
converting, by a first inverter circuit coupled to the capacitor, the DC bus voltage to alternate current (AC) voltages to drive a first set of stator windings of an electrical motor according to a first pulse width modulation (PWM) vector;
converting, by a second inverter circuit coupled to the capacitor, the DC bus voltage to AC voltages to drive a second set of stator windings of the electrical motor, in response to a second PWM vector, wherein the first PWM vector and the second PWM vector are substantially equal and opposite vectors; and
driving an output shaft by the electrical motor.
10 . The method of claim 9 , wherein the first set of stator windings and the second set of stator winding are shifted by substantially 180 degrees.
11 . The method of claim 9 , further comprising:
controlling the first inverter circuit using a center aligned space vector modulation.
12 . The method of claim 11 , further comprising:
controlling the second inverter circuit using an inverted center aligned space vector modulation.
13 . The method of claim 9 , further comprising:
output a first set of three-phase AC voltages by the first inverter circuit to drive the first set of stator windings; and
output a second set of three-phase AC voltages by the second inverter circuit to drive the second set of stator windings.
14 . The method of claim 13 , wherein a phase of the first set of three-phase AC voltages and a corresponding phase of the second set of three-phase AC voltages are two interleaved phases with a phase-shift of substantially 180 degrees.
15 . The method of claim 9 , further comprising:
reducing, by a DC common-mode filter coupled to the capacitor, common mode signals at a DC-side of the first inverter circuit and the second inverter circuit.
16 . The method of claim 9 , further comprising:
reducing, by one or more AC common-mode chokes coupled to an AC-side of the first inverter circuit or the second inverter circuit, common mode signals at the AC-side of the first inverter circuit and the second inverter circuit.
17 . An integrated circuit, comprising circuitry for performing a method for controlling a propulsion system, the circuitry is configured to:
control a first inverter circuit coupled to a capacitor, to convert a DC bus voltage to alternate current (AC) voltages to drive a first set of stator windings of an electrical motor according to a first pulse width modulation (PWM) vector; and
control a second inverter circuit coupled to the capacitor, to convert the DC bus voltage to AC voltages to drive a second set of stator windings of the electrical motor, in response to a second PWM vector, wherein the first PWM vector and the second PWM vector are substantially equal and opposite vectors to drive an output shaft by the electrical motor.
18 . The integrated circuit of claim 17 , wherein the first set of stator windings and the second set of stator winding are shifted by substantially 180 degrees.
19 . The integrated circuit of claim 17 , wherein the circuitry is further configured to control the first inverter circuit using a center aligned space vector modulation.
20 . The integrated circuit of claim 19 , wherein the circuitry is further configured to control the second inverter circuit using an inverted center aligned space vector modulation.
21 . The integrated circuit of claim 17 , wherein the circuitry is further configured to:
control the first inverter circuit to output a first set of three-phase AC voltages by the first inverter circuit to drive the first set of stator windings; and
control the second inverter circuit to output a second set of three-phase AC voltages by the second inverter circuit to drive the second set of stator windings.
22 . The integrated circuit of claim 21 , wherein a phase of the first set of three-phase AC voltages and a corresponding phase of the second set of three-phase AC voltages are two interleaved phases with a phase-shift of substantially 180 degrees.
23 . The integrated circuit of claim 17 , wherein a DC common-mode filter is coupled to the capacitor and configured to reduce common mode signals at a DC-side of the first inverter circuit and the second inverter circuit.
24 . The integrated circuit of claim 17 , wherein one or more AC common-mode chokes are coupled to an AC-side of the first inverter circuit or the second inverter circuit to reduce common mode signals.
25 .- 30 . (canceled)