Systems and methods for active discharge for inverter for electric vehicle
A system includes: an inverter configured to convert DC power from a battery to AC power to drive a motor, wherein the inverter includes: a bulk capacitor; one or more phase switches; and one or more controllers configured to control a gate voltage to the one or more phase switches to discharge the bulk capacitor, wherein the one or more controllers is configured to control the gate voltage based on one or more of a measured temperature of the one or more phase switches or an estimated temperature of the one or more phase switches.
1 . A system comprising:
an inverter configured to convert DC power from a battery to AC power to drive a motor, wherein the inverter includes:
a bulk capacitor to connect to a positive connection of the battery and a negative connection of the battery;
one or more phase switches; and
one or more controllers configured to control a gate voltage to the one or more phase switches to discharge the bulk capacitor,
wherein the one or more controllers is configured to reduce the gate voltage while maintaining a drain current of the one or more phase switches above a threshold level to discharge the bulk capacitor based on one or more of a measured temperature of the one or more phase switches or an estimated temperature of the one or more phase switches.
2 . The system of claim 1 , wherein the one or more controllers is a point-of-use controller.
3 . The system of claim 1 , wherein the one or more controllers is a gate driver for the one or more phase switches.
4 . The system of claim 1 , wherein the one or more phase switches includes one or more silicon carbide dies.
5 . The system of claim 1 , wherein the one or more controllers includes one or more thermal sensors to measure a temperature of the one or more phase switches.
6 . The system of claim 1 , wherein the inverter further includes:
one or more thermistors to measure a temperature of the one or more phase switches.
7 . The system of claim 1 , wherein the one or more controllers is further configured to control the gate voltage based on the measured temperature of the one or more phase switches measured prior to an active discharge of the inverter.
8 . The system of claim 1 , further comprising:
the battery configured to supply the DC power to the inverter; and
the motor configured to receive the AC power from the inverter to drive the motor.
9 . A system comprising:
a power module for an inverter configured to convert DC power to AC power, the power module including a drain terminal and a source terminal;
one or more phase switches configured to control a current flow between the drain terminal and the source terminal; and
a point-of-use controller configured to control a gate voltage to the one or more phase switches to discharge a bulk capacitor of the inverter,
wherein the point-of-use controller is configured to reduce the gate voltage while maintaining a drain current of the one or more phase switches above a threshold level to discharge the bulk capacitor based on one or more of a measured temperature of the one or more phase switches or an estimated temperature of the one or more phase switches, and the bulk capacitor is configured to connect to a positive connection of a battery and a negative connection of the battery.
10 . The system of claim 9 , wherein the point-of-use controller is an application-specific integrated circuit gate driver for the one or more phase switches.
11 . The system of claim 9 , wherein the one or more phase switches include one or more silicon carbide dies.
12 . The system of claim 9 , wherein the point-of-use controller includes one or more thermal sensors to measure a temperature of the one or more phase switches.
13 . The system of claim 9 , wherein the point-of-use controller is further configured to control the gate voltage based on the measured temperature of the one or more phase switches measured prior to an active discharge of the inverter.
14 . A system including one or more controllers configured to:
determine one or more of a measured temperature of a phase switch or an estimated temperature of the phase switch; and
control a gate voltage to the phase switch to discharge a bulk capacitor of an inverter, wherein the one or more controllers is configured to reduce the gate voltage while maintaining a drain current of the phase switch above a threshold level to discharge the bulk capacitor based on the determined one or more of the measured temperature of the phase switch or the estimated temperature of the phase switch and the bulk capacitor is configured to connect to a positive connection of a battery and a negative connection of the battery.
15 . The system of claim 14 , wherein the one or more controllers is a point-of-use controller.
16 . The system of claim 14 , wherein the one or more controllers is further configured to:
determine the measured temperature of the phase switch using a thermal sensor of the one or more controllers.
17 . The system of claim 14 , wherein the one or more controllers is further configured to:
control the gate voltage based on the measured temperature of the phase switch measured prior to an active discharge of the inverter.
18 . The system of claim 14 , wherein the one or more controllers is further configured to:
determine the measured temperature of the phase switch using a thermistor of the phase switch.
19 . The system of claim 14 , wherein the inverter does not use a resistive element or windings of a motor for the active discharge of the inverter.
20 . The system of claim 14 , wherein the one or more controllers are further configured to discharge the bulk capacitor using switching losses in the phase switch by controlling the phase switch on and off at a switching frequency, wherein a rate of discharge of the bulk capacitor is proportional to the switching frequency.