Latch dual-curve 3PS/6SO safe state for inverter

An inverter control system for an EV (electric vehicle) comprising:

• a high voltage circuit powered by a high DC voltage power source;
• a low voltage circuit powered by a low DC voltage power source that is substantially less than the voltage of the high voltage power source, the low voltage circuit being configured to power a microcontroller;
• and
• an inverter circuit having a plurality of high side switches and a plurality of low side switches, the inverter circuit being configured to deliver AC power to a traction motor,
• wherein:
• upon powerup of the high voltage circuit with the low voltage circuit being unpowered, the inverter control system is configured to establish an emergency tow state with each of the high side switches and each of the low side switches being open, with a motor RPM being less than a defined emergency tow state RPM threshold,
• when low voltage circuit is powered-up, the microcontroller is configured to cause exiting of the emergency tow state when it is determined that the EV is no longer in the emergency tow state, and
• after exiting the emergency tow state and prior to driving the traction motor, the microcontroller is configured to change a state of a signal to cause latching of a first safe state by opening of each of the high side switches and each of the low side switches when the motor RPM is less than a first threshold that is substantially below the emergency tow state RPM threshold, or to latch a second safe state by closing of all of the high side switches with all of the low side switches being open or closing all of the low side switches with all of the high side switches being open, when the motor RPM is greater than the first threshold and less than the emergency tow state RPM threshold.

An inverter control system for an EV (electric vehicle) comprising:

• a high voltage circuit powered by a high DC voltage power source;
• a low voltage circuit powered by a low DC voltage power source that is substantially less than the voltage of the high voltage power source, the low voltage circuit being configured to power a microcontroller;
• and
• an inverter circuit having a plurality of high side switches and a plurality of low side switches, the inverter circuit being configured to deliver AC power to a traction motor,
• wherein:
• upon powerup of the high voltage circuit with the low voltage circuit being unpowered, the inverter control system is configured to establish an emergency tow state with each of the high side switches and each of the low side switches being open, with a voltage of the high voltage circuit being less than a defined emergency tow state voltage threshold;
• when low voltage circuit is powered-up, the microcontroller is configured to cause exiting of the emergency tow state when it is determined that the EV is no longer in the emergency tow state, and
• after exiting the emergency tow state and prior to driving the traction motor, the microcontroller is configured change a state of a signal to cause latching of a first safe state by opening of each of the high side switches and each of the low side switches when a voltage of the high voltage circuit is less than a first voltage threshold that is substantially below the emergency tow state voltage threshold, or latch a second safe state by closing of all of the high side switches with all of the low side switches being open or closing all of the low side switches with all of the high side switches being open, when the voltage of the high voltage circuit is greater than the first voltage threshold and less than the emergency tow state voltage threshold.