Azure

Using an Azure DMOC AC motor driver (inverter) with an Lithiumate BMS.

A contactor is not required when using a DMOC motor driver, as they include internal contactors. However, its precharge time is extremely long, and unacceptable for vehicle applications. Therefore, it is best if the battery is always connected to the DMOC, and the DMOC is controlled off and on through low voltage signals.

A load current sensor is required when using a DMOC motor driver.

DMOC motor drivers are sold pre-configured for either wire control or CAN control.

Wire controlled

If configured for wire control, they can be used as any other analog motor driver:

• Gradual drive reduction can be done by driving the throttle pot from the BMS' DCL output
• Step reduction can be done by driving the DMOC's "Power Saver" input with the BMS' LLIM output
• The DMOC can be shut down at the end of charge by driving its "Drive Disable" input with the BMS' LLIM output
• The DMOC can be prevented from overcharging the battery by driving its "Regen Disable" input with the BMS' HLIM output

Interfacing the Azure motor driver (wire control) and the Elithion BMS

• Azure DMOC wire control (pdf)

CAN controlled

If configured for CAN bus control, they require a VCU (Vehicle Control Unit) to translate between the various signals on the CAN bus (BMS, throttle, etc.) and what the DMOC expects.

In particular, there are at least three reasons why a VCU is required:

• The DMOC expects speed control and torque control in the same message; but the formed comes from the throttle, and the latter from the BMS, each of which must use a different message ID; so, a VCU is required to combine the 2 pieces of data into a single message
• The BMS puts out a value for maximum battery current (Amps), but the DMOC expects a value for maximum torque at the motor output (N-m); so a VCU is required to calculate torque from battery current and other data
• The throttle puts out a value based on pedal position, but the DMOC expects a value for requested speed, which is not proportional to throttle position; so a VCU is required to calculate a requested speed (and max torque) mased on throttle pedal position and other factors

Interfacing the Azure motor driver (CAN control) and the Elithion BMS

• Azure DMOC CAN control (pdf)