The front end of the drive electronics consists of a Power Factor Corrector (PFC) running at 57kHz. Running in a Boost configuration, this PFC circuit converts the input AC line voltage to 375Vdc while maintaining a very high power factor.

This circuit can operate from 100Vac to a maximum of 264Vac (nominal 120Vac to 240Vac). With suitable modifications to the input protection devices, DC can also be supplied to the drive. In this case the PFC circuit is acting only as a boost converter. The DC input should be in the range of 100Vdc to 375Vdc.

The 375Vdc bus supplies power to a three-phase, six switch IGBT inverter. The power section of the inverter is an Intelligent Power Module utilizing 5th generation IGBTs with a 600V/50A rating. The power module also contains integrated drivers, short circuit protection and over temperature protection.

The revolutionary drive electronics of the TREZIUM® Electric Motor System

Drive to the inverter power module is from an ASIC that provides the basis for the Sensorless FOC (Field Oriented Control) of the motor. This IC provides open-loop startup of the motor to approximately 3,000rpm. From 3,000rpm to design speed, a controlled speed ramp is provided. Above the minimum speed, the FOC algorithm adjusts the drive to the motor in order to optimize the power output. Speed is regulated with a closed loop speed control algorithm that keeps the speed nearly constant from no-load to full-load.

The sinusoidal drive voltages are generated using a Space Vector PWM operating at 12kHz. At 30,000rpm the drive generates a three-phase 500Hz output at approximately 200Vac line to line. A limited amount of the mechanical energy from the motor can be regenerated into the DC bus upon deceleration. This ASIC also monitors fault conditions such as over/under voltage of the DC bus, loss of a motor phase, improper startup, over-current, over-speed, and other control parameters.

Supervisory control in the drive is handled by a separate dedicated micro-controller. This micro-controller monitors the input voltage, the DC bus voltage, as well as fault registers within the control ASIC. Higher level control algorithms such as output power levels, temperature controlled functionality, cool down timers, etc. can be custom programmed into this microcontroller. Heatsink temperature is monitored and shuts down the drive if the maximum temperature is exceeded.

Three-dimensional view now available.

The TREZIUM® controller is shown in 2-D below. You can also download a 3-D view that can be rotated, zoomed and disassembled for interior viewing.

• TREZIUM® Controller 3-D (250k file; right-click and select “Save As”)
• Requires the free eDrawings file viewer, available for download here.