Three-Phase Inverters With SiC MOSFET: A Key To Boosting Industrial Motor Efficiency

Industrial motors require reliable and efficient power solutions. This three-phase inverter, designed with Silicon Carbide (SiC) MOSFET technology, represents a significant step forward in meeting the power and efficiency demands of modern industrial applications. SiC MOSFETs are recognized for their lower on-resistance and higher breakdown voltage, making them ideal for high-voltage, high-efficiency applications. This article presents the inverter's specifications, key components, and operational features.

1. Key Specifications

This three-phase inverter is structured to optimize power conversion with a robust high-voltage output:

Input and Output Ratings: The inverter accepts a three-phase AC input of 340-440V, with a current handling capacity of up to 16A. The DC output range is 530-600V, supporting efficient power conversion for industrial motors.

Control Power Supply: A 20V control power supply is fed to the inverter board to ensure consistent power management across the circuit.

Drive System and Cooling: The inverter employs a 2-stage drive system with a maximum switching frequency of 100 kHz. It includes cooling options for convection or forced air, ensuring stable performance under load.

Dimensions: The board measures 250x145 mm, featuring a four-layer structure for a compact footprint and a high power rating.

2. Core Components and Connectivity

The inverter consists of an AC-DC circuit board and an inverter board, each incorporating essential components tailored for high-power, reliable output:

SiC MOSFETs: The inverter utilizes Toshiba's TW045Z120C and TW045N120C SiC MOSFETs, enabling efficient switching at high voltages, which is critical for demanding industrial applications.

Gate Driver and Isolation Amplifier: The TLP5774H gate driver ensures fast and isolated gate control, while the TLP7820 isolation amplifier provides isolated sensing of motor phase currents and bus voltage. This isolation enhances the safety and accuracy of the motor control system.

Main Terminals:

AC Input and DC Output Terminals: These terminals allow the inverter to connect to the three-phase AC power source, output DC power, and manage the control power between the AC-DC and inverter boards.

Temperature Sensing and Fault Detection: Temperature monitoring ensures the SiC MOSFETs operate within safe limits, while fault detection mechanisms address issues like overcurrent, overvoltage, and overtemperature.

3. Operational Overview

The operational structure of this inverter includes essential connection points and fault protection mechanisms:

Gate Voltage Setting: Gate voltage jumpers are set to control the SiC MOSFETs in their on/off states. They can be configured for 18V (on-state) and -2V (off-state), enabling effective control of both high-side and low-side MOSFETs.

Fault Detection and Protection: The system is designed to handle various fault conditions, such as overcurrent, overvoltage, and high temperature. Under these conditions, the MOSFETs are automatically shut down to prevent damage, resuming operation when safe conditions are restored.

4. Efficiency and Practical Application

In efficiency testing, the inverter demonstrated a peak efficiency of 98.6% under optimal conditions-specifically, when driving a 2.2 kW motor with a 400V AC input and a 440V output. This high efficiency underscores the inverter's suitability for heavy-duty applications where energy savings and reliable performance are prioritized.

Toshiba's three-phase inverter utilizing SiC MOSFETs demonstrates advancements in industrial motor efficiency and safety. With its compact design, high efficiency, and built-in protection features, it provides a robust solution for powering modern industrial motors. SiC MOSFET technology ensures this inverter is future-proof, offering dependable support for high-voltage, high-performance applications.