Build A System For Powering AC Induction MotorsThe Electric Vehicle （EV） Inverter project is a starting point for the conversion of a vehicle with a gas engine to one with an electric motor. The inverter was built using a control board and software based on Microchip Technologys MC-1 development board. The finished design can power a wide range of AC induction motors.The world is in the process of advancing alternative sources of energy， and the concept of electric vehicle （EV）conversion is becoming more and more popular. But anyone interested in this concept will discover that the process of converting a gas-powered vehicle to electric power is fairly cost-prohibitive. This challenge led instructors in the Electronics Engineering Technology program at Camosun College in Victoria， BC， to pitch the idea of an opensource EV conversion kit to our class to take on as our final project. We accepted and the EV Drive Team was formed.The open-source concept of an EV design has numerous benefits， such as accessibility， cost， and advancement. You should be able to easily obtain all of the inverters components（if not purchase an assembled system）， and once constructed，it will be able to power a wide range of AC induction motors （ACIMs）。 Obtaining a typical three-phase highpower inverter for driving an ACIM can cost between $8，000 and $25，000. In this article， we will present a costeffective method of applying an alternative source of energy. Any technically minded person should be able to complete this project for around $2，500.Our inverter was constructed with a control board and software based on Microchip Technologys MC-1 development board and three dual-IGBT modules with gate driver boards from Powerex. We used these development tools to build a basic 100-kW three-phase inverter in an opensource process，which can be continually improved on.All of the inverters components of the inverter design are off-the-shelf units readily available at several electronics distributors. The parts are subject to change if the open-source design is modified to suit a users needs or improved by advancing technology. This aspect of the inverters design provides for the non-restrictive application of the system. It gives you the freedom to choose a motor that was not originally designed for a vehicle. For example，we used an ACIM that was intended to drive an elevator.The ACIM is the simplest and most rugged electric motor. It consists of two basic electrical assemblies： the wound stator and the rotor assembly. The outer stationary stator consists of coils that are supplied with an AC current to produce a rotating magnetic field. The inner non-stationary rotor revolves as a result of the torque that is created by the rotating magnetic field. The induction AC motor derives its name from currents flowing in the rotor that are induced by alternating currents flowing in the stator.You can control the speed of an ACIM by varying the frequency and amplitude of the drive voltage. Early configurations of drives used SCRs fired at the appropriate times to create an unsophisticated sinusoidal input waveform. As the semiconductor industry evolved， SCRs were replaced with MOSFET or IGBT devices， which are more efficient than the SCR， and could be switched at higher frequencies to continuously generate variable-drive voltages and currents that closely resemble a sinusoidal waveform.The AC current that is supplied to the stator， which produces the rotating magnetic field， can be controlled by a PWM algorithm that directly influences the speed of the rotating field and the output RPM of the rotor. We used a PWM technique known as space vector modulation.POWER INVERTERPowerex CM400DU-12F insulated gate bipolar transistor（IGBT） modules and their companion BG2B gate-driver circuits provide a relatively low-cost method for generating three-phase AC power from DC power.1 The DC power from the EV battery pack is converted to three-phase AC to drive an AC induction motor. We configured each phase of the IGBT module design with RCD snubber protection （see Figure 1）。2 The gate driver circuit can be seen in the application note for the BG2B universal gate drive board from Powerex using two VLA106-15242 DC/DC converters and two VLA503-01 gate drivers.3 The gate driver boards are recommended by Powerex for use with the dual-IGBT modules and provide 2，500 VRMS of control signal isolation via high-speed optocouplers and desaturation detection to prevent short-circuit conditions on the IGBTs. The CM400DU-12F modules are rated with a collector-emitter voltage of 600 V and a continuous emitter current of 400 A with a peak rating of 800 A. The modules are able to provide switching speeds of up to 30 kHz， we used 20 kHz. The frequency range promotes efficient operation of the spatial vector modulation （SVM） algorithms used to drive the IGBTs and bring the switching noise out of audible range.Because the