A Space-Vector PWM Voltage-Source Inverter for a Three-Phase Induction Motor Based on the dsPIC30F3011

This paper presents the design and implementation of a voltage source inverter in the fixed point Digital Signal Processor (DSP) dsPIC30F3011. The space-vector pulse- width-modulated algorithm was used in the development of the three-phase three-wire IGBT inverter. A switching frequency of 18 kHz was employed and it is shown that a 30 MIPS DSP can handle the intensive computation required by the modulation algorithm, the speed measurement and the proportional-integral controller. To illustrate the application of the inverter, a scalar (V/f) closed-loop control scheme was successfully applied to an induction motor of: 0.5 HP, 220 V, 1800, 60 Hz.

I. Introduction

Advances in the last decade in power electronics and high performance digital processors have allowed a better electric power control in electrical machines. Most industrial processes require some form of adjustments or controls for their normal operation. These type of controls are normally achieved with the use of a variable speed drive (VSD). An electrical VSD system consists of the power converter, the electrical machine and the control system. The electrical machine is connected to the load; the power converter controls the power flow from the AC mains to the electrical machine by means of high speed power semiconductor switches and the controller generates the control signal needed to get the desired speed or torque reference. Voltage source inverters used in VSD, can also be found in railway propulsion systems applications, uninterruptible power supplies, induction heating, alternative power generation and active filters [1], [2]. The VSDs are also useful in recent investigation on multiphase electrical machines and sensorless control of induction motors [3], [4], [5].