Portable Electrical Tool's Frequency Control And Speed Adjustment System Design

Portable electrical tools are always widely used in all areas of our daily living and industrial producing. What we will introduce to you in this paper is such a set of the frequency control and speed adjustment device which is mainly designed for the purpose of driving some tools like portable electrical drills, electrical saws and so on,This paper make a detailed and full description to the design plan and the concrete operation, and mainly including a lot of items as follows. Rectifying and starting with a limited currency circuit, half-bridged switching power supply circuit which is formed by IR2153, the controller board formed by dsPIC30F2010, power inverting circuit by PS21564 IPM, and also some other interfacing part such as display, input, and 232 communication. In software, the leading task is the realization of the SPWM controlling algorithm with the controller dsPIC30F2010, and also including the AD, display and some other subprograms.This design resolves some problems as follows.(1) Made a analysis to the particularity of the frequency control and speed adjustment device used in portable electrical tools, and also made a contrast and reasoning to the whole system with a full consideration to the special requirements like weight, volume, cost, reliability and bad working environment.(2) Made a contrast to some kinds of controller and hardware topology, and finally chose the dsPIC30F2010 as controller chip while the PS21564 served as the power inverting module, this combination reduce the system cost greatly and can perform well to satisfy those special requirements too.(3) With consideration to the real need of the whole part, we chose the SPWM as the core control algorithm, and it proves that this choice make use of the hardware fully and perform excellently.(4) Almost all kinds of protecting applications are used in this system, they include the voltage/currency protect both in the DC and load side, and also the overvoltage, undervoltage and temperature protect too. These measures maximize the reliability and security.