ABSTRACT
This chapter is devoted to describing various motor controls and switching of high-voltage control devices. The design examples include relay and DC motor control; AC motor and brushless DC (BLDC) motor control; stepper motor systems; automatic fuel level (solenoid valve) control; voltage and current measurement; power electronic, i.e., solid state, switches: thyristor/SCR, Triac and Diac; and real-time process control. The significance, design and working principles of different types of relays, solenoid valves, opto-isolators and DC motors are explained, with construction diagrams and design examples. The construction differences between DC, servo and BLDC motors; working principles of a BLDC motor and design examples for interfacing it with the FPGA are described. The design of different pole stepper motors, direct/electric drive stepper motors and full/micro step angle stepper motors are explained, with circuits and illustrations. The design of a liquid level measurement system and working principles of the fuel level indicator/controller are presented through which the readers will come to know the different methodologies of liquid level measurement techniques. A simple method of measuring voltage and current using voltage and current transformers is presented, with design examples. Controlling of AC signal using the SCR, Triac and Diac is presented, with simple control examples. This chapter ends with a process control example and laboratory exercises.
