Control Strategies for Power Converters

This chapter deals with the control actions needed to keep a specific variable of the converter under control, for instance, in a motor drive system where the speed must be controlled electronically through a power converter, or in a circuit designed to correct the power factor actively. It presents some principles of the controllers for systems using power converters as actuators. The chapter also deals with a nonlinear control technique called hysteresis control, and highlights some advantages and disadvantages of this technique. It considers two applications: dc motor drive system and regulation of an ac variable. The classic linear controllers (P, PI, and PID) are presented for dc variables. The chapter presents a linear type of controller for ac variables. A more complex control technique is presented with a cascade strategy for systems dealing with control of two variables with different dynamic responses.