An Input Voltage Sensorless Input Current Shaping Method for Three Level Three Phase High Power Factor Boost Rectifier

This paper proposes a simple digital control scheme to achieve high power factor operation for three level three phase boost rectifier. The controller uses a resistor emulator concept in discrete domain to shape the input current like the input voltage. It is based on fixed switching frequency, continuous conduction mode (CCM) operation of the converter. The control law is input voltage sensorless, as a result a phase locked loop (PLL) is not required. Structurally it is different from vector control type of control scheme because the controller works in the stationary reference frame and inner loop current regulators are not required. The PWM generation is based on symmetric space vector method. In each control period only six devices (including three complementary) change states. The switching frequency can therefore be half compared to the two level switching rectifiers for the same quality input current waveform. The details of the digital control algorithm has been explained for the hardware platform of Texas Instruments's DSP based unit TMS320F240 EVM