Digital controller based on delta operator for high-frequency DC-DC switching converters

Both the stability and the control accuracy of digital controllers for DC-DC switching converters utilising shift operators severely degrade under high switching frequencies. This study presents a digital-proportion integration differentiation (D-PID) controller based on a delta operator for DC-DC converters with high switching frequencies. Both the stability and the control accuracy of the digitally controlled converters were effectively improved when using the delta operator instead of the shift operator. The hardware cost and the processing speed requirements were also considerably reduced. The performance advantages of such a D-PID controller were theoretically analysed, and then simulated using the Simulink platform. Finally, both the proposed D-PID controller and a conventional shift operator-based controller were implemented for DC-DC switching converters on a field-programmable gate array (FPGA) platform. The benefits of using the delta operator over the shift operator were experimentally verified, and the test results indicated that for the DC-DC switching converter with 2MHz switching frequency, better control accuracy can be obtained by using the delta operator than using the shift operator.