| With the development of power electronics and digital control techniques, microprocessor based digital controlled DC/DC converters has received much attention in power electronic circuits. However, even high-performance microprocessor or digital processor (DSP) has some problems when applied in high-frequency PWM converters.This paper aimed at digital controlled high frequency converters. Firstly, the advantage and disadvantage of digital control in power electronics field is analyzed, and the main problems are advanced. The fact that the low resolution of digital PWM that will cause low output precision even unstable in the system is emphasized. Background of digital PWM is expounded, and different solutions for different applications are compared.A novel strategy of improving digital PWM resolution is put forward in the paper. The limit-cycle can be suppressed dramatically with the proposal algorithm. The quantization error is corrected in PWM module so that it will not propagate to the output directly. The theoretical analysis is verified by simulation and circuit experiment. A DSP controlled DC/DC converter can operate at 100kHz without precision degradation. |
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