A compensation method for reducing the non-linearity caused by adc quantization effect of dc/dc converter

Abstract

A compensation method for reducing the non-linearity caused by the quantization effect of the DC / DC converter ADC, based on a buck-type DC / DC converter main topology module, a sample and hold module, an ADC module, a digital compensator, a digital pulse width modulation module and a driver In the closed-loop system composed of modules, the digital compensator is realized by Verilog language on FPGA. By establishing the z-domain model of the system, the parameter boundary of the integral gain Ki that ensures the stability of the system is obtained, so as to design a digital compensator that reduces the quantization effect of the ADC. The limitations and deficiencies of conventional digital compensators in ADC quantization are overcome, and the system can still have good stability under the condition that ADC quantization effect exists.

Description

technical field [0001] The invention relates to a Buck type digital DC / DC switching converter, in particular to a compensation method for reducing the non-linearity caused by the ADC quantization effect of a DC / DC converter. The compensation method can effectively reduce the impact of the quantization error of an analog-to-digital converter (ADC) impact on system stability. Background technique [0002] Digital control technology is increasingly widely used in switching power supplies. Compared with the traditional analog control method, it has the advantages of being programmable, less affected by parameter changes, reducing the number of external passive components, and easy to implement various advanced control and protection algorithms. Still, digital control technology can pose some problems. On the one hand, the sample-and-hold link in the digital control loop will increase the phase lag and reduce the stability of the system. On the other hand, the quantizers, name...

AI Technical Summary

Problems solved by technology

On the one hand, the sample-and-hold link in the digital control loop will increase the phase lag and reduce the stability of the system

On the other hand, the quantizers, i.e. the analog-to-digital converter (ADC) and digital pulse-width modulator (DPWM), introduce quantization errors that lead to limit cycle oscillations in the system

[0003] Due to the late start of the research and application of digital control technology, there are relatively few studies on nonlinear phenomena in digitally controlled DC-DC converters, which leads to the current digital compensator often ignoring the ADC quantization effect

However, with the continuous development of FPGA and DSP, high-resolution DPWM is becoming easier to implement, which makes the quantization effect of ADC further significant

Therefore, considering a digitally controlled DC-DC converter, this ADC quantization effect will have a greater impact on the system after analog-to-digital conversion

The usual digital compensator is the same as the compensator used in analog control. It is mainly dedicated to improving the system phase margin and ensuring the stability of the system, while ignoring the nonlinearity caused by the ADC quantization effect to the system.

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