Double-loop control method and high-precision AC current source based on digital delta-sigma and pid

Abstract

The invention discloses a digital delta-sigma control method, a double-loop control method and a high-precision AC current source, belonging to the field of switching power supplies. The outer-loop PID control in the double-loop control method is: sampling and decoding target sampling points and digital PID adjustment ; The inner loop delta-sigma control is: carry out delta-sigma type AD sampling at the sampling point, obtain single-bit data stream, complete decoding when the number of digits of this data stream reaches M, and update the latest when each new one is added The M-bit data is filtered and decoded to obtain an effective sampling value. The inner loop control integrates and quantizes the difference between the sampling value and the output value of the digital PID device to obtain a control signal to control the switch circuit. The filtering algorithm is simplified to reduce the time delay. The noise shaping function of the delta-sigma ADC can ensure the accuracy of the sampling data in the middle and low frequency bands, and the error in the high-frequency band is filtered out by the integrator, which solves the problem of low sampling speed, large time delay and high precision of the existing digital delta-sigma control. low problem. Double-loop control can effectively improve the control precision and response speed of the system.

Description

Dual-loop control method and high-precision communication based on digital delta-sigma and PID current source technical field The invention belongs to the field of switching power supplies, more specifically, relate to a kind of digital delta-sigma control method, dual A loop control method and a high-precision AC current source. Background technique [0002] High-precision AC power has important applications in precision manufacturing, precision measurement and medical fields. Among them, the switch It is difficult to achieve high accuracy due to the dead-band error of the source, the error generated by the output filter, etc. The current traditional high-precision PWM type The current source adopts analog control, which has poor portability and has certain design difficulties. In addition, analog-style delta‑ sigma modulation can effectively suppress the dead zone to achieve high-accuracy AC power, but analog control is easy when the power is large The accurac...

AI Technical Summary

Problems solved by technology

[0004] Aiming at the defects and improvement needs of the prior art, the present invention provides a digital delta-sigma control method, a double-loop control method and a high-precision AC current source, and its purpose is to solve the problem of low sampling speed in the existing digital delta-sigma control , large time delay and low precision

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