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Digital current hysteresis tracking control method for BUCK converter

A technology of current hysteresis and tracking control, which is applied in the direction of converting DC power input to DC power output, control/regulation systems, instruments, etc., and can solve problems such as unfixed switching frequency and difficulties in designing filters on the output side of power converters. Achieve the effect that the digital algorithm is simple and easy to implement

Inactive Publication Date: 2021-05-28
江苏奥文仪器科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, one of the main disadvantages of the traditional hysteresis current controller with fixed loop width is that the switching frequency is not fixed, which makes the design of the filter on the output side of the power converter difficult.

Method used

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  • Digital current hysteresis tracking control method for BUCK converter
  • Digital current hysteresis tracking control method for BUCK converter
  • Digital current hysteresis tracking control method for BUCK converter

Examples

Experimental program
Comparison scheme
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Embodiment 1

[0045] In this embodiment, a digital current hysteresis tracking control method for a BUCK converter includes:

[0046] S1: The current value is measured, and the current value of the filter inductor of the BUCK converter is obtained by sampling through the sampling module;

[0047] S2: Calculate the error current e i ;

[0048] S3: Use a zero-crossing comparator to generate a logic flag signal S for the zero-crossing point of the error current i ,

[0049] S4: Timing for its adjacent zero-crossing error current, that is, at S i During the high level period, use Timer 1 to time its adjacent zero-crossing error current; i During the low-level period, use Timer 2 to time its adjacent zero-crossing error current;

[0050] S5: Calculate the hysteresis upper / lower threshold of the current switching cycle; that is, use the timer 1 timing value to calculate the hysteresis upper threshold of the current switching cycle; use the timer 2 timing value to calculate the hysteresis low...

Embodiment 2

[0075] A digital current hysteresis control system based on FPGA, comprising a first unit for calculating the current hysteresis upper / lower threshold value according to the sampled inductor current; a second unit for setting the current hysteresis upper / lower threshold The threshold value is compared with the error current to generate the switching signal of the power device to realize the current tracking control;

[0076] Among them, the first unit includes: ADC sampling control module, used to sample the inductor current; error current calculation module, subtracting the reference current from the inductor current to obtain the error current; error current zero-crossing comparison module, using the error current zero-crossing point Generate timing control logic signals at all times; two timing modules are used to calculate the corresponding upper / lower thresholds;

[0077] The second unit includes: a hysteresis comparison module, which is used to compare the magnitude of t...

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Abstract

The invention discloses a digital current hysteresis tracking control method for a BUCK converter. The method comprises the steps of sampling by a sampling module to obtain a current value of a filter inductor of the BUCK converter; calculating an error current ei; generating a logic marking signal Si of an error current zero-crossing point by adopting a zero-crossing comparator, and timing the adjacent error current zero-crossing point; calculating a hysteresis upper / lower threshold value of the current switching period, that is, calculating a hysteresis upper threshold value of the current switching period by using a timing value of a timer 1; and calculating a hysteresis lower threshold value of the current switching period by using a timing value of a timer 2; and comparing the error current obtained in the step 2 and the step 5 with the hysteresis upper / lower threshold value in real time to generate a PWM control signal. By adopting the control method, the unstable switching frequency caused by the conditions of input voltage change, load change and the like is avoided, and the working stability of the whole system is improved; the digital algorithm is simple and easy to implement; and the method can be applied to a voltage control mode, and further popularization and application are facilitated by combining the characteristics of the control mode.

Description

technical field [0001] The invention belongs to the technical field of power electronics, in particular to a digital current hysteresis tracking control method for a BUCK converter. Background technique [0002] PWM converters based on current tracking control have a very wide range of applications, such as active power filters, motor drives, grid-connected inverters, and high-performance power converters. The quality of the current controller determines the performance of the entire control system. According to the research reports of scholars at home and abroad, it can be seen that the research of current controller mainly includes two aspects: (1) linear PI controller; (2) hysteresis controller. The linear PI current controller can keep the switching frequency of the system fixed; however, in order to balance the stability and fastness of the system, the parameters of the linear PI current controller must be strictly designed, which will cause the system dynamic response...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02M3/157
CPCH02M3/157
Inventor 毛惠丰武文英乔涛曹海峰
Owner 江苏奥文仪器科技有限公司