Control algorithm capable of effectively improving PFC dynamic response

Abstract

The invention relates to a control algorithm capable of effectively improving PFC dynamic response. Specifically, the invention relates to the digital power supply field. The control algorithm employsa bridge PFC, and a double-power-frequency band elimination filter H(s) is added to a voltage feedback end of the bridge PFC. A load current feedforward control component Vload_ctrl is added to the output end of a voltage loop feedforward controller of the bridge PFC. The double-power-frequency band elimination filter H(s) is used for expanding the bandwidth of a voltage loop, thereby improving the dynamic response of the whole control system, and keeping a power factor value unchanged; the load current feedforward control component Vload_ctrl is used for enabling the system to reach a new state of input and output power balance in a short time when disturbance occurs to the load. According to the invention, the algorithm can effectively improve the dynamic response under the condition that the power factor is not weakened, the reliability and stability of the AC-DC power supply are enhanced, and the method has certain reliability and practicability.

Description

technical field [0001] The invention relates to the field of digital power supplies, in particular to a control algorithm capable of effectively improving the dynamic response of PFC. Background technique [0002] Whether the existing PFC technology adopts linear or nonlinear control algorithms, there is a contradiction between power factor and dynamic response, that is, while the power factor is improved, the dynamic response performance is weakened; the dynamic response is enhanced, and the power factor But it fell because of it. [0003] Generally, the control scheme of AC-DC power supply is to build a double closed-loop control form in which the outer loop of the bus voltage is connected in series with the inner loop of the input current, that is, the output of the voltage loop calculation is used as a reference value for the current loop calculation, and the function of the voltage loop is mainly to stabilize the PFC bus voltage. However, the second harmonic component ...

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Problems solved by technology

[0003] Generally, the control scheme of AC-DC power supply is to build a double closed-loop control form in which the outer loop of the bus voltage is connected in series with the inner loop of the input current, that is, the output of the voltage loop calculation is used as a reference value for the current loop calculation, and the function of the voltage loop is mainly to stabilize the PFC bus voltage. However, the second harmonic component doped in the bus voltage will be introduced into the current inner loop through the output of the voltage loop, which will cause the input current to be doped with the third harmonic component and affect the power factor value of the power supply. Traditionally, the third harmonic component should be avoided. The best method is to reduce the bandwidth of the voltage loop as much as possible, so as to ensure that the input current will not be too much mixed into the third harmonic, thereby effectively improving the power factor value, but this method is at the expense of the dynamic response of the voltage loop. Extremely unstable against external disturbances, especially load disturbances

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