CN-115001242-B - Control modeling method of variable frequency modulation power supply

CN115001242BCN 115001242 BCN115001242 BCN 115001242BCN-115001242-B

Abstract

The invention discloses a control modeling method of a variable frequency modulation power supply in the field of power electronics, which comprises the following steps of 1) controlling a difference value between an output voltage sampling signal of the variable frequency modulation power supply and an output given voltage to a voltage ring controller, 2) establishing a control-to-output current transfer function, inputting a periodic control signal output by the voltage ring controller to the output current transfer function to obtain an output current signal, and 3) establishing a current-to-voltage transfer function, inputting the current-to-voltage transfer function to the output current signal of the output current transfer function to obtain an output voltage signal of the variable frequency modulation power supply, and obtaining the sampling signal of the output voltage by the output voltage signal of the variable frequency modulation power supply through feedback gain.

Inventors

FANG YU
WANG XIAOFEI
MENG FEI
Ju Yuyan
Shu Kaixin
TENG JIAN
GU QIUYANG
Zhuge yang
CAO SONGYIN

Assignees

扬州大学

Dates

Publication Date: 20260505
Application Date: 20220715

Claims (4)

1. The control modeling method of the variable frequency modulation power supply is characterized by comprising the following steps of: step 1), controlling a difference value between a sampling signal of the output voltage of the variable-frequency modulation power supply and an output given voltage to be sent to a voltage ring controller; Step 2) establishing a transfer function from control to output current, and inputting a periodic control signal output by the voltage loop controller to control the transfer function to the output current to obtain an output current signal; Step 3) establishing a current-to-voltage transfer function, controlling an output current signal to an output current transfer function to input the current-to-voltage transfer function, and obtaining an output voltage signal of the variable frequency modulation power supply, wherein the output voltage signal of the variable frequency modulation power supply obtains a sampling signal of the output voltage through feedback gain; The control-to-output current transfer function comprises a PFM modulation period gain and a current closed loop transfer function, wherein a period control signal output by the voltage loop controller is input into the PFM modulation period gain to obtain a period duty cycle signal, and the period duty cycle signal is subjected to the current closed loop transfer function to obtain an output current signal; the current closed loop transfer function comprises a duty ratio-to-output current transfer function and a current error-to-duty ratio transfer function, wherein the duty ratio-to-output current transfer function receives a periodic duty ratio signal and outputs two paths of current signals, the difference value between one path of current signal and a reference current is sent to the current error-to-duty ratio transfer function and then outputs a disturbance duty ratio signal, and the other path of current signal is input into the current-to-voltage transfer function; The transfer function from the current error to the duty ratio comprises a transfer function from the error current to the on time and PFM modulation on gain, the transfer function from the error current to the on time receives a path of current signal output from the duty ratio to the output current transfer function, and a on time signal of a switching tube in the variable-frequency modulation power supply is obtained, and the on time signal outputs a disturbance duty ratio signal through the PFM modulation on gain; respectively designing a PFM modulation period gain and a PFM modulation conduction gain in a control-to-output current transfer function model: Deriving a periodic signal output by the voltage loop controller to obtain a periodic duty cycle signal, deriving a transfer function from the period to the duty cycle, and establishing a PFM modulation period gain model; conducting time disturbance signals caused by the peak current errors are derived, disturbance duty ratio signals can be obtained, so that transfer functions from the peak current errors to the duty ratios are deduced, and a PFM modulation conducting gain model is established; the PFM modulation conducting gain model, the transfer function from the duty ratio to the output current and the transfer function from the error current to the conducting time are used for deriving a current closed loop transfer function; and deducing a control-to-output current transfer function from the PFM modulation period gain and the current closed loop transfer function, thereby establishing a control model of the peak current inner loop.
2. The control modeling method of a variable frequency modulated power supply according to claim 1, wherein the duty cycle To output current Is a transfer function of (2) The method comprises the following steps: Electric current To voltage Is a transfer function of (2) The method comprises the following steps: Transfer function of error current to on-time : Wherein V I is input voltage, N is the turn ratio of the primary winding and the secondary winding of the transformer, D is the direct current component of the duty ratio, C is the energy storage capacitor, R is the load resistor, and L is the secondary inductance of the transformer.
3. The method for modeling control of a variable frequency modulated power supply of claim 2, The PFM modulation period gain KT PFM (s) is: The PFM modulation on-gain KO PFM (s) is: Wherein, V O is output feedback voltage, T on is voltage regulator on time, V c is voltage regulator output voltage, rs1 is controller divider resistor, rs2 is FB pin internal resistor, C Ct is oscillation capacitor, C TR is FB pin built-in capacitor, and I Ct is CT pin chip internal constant current source.
4. A control modeling method of a variable frequency modulated power supply as claimed in claim 3, wherein the voltage loop controller The method comprises the following steps: wherein, R 1 is the voltage controller input resistance, R 2 is the voltage controller feedback resistance, C 1 is the controller charging capacitance, and C 2 is the controller differential capacitance.

Description

Control modeling method of variable frequency modulation power supply Technical Field The invention relates to the technical field of power electronics and electrician, in particular to a control modeling method of a variable frequency modulation power supply. Background Flyback conversion circuits have been widely studied because of their compact structure, simple control, electrical isolation, high step-up ratio, and the like. In three-phase converter, photovoltaic energy storage and other systems, flyback conversion circuits are often used as wide-input and multi-output auxiliary power supplies. The conventional PWM (Pulse Width Modulation) modulation technology commonly used is used for fixing the switching period, adjusting the on time generates a duty cycle control signal, and the phenomenon of hiccup is often generated under the condition of light load, so that the efficiency is low, the regulation formulated by European Commission and European consumer electronics manufacturer association (EACEC) for consumer products is difficult to meet, and the maximum no-load power consumption of all power supply products is not more than 0.3W. The PFM (Pulse Frequency Modulation) modulation method generates a periodic duty ratio signal by Constant On Time (COT) and adjusting the switching period, and has the advantages of high light load efficiency, high transient response speed and the like. Therefore, the flyback converter for realizing the PFM control based on the NCP1351B controller is widely applied to a network router, a high-power grid-connected inverter and an energy storage device at present, and provides a multipath output auxiliary power supply for a control circuit, a sampling circuit, a driving circuit, a relay circuit and the like. The NCP1351B controller of Ansen America company is a current type control chip with fixed on time, which changes the switching period to realize PFM, has excellent conversion efficiency, and has excellent performance under light load and no-load conditions, and meets the design standard of green and energy conservation. However, the single primary side peak current control model of the variable frequency flyback power supply is inaccurate, so that control parameters are difficult to set. Disclosure of Invention Aiming at the defects existing in the prior art, the invention provides a control modeling method of a variable frequency modulation power supply, which solves the problem that control parameters are difficult to design caused by inaccurate control model of the current variable frequency flyback converter. The invention aims to realize the control modeling method of the variable frequency modulation power supply, which comprises the following steps: step 1), controlling a difference value between a sampling signal of the output voltage of the variable-frequency modulation power supply and an output given voltage to be sent to a voltage ring controller; Step 2) establishing a transfer function from control to output current, and inputting a periodic control signal output by the voltage loop controller to control the transfer function to the output current to obtain an output current signal; And 3) establishing a current-to-voltage transfer function, and controlling an output current signal to an output current transfer function to input the current-to-voltage transfer function to obtain an output voltage signal of the variable frequency modulation power supply, wherein the output voltage signal of the variable frequency modulation power supply obtains a sampling signal of the output voltage through feedback gain. As a further limitation of the present invention, the control-to-output current transfer function includes PFM modulation period gain and a current closed loop transfer function, and the period control signal output by the voltage loop controller is input into the PFM modulation period gain to obtain a period duty cycle signal, and the period duty cycle signal obtains the output current signal through the current closed loop transfer function. As a further limitation of the present invention, the current closed loop transfer function includes a duty cycle to output current transfer function and a current error to duty cycle transfer function, the duty cycle to output current transfer function receives a periodic duty cycle signal, outputs two current signals, one of which is sent to the current error to duty cycle transfer function and then outputs a disturbance duty cycle signal, and the other of which is input to the voltage transfer function. As a further limitation of the invention, the transfer function from the current error to the duty cycle comprises a transfer function from the error current to the on time and a PFM modulation on gain, the transfer function from the error current to the on time receives a current signal outputted from the transfer function from the duty cycle to the output current, and a conducting time signal of a switching tub