CN-122026692-A - Self-adaptive input converter circuit topology structure and control method

CN122026692ACN 122026692 ACN122026692 ACN 122026692ACN-122026692-A

Abstract

The invention discloses a self-adaptive input converter circuit topology structure and a control method, and relates to the technical field of power electronics. The invention comprises a front-stage reconstruction bridge arm circuit, a rear-stage inverter circuit and a control module, wherein the front-stage reconstruction bridge arm circuit is used for switching into an AC-DC rectification mode or a DC-DC boost mode according to an AC or DC input type, the rear-stage inverter circuit is cascaded behind the front-stage reconstruction bridge arm circuit and is used for inverting direct current output by the front-stage reconstruction bridge arm circuit into stable alternating current, and the control module is used for dynamically modulating a switching signal according to the AC or DC input type and realizing mode switching by controlling the closing and the conduction of a switching tube. The invention can realize seamless switching of AC/DC input according to the mode of switching the input power supply to AC or DC rapidly, ensures the continuity and stability of power supply of the system, solves the problem that the existing single-input type converter cannot realize normal operation under the AC/DC mixed input scene, and reduces the switching loss.

Inventors

ZHAO CHENGXUAN
LIU HAO
GAO JIUZHI

Assignees

安徽理工大学

Dates

Publication Date: 20260512
Application Date: 20260204

Claims (10)

1. An adaptive input converter circuit topology, comprising: The front-stage reconstruction bridge arm circuit is used for switching to an AC-DC rectification mode or a DC-DC boost mode according to an AC or DC input type, switching to the AC-DC rectification mode when the AC type is input, and switching to the DC-DC boost mode when the DC type is input; the back-stage inverter circuit is cascaded behind the front-stage reconstruction bridge arm circuit and is used for inverting the direct current output by the front-stage reconstruction bridge arm circuit into stable alternating current; and the control module is used for dynamically modulating a switching signal according to the alternating current or direct current input type and realizing the switching between an AC-DC rectification mode and a DC-DC boosting mode by controlling the closing and the conduction of the switching tube.
2. The circuit topology of claim 1, further comprising an input detection module, disposed at the input port, for identifying an ac or dc input type according to a rate of change of amplitude and a frequency characteristic of the input voltage, wherein the specific judgment principle is as follows: If the amplitude change rate of the input voltage exceeds a threshold value and periodic frequency characteristics exist, judging that the input voltage is AC input; and if the amplitude change rate of the input voltage is continuously lower than the threshold value, judging that the input voltage is the direct current input.
3. The circuit topology of claim 2, wherein the pre-stage reconstruction bridge arm circuit comprises four IGBT switching tubes, Q1, Q2, Q3, Q4, a signal switch and an inductor L1; Wherein: the emitter of the Q1 is connected with the collector of the Q2 and the inductor; the collector of Q1 is connected with the collector of Q3; The emitter of Q3 is connected with the collector of Q4; the emitter of Q2 is connected to the emitter of Q4 when the input is dc, and changes to be connected to the collector of Q4 when the input is ac.
4. The circuit topology of claim 3, wherein the input end of the back-stage inverter circuit is connected with the output end of the reconfigurable bridge arm circuit, and the back-stage inverter circuit comprises four fully-controlled IGBT switching tubes Q5, Q6, Q7, Q8, an inductor L2, a capacitor C2 and a load R2; Wherein: The Q5 collector and the Q6 collector are commonly connected with the positive electrode of the direct current bus, and the Q7 emitter and the Q8 emitter are commonly connected with the negative electrode of the direct current bus; The collector electrode of the Q5 emitter is connected with the output positive electrode; The Q6 emitter is connected with the Q8 collector and is connected with the output cathode; the inductor L2 and the capacitor C2 form an LC filter, and the load R1 is connected to the alternating current output end through the LC filter and used for stabilizing the output voltage of the load R1 end.
5. An adaptive input converter circuit topology as recited in claim 4, wherein said signal switch has two operating positions: when the position 1 is closed, the collector electrode of the Q2 is directly connected with the input anode to form an AC-DC full-bridge rectification mode; When position 2 is closed, the collector of Q2 is grounded, and Q1 and Q2 form a BOOST circuit by using a flywheel diode.
6. The circuit topology of an adaptive input converter of claim 5, wherein a load R1 is further disposed between the front-stage reconstruction bridge arm circuit and the rear-stage inverter circuit, a capacitor C1 is connected in parallel with the front of the load R1 for filtering, and a diode D1 is connected with the rear of the load R1 for controlling mutual impact between the front-stage reconstruction bridge arm circuit and the rear-stage inverter circuit.
7. The circuit topology of an adaptive input converter of claim 6, wherein an anode of said diode D1 is connected to an intersection of an inductor L1 and a positive electrode of a capacitor C1, and a cathode of said diode D1 is connected to a positive electrode of a DC bus for blocking reverse current surge.
8. An adaptive input converter circuit topology as recited in claim 1, wherein said control module controls a strategy in a DC-DC boost mode of: the signal switch is switched to a position 2, so that the collector electrode of the Q2 is grounded, the switching tubes Q1, Q3 and Q4 are turned off, and the freewheeling diode of the switching tube Q1 is turned on to form a BOOST loop; And the PWM duty ratio of the Q2 is dynamically regulated by the PI controller, so that the direct-current voltage is boosted to a target value.
9. The adaptive input converter circuit topology of claim 8, wherein said control module controls a strategy in an AC-DC rectification mode of: The signal switch is switched to a position 1, and the switching tubes Q1-Q4 are conducted to form a PWM rectifier bridge; the output voltage is regulated by an outer loop PI controller, and the inner loop PI controller tracks the input current waveform to generate PWM driving signals of the switching tubes Q1-Q4.
10. The control method of the circuit topology structure of the self-adaptive input converter is characterized by comprising the following steps: S1, identifying an alternating current or direct current input type according to an input detection module, and judging that the alternating current input is performed if the amplitude change rate of the input voltage exceeds a threshold value and the periodic frequency characteristic exists; S2, determining a control mode according to the input type of direct current or alternating current and executing corresponding control operation, wherein the control mode specifically comprises a DC-DC boosting mode and an AC-DC rectifying mode: s21, when the DC-DC boosting mode is in, the control steps are as follows: (S21.1) calculating a difference between the output voltage reference value V and the actual output voltage value V0; (S21.2) processing the calculated difference value through a proportional-integral controller to obtain a duty ratio signal for dynamically adjusting the switching tube Q2; (S21.3) directly transmitting the duty ratio signal to the PWM module in the simulink to compare the PWM signals for controlling the Q2 switch; s22, when the AC-DC rectification mode is in, the control steps are as follows: (S22.1) calculating a difference between the output voltage reference value V and the actual output voltage value V0; (S22.2) processing (S22.1) the calculated difference value by the first proportional-integral controller to obtain a reference deviation of the duty cycle; (S22.3) multiplying the input voltage by a gain and by a reference deviation, and then comparing with the input current to calculate a difference; (S22.4) processing (S22.3) the difference calculated in the second proportional-integral controller and generating PWM control signals for controlling the switches Q1 to Q4 after comparing with the fundamental wave; S3, inputting the direct current output by the front-stage reconstruction bridge arm circuit into a rear-stage inversion circuit, and inverting the direct current into stable alternating current, wherein the method comprises the following steps of: (S31) measuring the voltage of the output load and calculating the root mean square thereof, and comparing the calculated root mean square value with the ideal value to obtain a difference value: (S32) inputting the difference value obtained in (S31) to a proportional-integral controller, and multiplying the difference value by a sine wave to generate a modulation signal; (S33) comparing the modulated signal obtained in (S32) with a triangular carrier wave to generate an SPWM wave to achieve a stable AC output.

Description

Self-adaptive input converter circuit topology structure and control method Technical Field The invention relates to the technical field of power electronics, in particular to a self-adaptive input converter circuit topology structure and a control method. Background With the diversification development of energy systems and the large-scale application of power electronic devices, the converter needs to have the capability of simultaneously adapting to Alternating Current (AC) and Direct Current (DC) inputs, and meanwhile, needs to ensure the stability of self output. This requirement is particularly pronounced in the context of light storage and charging integrated power stations, mobile emergency power supplies, industrial general power supplies and the like, because these systems often require flexible access to a variety of power supplies such as grid alternating current, photovoltaic direct current or battery pack direct current. However, conventional converters generally process only a single type of input, such that there is a limit to the interconversion of dc and ac in the same system, and the type of output is relatively fixed and single. When the power supply source is switched between alternating current and direct current, the prior art either relies on a mechanical relay to perform physical switching but the mode is easy to generate electric arc and power interruption, and two converter cascading schemes can be adopted, but the combination also has obvious defects that the rectifier bridge generates extra loss during direct current input and causes current waveform distortion during alternating current input. These problems directly affect the reliability and efficiency of the hybrid power supply system. For example, in an optical storage charging system, when a photovoltaic direct current and a grid alternating current need to be switched seamlessly, the response delay of the existing converter may cause restarting of equipment or energy waste, and therefore, the invention provides a circuit topology structure and a control method of an adaptive input converter. Disclosure of Invention The invention aims to provide a circuit topology structure and a control method of a self-adaptive input converter, which are used for realizing automatic identification and seamless switching of input types by detecting the intelligent switching of the input types, so that single-circuit compatible AC/DC input is realized, the input types are automatically identified and the working modes are switched, redundant rectifying devices are eliminated, the switching loss is optimized through a dynamic modulation strategy, the efficiency of the whole converter is improved, and the problem that the conventional single-input type converter cannot realize normal operation under an AC/DC mixed input scene is solved. According to a first aspect of the present invention, to achieve the above object, the present invention provides a circuit topology of an adaptive input converter, including: The front-stage reconstruction bridge arm circuit is used for switching to an AC-DC rectification mode or a DC-DC boost mode according to an AC or DC input type, switching to the AC-DC rectification mode when the AC type is input, and switching to the DC-DC boost mode when the DC type is input; the back-stage inverter circuit is cascaded behind the front-stage reconstruction bridge arm circuit and is used for inverting the direct current output by the front-stage reconstruction bridge arm circuit into stable alternating current; and the control module is used for dynamically modulating a switching signal according to the alternating current or direct current input type and realizing the switching between an AC-DC rectification mode and a DC-DC boosting mode by controlling the closing and the conduction of the switching tube. Further, the device also comprises an input detection module, which is arranged at the input port and is used for identifying the type of alternating current or direct current input according to the amplitude change rate and the frequency characteristic of the input voltage, wherein the specific judgment principle is as follows: If the amplitude change rate of the input voltage exceeds a threshold value and periodic frequency characteristics exist, judging that the input voltage is AC input; and if the amplitude change rate of the input voltage is continuously lower than the threshold value, judging that the input voltage is the direct current input. For the technical scheme of this embodiment, the front-stage reconstruction bridge arm circuit includes four IGBT switching tubes, which are Q1, Q2, Q3, Q4, a signal switch, and an inductor L1, respectively; Wherein: the emitter of the Q1 is connected with the collector of the Q2 and the inductor; the collector of Q1 is connected with the collector of Q3; The emitter of Q3 is connected with the collector of Q4; the emitter of Q2 is connected to the emitter of Q4 when th