Digital control synchronous current-doubling rectification full-bridge soft switching constant voltage power supply

Abstract

The invention provides a digital control synchronous double-current rectification full-bridge soft switching constant-voltage power supply which comprises a full-bridge inverter circuit, a transformer T, a double-current rectification circuit and a control circuit. The full-bridge inverter circuit is composed of a direct-current power supply VDC, a leakage inductor Lr, a transformer primary coil Np and main power tubes Q1, Q2, Q3 and Q4; the transformer T is composed of a leakage inductor Lr, an excitation inductor Lm, a primary coil Np, an iron core T and a secondary coil Ns; the current doubling rectifying circuit is composed of a secondary coil Ns, synchronous rectifying tubes QS1 and QS2, an output inductor Lf1, an output inductor Lf2, an output capacitor Co and a load Ro; the control circuit is used for providing a main power tube control signal and a synchronous rectifier tube control signal.

Description

Technical Field

[0001] The invention relates to the technical field of switching power supplies, in particular to a digitally controlled synchronous current-doubling rectifier full-bridge soft-switching constant-voltage power supply. Background Art

[0002] With the rapid development of electronic information technology, miniaturized and integrated electronic devices are emerging in an endless stream. Electronic devices in fields such as the Internet of Things, industrial electronics, and automotive electronics present both opportunities and challenges. This has led to widespread attention in the integrated circuit field regarding power management technology. At the same time, the increasing diversification of electronic product functionality and miniaturization are also raising the performance and application requirements of power supplies to an even more stringent level.

[0003] Switching power supplies (SMPS) control the energy transfer and conversion process by periodically switching the power switches in the system, thereby adjusting the output voltage. These power supplies offer significant advantages, including compact size, low power consumption, high efficiency, and a wide adjustment range. In high-power isolated applications, full-bridge converters offer higher efficiency, lower voltage and current stresses, better electromagnetic compatibility, and higher transformer utilization compared to other common switching power supply topologies. Full-bridge converters also facilitate soft switching, reducing switching losses at high frequencies. Therefore, achieving higher efficiency in switching power supplies necessitates the implementation of soft switching and synchronous rectification technologies.

[0004] Switching power supplies have different operating characteristics under different operating conditions. When the system operates in DCM, the conversion efficiency is high, but the inductor current ripple is large. When the system operates in CCM, the conversion efficiency is lower than DCM, and the inductor current ripple can be controlled to less than 10% of the current flowing through it.

[0005] For switching power supplies operating at high frequencies, the three main loss sources are snubber circuit losses, secondary rectifier reverse conduction losses, and switching losses. The switching losses of the switching power supply's switches are proportional to the operating frequency, significantly impacting the power supply's efficiency. Therefore, reducing the switching losses of the converter's switches is crucial. Summary of the Invention

[0006] In response to the above technical problems, the present invention provides a digitally controlled synchronous current-doubling rectifier full-bridge soft-switching constant-voltage power supply, which can achieve zero-voltage turn-on for all switching tubes of the circuit system type, reducing the turn-on loss in the switching power supply to 0. The control part of the present invention uses a phase-shift control algorithm, and by adding dead time and phase-shift control methods, the resonant inductor and the junction capacitance of each main power tube resonate within the dead time, thereby discharging the junction capacitance of each main power tube. When the charge stored in the junction capacitance of each main power tube is zero, the voltage across each main power tube is zero. At this time, turning on the main power tubes separately can achieve zero-voltage turn-on (ZVS) of each switching tube of the leading bridge arm and the lagging bridge arm of the primary-side full-bridge inverter circuit. In the topology structure based on the current-doubling rectifier circuit, the secondary-side rectifier circuit uses Sic-MOSFET as a synchronous rectifier tube instead of a rectifier diode. During the power supply's soft-start phase, the synchronous rectifier's body diode replaces the rectifier diode. After the power supply starts normally, when the voltage at the secondary winding's common-signal terminals is positive, synchronous rectifier 1 turns on and synchronous rectifier 2 turns off. Similarly, when the voltage at the secondary winding's common-signal terminals is negative, synchronous rectifier 2 turns on and synchronous rectifier 1 turns off. Due to the duty cycle loss characteristic of the phase-shifted full-bridge topology, the secondary winding shorts before the secondary synchronous rectifier turns on. This creates a resonant circuit between the output capacitor, the synchronous rectifier's junction capacitance, and the secondary winding, charging the output capacitor to the synchronous rectifier's junction capacitance. When the main power transistor turns on again, energy from the primary side begins to transfer to the secondary winding, causing the secondary winding voltage to rise. At this point, the synchronous rectifier remains closed, and a resonant circuit between the secondary winding, the synchronous rectifier's junction capacitance, and the output capacitor forms a reverse discharge. When the secondary winding voltage rises to equal the output voltage, the synchronous rectifier's drain voltage equals the source voltage. Turning on the synchronous rectifier at this time can achieve zero voltage turn-on (ZVS) of the synchronous rectifier and reduce system switching losses.

[0007] To achieve the above object, the present invention provides the following technical solutions: a digitally controlled synchronous current-doubling rectifier full-bridge soft-switching constant-voltage power supply, comprising a primary full-bridge inverter circuit, a transformer T, a current-doubling rectifier circuit, and a control circuit; The primary full-bridge inverter circuit is powered by a DC power supply V DC , input capacitor C IN , leakage inductance L r 、Transformer primary coil N p , main power tube Q1, main power tube Q2, main power tube Q3, main power tube Q4; Among them, the DC power supply V DC Positive electrode and input capacitor C IN The positive pole is connected to the DC power supply V DC Negative electrode and input capacitor C IN The negative electrode is connected to the primary reference ground, and the drain of the main power tube Q1 is connected to the DC power supply V DCThe positive electrode is connected to the source of the main power tube Q2 and the DC power supply V DC The negative pole is connected, the source of the main power tube Q1 is connected to the drain of the main power tube Q2 to form a leading bridge arm, and the drain of the main power tube Q3 is connected to the DC power supply V DC The positive electrode is connected to the source of the main power tube Q4 and the DC power supply V DC The negative poles are connected, the source of the main power tube Q3 is connected to the drain of the main power tube Q4 to form a lagging bridge arm, and the leakage inductance L r The left end is connected to the connection node of the source of the main power tube Q1 and the drain of the main power tube Q2, and the leakage inductance L r The right end is connected to the primary coil N of the transformer p The same-name terminals are connected, and the transformer primary coil N p The opposite-name terminal is connected to a connection node between the source of the main power tube Q3 and the drain of the main power tube Q4.

[0008] The transformer T consists of a leakage inductance L r , excitation inductance L m 、Transformer primary coil N p , iron core T, transformer secondary coil N s constitute; Among them, the excitation inductance L m With the transformer primary coil N p In parallel, leakage inductance L r and the excitation inductance L m and transformer primary winding N p In series, the transformer connects the primary coil N of the transformer through the iron core T p Energy is transferred to the transformer secondary winding N s .

[0009] The current doubler rectifier circuit consists of a transformer secondary coil N s , synchronous rectifier Q S1 , synchronous rectifier Q S2 , output inductor L f1 , output inductor L f2 , output capacitor C o 、Load R o Composition: Transformer secondary coil N s The same-name terminal and the synchronous rectifier Q S1 Source and output inductor L f2 The upper end is connected to the transformer secondary coil N s The opposite end and the synchronous rectifier Q S2 Source and output inductor L f1 The lower end is connected to the output inductor L f1 The upper end and the output inductor L f2 The lower end is connected to the secondary reference ground, the synchronous rectifier Q S1 Drain and synchronous rectifier Q S2The drain is connected to the output capacitor C o Positive electrode and load R o Positive electrode, output capacitor C o Negative electrode and load R o The negative terminal is connected to the secondary reference ground.

[0010] The control circuit is used to provide a main power tube control signal and a synchronous rectifier tube control signal to respectively control the main power tube Q1, the main power tube Q2, the main power tube Q3, the main power tube Q4 and the synchronous rectifier tube Q S1 , synchronous rectifier Q S2 The switching state of the leading bridge arm, the lagging bridge arm and the synchronous rectifier tube are turned on at zero voltage.

[0011] Furthermore, a digitally controlled synchronous current-doubling rectifier full-bridge soft-switching constant voltage power supply, the control circuit includes: An acquisition unit, configured to acquire voltage and current signals of the digitally controlled synchronous current-doubling rectifier full-bridge soft-switching constant-voltage power supply; A feedback unit, which adjusts the signal obtained by the acquisition unit to obtain a compensation signal; The driving unit generates a control signal for the main power tube and a control signal for the synchronous rectifier tube according to the compensation signal obtained by the feedback unit.

[0012] Furthermore, a digitally controlled synchronous current-doubling rectifier full-bridge soft-switching constant voltage power supply, the acquisition unit includes: A current sampling unit, used for sampling the primary current and output current of the digitally controlled synchronous current-doubling rectifier full-bridge soft-switching constant voltage power supply; The voltage sampling unit is used to sample the input and output voltages of the digitally controlled synchronous current-doubling rectifier full-bridge soft-switching constant-voltage power supply.

[0013] Furthermore, a digitally controlled synchronous current-doubling rectifier full-bridge soft-switching constant voltage power supply, the feedback unit includes: An isolated feedback device, used to feed back the output of the current and voltage sampling units to the main controller, wherein the input end of the isolated feedback device is connected to the output end of the current sampling unit and the output end of the voltage sampling unit respectively, and the output end of the isolated feedback device is connected to the positive input end of the first adder; The compensation signal generating unit is used to adjust the signal fed back by the isolated feedback device and then output it to the driving unit to obtain a control signal for adjusting the switch tube.

[0014] Furthermore, in a digitally controlled synchronous current-doubling rectifier full-bridge soft-switching constant-voltage power supply, the compensation signal generating unit includes: Soft start unit, error amplifier, PWM compensator, limiter, output overvoltage protection unit; Among them, the voltage feedback signal is input into the PWM compensator through the error amplifier, and after passing through the limiter, the signal is input into the DSP square wave signal driving unit, and finally outputs the square wave control signal; when the system is powered on, the voltage feedback signal is very small, which causes the compensator output signal to be too large, resulting in output voltage overshoot. The soft start unit is used to simulate the system voltage feedback signal at power-on, so that it rises in a certain linear trend within a certain period of time; the output overvoltage protection unit is used to detect whether the output voltage is overvoltage. When the above signal exceeds a certain threshold, the above protection unit outputs a signal to the square wave generator to limit the output voltage.

[0015] Furthermore, in a modulation mode switching digitally controlled synchronous current-doubling rectifier full-bridge soft-switching constant voltage power supply, the isolation drive unit includes: DSP square wave signal driving unit, generating main switch tube driving signal and synchronous rectifier tube driving signal; The isolated drive signal generating unit is used to electrically isolate the DSP system from the main topology structure, and convert the low-voltage control signal generated by the DSP system into the main switch tube control signal and the synchronous rectifier tube control signal to control the switching state of the main switch tube Q1 and the synchronous rectifier tube Q2, and convert it into a square wave signal sufficient to drive the switching state of the switch tube.

[0016] Furthermore, in a digitally controlled synchronous current-doubling rectifier full-bridge soft-switching constant-voltage power supply, the drive signal generating unit includes: Square wave signal generating unit, phase shift signal generating unit, dead zone signal generating unit, synchronous rectification signal generating unit; The square wave signal generating unit includes a sawtooth wave signal generator, a comparator, and a compensation signal input. The positive input port of the sawtooth wave signal generator is connected to the negative input port of the comparator, the compensation signal input port is connected to the positive input port of the comparator, and the output port of the square wave signal generating unit outputs a square wave switching signal to the phase shift signal generating unit. The dead zone signal generating unit includes a first analog signal delay unit, a second analog signal delay unit, a third analog signal delay unit, a fourth analog signal delay unit, a first dual-channel input AND gate, a second dual-channel input AND gate, a third dual-channel input AND gate, and a fourth dual-channel input AND gate. The in-phase output terminal of the first monostable trigger is connected to the input port of the first analog signal delay unit and the first input channel of the first AND gate, and the second input channel of the first AND gate is connected to the output port of the first analog signal delay unit. At this time, the output signal of the first AND gate is the control signal of the main power tube Q1 with dead zone control; similarly, the inverting output terminal of the first monostable trigger is connected to the input port of the second analog signal delay unit and the first input channel of the second AND gate, and the second input channel of the second AND gate is connected to the output port of the second analog signal delay unit. At this time, the output signal of the second AND gate is the control signal of the main power tube Q2 ... In principle, the inverting output terminal of the second monostable trigger is connected to the input port of the third analog signal delay unit and the first input channel of the third AND gate, and the second input channel of the third AND gate is connected to the output port of the third analog signal delay unit. At this time, the output signal of the third AND gate is the control signal of the main power tube Q3 with dead-zone control; similarly, the non-inverting output terminal of the second monostable trigger is connected to the input port of the fourth analog signal delay unit and the first input channel of the fourth AND gate, and the second input channel of the fourth AND gate is connected to the output port of the fourth analog signal delay unit. At this time, the output signal of the fourth AND gate is the control signal of the main power tube Q4 with dead-zone control; Wherein, the synchronous rectification signal generating unit includes a soft start completion detection signal, a first dual-channel input NOR gate, a second dual-channel input NOR gate, a fifth dual-channel input AND gate, and a sixth dual-channel input AND gate; wherein, the output port of the first dual-channel input NOR gate is connected to the second input channel of the fifth dual-channel input AND gate to form a first three-channel input XNOR gate, and the output port of the second dual-channel input NOR gate is connected to the second input channel of the sixth dual-channel input AND gate to form a second three-channel input XNOR gate; the output signal of the first AND gate is connected to the first input channel of the first three-channel input XNOR gate, the output signal of the fourth AND gate is connected to the second input channel of the first three-channel input XNOR gate, and the soft start completion detection signal is connected to the third input channel of the first three-channel input XNOR gate. At this time, the output signal of the first three-channel input XNOR gate is the synchronous rectifier tube Q S1 Control signal; Similarly, the second AND gate output signal is connected to the first input channel of the second three-channel input NOR gate, the third AND gate output signal is connected to the second input channel of the second three-channel input NOR gate, and the soft start completion detection signal is connected to the third input channel of the second three-channel input NOR gate. At this time, the output signal of the first three-channel input NOR gate is the synchronous rectifier tube Q S1 Control signal. During the soft start period, the synchronous rectification signal generating unit controls the synchronous rectifier tube to turn off. At this time, the synchronous rectifier tube QS1 The body diode D S1 With synchronous rectifier Q S2 The body diode D S2 Perform asynchronous rectification.

[0017] Furthermore, in a digitally controlled synchronous current-doubling rectifier full-bridge soft-switching constant-voltage power supply, the gate drive voltage of the main switch tube and the synchronous rectifier tube in the drive signal generating unit is +15V when they are turned on, and the gate drive voltage of the main switch tube and the synchronous rectifier tube is -3V when they are turned off.

[0018] The beneficial effects of the present invention are: 1. The present invention replaces the main power tube and synchronous rectifier tube in the full-bridge constant-voltage power supply with SiC-MOSFET, and utilizes the low on-resistance, parasitic capacitance, and reverse fast recovery characteristics of the body diode of SiC-MOSFET to achieve high frequency and high efficiency of the full-bridge constant-voltage power supply.

[0019] 2. The digitally controlled synchronous current-doubling rectifier full-bridge soft-switching constant-voltage power supply of the embodiment of the present invention realizes zero-voltage turn-on of all switches by controlling the dead time and phase of the driving signal, thereby reducing the turn-on loss of the system and achieving high power efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The figure is a schematic diagram of the overall structure of a digitally controlled synchronous current-doubling rectifier full-bridge soft-switching constant-voltage power supply according to the present invention.

[0021] Figure 2 This is a principle diagram of a feedback unit of a digitally controlled synchronous current-doubling rectifier full-bridge soft-switching constant-voltage power supply according to the present invention.

[0022] Figure 3 This is a schematic diagram of a driving signal generating unit of a digitally controlled synchronous current-doubling rectifier full-bridge soft-switching constant-voltage power supply according to the present invention.

[0023] Figure 4 This is a single-cycle drive signal timing diagram of a digitally controlled synchronous current-doubling rectifier full-bridge soft-switching constant-voltage power supply and a corresponding synchronous rectifier tube zero-voltage turn-on waveform diagram.

[0024] Figure 5 This is a single-cycle drive signal timing diagram of a digitally controlled synchronous current-doubling rectifier full-bridge soft-switching constant-voltage power supply and a corresponding main power tube zero-voltage turn-on waveform diagram.

[0025] Figure 6 This is a simulated waveform diagram of the output current and output voltage of a digitally controlled synchronous current-doubling rectifier full-bridge soft-switching constant-voltage power supply under heavy load conditions with a 390V input.

[0026] Figure 7This is a simulated waveform diagram of the output current and output voltage of a digitally controlled synchronous current-doubling rectifier full-bridge soft-switching constant-voltage power supply of the present invention when the load is switched at 390V input. DETAILED DESCRIPTION

[0027] To facilitate understanding of the present invention, the present invention will be described in more detail below with reference to the accompanying drawings. The accompanying drawings illustrate embodiments of the present invention. However, the present invention can be implemented in various forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the present disclosure.

[0028] like Figure 1 As shown, the digitally controlled synchronous current-doubling rectifier full-bridge soft-switching constant voltage power supply in the embodiment of the present invention includes: a primary full-bridge inverter circuit, a transformer T, a current-doubling rectifier circuit and a control circuit.

[0029] The primary full-bridge inverter circuit is powered by a DC power supply V DC , input capacitor C IN , leakage inductance L r 、Transformer primary coil N p , main power tube Q1, main power tube Q2, main power tube Q3, main power tube Q4; Among them, the DC power supply V DC Positive electrode and input capacitor C IN The positive pole is connected to the DC power supply V DC Negative electrode and input capacitor C IN The negative electrode is connected to the primary reference ground, and the drain of the main power tube Q1 is connected to the DC power supply V DC The positive electrode is connected to the source of the main power tube Q2 and the DC power supply V DC The negative pole is connected, the source of the main power tube Q1 is connected to the drain of the main power tube Q2 to form a leading bridge arm, and the drain of the main power tube Q3 is connected to the DC power supply V DC The positive electrode is connected to the source of the main power tube Q4 and the DC power supply V DC The negative poles are connected, the source of the main power tube Q3 is connected to the drain of the main power tube Q4 to form a lagging bridge arm, and the leakage inductance L r The left end is connected to the connection node of the source of the main power tube Q1 and the drain of the main power tube Q2, and the leakage inductance L r The right end is connected to the primary coil N of the transformer p The same-name terminals are connected, and the transformer primary coil N p The opposite-name terminal is connected to the connection node of the source of the main power tube Q3 and the drain of the main power tube Q4; The transformer T consists of a leakage inductance L r , excitation inductance L m 、Transformer primary coil N p , iron core T, transformer secondary coil N s constitute; Among them, the excitation inductance L m With the transformer primary coil N p In parallel, leakage inductance L r and the excitation inductance L m and transformer primary winding N p In series, the transformer connects the primary coil N of the transformer through the iron core T p Energy is transferred to the transformer secondary winding N s ; The current doubler rectifier circuit consists of a transformer secondary coil N s , synchronous rectifier Q S1 , synchronous rectifier Q S2 , output inductor L f1 , output inductor L f2 , output capacitor C o 、Load R o Composition: Transformer secondary coil N s The same-name terminal and the synchronous rectifier Q S1 Source and output inductor L f2 The upper end is connected to the transformer secondary coil N s The opposite end and the synchronous rectifier Q S2 Source and output inductor L f1 The lower end is connected to the output inductor L f1 The upper end and the output inductor L f2 The lower end is connected to the secondary reference ground, the synchronous rectifier Q S1 Drain and synchronous rectifier Q S2 The drain is connected to the output capacitor C o Positive electrode and load R o Positive electrode, output capacitor C o Negative electrode and load R o The negative terminal is connected to the secondary reference ground.

[0030] The control circuit is used to provide the main power tube control signal and the synchronous rectifier tube control signal to respectively control the main power tube Q1, the main power tube Q2, the main power tube Q3, the main power tube Q4 and the synchronous rectifier tube Q S1 , synchronous rectifier Q S2 The switching state of the leading bridge arm, the lagging bridge arm and the synchronous rectifier tube are turned on at zero voltage.

[0031] The principle diagram of the feedback unit of the digitally controlled synchronous current-doubling rectifier full-bridge soft-switching constant voltage power supply is as follows: Figure 2 As shown, after the current and voltage signals are collected by the sampling unit, they are output to the isolated feedback device in the feedback unit for electrical isolation. The reference voltage is connected to the positive input of the adder, the feedback voltage is connected to the negative input of the adder, and the output of the adder is connected to the input of the PI compensator. The limiter outputs the compensation signal. The principle diagram of the driving signal generating unit of the digitally controlled synchronous current-doubling rectifier full-bridge soft-switching constant voltage power supply is as follows: Figure 3 As shown, it is used to convert the compensation signal obtained by the feedback unit into a main power tube control signal and a synchronous rectifier tube control signal.

[0032] The single cycle driving timing signal of the digitally controlled synchronous current doubling rectifier full-bridge soft switching constant voltage power supply and the corresponding synchronous rectifier zero voltage turn-on waveform are shown in the figure. Figure 4 As shown in the figure. Due to the duty cycle loss characteristic of the phase-shifted full-bridge topology, the secondary winding is short-circuited before the secondary synchronous rectifier turns on. This creates a resonant circuit between the output capacitor, the synchronous rectifier junction capacitance, and the secondary winding, charging the output capacitor. When the main power transistor turns on again, energy from the primary side begins to transfer to the secondary winding, causing the secondary winding voltage to rise. At this point, the synchronous rectifier remains closed, and a resonant circuit is formed between the secondary winding, the synchronous rectifier junction capacitance, and the output capacitor. This reverse discharges the synchronous rectifier junction capacitance. When the secondary winding voltage rises to equal the output voltage, the synchronous rectifier drain voltage equals the source voltage. Turning on the synchronous rectifier at this point achieves zero voltage turn-on (ZVS) and reduces system switching losses.

[0033] The single cycle driving timing signal of the digitally controlled synchronous current doubling rectifier full-bridge soft switching constant voltage power supply and the corresponding zero voltage turn-on waveform of each main power tube are shown in the figure below: Figure 5 As shown in the figure, by adding dead time and phase shift control, the resonant inductor resonates with the junction capacitance of each main power transistor during the dead time, discharging the junction capacitance of each main power transistor. When the charge stored in the junction capacitance of the main power transistor is zero, the voltage across the main power transistor is zero. At this time, turning on the main power transistor can achieve zero-voltage turn-on of the primary-side full-bridge inverter circuit.

[0034] The above embodiments are merely illustrative of the present invention and do not limit its scope of protection. Those skilled in the art may also make partial changes thereto and change the selection of the regulator according to actual conditions to generate a better compensation signal. Any form of equivalent replacement that complies with the spirit of the invention falls within the scope of protection of the present invention.

Claims

1. A digitally controlled synchronous current-doubling rectifier phase-shifted full-bridge soft-switching constant-voltage power supply, characterized in that: include: It includes a primary full-bridge inverter circuit, a transformer T, a current doubler rectifier circuit and a control circuit; The primary full-bridge inverter circuit is powered by a DC power supply V DC , input capacitor C IN , leakage inductance L r 、Transformer primary coil N p , main power tube Q1, main power tube Q2, main power tube Q3, main power tube Q4; Among them, the DC power supply V DC Positive electrode and input capacitor C IN The positive pole is connected to the DC power supply V DC Negative electrode and input capacitor C IN The negative electrode is connected to the primary reference ground, and the drain of the main power tube Q1 is connected to the DC power supply V DC The positive electrode is connected to the source of the main power tube Q2 and the DC power supply V DC The negative pole is connected, the source of the main power tube Q1 is connected to the drain of the main power tube Q2 to form a leading bridge arm, and the drain of the main power tube Q3 is connected to the DC power supply V DC The positive electrode is connected to the source of the main power tube Q4 and the DC power supply V DC The negative poles are connected, the source of the main power tube Q3 is connected to the drain of the main power tube Q4 to form a lagging bridge arm, and the leakage inductance L r The left end is connected to the connection node of the source of the main power tube Q1 and the drain of the main power tube Q2, and the leakage inductance L r The right end is connected to the primary coil N of the transformer p The same-name terminals are connected, and the transformer primary coil N p The opposite-name terminal is connected to the connection node of the source of the main power tube Q3 and the drain of the main power tube Q4; The transformer T consists of a leakage inductance L r , excitation inductance L m 、Transformer primary coil N p , iron core T, transformer secondary coil N s constitute; Among them, the excitation inductance L m With the transformer primary coil N p In parallel, leakage inductance L r and the excitation inductance L m and transformer primary winding N p In series, the transformer connects the primary coil N of the transformer through the iron core T p Energy is transferred to the transformer secondary winding N s ; The current doubler rectifier circuit consists of a transformer secondary coil N s , synchronous rectifier Q S1 , synchronous rectifier Q S2 , output inductor L f1 , output inductor L f2 , output capacitor C o 、Load R o Composition: Transformer secondary coil N s The same-name terminal and the synchronous rectifier Q S1 Source and output inductor L f2 The upper end is connected to the transformer secondary coil N s The opposite end and the synchronous rectifier Q S2 Source and output inductor L f1 The lower end is connected to the output inductor L f1 The upper end and the output inductor L f2 The lower end is connected to the secondary reference ground, the synchronous rectifier Q S1 Drain and synchronous rectifier Q S2 The drain is connected to the output capacitor C o Positive electrode and load R o Positive electrode, output capacitor C o Negative electrode and load R o The negative electrode is connected to the secondary reference ground. The control circuit is used to provide the main power tube control signal and the synchronous rectifier tube control signal to respectively control the main power tube Q1, the main power tube Q2, the main power tube Q3, the main power tube Q4 and the synchronous rectifier tube Q S1 , synchronous rectifier Q S2 The switching state of the leading bridge arm, the lagging bridge arm and the synchronous rectifier tube is realized by zero voltage conduction, wherein the control circuit includes: An acquisition unit, configured to acquire voltage and current signals of the digitally controlled synchronous current-doubling rectifier phase-shifted full-bridge soft-switching constant-voltage power supply; A feedback unit, which adjusts the signal obtained by the acquisition unit to obtain a compensation signal; The driving unit generates a control signal for the main power tube and a control signal for the synchronous rectifier tube according to the compensation signal obtained by the feedback unit.

2. According to claim 1, the digitally controlled synchronous current-doubling rectifier phase-shifted full-bridge soft-switching constant voltage power supply is characterized in that: The main power tube and synchronous rectifier tube must be trench silicon carbide (SiC) metal-oxide semiconductor field effect transistors (MOSFETs) to achieve high efficiency of the digitally controlled synchronous current doubler rectifier phase-shifted full-bridge soft switching constant voltage power supply.

3. The digitally controlled synchronous current-doubling rectifier full-bridge soft-switching constant voltage power supply according to claim 1, characterized in that: The sampling unit of the control circuit includes: A current sampling unit, used to sample the primary current and output current of the digitally controlled synchronous current-doubling rectifier full-bridge soft-switching constant-voltage power supply; The voltage sampling unit is used to sample the input and output voltages of the digitally controlled synchronous current-doubling rectifier full-bridge soft-switching constant-voltage power supply.

4. The digitally controlled synchronous current-doubling rectifier full-bridge soft-switching constant voltage power supply according to claim 1, characterized in that: The feedback unit of the control circuit includes: An isolated feedback device, used to feed back the output of the current and voltage sampling units to the main controller, wherein the input end of the isolated feedback device is connected to the output end of the current sampling unit and the output end of the voltage sampling unit respectively, and the output end of the isolated feedback device is connected to the positive input end of the first adder; The compensation signal generating unit is used to adjust the signal fed back by the isolated feedback device and then output it to the driving unit to obtain a control signal for adjusting the switch tube.

5. The digitally controlled synchronous current-doubling rectifier full-bridge soft-switching constant voltage power supply according to claim 1, characterized in that: The driving unit of the control circuit includes: The driving signal generating unit is used to generate the main power tube control signal and the synchronous rectifier tube control signal to control the main power tube Q1, the main power tube Q2, the main power tube Q3, the main power tube Q4 and the synchronous rectifier tube Q S1 , synchronous rectifier Q S2 The switch status; The PWM drive unit converts the main power tube control signal and the synchronous rectifier tube control signal generated by the drive signal generating unit into a square wave signal that can control the switching state of the switch tube. The characteristic is that the gate drive voltage of the main power tube and the synchronous rectifier tube when they are turned on is +15V, and the gate drive voltage of the main power tube and the synchronous rectifier tube when they are turned off is -3V.

6. The digitally controlled synchronous current-doubling rectifier full-bridge soft-switching constant voltage power supply according to claim 4, characterized in that: The compensation signal generating unit includes: a soft start unit, an error amplifier, a PWM compensator, a limiter, and an output overvoltage protection unit; Among them, the voltage feedback signal is input into the PWM compensator through the error amplifier, and after passing through the limiter, the signal is input into the DSP square wave signal driving unit, and finally outputs the square wave control signal; when the system is powered on, the voltage feedback signal is very small, which causes the compensator output signal to be too large, resulting in output voltage overshoot. The soft start unit is used to simulate the system voltage feedback signal at power-on, so that it rises in a certain linear trend within a certain period of time; the output overvoltage protection unit is used to detect whether the output voltage is overvoltage. When the above signal exceeds a certain threshold, the above protection unit outputs a signal to the square wave generator to limit the output voltage.

7. The digitally controlled synchronous current-doubling rectifier full-bridge soft-switching constant voltage power supply according to claim 5, characterized in that: The driving signal generating unit includes: a square wave signal generating unit, a phase shift signal generating unit, a dead zone signal generating unit, and a synchronous rectification signal generating unit; The square wave signal generating unit includes a sawtooth wave signal generator, a first comparator, and a compensation signal input. The positive input port of the sawtooth wave signal generator is connected to the negative input port of the comparator, the compensation signal input port is connected to the positive input port of the comparator, and the output port of the square wave signal generating unit outputs a square wave switching signal to the phase shift signal generating unit. The phase-shift signal generating unit includes a first monostable trigger and a second monostable trigger. The rising edge trigger terminal of the first monostable trigger is connected to the output terminal of the square wave signal generating unit, and the falling edge trigger terminal is connected to the reference ground. The rising edge trigger terminal of the second monostable trigger is connected to the reference ground, and the falling edge trigger terminal is connected to the output terminal of the square wave signal generating unit. The dead zone signal generating unit includes a first analog signal delay unit, a second analog signal delay unit, a third analog signal delay unit, a fourth analog signal delay unit, a first dual-channel input AND gate, a second dual-channel input AND gate, a third dual-channel input AND gate, and a fourth dual-channel input AND gate. The in-phase output terminal of the first monostable trigger is connected to the input port of the first analog signal delay unit and the first input channel of the first AND gate, and the second input channel of the first AND gate is connected to the output port of the first analog signal delay unit. At this time, the output signal of the first AND gate is the control signal of the main power tube Q1 with dead zone control; similarly, the inverting output terminal of the first monostable trigger is connected to the input port of the second analog signal delay unit and the first input channel of the second AND gate, and the second input channel of the second AND gate is connected to the output port of the second analog signal delay unit. At this time, the output signal of the second AND gate is the control signal of the main power tube Q2 ... In principle, the inverting output terminal of the second monostable trigger is connected to the input port of the third analog signal delay unit and the first input channel of the third AND gate, and the second input channel of the third AND gate is connected to the output port of the third analog signal delay unit. At this time, the output signal of the third AND gate is the control signal of the main power tube Q3 with dead-zone control; similarly, the non-inverting output terminal of the second monostable trigger is connected to the input port of the fourth analog signal delay unit and the first input channel of the fourth AND gate, and the second input channel of the fourth AND gate is connected to the output port of the fourth analog signal delay unit. At this time, the output signal of the fourth AND gate is the control signal of the main power tube Q4 with dead-zone control; Wherein, the synchronous rectification signal generating unit includes a soft start completion detection signal, a first dual-channel input NOR gate, a second dual-channel input NOR gate, a fifth dual-channel input AND gate, and a sixth dual-channel input AND gate; wherein, the output port of the first dual-channel input NOR gate is connected to the second input channel of the fifth dual-channel input AND gate to form a first three-channel input XNOR gate, and the output port of the second dual-channel input NOR gate is connected to the second input channel of the sixth dual-channel input AND gate to form a second three-channel input XNOR gate; the output signal of the first AND gate is connected to the first input channel of the first three-channel input XNOR gate, the output signal of the fourth AND gate is connected to the second input channel of the first three-channel input XNOR gate, and the soft start completion detection signal is connected to the third input channel of the first three-channel input XNOR gate. At this time, the output signal of the first three-channel input XNOR gate is the synchronous rectifier tube Q S1 Control signal; Similarly, the second AND gate output signal is connected to the first input channel of the second three-channel input NOR gate, the third AND gate output signal is connected to the second input channel of the second three-channel input NOR gate, and the soft start completion detection signal is connected to the third input channel of the second three-channel input NOR gate. At this time, the output signal of the first three-channel input NOR gate is the synchronous rectifier tube Q S1 During the soft start period, the synchronous rectification signal generating unit controls the synchronous rectifier tube to turn off. At this time, the synchronous rectifier tube Q S1 The body diode D S1 With synchronous rectifier Q S2 The body diode D S2 Perform asynchronous rectification.

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