Power converter based on high-efficiency synchronous rectification circuit

Abstract

A power converter based on a high-efficiency synchronous rectification circuit is characterized in that three groups of switch tubes are connected in parallel to a secondary side, namely a synchronous rectification end, of a transformer, and each group consists of two MOS (Metal Oxide Semiconductor) tubes, so that the current derating is improved, and the current is increased; the conduction internal resistance is reduced, and the efficiency is improved; the output end voltage is prevented from upside down; a synchronous rectification driving controller is added in the synchronous rectification circuit, so that the secondary side output waveform of the transformer is optimized, the conduction of a switching tube is facilitated, and the loss is reduced; current at the output end of the transformer is weak, and the synchronous rectification driving controller is added for current expansion, so that the driving capability is enhanced.

Description

Technical Field

[0001] The invention belongs to the technical field of secondary power supplies and relates to a power converter based on a high-efficiency synchronous rectification circuit. Background Art

[0002] With the development of my country's space-borne space stations, a new generation of communication satellites is gradually emerging. The new generation of satellites pays attention to satellite size and cost and uses modular power supplies. With the gradual application of phased array radars in space, the demand for large current and high power is gradually increasing. The traditional synchronous rectification circuit is only used by two MOS tubes in series. When used for a secondary power supply with large current, the current derating is not enough, and it cannot provide large current, and it causes great damage to the MOS tube. The traditional synchronous rectification circuit has a large on-resistance and high loss, which makes the converter conversion efficiency low. Summary of the invention

[0003] In order to solve the above technical problems, the present invention provides a power converter based on a high-efficiency synchronous rectification circuit. The power converter based on the high-efficiency synchronous rectification circuit increases the current derating and increases the current by connecting three groups of switch tubes in parallel on the secondary side of the transformer, i.e., the synchronous rectification end, each group consists of two MOS tubes, thereby increasing the current; reducing the conduction internal resistance and improving the efficiency; and preventing the output end voltage from being inverted. In addition, a synchronous rectification drive controller is added to the synchronous rectification circuit to optimize the output waveform of the transformer secondary side, which is conducive to the conduction of the switch tube and reduces the loss; the current at the output end of the transformer is relatively weak, and the current is expanded by adding a synchronous rectification drive controller to enhance the driving capability.

[0004] The present invention is achieved through the following technical solutions.

[0005] The present invention provides a power converter based on a high-efficiency synchronous rectification circuit, comprising a PWM controller, MOS tubes Q1-Q10, a transformer T1, a CT1 current transformer, a CT2 current transformer, a voltage and current sampling circuit, a primary side main power drive circuit 1-2 and a synchronous rectification drive circuit 1-2. The signal output end of the PWM controller is connected to the signal input end of the primary main power drive circuit 1, the primary main power drive circuit 2, the synchronous rectification drive circuit 1 and the synchronous rectification drive circuit 2 respectively, and outputs a drive control signal to the primary main power drive circuit 1, the primary main power drive circuit 2, the synchronous rectification drive circuit 1 and the synchronous rectification drive circuit 2; The gates of the MOS transistors Q1 and Q4 are connected to the output end of the primary main power driving circuit 1, the gates of the MOS transistors Q2 and Q3 are connected to the output end of the primary main power driving circuit 2, the gates of the MOS transistors Q5, Q7, and Q9 are connected to the signal output end of the synchronous rectification driving circuit 1, and the gates of the MOS transistors Q6, Q8, and Q10 are connected to the signal output end of the synchronous rectification driving circuit 2; The first end of the primary winding of the transformer T1 is connected to the source of the MOS transistor Q1 and the drain of the MOS transistor Q3, the second end of the primary winding of the transformer T1 is connected to the source of the MOS transistor Q2 and the drain of the MOS transistor Q4, the drain of the MOS transistor Q1 and the drain of the MOS transistor Q2 are connected to the positive electrode of the power input terminal Uin, and the drain of the MOS transistor Q3 and the drain of the MOS transistor Q4 are connected to the negative electrode of the power input terminal Uin; The third end of the secondary winding of the transformer T1 is connected to the drains of the MOS transistors Q5, Q7, and Q9, the fifth end of the secondary winding of the transformer T1 is connected to the sources of the MOS transistors Q6, Q8, and Q10 and the negative electrode of the power output terminal Uout, the source of the MOS transistor Q5 is connected to the drain of the MOS transistor Q6, the source of the MOS transistor Q7 is connected to the drain of the MOS transistor Q8, the source of the MOS transistor Q9 is connected to the drain of the MOS transistor Q10, and the fourth end of the secondary winding of the transformer T1 is connected to the positive electrode of the power output terminal Uout; The input end of the CT1 current transformer is connected to the first end of the primary winding of the transformer T1, and outputs the signal to the PWM controller. The input end of the CT2 current transformer is connected to the negative pole of the power output end Uout, and inputs the signal to the voltage and current sampling circuit. The input end of the voltage and current sampling circuit is also connected to the power output end Uout, and outputs the processed sampled voltage signal and sampled current signal to the PWM controller.

[0006] Furthermore, it also includes capacitors C1 and C2, and the capacitors C1 and C2 are connected in parallel between the positive and negative electrodes of the power input terminal.

[0007] Furthermore, it also includes an inductor L1, capacitors C3, C4 and a resistor R13, one end of the inductor L1 is connected to the third end of the secondary winding of the transformer T1, and the other end is connected to the capacitors C3, C4, the resistor R13 and the positive electrode of the power output terminal Uout, and the other ends of the capacitors C3, C4 and the resistor R13 are connected to the negative electrode of the power output terminal Uout.

[0008] Furthermore, it also includes an overcurrent protection circuit, the signal input end of the overcurrent protection circuit is connected to the current signal output end of the voltage and current sampling circuit, and the processed signal is output to the PWM controller.

[0009] Furthermore, it also includes an overvoltage protection circuit, the signal input end of the overvoltage protection circuit is connected to the voltage signal output end of the voltage and current sampling circuit, and the processed signal is output to the PWM controller.

[0010] Furthermore, it also includes a soft start circuit, the signal input end of the soft start protection circuit is connected to the voltage signal output end of the voltage and current sampling circuit, and the processed signal is output to the PWM controller.

[0011] Furthermore, it also includes an auxiliary power supply, which is connected to the PWM controller, the primary main power drive circuit 1, the primary main power drive circuit 2, the synchronous rectification drive circuit 1 and the synchronous rectification drive circuit 2 for power supply.

[0012] Furthermore, the auxiliary power supply is an isolated auxiliary power supply.

[0013] Furthermore, the transformer T1 is an isolation transformer.

[0014] The beneficial effects of the present invention are as follows: (1) compared with the traditional synchronous rectification circuit, a power converter based on the high-efficiency synchronous rectification circuit can improve the current derating, increase the current, and meet the high-power and high-current requirements of the satellite-borne space station; (2) three groups of switch tubes are connected in parallel at the synchronous rectification end, that is, MOS tubes Q5 to Q10 are connected in parallel on the secondary side of the transformer, wherein MOS tube Q5 and MOS tube Q6 form a group, MOS tube Q7 and MOS tube Q8 form a group, and MOS tube Q9 and MOS tube Q10 form a group, and the three groups are connected in parallel, thereby reducing the on-state internal resistance and improving the efficiency. High efficiency; (3) Compared with the traditional synchronous rectification circuit, multiple switches in parallel can better prevent the problem of output voltage inversion; (4) Compared with the traditional synchronous rectification circuit, multiple switches in parallel can reduce the current carrying capacity of a single switch and reduce the damage to the MOS tube; (5) Adding a synchronous rectification drive circuit to the synchronous rectification circuit optimizes the output waveform of the secondary side of the transformer, which is beneficial to the conduction of the switch and reduces the loss; (6) The current at the output end of the transformer is weak, and the current is expanded by adding a synchronous rectification drive controller to enhance the driving capability. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 The invention discloses a principle block diagram of a power converter based on a high-efficiency synchronous rectification circuit. DETAILED DESCRIPTION

[0016] The technical solution of the present invention is further described below, but the scope of protection claimed is not limited to the description.

[0017] like Figure 1 As shown, the power converter based on the high-efficiency synchronous rectification circuit of the present invention includes a main power circuit, a control circuit, and an auxiliary power supply.

[0018] The main power circuit uses 10 MOS tubes (Q1~Q10), a transformer T1, 4 MOS tubes are used on the primary side of the transformer, that is, a full-bridge circuit, and two primary side main power drive circuits are added; 6 MOS tubes are used on the secondary side of the transformer, and two synchronous rectification drive circuits are added to better drive the secondary side MOS tubes.

[0019] Compared with the traditional synchronous rectification circuit, a power converter based on the high-efficiency synchronous rectification circuit can improve the current derating, increase the current, and meet the high-power and high-current requirements of the satellite-borne space station; reduce the on-resistance and improve the efficiency; multiple switches connected in parallel can better prevent the problem of output voltage inversion; reduce the current bearing capacity of a single switch and reduce the damage to the MOS tube; add a synchronous rectification drive controller to the synchronous rectification circuit to optimize the output waveform of the transformer secondary side, which is conducive to the conduction of the switch tube and reduces the loss; the current at the output end of the transformer is weak, and the synchronous rectification drive controller is added to expand the current to enhance the driving capability.

[0020] The transformer T1 uses an isolation transformer to completely isolate the primary side from the secondary side, suppressing the high-frequency noise of the primary side from entering the control circuit, playing a good filtering role, thereby providing a pure power supply voltage to the electrical equipment.

[0021] Two capacitors C1 and C2 are added to the input end Uin of the main power circuit to filter the input voltage; an inductor L1, two capacitors C3 and C4, and a load R13 are added to the output end to filter the output voltage of the main power circuit.

[0022] The auxiliary power supply uses an isolated auxiliary power supply to provide a pure working power supply for the control circuit, the primary side main power drive circuit, and the synchronous rectification drive circuit.

[0023] The control circuit includes a PWM controller, a voltage and current sampling circuit, an overcurrent protection circuit, an overvoltage protection circuit, a soft start circuit, a CT1 current transformer, and a CT2 current transformer. The CT1 current transformer is used to collect the current of port 1 of the transformer T1, and the current collected by the CT1 current transformer is input into the PWM controller for processing; the CT2 current transformer is used to collect the current at one end of the capacitor C4, and the collected current is input into the voltage and current sampling circuit, and the voltage and current sampling circuit collects the voltage Uout at the output end of the main power circuit, and the collected voltage Uout and current Iout are input into the PWM controller for processing; the collected voltage Uout is simultaneously input into the overvoltage protection circuit and the soft start circuit, and is processed by the overvoltage protection circuit and the soft start circuit, and a signal is output to the PWM controller; the collected current Iout is input into the overcurrent protection circuit, and is processed by the overcurrent protection circuit, and a signal is output to the PWM controller, the PWM controller processes the signal, and outputs a control signal to the primary main power drive circuit and the synchronous rectification drive circuit, and drives and controls 10 MOS tubes, so as to achieve the effects of overvoltage and overcurrent protection and soft start for the power converter.

Claims

1. A power converter based on a high-efficiency synchronous rectification circuit, characterized in that: It includes PWM controller, MOS tubes Q1~Q10, transformer T1, CT1 current transformer, CT2 current transformer, voltage and current sampling circuit, primary side main power drive circuit 1~2 and synchronous rectification drive circuit 1~2. The signal output end of the PWM controller is connected to the signal input end of the primary main power drive circuit 1, the primary main power drive circuit 2, the synchronous rectification drive circuit 1 and the synchronous rectification drive circuit 2 respectively, and outputs a drive control signal to the primary main power drive circuit 1, the primary main power drive circuit 2, the synchronous rectification drive circuit 1 and the synchronous rectification drive circuit 2; The gates of the MOS transistors Q1 and Q4 are connected to the output end of the primary main power driving circuit 1, the gates of the MOS transistors Q2 and Q3 are connected to the output end of the primary main power driving circuit 2, the gates of the MOS transistors Q5, Q7, and Q9 are connected to the signal output end of the synchronous rectification driving circuit 1, and the gates of the MOS transistors Q6, Q8, and Q10 are connected to the signal output end of the synchronous rectification driving circuit 2; The first end of the primary winding of the transformer T1 is connected to the source of the MOS transistor Q1 and the drain of the MOS transistor Q3, the second end of the primary winding of the transformer T1 is connected to the source of the MOS transistor Q2 and the drain of the MOS transistor Q4, the drain of the MOS transistor Q1 and the drain of the MOS transistor Q2 are connected to the positive electrode of the power input terminal Uin, and the drain of the MOS transistor Q3 and the drain of the MOS transistor Q4 are connected to the negative electrode of the power input terminal Uin; The third end of the secondary winding of the transformer T1 is connected to the drains of the MOS transistors Q5, Q7, and Q9, the fifth end of the secondary winding of the transformer T1 is connected to the sources of the MOS transistors Q6, Q8, and Q10 and the negative electrode of the power output terminal Uout, the source of the MOS transistor Q5 is connected to the drain of the MOS transistor Q6, the source of the MOS transistor Q7 is connected to the drain of the MOS transistor Q8, the source of the MOS transistor Q9 is connected to the drain of the MOS transistor Q10, and the fourth end of the secondary winding of the transformer T1 is connected to the positive electrode of the power output terminal Uout; The input end of the CT1 current transformer is connected to the first end of the primary winding of the transformer T1, and outputs the signal to the PWM controller. The input end of the CT2 current transformer is connected to the negative pole of the power output end Uout, and inputs the signal to the voltage and current sampling circuit. The input end of the voltage and current sampling circuit is also connected to the power output end Uout, and outputs the processed sampled voltage signal and sampled current signal to the PWM controller.

2. The power converter based on the high-efficiency synchronous rectification circuit as claimed in claim 1, characterized in that: It also includes capacitors C1 and C2, and the capacitors C1 and C2 are connected in parallel between the positive and negative electrodes of the power input terminal.

3. The power converter based on the high-efficiency synchronous rectification circuit as claimed in claim 1, characterized in that: It also includes an inductor L1, capacitors C3, C4 and a resistor R13, one end of the inductor L1 is connected to the third end of the secondary winding of the transformer T1, and the other end is connected to the capacitors C3, C4, the resistor R13 and the positive electrode of the power output terminal Uout, and the other ends of the capacitors C3, C4 and the resistor R13 are connected to the negative electrode of the power output terminal Uout.

4. The power converter based on the high-efficiency synchronous rectification circuit as claimed in claim 1, characterized in that: It also includes an overcurrent protection circuit, the signal input end of the overcurrent protection circuit is connected to the current signal output end of the voltage and current sampling circuit, and outputs the processed signal to the PWM controller.

5. The power converter based on the high-efficiency synchronous rectification circuit as claimed in claim 1, characterized in that: It also includes an overvoltage protection circuit, the signal input end of the overvoltage protection circuit is connected to the voltage signal output end of the voltage and current sampling circuit, and outputs the processed signal to the PWM controller.

6. The power converter based on the high-efficiency synchronous rectification circuit as claimed in claim 1, characterized in that: It also includes a soft start circuit, the signal input end of the soft start protection circuit is connected to the voltage signal output end of the voltage and current sampling circuit, and outputs the processed signal to the PWM controller.

7. The power converter based on the high-efficiency synchronous rectification circuit as claimed in claim 1, characterized in that: It also includes an auxiliary power supply, which is connected to the PWM controller, the primary main power drive circuit 1, the primary main power drive circuit 2, the synchronous rectification drive circuit 1 and the synchronous rectification drive circuit 2 for power supply.

8. The power converter based on the high-efficiency synchronous rectification circuit as claimed in claim 7, characterized in that: The auxiliary power supply is an isolated auxiliary power supply.

9. The power converter based on the high-efficiency synchronous rectification circuit as claimed in claim 1, characterized in that: The transformer T1 is an isolation transformer.

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