A high-voltage input and high-power output switching power supply and method

Abstract

This invention provides a high-voltage input, high-power output switching power supply and method, comprising: multiple sets of half-bridge power supply main circuits connected to a high-voltage input power supply, wherein the input sides of the multiple sets of half-bridge power supply main circuits are connected in series and the output sides are connected in parallel, used to convert the high-voltage input power supply on the input side into a low-voltage power supply; each set of half-bridge power supply series main circuits includes: a bus capacitor series circuit, a transformer output circuit, a half-bridge power supply MOS circuit, and an isolation drive control circuit. This invention uses multiple sets of series capacitors connected in parallel between the positive and negative buses for voltage equalization, with each set of capacitors corresponding to a half-bridge MOS power supply circuit. A PWM signal is output through a power control chip, and after push-pull output, it is connected to the input side of the isolation transformer. Multiple isolation drive signals are output to simultaneously control the on / off state of the MOS transistors of each set of half-bridge power supplies. After low-voltage processing through a high-frequency transformer, the parallel output achieves a power control strategy of high-voltage input and high-power output.

Description

Technical Field

[0001] This invention belongs to the field of switching power supply technology, specifically relating to a switching power supply and method with high voltage input and high power output. Background Technology

[0002] Switching power supplies, as auxiliary power supply equipment, are widely used in various complex power electronic conversion systems, and are often used to power board-level control systems and relay contactor systems.

[0003] Typically, in electronic devices operating in DC conditions, when the DC voltage requirement reaches 500V or higher, conventional low-operating-voltage AC-DC converters are insufficient. In such cases, high-voltage MOSFETs are needed to meet the low-power requirements of bus voltages of 1000V and below. However, existing MOSFET components and circuit designs are inadequate for applications involving even higher bus voltages. Therefore, a power supply is needed that is suitable for applications with DC voltages above 1000V, requiring a large output power to meet the operational needs of various electronic loads. Summary of the Invention

[0004] To address the aforementioned shortcomings of existing technologies, this invention provides a high-voltage input, high-power output switching power supply and method, solving the problem of low input voltage and low output power of conventional power supplies.

[0005] This invention provides a high-voltage input, high-power output switching power supply, comprising:

[0006] Multiple sets of half-bridge power supply main circuits connected to a high-voltage input power supply, wherein the input sides of the multiple sets of half-bridge power supply main circuits are connected in series and the output sides are connected in parallel, are used to convert the high-voltage input power supply on the input side into a low-voltage power supply.

[0007] The series main circuit of each group of half-bridge power supplies includes:

[0008] A bus capacitor series circuit, including a DC power supply composed of series capacitors;

[0009] The transformer output circuit includes a high-frequency transformer T that converts a high-voltage input power supply into a low-voltage output power supply.

[0010] The half-bridge power supply MOS circuit includes two alternately conducting MOS transistors Q1 and Q2, which are used to control the output power of the high-frequency transformer T.

[0011] The isolated drive control circuit is used to receive the drive signal generated by the control chip based on the feedback of the parallel output voltage, and to control the on / off state of MOSFETs Q1 and Q2 in the half-bridge power supply MOS circuit.

[0012] Furthermore, the bus capacitor series circuit includes: at least two series-connected voltage divider capacitors C1 and C2, the connection point of voltage divider capacitors C1 and C2 is connected to inductor L1, and inductor L1 is connected to the opposite terminal of high-frequency transformer T, the connection point is marked DC1 as the return point; capacitors C1 and C2 are respectively connected in parallel to equalizing resistors R1 and R2.

[0013] Furthermore, the connection point DC11 of the two series-connected MOS transistors Q1 and Q2 in the half-bridge power supply MOS circuit is connected to the same-name terminal of the high-frequency transformer T.

[0014] Each MOSFET is connected in parallel with a buffer circuit. MOSFET Q1 is connected in parallel with a series resistor R3 and a capacitor C3, while MOSFET Q2 is connected in parallel with a series resistor R4 and a capacitor C4.

[0015] In the first group of half-bridge power supply MOS circuits, the drain of MOS transistor Q1 and one end of resistor R3 are connected to the positive bus; in the last group of half-bridge power supply MOS circuits, the source of MOS transistor Q2 and one end of capacitor C4 are connected to the negative bus.

[0016] Furthermore, the transformer output circuit includes a high-frequency transformer T, diodes D1 and D2, inductor L2, capacitor C5, and resistor R5;

[0017] The input winding of the high-frequency transformer T is connected to the connection point DC11 of two series-connected MOSFETs Q1 and Q2.

[0018] The opposite-named terminal of the input winding of the high-frequency transformer T is connected to the output terminal of the inductor L1;

[0019] The output winding of the high-frequency transformer T consists of two windings. The same-named terminals of the first winding and the opposite-named terminals of the second winding are connected to diodes D1 and D2, respectively. The cathodes of diodes D1 and D2 are connected in parallel to one end of inductor L2. The other end of inductor L2 is connected to a parallel capacitor C5 and a resistor R5, serving as the positive terminal of the switching power supply. The other end of the parallel connection between capacitor C5 and resistor R5 is connected to the center tap of the two output windings of the high-frequency transformer T, serving as the negative terminal of the switching power supply.

[0020] Furthermore, the isolation drive control circuit includes: resistors R6, R7, R8, and R9; an isolation transformer TR; transistors P1, P2, P3, P4, P5, and P6; and diodes D3 and D4.

[0021] Resistor R6 is connected to the base of transistor P1 and the base of transistor P2; the connection point of the emitter of transistor P1 and the emitter of transistor P2 is connected to the same-name terminal of the input winding of isolation transformer TR; the collector of transistor P1 is connected to power supply VCC; and the collector of transistor P2 is grounded.

[0022] Resistor R7 is connected to the base of transistor P3 and the base of transistor P4; the connection point of the emitter of transistor P3 and the emitter of transistor P4 is connected to the opposite-name terminal of the input winding of isolation transformer TR; the collector of transistor P3 is connected to power supply VCC; and the collector of transistor P4 is grounded.

[0023] The output winding of the isolation transformer TR includes a third winding and a fourth winding. The same-name terminal of the third winding is connected to one end of resistors R8 and R9. The other end of R8 is connected to the base of transistor P5. The other end of resistor R9 is connected to the anode of diode D3. The cathode of diode D3 is connected to the emitter of transistor P5, and the connection point is VG1. The collector of transistor P5 is connected to the opposite-name terminal of the third winding, and the connection point is VS1. Connection point VG1 is connected to the gate of MOSFET Q1, and connection point VS1 is connected to the source of MOSFET Q1.

[0024] The opposite-named terminal of the fourth winding is connected to one end of resistors R11 and R10. The other end of resistor R10 is connected to the base of transistor P6. The other end of resistor R11 is connected to the anode of diode D4. The cathode of diode D4 is connected to the emitter of transistor P6, and the connection point is marked VG2. The collector of transistor P6 is connected to the same-named terminal of the fourth winding, and the connection point is marked VS2. Connection point VG2 is connected to the gate of MOSFET Q2, and connection point VS2 is connected to the source of MOSFET Q2.

[0025] Secondly, the present invention provides a method for high-voltage input and high-power output, comprising:

[0026] The main circuit of the N-group half-bridge power supply is connected in series on the input side to achieve boost input. The high-voltage input power is divided into a stable and balanced DC power supply through the series circuit of bus capacitors.

[0027] In each half-bridge power supply main circuit, the high-voltage input power is converted into low-voltage output power through a high-frequency transformer T, and multiple sets of low-voltage output power supplies are connected in parallel.

[0028] The output power of the high-frequency transformer is controlled by two alternately conducting MOSFETs Q1 and Q2. After full-wave rectification by diodes and filtering by inductors, n sets of output sides are directly connected in parallel to achieve a power expansion of n times.

[0029] It receives the drive signal generated by the controlled chip based on the feedback of the parallel output voltage, and controls the switching on and off of MOSFETs Q1 and Q2 in the half-bridge power supply MOS circuit.

[0030] The beneficial effects of this invention are as follows: This invention provides a high-voltage input, high-power output switching power supply and method. A high-voltage power supply is input via a DC bus voltage. Multiple sets of series capacitors are connected in parallel between the positive and negative buses to equalize the voltage. Each set of capacitors corresponds to a half-bridge MOS power supply circuit. A power control chip outputs a PWM signal, which is then pushed-pull to the input side of multiple isolation transformers. Multiple isolated drive signals simultaneously control the on / off state of the MOS transistors in each half-bridge power supply. Low-voltage conversion is achieved through isolation by the respective half-bridge high-frequency transformers, resulting in parallel output. This achieves a power control strategy of high-voltage input and high-power output. Compared to conventional high-voltage MOS transistor switching power supply designs, this invention offers flexible circuit configuration, simple control, and scalability for higher voltage applications. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a high-voltage input, high-power output switching power supply provided in one embodiment of the present invention.

[0033] Figure 2 This is an isolated drive control circuit for a switching power supply provided in one embodiment of the present invention. Detailed Implementation

[0034] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0035] like Figure 1 As shown in the figure, an embodiment of the present invention provides a high-voltage input, high-power output switching power supply, comprising:

[0036] Multiple sets of half-bridge power supply main circuits connected to a high-voltage input power supply, wherein the input sides of the multiple sets of half-bridge power supply main circuits are connected in series and the output sides are connected in parallel, are used to convert the high-voltage input power supply on the input side into a low-voltage power supply.

[0037] The series main circuit of each group of half-bridge power supplies includes:

[0038] A bus capacitor series circuit, including a DC power supply composed of series capacitors;

[0039] The transformer output circuit includes a high-frequency transformer T that converts a high-voltage input power supply into a low-voltage output power supply.

[0040] The half-bridge power supply MOS circuit includes two alternately conducting MOS transistors Q1 and Q2, which are used to control the output power of the high-frequency transformer T.

[0041] The isolated drive control circuit is used to receive the drive signal generated by the control chip based on the feedback of the parallel output voltage, and to control the on / off state of MOSFETs Q1 and Q2 in the half-bridge power supply MOS circuit.

[0042] The high-voltage input, high-power output switching power supply provided in this embodiment of the invention includes a bus capacitor series circuit for providing a stable and balanced DC power supply to the half-bridge power supply circuit; a half-bridge power supply MOS circuit for realizing the alternating switching of the upper and lower MOS transistors of the half-bridge power supply, with two energy conversions in one cycle; a high-frequency transformer output parallel circuit for electromagnetically isolating and transmitting the input-side alternating energy to the output stage, and converting it into a stable DC power supply after rectification and filtering; and an isolation drive control circuit for realizing transformer-isolated output of the complementary drive signal output by the control chip to control the on / off state of the MOS transistors in each group of half-bridge power supply MOS circuits.

[0043] Optionally, as an embodiment of the present invention, the bus capacitor series circuit includes: at least two series-connected voltage divider capacitors C1 and C2, the connection point of the voltage divider capacitors C1 and C2 is connected to an inductor L1, and the inductor L1 is connected to the opposite terminal of the high-frequency transformer T in the transformer output circuit as a return point; capacitors C1 and C2 are respectively connected in parallel to a voltage equalization resistor R1 and R2.

[0044] Taking a high voltage of 2000V as an example, the bus capacitor series circuit provided by this invention will be described as follows: Figure 1 As shown, three sets of half-bridge power supply series main circuits are connected between the bus voltages consisting of the positive bus DC2000V+ and the negative bus DC2000V-. The three sets of bus capacitor series circuits are connected in series. The positive bus DC2000V+ is connected to one end of the resistor R1 and capacitor C1 of the first set, and the negative bus DC2000V- is connected to one end of the resistor R1 and capacitor C1 of the third set. The other end of the parallel connection of R1 and C1 is connected to one end of R2 and C2. The connection point of capacitors C1 and C2 is connected to one end of inductor L1, and the other end of inductor L1 is marked as DC1. DC1 is also connected to the opposite-name terminal of the input winding of the high-frequency transformer T. The other end of the parallel connection of resistor R2 and capacitor C2 is connected to one end of the second set of bus capacitor series circuits, and the connection point is marked as DC0. DC0 is also connected to the source of MOSFET Q2 and one pin of C8.

[0045] Optionally, as an embodiment of the present invention, the connection point DC11 of the two series-connected MOS transistors Q1 and Q2 in the half-bridge power supply MOS circuit is connected to the same-name terminal of the high-frequency transformer T in the transformer output circuit.

[0046] Each MOSFET is connected in parallel with a buffer circuit. MOSFET Q1 is connected in parallel with a series resistor R3 and a capacitor C3, while MOSFET Q2 is connected in parallel with a series resistor R4 and a capacitor C4.

[0047] In the first group of half-bridge power supply MOS circuits, the drain of MOS transistor Q1 and one end of resistor R3 are connected to the positive bus; in the last group of half-bridge power supply MOS circuits, the source of MOS transistor Q2 and one end of capacitor C4 are connected to the negative bus.

[0048] Taking a high voltage of 2000V as an example, the bus capacitor series circuit provided by this invention will be described as follows: Figure 1 As shown, a series main circuit of three sets of half-bridge power supplies is connected between the bus voltages formed by the positive bus DC2000V+ and the negative bus DC2000V-. In the first set, the drain of MOSFET Q1 and one end of R3 are connected to the positive bus DC2000V+; the source of MOSFET Q1 is connected to the drain of MOSFET Q2, and the connection point is marked as DC11. DC11 is connected to the input winding terminal of transformer T. One end of capacitor C4 in the first set is connected in series with resistor R4, and the other end of capacitor C4 is connected to the source of MOSFET Q2, with the connection point being DC0. In the second group, the drain of MOSFET Q1 and one end of R3 are connected to DC0. In the second group of half-bridge power supply MOSFET circuits, the source of MOSFET Q2 and one end of resistor R4 are connected to DC00. The other designs are the same as the first group. In the third group, the drain of MOSFET Q1 and one end of R3 are connected to DC00. In the third group, the source of MOSFET Q2 and one end of resistor R4 are connected to the positive bus DC2000V-. The other designs are the same as the first group.

[0049] Optionally, as an embodiment of the present invention, the transformer output circuit includes a high-frequency transformer T, diode D1, diode D2, inductor L2, capacitor C5, and resistor R5;

[0050] The input winding of the high-frequency transformer T is connected to the connection point DC11 of two series-connected MOSFETs Q1 and Q2.

[0051] The opposite-named terminal of the input winding of the high-frequency transformer T is connected to the output terminal of the inductor L1;

[0052] The output winding of the high-frequency transformer T includes two windings. The same-name terminal of the first winding and the opposite-name terminal of the second winding are respectively connected to a diode D1 and a diode D2. The cathodes of the diodes D1 and D2 in parallel are connected to one end of the inductor L2. The other end of the inductor L2 is connected to a parallel capacitor C5 and a resistor R5, which is the positive terminal of the switching power supply. The other end of the parallel capacitor C5 and resistor R5 is connected to the center tap of the two output windings of the high-frequency transformer T, which is the negative terminal of the switching power supply.

[0053] Taking a high voltage of 2000V as an example, the bus capacitor series circuit provided by this invention will be described as follows: Figure 1 As shown, three sets of half-bridge power supply series main circuits are connected between the bus voltages formed by the positive bus DC2000V+ and the negative bus DC2000V-. Each set of half-bridge power supply series main circuits distributes a DC voltage of 667V. In the first set of transformer output circuits, the same-name terminal of the input winding of the high-frequency transformer T is connected to the source of MOSFET Q1 and the drain of MOSFET Q2 at connection point DC11. The opposite-name terminal of the input winding of the high-frequency transformer T is connected to one end of inductor L1. The anodes of diodes D1 and D2 are connected in series at both ends of the output winding of the high-frequency transformer T. The cathodes of diodes D1 and D2 are connected in parallel and output to one end of inductor L2. The other end of inductor L2 is connected to one pin of capacitor C5 and resistor R5 at connection point DC24V+. The other pin of capacitor C5 and resistor R5 in parallel is connected to the center tap of the high-frequency transformer T at connection point DC24V-. The output power supplies of the three high-frequency transformers T (T1, T2) are all connected in parallel to generate a total output of DC24V+ to DC24V-. The circuit structures of the other two groups are the same.

[0054] Optionally, as an embodiment of the present invention, the isolation drive control circuit includes: resistors R6, R7, R8, and R9; an isolation transformer TR; transistors P1, P2, P3, P4, P5, and P6; and diodes D3 and D4.

[0055] Resistor R6 is connected to the base of transistor P1 and the base of transistor P2; the connection point of the emitter of transistor P1 and the emitter of transistor P2 is connected to the same-name terminal of the input winding of isolation transformer TR; the collector of transistor P1 is connected to power supply VCC_+15; and the collector of transistor P2 is grounded.

[0056] Resistor R7 is connected to the base of transistor P3 and the base of transistor P4; the connection point of the emitter of transistor P3 and the emitter of transistor P4 is connected to the opposite-name terminal of the input winding of isolation transformer TR; the collector of transistor P3 is connected to the power supply VCC_+15V; and the collector of transistor P4 is grounded.

[0057] The output winding of the isolation transformer TR includes a third winding and a fourth winding. The same-name terminal of the third winding is connected to one end of resistors R8 and R9. The other end of R8 is connected to the base of transistor P5. The other end of resistor R9 is connected to the anode of diode D3. The cathode of diode D3 is connected to the emitter of transistor P5, and the connection point is VG1. The collector of transistor P5 is connected to the opposite-name terminal of the third winding, and the connection point is VS1. Connection point VG1 is connected to the gate of MOSFET Q1, and connection point VS1 is connected to the source of MOSFET Q1.

[0058] The opposite-named terminal of the fourth winding is connected to one end of resistors R11 and R10. The other end of resistor R10 is connected to the base of transistor P6. The other end of resistor R11 is connected to the anode of diode D4. The cathode of diode D4 is connected to the emitter of transistor P6, and the connection point is marked VG2. The collector of transistor P6 is connected to the same-named terminal of the fourth winding, and the connection point is marked VS2. Connection point VG2 is connected to the gate of MOSFET Q2, and connection point VS2 is connected to the source of MOSFET Q2.

[0059] Taking a high voltage of 2000V as an example, the bus capacitor series circuit provided by this invention will be described as follows: Figure 2 As shown, three sets of half-bridge power supply series main circuits are connected between the bus voltage consisting of the positive bus DC2000V+ and the negative bus DC2000V-. The voltage feedback signals of the three sets of half-bridge power supply series main circuits are all input to the same power control chip U1. The power control chip U1 outputs PWM1 and PWM2 signals, which are respectively connected to three sets of isolated drive control circuits with identical circuit configurations. In this embodiment, the power control chip U1 has a built-in oscillator to generate a switching frequency. Based on the voltage feedback signal from the output side of the switching power supply, a logical comparison is performed to adjust the duty cycle of the output signal, thereby achieving the purpose of outputting a stable voltage.

[0060] like Figure 2As shown, taking the first group of isolated drive control circuits as an example, the power control chip U1 can be a TL494. In this embodiment, pin 8 of the TL494 is connected to one end of resistor R6, and the other end of R6 is connected to the base of transistors P1 and P2. The connection point between the emitters of transistors P1 and P2 is connected to the same-name terminal of the input winding of the isolation transformer TR. The collector of transistor P1 is connected to the power supply VCC_+15V, and the collector of transistor P2 is connected to GND. Pin 11 of the TL494 is connected to one end of resistor R7, and the other end of R7 is connected to the base of transistors P3 and P4. The connection point between the emitters of transistors P3 and P4 is connected to the opposite-name terminal of the input winding of the isolation transformer TR. The collector of transistor P3 is connected to the power supply VCC_+15V, and the collector of transistor P3 is connected to GND. The output winding of the isolation transformer TR has its corresponding terminal connected to one end of resistors R8 and R9. The other end of R8 is connected to the base of transistor P5, and the other end of R9 is connected to the anode of diode D3. The cathode of D3 is connected to the emitter of transistor P5. This connection point is marked VG1. The collector of transistor P5 is connected to the opposite terminal of winding 1. This connection point is marked VS1. VG1 and VS1 are connected to the gate and source of MOSFET Q1, respectively. The fourth winding of transformer TR has its opposite terminal connected to one end of resistors R10 and R11. The other end of R10 is connected to the base of transistor P6, and the other end of R11 is connected to the anode of diode D4. The cathode of D4 is connected to the emitter of transistor P6. This connection point is marked VG2. The collector of transistor P6 is connected to the corresponding terminal of the fourth winding. This connection point is marked VS2. VG2 and VS2 are connected to the gate and source of MOSFET Q2, respectively.

[0061] In this embodiment, the gate drive signals of the two MOSFETs are provided by the output of the isolation transformer TR. The gate drive signals of the two MOSFETs are complementary and highly isolated, thus forming a standard half-bridge MOSFET power supply circuit. Therefore, three sets of standard half-bridge power supply circuits are connected in series on the input side in this form to realize the series operation of the low-voltage half-bridge power supply circuit under high DC power supply conditions. The output of each high-frequency transformer T is rectified by diode full-wave processing, and then filtered by inductors and capacitors to output a stable DC voltage of 24V. The output power of the three high-frequency transformers is directly connected in parallel to form the total output power, thereby realizing a high-power output of 24V.

[0062] Taking the first group of half-bridge power supplies as an example, the working principle of the high-voltage input, high-power output switching power supply provided by this invention is explained as follows: In the first group of bus capacitor series power supplies, capacitors C1 and C2 are connected in series between the positive bus DC2000V+ and DC0. C1 and C2 are connected in parallel with resistors R1 and R2, respectively, to ensure a balanced voltage distribution among the capacitors. The connection point of the two capacitors C1 and C2 is connected to the opposite-name terminal of the high-frequency transformer T through inductor L1, serving as its return point. The operating voltage of this group of power supplies is one-third of the total DC voltage, thus reducing the voltage of the high-voltage input power supply.

[0063] When the power control chip U1 outputs drive signals PWM1 at a high level and PWM2 at a low level, each drive signal is output via a push-pull transistor and connected to the same-name and opposite-name terminals of the input winding of the isolation transformer TR, respectively. The same-name terminal in the input winding has a high potential, and the opposite-name terminal has a low potential. The isolation transformer TR isolates the output side, generating two output windings. The first winding, conditioned by resistors R8 and R9, diode D3, and transistor P5, outputs signal VG1 at a high level. The second winding, conditioned by resistors R10 and R11, diode D4, and transistor P6, outputs signal VG2 at a low level. This corresponds to the control of MOSFET Q1's gate being turned on and Q2's gate being turned off. Therefore, the upper half of the half-bridge MOSFET circuit is turned on, the same-name terminal of the high-frequency transformer T's input winding has a high potential, and the opposite-name terminal has a low potential. Correspondingly, the same-name terminal of the third output winding has a high potential, and diode D1 conducts. After filtering by inductor L2 and capacitor C5, the power supply is output.

[0064] Conversely, when the power control chip U1 outputs drive signals PWM1 at a low level and PWM2 at a high level, each drive signal is output via a push-pull transistor and connected to the same-name and opposite-name terminals of the input winding of the isolation transformer TR, respectively. The same-name terminal of the input winding has a low potential, and the opposite-name terminal has a high potential. The isolation transformer T isolates the output side, generating two windings. The third winding, after being conditioned by resistors R8 and R9, diode D3, and transistor P5, outputs signal VG1 at a low level. The fourth winding, after being conditioned by resistors R10 and R11, diode D4, and transistor P6, outputs signal VG2 at a high level. This correspondingly controls the gate of MOSFET Q1 to turn off and the gate of MOSFET Q2 to turn on. Therefore, the lower half of the half-bridge MOSFET circuit is turned on. The same-name terminal of the input winding of the high-frequency transformer T has a low potential, and the opposite-name terminal has a high potential. The corresponding fourth winding of the output winding has a high potential, and diode D2 conducts. After filtering by inductor L2 and capacitor C5, the power supply is output, achieving two electromagnetic energy conversions and transmissions within one cycle.

[0065] The other two half-bridge power supply circuits operate on the same principle. All three half-bridge power supplies maintain the same operating state, ensuring that the capacitor voltage on the bus does not change abruptly when the MOSFETs alternately turn on or off, and the capacitor voltage remains stable after a long period of accumulation. Three transformers perform energy conversion and transmission, increasing the output power by three times, thus realizing the application of high-voltage, high-power power supply control strategies.

[0066] In this embodiment, each group of bus capacitors and a half-bridge power supply form a low-voltage power supply circuit. Both MOSFETs in each circuit switch simultaneously, and their maximum turn-off voltage is clamped to be the same as the voltage of one group of bus capacitors. These three identical power supply circuits are connected in series, evenly distributing the entire bus voltage. Their identical operating states ensure simultaneous turn-on and turn-off. The output-side power load is also balanced through current sharing, ensuring balanced operation and output power for the three forward converters. Following this approach, more power supplies can be connected in series, allowing operation at higher bus voltages.

[0067] This invention also provides a method for high-voltage input and high-power output, comprising:

[0068] The high-voltage input power supply is divided into a stable and balanced DC power supply through a series circuit of bus capacitors.

[0069] In each half-bridge power supply main circuit, the high-voltage input power is converted into low-voltage output power through a high-frequency transformer T, and multiple sets of low-voltage output power supplies are connected in parallel.

[0070] The output power of the high-frequency transformer is controlled by two alternately conducting MOSFETs Q1 and Q2.

[0071] The receiving control chip generates a drive signal based on the feedback of the parallel output voltage, and controls the switching on and off of MOSFETs Q1 and Q2 in the half-bridge power supply MOS circuit.

[0072] The above three sets of half-bridge power supply circuits of the same type are connected in series on the input side to achieve voltage boost, that is, [the first set of DC200V+ / DC0 corresponding half-bridge] is connected in series with [the second set of DC0 / DC00 corresponding half-bridge] and [the DC00 / DC2000V- corresponding half-bridge];

[0073] The above three sets of half-bridge circuits of the same type are isolated on the output side by a transformer. After full-wave rectification by diodes and filtering by inductors, the three power supplies are directly connected in parallel to achieve a three-fold increase in power.

[0074] Although the present invention has been described in detail with reference to the accompanying drawings and preferred embodiments, the invention is not limited thereto. Various equivalent modifications or substitutions can be made to the embodiments of the invention by those skilled in the art without departing from the spirit and essence of the invention, and such modifications or substitutions should all be within the scope of the invention. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the invention should also be covered within the protection scope of the invention. Therefore, the protection scope of the invention should be determined by the scope of the claims.

Claims

1. A switching power supply with high voltage input and high power output, characterized in that, include: Multiple sets of half-bridge power supply main circuits connected to a high-voltage input power supply, wherein the input sides of the multiple sets of half-bridge power supply main circuits are connected in series and the output sides are connected in parallel, are used to convert the high-voltage input power supply on the input side into a low-voltage power supply. The series main circuit of each group of half-bridge power supplies includes: A bus capacitor series circuit, including a DC power supply composed of series capacitors; The transformer output circuit includes a high-frequency transformer T that converts a high-voltage input power supply into a low-voltage output power supply. The half-bridge power supply MOS circuit includes two alternately conducting MOS transistors Q1 and Q2, which are used to control the output power of the high-frequency transformer T. An isolated drive control circuit is used to receive the drive signal generated by the control chip based on the feedback of the parallel output voltage, and to control the on / off state of MOSFETs Q1 and Q2 in the half-bridge power supply MOS circuit. The connection point DC11 of the two series-connected MOS transistors Q1 and Q2 in the half-bridge power supply MOS circuit is connected to the same-name terminal of the high-frequency transformer T. Each MOSFET is connected in parallel with a buffer circuit. MOSFET Q1 is connected in parallel with a series resistor R3 and a capacitor C3, while MOSFET Q2 is connected in parallel with a series resistor R4 and a capacitor C4. In the first group of half-bridge power supply MOS circuits, the drain of MOS transistor Q1 and one end of resistor R3 are connected to the positive bus; in the last group of half-bridge power supply MOS circuits, the source of MOS transistor Q2 and one end of capacitor C4 are connected to the negative bus. The transformer output circuit includes a high-frequency transformer T, diode D1, diode D2, inductor L2, capacitor C5, and resistor R5. The input winding of the high-frequency transformer T is connected to the connection point DC11 of two series-connected MOSFETs Q1 and Q2. The opposite-named terminal of the input winding of the high-frequency transformer T is connected to the output terminal DC1 of the inductor L1. The output side of the high-frequency transformer T includes two windings. The same-name terminal of the first winding and the opposite-name terminal of the second winding are respectively connected to a diode D1 and a diode D2. The cathodes of diodes D1 and D2 are connected in parallel to one end of inductor L2. The other end of inductor L2 is connected to a parallel capacitor C5 and a resistor R5, which is the positive terminal of the switching power supply. The other end of the parallel capacitor C5 and resistor R5 is connected to the center tap of the two output windings of the high-frequency transformer T, which is the negative terminal of the switching power supply.

2. The high-voltage input, high-power output switching power supply according to claim 1, characterized in that, The bus capacitor series circuit includes: at least two series-connected voltage divider capacitors C1 and C2, the connection point of voltage divider capacitors C1 and C2 is connected to inductor L1, and inductor L1 is connected to the opposite terminal of high frequency transformer T in transformer output circuit as a return point; capacitors C1 and C2 are respectively connected in parallel with equalizing resistors R1 and R2.

3. The high-voltage input, high-power output switching power supply according to claim 1, characterized in that, The isolated drive control circuit includes: resistors R6, R7, R8, and R9; an isolation transformer TR; transistors P1, P2, P3, P4, P5, and P6; and diodes D3 and D4. Resistor R6 is connected to the base of transistor P1 and the base of transistor P2; the connection point of the emitter of transistor P1 and the emitter of transistor P2 is connected to the same-name terminal of the input winding of isolation transformer TR; the collector of transistor P1 is connected to power supply VCC; and the collector of transistor P2 is grounded. Resistor R7 is connected to the base of transistor P3 and the base of transistor P4; the connection point of the emitter of transistor P3 and the emitter of transistor P4 is connected to the opposite-name terminal of the input winding of isolation transformer TR; the collector of transistor P3 is connected to power supply VCC; and the collector of transistor P4 is grounded. The output winding of the isolation transformer TR includes a third winding and a fourth winding. The same-name terminal of the third winding is connected to one end of resistors R8 and R9. The other end of R8 is connected to the base of transistor P5. The other end of resistor R9 is connected to the anode of diode D3. The cathode of diode D3 is connected to the emitter of transistor P5, and the connection point is VG1. The collector of transistor P5 is connected to the opposite-name terminal of the third winding, and the connection point is VS1. Connection point VG1 is connected to the gate of MOSFET Q1, and connection point VS1 is connected to the source of MOSFET Q1. The opposite-named terminal of the fourth winding is connected to one end of resistors R11 and R10. The other end of resistor R10 is connected to the base of transistor P6. The other end of resistor R11 is connected to the anode of diode D4. The cathode of diode D4 is connected to the emitter of transistor P6, and the connection point is marked VG2. The collector of transistor P6 is connected to the same-named terminal of the fourth winding, and the connection point is marked VS2. Connection point VG2 is connected to the gate of MOSFET Q2, and connection point VS2 is connected to the source of MOSFET Q2.

4. The method for high-voltage input and high-power output switching power supply according to claim 1, characterized in that, include: The main circuit of the N-group half-bridge power supply is connected in series on the input side to achieve boost input. The high-voltage input power is divided into a stable and balanced DC power supply through the series circuit of bus capacitors. In each half-bridge power supply main circuit, the high-voltage input power is converted into low-voltage output power through a high-frequency transformer T, and multiple sets of low-voltage output power supplies are connected in parallel. The output power of the high-frequency transformer is controlled by two alternately conducting MOSFETs Q1 and Q2. After full-wave rectification by diodes and filtering by inductors, n sets of output sides are directly connected in parallel to achieve a power expansion of n times. It receives the drive signal generated by the controlled chip based on the feedback of the parallel output voltage, and controls the switching on and off of MOSFETs Q1 and Q2 in the half-bridge power supply MOS circuit.

Images