Power supply circuit, drive device, and power conversion apparatus

Abstract

The application relates to a power supply circuit, a driving device and a power conversion device. The power supply circuit comprises a first step-down conversion circuit, a secondary winding and a first bootstrap circuit; wherein the input end of the first step-down conversion circuit is used for connecting a direct-current power supply, the direct-current output end of the first step-down conversion circuit is connected with the input end of the first bootstrap circuit; the first bootstrap circuit is used for supplying power to the driving circuit corresponding to the floating ground switch tube in the first bridge arm circuit; the direct-current output end of the first step-down conversion circuit is also used for supplying power to the driving circuit corresponding to the ground switch tube in the first bridge arm circuit; the inductive element in the first step-down conversion circuit serves as the primary winding corresponding to the secondary winding, and the secondary winding is used for supplying power to the driving circuit corresponding to each switch tube in the alternating-current side conversion circuit in the power conversion circuit. The power conversion device with a smaller size can be realized by adopting the power supply circuit.

Description

Technical Field

[0001] This application relates to the field of power conversion technology, and in particular to a power supply circuit, a drive device, and a power conversion equipment. Background Technology

[0002] Power conversion equipment typically includes multiple active conversion circuits. Each switch in each active conversion circuit requires an independent drive circuit to provide a drive voltage. The locations of the emitter or source connections of each switch may differ, and the types of switches may also be different. Therefore, the magnitudes of the drive voltages for each switch are not entirely the same.

[0003] In related technologies, isolated power supply is used to power each drive circuit. Therefore, the secondary winding of the transformer in the power supply circuit needs to use more mutually isolated windings to achieve isolated power supply. This results in the transformer core in the power supply circuit needing a large surface area, making the transformer larger in size, and consequently making the power conversion equipment larger in size. Summary of the Invention

[0004] Therefore, it is necessary to provide a power supply circuit, drive device, and power conversion device that can reduce the size of the power conversion device in order to address the above-mentioned technical problems.

[0005] In a first aspect, a power supply circuit is provided for supplying power to the drive circuits corresponding to each switching transistor in a power conversion circuit, the power conversion circuit including a first bridge arm circuit on the DC side. The power supply circuit includes: a first buck converter circuit, a secondary winding, and a first bootstrap circuit; wherein...

[0006] The input terminal of the first buck converter circuit is used to connect to a DC power supply, and the DC output terminal of the first buck converter circuit is connected to the input terminal of the first bootstrap circuit.

[0007] The first bootstrap circuit is used to power the drive circuit corresponding to the floating switch in the first bridge arm circuit.

[0008] The DC output of the first buck converter circuit is also used to power the drive circuit corresponding to the grounding switch in the first bridge arm circuit.

[0009] In the first step-down converter circuit, the inductive element serves as the primary winding corresponding to the secondary winding. The secondary winding is used to supply power to the drive circuits corresponding to the switching transistors in the AC-side converter circuit of the power conversion circuit.

[0010] In one embodiment, the DC side of the power conversion circuit further includes a second bridge arm circuit, and the power supply circuit further includes a second bootstrap circuit, wherein...

[0011] The DC output terminal of the first buck converter circuit is also connected to the input terminal of the second bootstrap circuit;

[0012] The second bootstrap circuit is used to power the drive circuit corresponding to the floating switch in the second bridge arm circuit.

[0013] The DC output of the first buck converter circuit is also used to power the drive circuit corresponding to the grounding switch in the second bridge arm circuit.

[0014] In one embodiment, the power conversion circuit includes a third bridge arm circuit on the AC side, which is connected to the AC side winding in the power conversion circuit and is used to convert the AC current and pulsating current corresponding to the AC side winding.

[0015] The secondary winding includes a primary winding and a secondary winding. The power supply circuit also includes a first voltage regulator circuit and a second voltage regulator circuit.

[0016] The first voltage regulator circuit is connected to the first primary winding and is used to power the drive circuit corresponding to the floating switch in the third bridge arm circuit.

[0017] The second voltage regulator circuit is connected to the second stage winding and is used to supply power to the drive circuit corresponding to the grounding switch in the third bridge arm circuit.

[0018] In one embodiment, the power conversion circuit further includes a fourth bridge arm circuit on the AC side. The fourth bridge arm circuit and the third bridge arm circuit constitute a second full-bridge circuit on the AC side of the power conversion circuit. The second full-bridge circuit is used to convert the AC current and pulsating current corresponding to the AC side winding.

[0019] The secondary winding also includes a tertiary winding, and the power supply circuit also includes a third voltage regulator circuit.

[0020] The third voltage regulator circuit is connected to the third stage winding and is used to power the drive circuit corresponding to the floating ground switch in the fourth bridge arm circuit.

[0021] The second voltage regulator circuit is also used to power the drive circuit corresponding to the grounding switch in the fourth bridge arm circuit.

[0022] In one embodiment, the output terminals of the first voltage regulator circuit and the third voltage regulator circuit each include a positive voltage output terminal, a negative voltage output terminal, and a floating ground output terminal.

[0023] The output terminals of the second voltage regulator circuit include a positive voltage output terminal, a negative voltage output terminal, and a ground output terminal.

[0024] In one embodiment, the first voltage regulator circuit, the third voltage regulator circuit, and the second voltage regulator circuit adopt the same circuit topology, which includes: a first resistor, a second resistor, a first diode, a second diode, a first capacitor, a second capacitor, and a third capacitor, wherein...

[0025] The first end of the first resistor is connected to the first end of the corresponding secondary winding, the second end of the first resistor is connected to the positive terminal of the first diode, and the negative terminal of the first diode serves as the positive voltage output terminal of the circuit topology.

[0026] The first terminal of the first capacitor, the first terminal of the second capacitor, and the first terminal of the second resistor are all connected to the negative terminal of the first diode;

[0027] The second terminal of the first capacitor is connected to the second terminal of the corresponding secondary winding;

[0028] The second terminal of the second capacitor is connected to the first terminal of the third capacitor, and the second terminal of the third capacitor is connected to the second terminal of the first capacitor.

[0029] The second end of the second resistor is connected to the second end of the second capacitor and the negative terminal of the second diode;

[0030] The positive terminal of the second diode is connected to the second terminal of the third capacitor; the second diode is a voltage clamping diode.

[0031] The positive terminal of the second diode serves as the negative voltage output terminal of the circuit topology, while the negative terminal of the second diode serves as the ground output terminal or floating ground output terminal of the circuit topology.

[0032] In one embodiment, the output voltages of the positive voltage output terminals of the first voltage regulator circuit, the second voltage regulator circuit, and the third voltage regulator circuit range from 15 volts to 20 volts.

[0033] The output voltages of the negative voltage output terminals of the first, second, and third voltage regulator circuits range from -2V to -5V.

[0034] In one embodiment, the output terminals of both the first and third voltage regulator circuits include a positive voltage output terminal and a floating ground output terminal.

[0035] The output terminals of the second voltage regulator circuit include a positive voltage output terminal and a grounded output terminal.

[0036] In one embodiment, the power conversion circuit further includes a third full-bridge circuit on the AC side, which is connected to the second full-bridge circuit for mutual conversion between pulsating current and grid AC current.

[0037] The power supply circuit also includes a third bootstrap circuit and a fourth bootstrap circuit, wherein,

[0038] The third and fourth bootstrap circuits are used to power the drive circuits corresponding to the two floating ground switches in the third full-bridge circuit, respectively. The input terminals of the third and fourth bootstrap circuits are both connected to the power supply terminals of the drive circuits corresponding to the two grounded switches in the third full-bridge circuit.

[0039] In one embodiment, the third full-bridge circuit is a power frequency commutation circuit.

[0040] In one embodiment, the bootstrap capacitors in the third bootstrap circuit and the fourth bootstrap circuit are implemented using electrolytic capacitors.

[0041] In one embodiment, the input terminals of the third bootstrap circuit and the fourth bootstrap circuit are respectively connected to the output terminals of the second voltage regulator circuit.

[0042] The second voltage regulator circuit is also used to power the drive circuits corresponding to the two grounded switching transistors in the third full-bridge circuit.

[0043] In one embodiment, the on-state voltage of the switch in the third full-bridge circuit is less than the on-state voltage of the switch in the third bridge arm circuit. The output of the second voltage regulator circuit includes a positive voltage output terminal, a negative voltage output terminal and a ground output terminal. The power supply circuit also includes a second buck converter circuit.

[0044] The input terminal of the second buck converter circuit is connected to the positive voltage output terminal and the ground output terminal of the second voltage regulator circuit;

[0045] The input terminals of the third bootstrap circuit and the fourth bootstrap circuit are respectively connected to the positive output terminal of the second buck converter circuit.

[0046] The second buck converter circuit is used to power the drive circuits corresponding to the two grounded switching transistors in the third full-bridge circuit.

[0047] In one embodiment, the secondary winding is made of three layers of insulated wire.

[0048] Secondly, a driving device is provided, comprising:

[0049] Multiple driving circuits are used to drive the operation of each switching transistor in the power conversion circuit;

[0050] The power supply circuit provided in the first aspect is connected to each drive circuit and is used to supply power to each drive circuit.

[0051] Thirdly, a power conversion device is provided, comprising:

[0052] The power conversion circuit also includes a first bridge arm circuit on the DC side.

[0053] Such as the drive device provided in the second aspect.

[0054] In one embodiment, the power conversion circuit includes a third bridge arm circuit on the AC side, which is connected to the AC side winding in the power conversion device for mutual conversion between AC current and pulsating current corresponding to the AC side winding.

[0055] The switching transistors in the third bridge arm circuit are either silicon carbide switching transistors or silicon switching transistors.

[0056] In one embodiment, in the operating mode, the two switches of the first bridge arm circuit are turned on complementaryly at high frequency, and the driving duty cycle of each switch in the first bridge arm circuit ranges from 40% to 50%.

[0057] The two switching transistors in the third bridge arm circuit are turned on complementaryly at high frequency, and the driving duty cycle of each switching transistor in the third bridge arm circuit ranges from 40% to 50%.

[0058] The range of the outward phase shift angle between the first bridge arm circuit and the third bridge arm circuit is -90 degrees to 90 degrees.

[0059] The aforementioned power supply circuit, drive device, and power conversion equipment include a first buck converter circuit, a secondary winding, and a first bootstrap circuit. The input terminal of the first buck converter circuit is connected to a DC power supply, and the DC output terminal of the first buck converter circuit is connected to the input terminal of the first bootstrap circuit. The first bootstrap circuit supplies power to the drive circuit corresponding to the floating ground switch in the first bridge arm circuit. The DC output terminal of the first buck converter circuit also supplies power to the drive circuit corresponding to the grounding switch in the first bridge arm circuit. The inductive element in the first buck converter circuit serves as the primary winding corresponding to the secondary winding, and the secondary winding supplies power to the drive circuits of each switch in the AC-side conversion circuit of the power conversion circuit. Compared to related technologies that use a flyback circuit as a power supply circuit, which require a separate excitation winding or a separate secondary winding to power the drive circuits corresponding to the switches in the first bridge arm circuit, the power supply circuit described above uses the inductive element in the first buck converter circuit as the primary winding corresponding to the secondary winding. This allows DC voltage to be output from both the DC output terminal of the first buck converter circuit and the secondary winding, with the DC voltages at both ends isolated from each other by the primary winding, meeting safety standards. The first bootstrap circuit connects the DC output terminal of the first buck converter circuit to the drive circuits corresponding to the floating switches in the first bridge arm circuit. This means that the drive circuits corresponding to the switches in the first bridge arm circuit only need to be powered through the primary side of the power supply circuit. The secondary side of the power supply circuit does not need to have a corresponding winding for the first bridge arm circuit, thus achieving isolated power supply between the first bridge arm circuit and the AC conversion circuit in the power conversion circuit. Using the above power supply circuit can reduce the number of secondary windings, reduce the surface area of ​​the transformer core in the power supply circuit, and thus reduce the size of the transformer, thereby realizing a smaller power conversion device. Attached Figure Description

[0060] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the drawings used in the description of the embodiments of this application or related technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0061] Figure 1 This is a schematic diagram of the topology of an isolated bidirectional DC-AC converter circuit.

[0062] Figure 2 This is a schematic diagram of the topology of another type of isolated bidirectional DC-AC converter circuit;

[0063] Figure 3This is a schematic diagram of the topology of another isolated bidirectional DC-AC converter circuit;

[0064] Figure 4 This is a schematic diagram of the circuit topology of the power supply circuit in one embodiment;

[0065] Figure 5 A schematic diagram of the circuit topology of the power supply circuit in another embodiment;

[0066] Figure 6 A schematic diagram of the circuit topology of the power supply circuit in another embodiment;

[0067] Figure 7 A schematic diagram of the circuit topology of the power supply circuit in another embodiment;

[0068] Figure 8 This is a schematic diagram of the circuit topology of a voltage regulator circuit in one embodiment;

[0069] Figure 9 This is a schematic diagram of the circuit topology of the voltage regulator circuit in another embodiment;

[0070] Figure 10 A schematic diagram of the circuit topology of the power supply circuit in another embodiment;

[0071] Figure 11 A schematic diagram of the circuit topology of the power supply circuit in another embodiment;

[0072] Figure 12 A schematic diagram of the circuit topology of the power supply circuit in another embodiment;

[0073] Figure 13 This is a schematic diagram of the circuit topology of the power supply circuit in another embodiment.

[0074] Figure label:

[0075] 100, First buck converter circuit; 200, Secondary winding; 310, First bootstrap circuit; 320, Second bootstrap circuit; 330, Third bootstrap circuit; 340, Fourth bootstrap circuit; 410, First voltage regulator circuit; 420, Second voltage regulator circuit; 430, Third voltage regulator circuit; 500, Second buck converter circuit. Detailed Implementation

[0076] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0077] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0078] It is understood that the terms "first," "second," etc., used herein may be used to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another. For example, without departing from the scope of this application, a first resistor may be referred to as a second resistor, and similarly, a second resistor may be referred to as a first resistor. Both the first resistor and the second resistor are resistors, but they are not the same resistor.

[0079] It is understood that the term "connection" in the following embodiments should be understood as "electrical connection," "communication connection," etc., if the connected circuits, modules, units, etc., have electrical signal or data transmission with each other.

[0080] It is understood that the term "based on" as used in this application is used to describe one or more factors that influence the determination, but does not exclude other factors that may influence the determination. For example, the phrase "determine A based on B" means that the determination of A can be based entirely or at least partially on factor B. That is, B is a factor that influences the determination of A, but does not exclude the fact that the determination of A is also based on C.

[0081] When used herein, the singular forms of “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising / including” or “having,” etc., specify the presence of the stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not preclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. Meanwhile, the term “and / or” as used in this specification includes any and all combinations of the associated listed items.

[0082] The power conversion device involved in this application includes a power conversion circuit, a drive circuit that provides drive voltage to each switch in each active conversion circuit, and a power supply circuit that provides power to each drive circuit. The power conversion circuit generally includes multiple active conversion circuits. The power conversion circuit of the power conversion device in the embodiments of this application can adopt... Figure 1 The isolated bidirectional DC-AC converter circuit shown is shown.

[0083] Please refer to Figure 1This diagram illustrates the topology of an isolated bidirectional DC-AC converter circuit. The circuit includes a high-frequency DC-DC converter and a mains-frequency DC-AC converter. The high-frequency DC-DC converter includes a first full-bridge circuit on the DC side, a DC-side winding N11, an AC-side winding N12, and a second full-bridge circuit on the AC side. The first full-bridge circuit is connected to the DC-side winding N11 and is used for the conversion between the DC power supply and the AC current corresponding to the DC-side winding N11. The second full-bridge circuit is connected to the AC-side winding N12 of the power conversion device and is used for the conversion between the AC current corresponding to the AC-side winding N12 and the pulsating current. The mains-frequency DC-AC converter includes a third full-bridge circuit for the conversion between the pulsating current and the mains AC current. The circuit is connected to the AC mains via a relay S1. In the field of power conversion technology... Figure 1 The active converter circuit shown can be called a 1.5-stage DC-AC converter circuit.

[0084] For example, the DC power supply can be a photovoltaic module or a DC energy storage device.

[0085] Please refer to Figure 1 The first full-bridge circuit includes switching transistors Q1, Q2, Q3, and Q4. The source (S terminal) of transistor Q1 and the drain (D terminal) of transistor Q2 are connected at point AP1. The source of transistor Q3 and the drain of transistor Q4 are connected at point AP2. Points AP1 and AP2 are connected to the DC-side winding N11, meaning the sources of transistors Q1 and Q3 are connected through the DC-side winding N11. The sources of transistors Q2 and Q4 are connected and both connected to the negative terminal Bus- of the DC bus, meaning transistors Q2 and Q4 share a common ground. The drains of transistors Q1 and Q3 are connected to the positive terminal Bus+ of the DC bus. The first full-bridge circuit is connected in parallel with the DC bus capacitor C1, which is in parallel with the DC power supply DC. Among them, switch Q1 and switch Q3 are floating ground switches in the first full-bridge circuit, and switch Q2 and switch Q4 are ground switches in the first full-bridge circuit.

[0086] The second full-bridge circuit includes switching transistors Q5, Q6, Q7, and Q8. The source of transistor Q5 and the drain of transistor Q6 are connected at point BP1. The source of transistor Q7 and the drain of transistor Q8 are connected at point BP2. Points BP1 and BP2 are connected to the equivalent leakage inductance L1 (i.e., the transformer's built-in leakage inductance, which is also the resonant inductance corresponding to the second full-bridge circuit) and resonant capacitor C2 of the AC winding N12, respectively. The sources of transistors Q5 and Q7 are connected to the AC winding N12 via the equivalent leakage inductance L1, resonant capacitor C2, and the ground reference potentials of transistors Q5 and Q7 are different. The sources of transistors Q6 and Q8 are connected and both are connected to the negative terminal Cap- of filter capacitor C3, meaning transistors Q6 and Q8 share a common ground. The drains of transistors Q5 and Q7 are connected to the positive terminal Cap+ of filter capacitor C3. Among them, switch Q5 and switch Q7 are floating ground switches in the second full-bridge circuit, and switch Q6 and switch Q8 are ground switches in the second full-bridge circuit.

[0087] The third full-bridge circuit includes switching transistors Q9, Q10, Q11, and Q12. The source of Q9 is connected to the drain of Q10 at connection point L, and the source of Q11 is connected to the drain of Q12 at connection point N. The sources of Q10 and Q12 are connected together, and also connected to the sources of Q6 and Q8, all connected to the negative terminal Cap- of filter capacitor C3. That is, switching transistors Q10 and Q12 share a common ground, as do switching transistors Q6 and Q8. The first terminal of the third full-bridge circuit is connected in parallel with filter capacitor C3, and the second terminal is connected to the power grid via relay S1. Switches Q9 and Q11 are floating ground switches in the third full-bridge circuit, while switches Q10 and Q12 are grounded switches.

[0088] in, Figure 1 The switching transistors Q1 to Q12 shown in the diagram each require an independent driving circuit to provide the driving voltage.

[0089] In some embodiments, Figure 1 The first full-bridge circuit on the DC side of the bidirectional DC-AC converter circuit shown can also be replaced with a half-bridge circuit including one bridge arm circuit. For example, the first full-bridge circuit on the DC side can be replaced with a half-bridge circuit including one bridge arm circuit. Figure 1 Replace the switching transistors Q3 and Q4 with capacitors C20 and C21 respectively, as follows: Figure 2 As shown.

[0090] In some embodiments, Figure 1The second full-bridge circuit on the AC side of the bidirectional DC-AC converter circuit shown can also be replaced with a half-bridge circuit including one bridge arm circuit; for example, the second full-bridge circuit on the AC side can be replaced with a half-bridge circuit including one bridge arm circuit. Figure 1 Replace the switching transistors Q7 and Q8 with capacitors C23 and C24 respectively, as follows: Figure 3 As shown.

[0091] The power supply circuit provided in this application embodiment can be applied to other power conversion devices that include multiple active conversion circuits, such as a single-stage DC-AC conversion circuit or a two-stage DC-AC conversion circuit.

[0092] In some embodiments, the switching transistor may also be referred to as a power transistor, or a switching device, or a power device. The switching devices involved in the embodiments of this application may be implemented using, but are not limited to, MOS transistors (Metal-Oxide-Semiconductor Field-Effect Transistors) or IGBTs (Insulated Gate Bipolar Transistors). Unless otherwise specified, this application does not limit the specific type and model of the switching device.

[0093] In one exemplary embodiment, a power supply circuit is provided for supplying power to the drive circuits corresponding to each switching transistor in a power conversion circuit. The power conversion circuit includes a first bridge arm circuit on the DC side. For an example, please refer to... Figure 2 The first bridge arm circuit on the DC side includes switching transistors Q1 and Q2. Please refer to [reference needed]. Figure 4 The power supply circuit includes: a first step-down converter circuit 100, a secondary winding 200, and a first bootstrap circuit 310.

[0094] The input terminal of the first buck converter circuit 100 is connected to a DC power supply, and the DC output terminal of the first buck converter circuit 100 is connected to the input terminal of the first bootstrap circuit 310.

[0095] For example, the DC power supply can be Figure 1 The DC power supply connected to the medium power conversion circuit means that the power supply circuit in this example draws power from the DC side of the power conversion device.

[0096] The first bootstrap circuit 310 is used to power the drive circuit corresponding to the floating ground switch in the first bridge arm circuit. The DC output terminal of the first buck converter circuit 100 is also used to power the drive circuit corresponding to the ground switch in the first bridge arm circuit.

[0097] For example, refer to Figure 2 and Figure 4The first bootstrap circuit 310 is used to power the drive circuit U1 corresponding to the switch Q1 in the first bridge arm circuit, and the DC output terminal of the first buck converter circuit 100 is also used to power the drive circuit U2 corresponding to the switch Q2 in the first bridge arm circuit. For example, as... Figure 4 As shown, the first bootstrap circuit 310 includes a resistor R1, a diode D2, and a capacitor C5; capacitor C6 is the input filter capacitor corresponding to the drive circuit U2.

[0098] In the first buck converter circuit 100, the inductive element N21 serves as the primary winding corresponding to the secondary winding 200. The secondary winding 200 supplies power to the drive circuits corresponding to the switching transistors in the AC-side conversion circuit of the power conversion device. Specifically, the inductive element N21 acts as both a buck inductor in the first buck converter circuit 100 and the primary winding of the isolation transformer in the power supply circuit. When the switching transistors in the first buck converter circuit 100 are turned off, the energy in the inductive element N21 is released to the secondary winding 200, causing the secondary winding 200 to output a certain voltage, thus supplying power to the drive circuits of the switching transistors in the AC-side conversion circuit of the power conversion device.

[0099] In one possible implementation, such as Figure 4 As shown, the first buck converter circuit 100 includes a switching transistor Q13, a diode D1, an inductive element N21, and a capacitor C4. The drain of the switching transistor Q13 is connected to the positive terminal of the DC power supply DC. The source of the switching transistor Q13 is connected to the first terminal of the inductive element N21 and the negative terminal of the diode D1. The positive terminal of the diode D1 is connected to the negative terminal of the DC power supply DC. The second terminal of the inductive element N21 is connected to the first terminal of the capacitor C4, and the second terminal of the capacitor C4 is connected to the positive terminal of the diode D1. The inductive element N21 is anti-coupled with the secondary winding 200. When the switching transistor Q13 is turned off, the energy stored in the inductive element N21 is released to the secondary winding 200 and the DC output terminal (Vpri-Gnd).

[0100] Please refer to Figure 2 and Figure 4 The drive circuits U1 and U2 are powered by the output of the DC output terminal of the first step-down converter circuit 100, and the ground terminal of the drive circuit U2 is connected to the DC side ground terminal (i.e., Figure 1The negative terminal of the DC bus (Bus-) is connected in the circuit. The drive circuit U2 is powered by the power supply path "the positive terminal Vpri of the DC output terminal of the first buck converter circuit 100 - the DC side ground terminal Bus-". The drive circuit U1 is powered by the bootstrap circuit, that is, the drive circuit U1 is powered by the power supply path "the positive terminal Vpri of the DC output terminal of the first buck converter circuit 100 - resistor R1 - diode D2 - capacitor C5 - reference potential AP1". When the switch Q2 is turned on, the positive terminal Vpri of the DC output terminal of the first buck converter circuit 100 is connected to the DC side ground terminal Bus- by the switch Q1, so as to charge the capacitor C5 and ensure the drive voltage of the switch Q1.

[0101] In one possible implementation, each switch in the first bridge arm circuit is a silicon switch (SI switch for short), and the output voltage of the DC output terminal of the first buck converter circuit 100 ranges from 10V to 12V. For example, the output voltage of the DC output terminal of the first buck converter circuit 100 is 12V.

[0102] In the accompanying drawings of the embodiments of this application, the power supply terminal in each driving circuit is marked as Vcc, and the ground terminal is marked as Vee.

[0103] The power supply circuit provided in the above embodiment includes a first buck converter circuit 100, a secondary winding 200, and a first bootstrap circuit 310. The input terminal of the first buck converter circuit 100 is connected to a DC power supply, and the DC output terminal of the first buck converter circuit 100 is connected to the input terminal of the first bootstrap circuit 310. The first bootstrap circuit 310 is used to supply power to the drive circuit corresponding to the floating ground switch in the first bridge arm circuit. The DC output terminal of the first buck converter circuit 100 is also used to supply power to the drive circuit corresponding to the grounding switch in the first bridge arm circuit. The inductive element in the first buck converter circuit 100 serves as the primary winding corresponding to the secondary winding 200, and the secondary winding 200 is used to supply power to the drive circuits of each switch in the AC-side conversion circuit of the power conversion circuit. Compared to related technologies that use a flyback circuit as a power supply circuit, which require a separate excitation winding or a separate secondary winding 200 to power the drive circuits corresponding to the switches in the first bridge arm circuit, the power supply circuit provided in this embodiment uses the inductive element in the first buck converter circuit 100 as the primary winding corresponding to the secondary winding 200. This allows DC voltage to be output from both the DC output terminal of the first buck converter circuit 100 and the secondary winding 200. The DC voltages output from both ends are isolated from each other through the primary winding, which complies with safety regulations. The first bootstrap circuit 310 connects the DC output terminal of the first buck converter circuit 100 to the drive circuits corresponding to the floating switches in the first bridge arm circuit. This allows the drive circuits corresponding to the switches in the first bridge arm circuit to be powered only through the primary side of the power supply circuit. The secondary side of the power supply circuit does not need to provide a corresponding winding for the first bridge arm circuit, thus achieving isolated power supply between the first bridge arm circuit and the AC conversion circuit in the power conversion circuit. The power supply circuit provided by the above embodiment can reduce the number of secondary windings 200, reduce the surface area of ​​the transformer core in the power supply circuit, and thus reduce the transformer volume, thereby realizing a smaller power conversion device.

[0104] In one exemplary embodiment, the DC side of the power conversion circuit further includes a second bridge arm circuit. Please refer to... Figure 1 and Figure 3 The DC-side converter circuit of the power conversion circuit is a first full-bridge circuit, and the second bridge arm circuit includes switching transistors Q3 and Q4; please refer to... Figure 5 The power supply circuit also includes a second bootstrap circuit 320. The DC output terminal of the first buck converter circuit 100 is also connected to the input terminal of the second bootstrap circuit 320.

[0105] The second bootstrap circuit 320 is used to power the drive circuit corresponding to the floating ground switch in the second bridge arm circuit. The DC output terminal of the first buck converter circuit 100 is also used to power the drive circuit corresponding to the ground switch in the second bridge arm circuit.

[0106] Please refer to Figure 1 , Figure 3 and Figure 5 The second bootstrap circuit 320 is used to power the drive circuit U3 corresponding to the switching transistor Q3 in the first full-bridge circuit; the DC output terminal of the first buck converter circuit 100 is also used to power the drive circuit U4 corresponding to the switching transistor Q4 in the first full-bridge circuit. For example, as... Figure 5 As shown, the second bootstrap circuit 320 includes a resistor R2, a diode D3, and a capacitor C7; capacitor C8 is the input filter capacitor corresponding to the drive circuit U4.

[0107] Please refer to Figure 1 , Figure 3 and Figure 5 The drive circuits U1 to U4 are powered by the output of the DC output terminal of the first step-down converter circuit 100. The ground terminals of drive circuits U2 and U4 are connected to the DC side ground terminal (i.e., Figure 1 The negative terminal of the DC bus (Bus-) is connected in the circuit. Drive circuits U2 and U4 are powered by the power supply path "positive terminal Vpri of the DC output terminal of the first buck converter circuit 100 - DC side ground terminal Bus-". Drive circuits U1 and U3 can be powered by a bootstrap circuit. Drive circuit U1 is powered by the power supply path "positive terminal Vpri of the DC output terminal of the first buck converter circuit 100 - resistor R1 - diode D2 - capacitor C5 - reference potential AP1", and drive circuit U3 is powered by the power supply path "positive terminal Vpri of the DC output terminal of the first buck converter circuit 100 - resistor R2 - diode D3 - capacitor C7 - reference potential AP2". When the switching transistors Q2 and Q4 are turned on, the positive terminal Vpri of the DC output terminal of the first buck converter circuit 100 is connected to the DC side ground terminal Bus- by the switching transistors Q1 and Q3, thereby charging capacitors C5 and C7 and ensuring the driving voltage of the switching transistors Q1 and Q3.

[0108] In this embodiment, under operating mode, the two switches in the same bridge arm of the first full-bridge circuit conduct complementary high-frequency signals. The phase shift angle between the two floating switches in the first full-bridge circuit ranges from 0 to 180 degrees, and the drive duty cycle of each switch in the first full-bridge circuit ranges from 40% to 50%. Please refer to... Figure 1In the working mode, switching transistors Q1 and Q2 conduct in a complementary manner at high frequency, and switching transistors Q3 and Q4 conduct in a complementary manner at high frequency. The phase of switching transistors Q1 and Q3 can be dynamically adjusted from 0° to 180°. The driving duty cycle of switching transistors Q1 to Q4 is dynamically adjusted from 40% to 50%.

[0109] For example, the drive duty cycle of switches Q1 to Q4 fluctuates within the range of 40%-50%, so that in the working mode, capacitors C5 and C7 have sufficient charge stored when switches Q2 and Q4 are turned on, which satisfies the bootstrap drive of switches Q1 and Q3.

[0110] The power supply circuit provided in the above embodiment connects the DC output terminal of the first buck converter circuit 100 and the drive circuits corresponding to the two floating ground switches in the first full-bridge circuit through the first bootstrap circuit 310 and the second bootstrap circuit 320. This allows the drive circuits corresponding to each switch in the first full-bridge circuit to be powered only through the primary side of the power supply circuit. On the secondary side of the power supply circuit, it is not necessary to set up corresponding windings for the first full-bridge circuit to achieve isolated power supply between the drive circuits of the DC-side switches and the AC-side switches in the power conversion circuit. Using the power supply circuit provided in the above embodiment can reduce the number of secondary windings 200, reduce the surface area of ​​the transformer core in the power supply circuit, and thus reduce the transformer volume, achieving a smaller power conversion device.

[0111] In an exemplary embodiment, the power conversion circuit further includes a third bridge arm circuit on the AC side, which is connected to the AC side winding N12 in the power conversion circuit and is used to convert the AC current and pulsating current corresponding to the AC side winding N12. For example, please refer to... Figures 1 to 3 The third bridge arm circuit includes switching transistors Q5 and Q6. Please refer to [reference needed]. Figure 6 and Figure 7 The secondary winding in the power supply circuit provided in this embodiment includes a primary winding N22 and a secondary winding N23. The power supply circuit also includes a first voltage regulator circuit 410 and a second voltage regulator circuit 420.

[0112] The first voltage regulator circuit 410 is connected to the first primary winding N22 and is used to power the drive circuit corresponding to the floating ground switch in the third bridge arm circuit; the second voltage regulator circuit 420 is connected to the second primary winding N23 and is used to power the drive circuit corresponding to the grounding switch in the third bridge arm circuit.

[0113] The third bridge arm circuit constitutes a high-voltage, high-frequency AC-DC converter circuit on the AC side. When the switching transistor in the third bridge arm circuit is turned on and off at high frequency, the rate of change of the drain-source voltage dv / dt of the switching transistor is very large. In this embodiment, corresponding secondary windings and voltage regulator circuits are set for the floating ground switch and the ground switch in the third bridge arm circuit, respectively, to provide a stable and reliable drive voltage for the floating ground switch and the ground switch in the third bridge arm circuit on the AC side.

[0114] In an exemplary embodiment, the power conversion circuit further includes a fourth bridge arm circuit on the AC side. The fourth bridge arm circuit and the third bridge arm circuit constitute a second full-bridge circuit on the AC side of the power conversion circuit. The second full-bridge circuit is used to convert the AC current and pulsating current corresponding to the AC winding. Please refer to... Figure 1 and Figure 2 The fourth bridge arm circuit includes switching transistors Q7 and Q8. Please refer to [reference needed]. Figure 6 and Figure 7 In this embodiment, the secondary winding of the power supply circuit further includes a third secondary winding N24, and the power supply circuit also includes a third voltage regulator circuit 430. The third voltage regulator circuit 430 is connected to the third secondary winding N24 and is used to supply power to the drive circuit corresponding to the floating ground switch in the fourth bridge arm circuit. The second voltage regulator circuit 420 is also used to supply power to the drive circuit corresponding to the grounding switch in the fourth bridge arm circuit.

[0115] Please refer to Figure 1 and Figure 2 Switch Q7 and switch Q5 are connected via resonant inductor L1 and resonant capacitor C2, meaning the ground reference potentials of the two floating switches in the second full-bridge circuit on the AC side are different. In this embodiment, the drive circuits corresponding to the two floating switches in the second full-bridge circuit are equipped with independent secondary windings for power supply. The first voltage regulator circuit 410 and the third voltage regulator circuit 430 are used to convert the AC voltage output from the two secondary windings into stable DC voltages. The two grounded switches in the second full-bridge circuit share a common ground. In this embodiment, the second secondary winding N23 is set to power the drive circuits corresponding to the two grounded switches, and the second voltage regulator circuit 420 is used to convert the AC voltage output from the secondary winding into a stable DC voltage.

[0116] In Embodiment 1 of this example, the switching transistors in the second full-bridge circuit are silicon carbide (SiC) switching transistors that require positive voltage to turn on and negative voltage to turn off. For this Embodiment 1, please refer to... Figure 3The first voltage regulator circuit 410, the second voltage regulator circuit 420, and the third voltage regulator circuit 430 each have three output terminals. The first voltage regulator circuit 410 has a positive voltage output terminal Vsec11, a floating ground output terminal Vsec12, and a negative voltage output terminal Vsec13. The positive voltage output terminal Vsec11 and the negative voltage output terminal Vsec13 are connected to the power supply terminal of the drive circuit corresponding to the switching transistor Q5, and the floating ground output terminal Vsec12 is connected to the source of the switching transistor Q5, i.e., connected to the connection point BP1. The second voltage regulator circuit 420 has a positive voltage output terminal Vsec21, a ground output terminal Vsec22, and a negative voltage output terminal Vsec13. 23, wherein the positive voltage output terminal Vsec21 and the negative voltage output terminal Vsec23 are connected to the power supply terminals of the drive circuit corresponding to the switching transistor Q6 and the drive circuit corresponding to the switching transistor Q8, and the ground output terminal Vsec22 is connected to the AC side ground terminal Cap-; the output terminals of the third voltage regulator circuit 430 include a positive voltage output terminal Vsec31, a floating ground output terminal Vsec32 and a negative voltage output terminal Vsec33, wherein the positive voltage output terminal Vsec31 and the negative voltage output terminal Vsec33 are connected to the power supply terminals of the drive circuit corresponding to the switching transistor Q7, that is, connected to the connection point BP2, and the floating ground output terminal Vsec32 is connected to the source of the switching transistor Q7.

[0117] For example, the output voltage of the positive voltage output terminal Vsec11 of the first voltage regulator circuit 410, the positive voltage output terminal Vsec21 of the second voltage regulator circuit 420, and the positive voltage output terminal Vsec31 of the third voltage regulator circuit 430 ranges from 15V to 20V; the output voltage of the negative voltage output terminal Vsec13 of the first voltage regulator circuit 410, the negative voltage output terminal Vsec23 of the second voltage regulator circuit 420, and the negative voltage output terminal Vsec33 of the third voltage regulator circuit 430 ranges from -2V to -5V.

[0118] For example, the output voltages of the positive voltage output terminal Vsec11 of the first voltage regulator circuit 410, the positive voltage output terminal Vsec21 of the second voltage regulator circuit 420, and the positive voltage output terminal Vsec31 of the third voltage regulator circuit 430 are 18V, and the output voltages of the negative voltage output terminal Vsec13 of the first voltage regulator circuit 410, the negative voltage output terminal Vsec23 of the second voltage regulator circuit 420, and the negative voltage output terminal Vsec33 of the third voltage regulator circuit 430 are -3V.

[0119] In one possible implementation of this embodiment 1, the first voltage regulator circuit 410, the second voltage regulator circuit 420, and the third voltage regulator circuit 430 adopt the same circuit topology. Please refer to... Figure 8The circuit topology includes: a first resistor R3, a second resistor R4, a first diode D4, a second diode D5, a first capacitor C9, a second capacitor C10, and a third capacitor C11. The first terminal of the first resistor R3 is connected to the first terminal of the corresponding secondary winding, and the second terminal of the first resistor R3 is connected to the anode of the first diode D4. The cathode of the first diode D4 serves as the positive voltage output terminal of the circuit topology. The first terminals of the first capacitor C9, the second capacitor C10, and the second resistor R4 are all connected to the cathode of the first diode D4. The second terminal of the first capacitor C9 is connected to the corresponding secondary winding. The second end of the winding is connected; the second end of the second capacitor C10 is connected to the first end of the third capacitor C11, and the second end of the third capacitor C11 is connected to the second end of the first capacitor C9; the second end of the second resistor R4 is connected to the second end of the second capacitor C10 and the negative terminal of the second diode D5; the positive terminal of the second diode D5 is connected to the second end of the third capacitor C11, and the second diode D5 is a voltage clamping diode; the positive terminal of the second diode D5 serves as the negative voltage output terminal of the circuit topology, and the negative terminal of the second diode D5 serves as the ground output terminal or floating ground output terminal of the circuit topology.

[0120] For example, please refer to Figure 8 The three output ports of each voltage regulator circuit have potentials of 18V, 0V, and -3V relative to ground, respectively, which are the positive voltage output terminal, the grounded / floating output terminal, and the negative voltage output terminal of the voltage regulator circuit. "_X" represents the potential of the corresponding port relative to ground.

[0121] In Embodiment 2 of this example, the switching transistors in the second full-bridge circuit are silicon switching transistors (SI transistors) that require positive voltage to turn on and zero voltage to turn off. For this Embodiment 2, please refer to... Figure 7The first voltage regulator circuit 410, the second voltage regulator circuit 420, and the third voltage regulator circuit 430 each have two output terminals. The first voltage regulator circuit 410 has a positive voltage output terminal Vsec11 and a floating ground output terminal Vsec12. The positive voltage output terminal Vsec11 is connected to the power supply terminal of the drive circuit corresponding to the switching transistor Q5, and the floating ground output terminal Vsec12 is connected to the source of the switching transistor Q5, i.e., connected to the connection point BP1. The second voltage regulator circuit 420 has a positive voltage output terminal Vsec21 and a ground output terminal Vsec22. 22, wherein the positive voltage output terminal Vsec21 is connected to the power supply terminal of the drive circuit corresponding to the switching transistor Q6 and the power supply terminal of the drive circuit corresponding to the switching transistor Q8, and the ground output terminal Vsec22 is connected to the AC side ground terminal Cap-; the output terminals of the third voltage regulator circuit 430 include a positive voltage output terminal Vsec31 and a floating ground output terminal Vsec32, wherein the positive voltage output terminal Vsec31 is connected to the power supply terminal of the drive circuit corresponding to the switching transistor Q7, and the floating ground output terminal Vsec32 is connected to the source of the switching transistor Q7, that is, connected to the connection point BP2.

[0122] In this embodiment 2, the output voltages of the positive voltage output terminals Vsec11 of the first voltage regulator circuit 410, Vsec21 of the second voltage regulator circuit 420, and Vsec31 of the third voltage regulator circuit 430 range from 10V to 12V. For example, the output voltages of the positive voltage output terminals Vsec11 of the first voltage regulator circuit 410, Vsec21 of the second voltage regulator circuit 420, and Vsec31 of the third voltage regulator circuit 430 are 12V.

[0123] In one possible implementation of this embodiment 2, based on Figure 8 The circuit topology shown bypasses the third capacitor C11, replaces the second diode D5 with a 0Ω resistor, and short-circuits the output terminal to / floating ground and the negative voltage output terminal, thus making the original Figure 8 The potential of the -3V_X port relative to ground is zero, thus it becomes a grounded output port. Figure 8 The circuit topology shown is transformed into a circuit topology with only two ports: positive voltage output and ground output. Then, by changing the winding ratio of the secondary winding, the original... Figure 8 The potential of the 18V_X port relative to ground is compatible with the turn-on voltage of the silicon switching transistor, eliminating the need to redesign the circuit board. The same circuit board can be used to switch between a three-port voltage regulator circuit and a two-port voltage regulator circuit, making it suitable for power conversion circuits using different types of switching transistors and improving the flexibility of power supply circuit applications.

[0124] In one possible implementation of this embodiment 2, based on Figure 8The circuit topology shown can be modified by replacing the third capacitor C11 with a 0Ω resistor and removing the third diode D5. Figure 8 The 0V_X port shown is directly connected to the second terminal of the first capacitor C9 through a 0Ω resistor, making Figure 8 The circuit topology shown is transformed into a circuit topology with only two ports: a positive voltage output and a ground output, i.e., the original... Figure 8 The 18V_X and 0V_X ports are then used to change the winding ratio of the secondary winding, thus making the original Figure 8 The potential of the 18V_X port relative to ground is compatible with the turn-on voltage of the silicon switching transistor, eliminating the need to redesign the circuit board. The same circuit board can be used to switch between a three-port voltage regulator circuit and a two-port voltage regulator circuit, making it suitable for power conversion circuits using different types of switching transistors and improving the flexibility of power supply circuit applications.

[0125] In one possible implementation of this embodiment 2, the first voltage regulator circuit 410, the second voltage regulator circuit 420, and the third voltage regulator circuit 430 employ the same voltage regulator circuit topology. Please refer to... Figure 9 This is a schematic diagram of an exemplary topology of the voltage regulator circuit in this implementation. Figure 9 As shown, the voltage regulator circuit includes a resistor R5, a diode D6, and a capacitor C12. For example, the potentials of the two output ports of the voltage regulator circuit relative to ground are 12V and 0V, respectively, which are the positive voltage output terminal and the grounded / floating output terminal of the voltage regulator circuit.

[0126] In the power supply circuit provided in the above embodiment, the secondary winding includes a first secondary winding N22, a second secondary winding N23, and a third secondary winding N24. The power supply circuit also includes a first voltage regulator circuit 410, a second voltage regulator circuit 420, and a third voltage regulator circuit 430. The first voltage regulator circuit 410 is connected to the first secondary winding N22 and is used to supply power to the drive circuit corresponding to one floating ground switch in the second full-bridge circuit. The third voltage regulator circuit 430 is connected to the third secondary winding N24 and is used to supply power to the drive circuit corresponding to another floating ground switch in the second full-bridge circuit. The second voltage regulator circuit 420 is connected to the second secondary winding N23 and is used to supply power to the drive circuits corresponding to the two grounded switches in the second full-bridge circuit. In this way, the drive circuits corresponding to each switch in the second full-bridge circuit on the AC side of the power conversion circuit are powered through the corresponding secondary windings, achieving mutual isolation between the power supply of the drive circuits corresponding to each switch in the first full-bridge circuit on the DC side. At the same time, the two grounded switches sharing a common ground are powered by the same secondary winding, thereby reducing the number of secondary windings while meeting electrical safety regulations.

[0127] In one exemplary embodiment, please refer to Figure 1 , Figure 2 and Figure 3 The power conversion circuit also includes a third full-bridge circuit on the AC side, which is connected to the second full-bridge circuit and is used for mutual conversion between pulsating current and grid AC current. Please refer to [reference needed]. Figure 10 The power supply circuit also includes a third bootstrap circuit 330 and a fourth bootstrap circuit 340. The third bootstrap circuit 330 and the fourth bootstrap circuit 340 are used to supply power to the drive circuits corresponding to the two floating ground switches in the third full-bridge circuit. The input terminals of the third bootstrap circuit 330 and the fourth bootstrap circuit 340 are both connected to the power input terminals of the drive circuits corresponding to the two grounded switches in the third full-bridge circuit.

[0128] For example, please refer to Figure 1 , Figure 2 , Figure 3 and Figure 10 The third bootstrap circuit 330 is used to power the drive circuit U9 corresponding to the switch Q9 in the third full-bridge circuit, and the fourth bootstrap circuit 340 is used to power the drive circuit U11 corresponding to the switch Q11 in the third full-bridge circuit. The input terminals of the third bootstrap circuit 330 and the fourth bootstrap circuit 340 are connected to the positive voltage output terminal Vsec41. ​​The power supply terminals of the drive circuit U10 corresponding to the switch Q10 and the drive circuit U12 corresponding to the switch Q12 in the first full-bridge circuit are also connected to the positive voltage output terminal Vsec41.

[0129] For example, such as Figure 10 As shown, the third bootstrap circuit 330 includes a resistor R6, a diode D7, and a capacitor C13, and the fourth bootstrap circuit 340 includes a resistor R7, a diode D8, and a capacitor C15; capacitors C14 and C16 are the input filter capacitors corresponding to drive circuits U10 and U12, respectively.

[0130] Please refer to Figure 1 , Figure 2 , Figure 3 and Figure 10The grounding terminals of drive circuit U10 and drive circuit U12 are connected to the AC side grounding terminal Cap-. Drive circuits U10 and U12 are powered by the power supply path “positive voltage output terminal Vsec41-AC side grounding terminal Cap-”. Drive circuits U9 and U11 are powered by a bootstrap circuit. Drive circuit U9 is powered by the power supply path “positive voltage output terminal Vsec41-resistor R6-diode D7-capacitor C13-reference potential L”, and drive circuit U11 is powered by the power supply path “positive voltage output terminal Vsec41-resistor R7-diode D7-capacitor C15-reference potential N”. When switching transistors Q10 and Q12 are turned on, the positive voltage output terminal Vsec41 is connected to the AC side grounding terminal Cap- through switching transistors Q10 and Q12, thereby charging capacitors C13 and C15 and ensuring the drive voltage of switching transistors Q9 and Q11.

[0131] In this embodiment, in the operating mode, the two switches in the same bridge arm of the third full-bridge circuit are complementary in conduction at the power frequency. The switching frequency of the third full-bridge circuit is consistent with the power grid frequency. When the power grid voltage is greater than zero, switches Q9 and Q12 are turned on, and switches Q10 and Q11 are turned off. When the power grid voltage is less than zero, switches Q9 and Q12 are turned off, and switches Q10 and Q11 are turned on. This ensures that in the operating mode, capacitors C13 and C15 have sufficient charge stored when switches Q10 and Q12 are turned on, which satisfies the bootstrap drive of switches Q9 and Q11.

[0132] In one possible implementation, the third full-bridge circuit is a power frequency commutation circuit, wherein the switching frequency of each switch is 50Hz or 60Hz. In this implementation, the bootstrap capacitors C15 and C13 need to have relatively large capacitance values. For example, the bootstrap capacitors C15 and C13 are implemented using electrolytic capacitors.

[0133] In one possible implementation 3, the secondary winding further includes a fourth secondary winding, and the power supply circuit further includes a fourth voltage regulator circuit. The input terminal of the fourth voltage regulator circuit is connected to the fourth secondary winding, and the output terminal of the fourth voltage regulator circuit is connected to the power supply terminal of the drive circuit corresponding to the two grounded switching transistors in the third full-bridge circuit, the input terminal of the third bootstrap circuit 330, and the input terminal of the fourth bootstrap circuit 340, so as to realize that a fourth secondary winding is used to supply power to the drive circuits corresponding to each switching transistor in the third full-bridge circuit.

[0134] In one possible implementation 4, the input terminals of the third bootstrap circuit 330 and the fourth bootstrap circuit 340 are respectively connected to the output terminal of the second voltage regulator circuit 420. The second voltage regulator circuit 420 is also used to supply power to the drive circuits corresponding to the two grounded switching transistors in the third full-bridge circuit. Since both the third full-bridge circuit and the second full-bridge circuit are AC-side conversion circuits of power conversion equipment, and their ground terminals are connected together, in this embodiment, the second stage winding N23, which supplies power to the drive circuits corresponding to the grounded switching transistors in the second full-bridge circuit, and the second voltage regulator circuit 420 supply power to the drive circuits corresponding to the switching transistors in the third full-bridge circuit.

[0135] In one possible implementation of this embodiment 4, each switch in the third full-bridge circuit and each switch in the second full-bridge circuit are positive voltage turn-on and zero voltage turn-off switches; please refer to Figure 7 In this implementation, the positive voltage output terminal Vsec41 is also the positive voltage output terminal Vsec21 of the second voltage regulator circuit 420.

[0136] In one possible implementation of this embodiment 4, the on-state voltage of the switching transistors in the third full-bridge circuit is less than the on-state voltage of the switching transistors in the second full-bridge circuit. That is, each switching transistor in the third full-bridge circuit is a positive voltage turn-on and zero voltage turn-off switching transistor, and each switching transistor in the second full-bridge circuit is a positive voltage turn-on and negative voltage turn-off switching transistor. For example, each switching transistor in the third full-bridge circuit is a silicon switching transistor, and each switching transistor in the second full-bridge circuit is a silicon carbide switching transistor.

[0137] Please refer to Figure 11 The output terminals of the second voltage regulator circuit 420 include a positive voltage output terminal Vsec21, a negative voltage output terminal Vsec23, and a ground output terminal Vsec22. The power supply circuit also includes a second buck converter circuit 500, wherein the input terminal of the second buck converter circuit 500 is connected to the positive voltage output terminal Vsec21 and the ground output terminal Vsec22 of the second voltage regulator circuit 420. The input terminals of the third bootstrap circuit 330 and the fourth bootstrap circuit 340 are respectively connected to the positive voltage output terminal Vsec41 of the second buck converter circuit 500. The second buck converter circuit 500 is used to supply power to the drive circuits corresponding to the two grounded switching transistors in the third full-bridge circuit.

[0138] For example, the second buck converter circuit 500 can be a BUCK buck circuit.

[0139] In this implementation, when the on-state voltage of the switching transistor in the third full-bridge circuit is less than the on-state voltage of the switching transistor in the second full-bridge circuit, the second step-down converter circuit 500 allows the driving circuits corresponding to each switching transistor in the third full-bridge circuit to draw power from the second secondary winding N23 and the second voltage regulator circuit 420, eliminating the need to separately set up secondary windings for the driving circuits corresponding to each switching transistor in the third full-bridge circuit, thus reducing the number of secondary windings in the power supply circuit.

[0140] like Figures 1 to 3 As shown, in a power conversion circuit using a series resonant converter (SRC) topology, when abnormal grid conditions or other reasons cause the switching transistors in the third and / or fourth arm circuits on the AC side to not be fully soft-switched, the circuit degenerates into hard switching. The operating voltage of the third and / or fourth arm circuits is high, and when the switching transistors are hard-switched, a very high dV / dt will occur. The high dV / dt will be coupled to the primary winding side through the interlayer capacitance of the transformer, generating a high-frequency spike voltage at the switch node (SW point) of the switching transistor Q13 in the first buck converter circuit 100, causing abnormal switching action of the switching transistor Q13, resulting in abnormal output voltage of the first buck converter circuit 100. Using the power supply circuit provided in Embodiment 4 above, the drive circuits corresponding to each switching transistor in the third full-bridge circuit can be powered by the secondary winding N23 and the second voltage regulator circuit 420. There is no need to set up a secondary winding separately for the drive circuits corresponding to each switching transistor in the third full-bridge circuit, thus reducing the number of secondary windings in the power supply circuit. The interlayer capacitance of the transformer is the parallel connection of the interlayer capacitance between each secondary winding and the interlayer capacitance between the secondary winding and the primary winding. The fewer the number of windings, the smaller the capacitance value of the transformer's interlayer capacitance, and the larger the capacitive reactance of the corresponding transformer's interlayer capacitance. This can reduce the impact on the switching transistor Q13 in the first buck converter circuit 100 when the third bridge arm circuit and / or the fourth bridge arm circuit on the AC side degenerates into a hard switch, improve the anti-interference capability of the switching nodes in the first buck converter circuit, and improve the power supply reliability and stability of the power supply circuit.

[0141] In one implementation of embodiment 4, the physical distance between the primary winding and the secondary winding, as well as the physical distance between adjacent secondary windings, is increased, the capacitance value of the interlayer capacitance of the transformer is reduced, the anti-interference capability of the switching nodes in the first step-down conversion circuit 100 is improved, and the power supply reliability and stability of the power supply circuit are enhanced.

[0142] For example, the physical distance between the primary and secondary windings can be increased by adding insulating tape between the primary and secondary windings, and the physical distance between adjacent secondary windings can be increased by adding insulating tape between adjacent secondary windings.

[0143] For example, the secondary winding is made of three layers of insulated wire, that is, the primary winding, the secondary winding, and the tertiary winding are each made of three layers of insulated wire. Each of the three layers of insulated wire has three independent insulating coatings or films outside the copper conductor. Thus, by utilizing the multiple high-voltage resistant insulating layers of the three-layer insulated wire, the effective physical distance between the primary and secondary windings is increased, the interlayer capacitance is reduced, and the anti-interference capability against high dv / dt on the secondary side is enhanced.

[0144] In one exemplary embodiment, please refer to Figure 12 This provides a power supply circuit for supplying power to the drive circuits corresponding to each switching transistor in a power conversion circuit. For example... Figure 12 As shown, the power supply circuit includes a first step-down converter circuit 100, a secondary winding 200, a first bootstrap circuit 310, a second bootstrap circuit 320, a third bootstrap circuit 330, a fourth bootstrap circuit 340, a first voltage regulator circuit 410, a second voltage regulator circuit 420, a third voltage regulator circuit 430, and a second step-down converter circuit 500.

[0145] The input terminal of the first buck converter circuit 100 is connected to a DC power supply, and the DC output terminal of the first buck converter circuit 100 is connected to the input terminals of the first bootstrap circuit 310 and the second bootstrap circuit 320. The first bootstrap circuit 310 and the second bootstrap circuit 320 are respectively used to power the drive circuits corresponding to the two floating ground switches in the first full-bridge circuit. The DC output terminal of the first buck converter circuit 100 is also used to power the drive circuits corresponding to the two grounded switches in the first full-bridge circuit.

[0146] In the first buck converter circuit 100, the inductive element N21 serves as the primary winding corresponding to the secondary winding 200. The secondary winding 200 includes a first secondary winding N22, a second secondary winding N23, and a third secondary winding N24. The first voltage regulator circuit 410 is connected to the first secondary winding N22 and is used to power the drive circuit corresponding to one floating ground switch in the second full-bridge circuit. The third voltage regulator circuit 430 is connected to the third secondary winding N24 and is used to power the drive circuit corresponding to another floating ground switch in the second full-bridge circuit. The second voltage regulator circuit 420 is connected to the second secondary winding N23 and is used to power the drive circuits corresponding to the two grounded switches in the second full-bridge circuit.

[0147] The first voltage regulator circuit 410 has an output terminal including a positive voltage output terminal Vsec11, a floating ground output terminal Vsec12, and a negative voltage output terminal Vsec13. The second voltage regulator circuit 420 has an output terminal including a positive voltage output terminal Vsec21, a ground output terminal Vsec22, and a negative voltage output terminal Vsec23. The third voltage regulator circuit 430 has an output terminal including a positive voltage output terminal Vsec31, a floating ground output terminal Vsec32, and a negative voltage output terminal Vsec33. The output voltage range of the positive voltage output terminals Vsec11 of the first voltage regulator circuit 410, Vsec21 of the second voltage regulator circuit 420, and Vsec31 of the third voltage regulator circuit 430 is 15V to 20V. The output voltage range of the negative voltage output terminals Vsec13 of the first voltage regulator circuit 410, Vsec23 of the second voltage regulator circuit, and Vsec33 of the third voltage regulator circuit 430 is -2V to -5V.

[0148] The input terminal of the second buck converter circuit 500 is connected to the positive voltage output terminal Vsec21 and the ground output terminal Vsec22 of the second voltage regulator circuit 420. The input terminals of the third bootstrap circuit 330 and the fourth bootstrap circuit 340 are respectively connected to the positive voltage output terminal Vsec41 of the second buck converter circuit 500. The third bootstrap circuit 330 is used to power the drive circuit U9 corresponding to the switch Q9 in the third full-bridge circuit. The fourth bootstrap circuit 340 is used to power the drive circuit U11 corresponding to the switch Q11 in the third full-bridge circuit. The second buck converter circuit 500 is also used to power the drive circuits corresponding to the two grounded switches in the third full-bridge circuit.

[0149] The power supply circuit provided in this embodiment is suitable for power conversion devices that use a mixture of SiC and SiC switching transistors. It is simple to design and easy to implement, effectively reducing the size of the isolation transformer in the power supply circuit, reducing the size and hardware cost of the power supply circuit, and thus reducing the size and hardware cost of the power conversion device.

[0150] In one exemplary embodiment, please refer to Figure 13 This provides a power supply circuit for supplying power to the drive circuits corresponding to each switching transistor in a power conversion circuit. For example... Figure 10 As shown, the power supply circuit includes a first step-down converter circuit 100, a secondary winding 200, a first bootstrap circuit 310, a second bootstrap circuit 320, a third bootstrap circuit 330, a fourth bootstrap circuit 340, a first voltage regulator circuit 410, a second voltage regulator circuit 420, and a third voltage regulator circuit 430.

[0151] The input terminal of the first buck converter circuit 100 is connected to a DC power supply, and the DC output terminal of the first buck converter circuit 100 is connected to the input terminals of the first bootstrap circuit 310 and the second bootstrap circuit 320. The first bootstrap circuit 310 and the second bootstrap circuit 320 are respectively used to power the drive circuits corresponding to the two floating ground switches in the first full-bridge circuit. The DC output terminal of the first buck converter circuit 100 is also used to power the drive circuits corresponding to the two grounded switches in the first full-bridge circuit.

[0152] In the first buck converter circuit 100, the inductive element N21 serves as the primary winding corresponding to the secondary winding 200. The secondary winding 200 includes a primary winding N22, a secondary winding N23, and a tertiary winding N24. A first voltage regulator circuit 410 is connected to the primary winding N22, a second voltage regulator circuit 420 is connected to the secondary winding N23, and a third voltage regulator circuit 430 is connected to the tertiary winding N24. The outputs of both the first and third voltage regulator circuits 410 and 430 include a positive voltage output and a floating ground output. The output of the second voltage regulator circuit 420 includes a positive voltage output and a grounded output. The first voltage regulator circuit 410 supplies power to the drive circuit corresponding to one floating ground switch in the second full-bridge circuit; the third voltage regulator circuit 430 supplies power to the drive circuit corresponding to another floating ground switch in the second full-bridge circuit; and the second voltage regulator circuit 420 supplies power to the drive circuits corresponding to two grounded switches in the second full-bridge circuit and to the drive circuits corresponding to two grounded switches in the third full-bridge circuit. The third bootstrap circuit 330 and the fourth bootstrap circuit 340 are used to power the drive circuits corresponding to the two floating ground switches in the third full-bridge circuit, respectively. The input terminals of the third bootstrap circuit 330 and the fourth bootstrap circuit 340 are respectively connected to the output terminal of the second voltage regulator circuit 420.

[0153] The power supply circuit provided in this embodiment is suitable for power conversion devices using a single SI switch. It is simple to design and easy to implement, effectively reducing the size of the isolation transformer in the power supply circuit, thereby reducing the size and hardware cost of the power supply circuit, and consequently reducing the size and hardware cost of the power conversion device.

[0154] In one exemplary embodiment, a driving device is provided, comprising: a plurality of driving circuits and a power supply circuit provided in the above embodiments. Each driving circuit is used to drive each switching transistor in a power conversion circuit to operate; the power supply circuit is connected to each driving circuit and is used to supply power to each driving circuit.

[0155] In one exemplary embodiment, a power conversion device is provided, which includes a power conversion circuit and a drive device provided in the foregoing embodiments. The power conversion circuit further includes a first bridge arm circuit on the DC side.

[0156] The power supply circuit includes a first buck converter circuit, a secondary winding, and a first bootstrap circuit. The input terminal of the first buck converter circuit is connected to a DC power supply, and the DC output terminal of the first buck converter circuit is connected to the input terminal of the first bootstrap circuit. The first bootstrap circuit supplies power to the drive circuit corresponding to the floating ground switch in the first bridge arm circuit. The DC output terminal of the first buck converter circuit also supplies power to the drive circuit corresponding to the grounding switch in the first bridge arm circuit. The inductive element in the first buck converter circuit serves as the primary winding corresponding to the secondary winding, and the secondary winding supplies power to the drive circuits corresponding to each switch in the AC-side conversion circuit of the power conversion circuit.

[0157] In an exemplary embodiment, the power conversion circuit in the provided power conversion device includes a third bridge arm circuit on the AC side, which is connected to the AC side winding in the power conversion device and is used for mutual conversion between the AC current and the pulsating current corresponding to the AC side winding; each switch in the third bridge arm circuit is a silicon carbide switch or a silicon switch.

[0158] In an exemplary embodiment, in the operating mode of the provided power conversion device, the two switching transistors of the first bridge arm circuit are complementaryly turned on at high frequency, and the driving duty cycle of each switching transistor in the first bridge arm circuit ranges from 40% to 50%; the two switching transistors of the third bridge arm circuit are complementaryly turned on at high frequency, and the driving duty cycle of each switching transistor in the third bridge arm circuit ranges from 40% to 50%; the outward phase angle between the first bridge arm circuit and the third bridge arm circuit ranges from -90 degrees to 90 degrees.

[0159] In an exemplary embodiment, the provided power conversion device further includes a second bridge arm circuit on the DC side and a fourth bridge arm circuit on the AC side. The first and second bridge arm circuits constitute a first full-bridge circuit on the DC side, and the third and fourth bridge arm circuits constitute a second full-bridge circuit on the AC side. In the first full-bridge circuit, the two switches of the same bridge arm are complementaryly conducted at high frequency, the inner phase shift angle between the two floating switches in the first full-bridge circuit ranges from 0 to 180 degrees, and the drive duty cycle of each switch in the first full-bridge circuit ranges from 40% to 50%. In the second full-bridge circuit, the two switches of the same bridge arm are complementaryly conducted at high frequency, the drive duty cycle of each switch in the second full-bridge circuit ranges from 40% to 50%, and the outer phase shift angle between the first and second full-bridge circuits ranges from -90 degrees to 90 degrees.

[0160] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0161] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A power supply circuit, characterized in that, The power supply circuit is used to supply power to the drive circuits corresponding to each switching transistor in the power conversion circuit. The power conversion circuit includes a first bridge arm circuit on the DC side. The power supply circuit includes: a first buck converter circuit, a secondary winding, and a first bootstrap circuit. The input terminal of the first buck converter circuit is used to connect to a DC power supply, and the DC output terminal of the first buck converter circuit is connected to the input terminal of the first bootstrap circuit. The first bootstrap circuit is used to power the drive circuit corresponding to the floating switch in the first bridge arm circuit. The DC output terminal of the first buck converter circuit is also used to power the drive circuit corresponding to the grounding switch in the first bridge arm circuit. The inductive element in the first buck converter circuit serves as the primary winding corresponding to the secondary winding, and the secondary winding is used to supply power to the drive circuits corresponding to each switch in the AC-side converter circuit of the power conversion circuit.

2. The power supply circuit according to claim 1, characterized in that, The DC side of the power conversion circuit further includes a second bridge arm circuit, and the power supply circuit further includes a second bootstrap circuit, wherein, The DC output terminal of the first buck converter circuit is also connected to the input terminal of the second bootstrap circuit; The second bootstrap circuit is used to power the drive circuit corresponding to the floating switch in the second bridge arm circuit; The DC output terminal of the first buck converter circuit is also used to power the drive circuit corresponding to the grounding switch in the second bridge arm circuit.

3. The power supply circuit according to any one of claims 1-2, characterized in that, The power conversion circuit includes a third bridge arm circuit on the AC side, which is connected to the AC side winding in the power conversion circuit and is used to convert the AC current and pulsating current corresponding to the AC side winding. The secondary winding includes a primary winding and a secondary winding, and the power supply circuit further includes a first voltage regulator circuit and a second voltage regulator circuit, wherein... The first voltage regulator circuit is connected to the first primary winding and is used to supply power to the drive circuit corresponding to the floating switch in the third bridge arm circuit. The second voltage regulator circuit is connected to the second stage winding and is used to supply power to the drive circuit corresponding to the grounding switch in the third bridge arm circuit.

4. The power supply circuit according to claim 3, characterized in that, The power conversion circuit also includes a fourth bridge arm circuit on the AC side. The fourth bridge arm circuit and the third bridge arm circuit constitute a second full-bridge circuit on the AC side of the power conversion circuit. The second full-bridge circuit is used to convert the AC current and pulsating current corresponding to the AC winding. The secondary winding further includes a tertiary winding, and the power supply circuit further includes a third voltage regulator circuit, wherein... The third voltage regulator circuit is connected to the third stage winding and is used to supply power to the drive circuit corresponding to the floating switch in the fourth bridge arm circuit. The second voltage regulator circuit is also used to supply power to the drive circuit corresponding to the grounding switch in the fourth bridge arm circuit.

5. The power supply circuit according to claim 4, characterized in that, Both the output terminals of the first voltage regulator circuit and the third voltage regulator circuit include a positive voltage output terminal, a negative voltage output terminal, and a floating ground output terminal. The output terminals of the second voltage regulator circuit include a positive voltage output terminal, a negative voltage output terminal, and a ground output terminal.

6. The power supply circuit according to claim 5, characterized in that, The first voltage regulator circuit, the third voltage regulator circuit, and the second voltage regulator circuit adopt the same circuit topology, which includes: a first resistor, a second resistor, a first diode, a second diode, a first capacitor, a second capacitor, and a third capacitor. The first end of the first resistor is connected to the first end of the corresponding secondary winding, the second end of the first resistor is connected to the positive terminal of the first diode, and the negative terminal of the first diode serves as the positive voltage output terminal of the circuit topology. The first terminal of the first capacitor, the first terminal of the second capacitor, and the first terminal of the second resistor are all connected to the negative terminal of the first diode; The second terminal of the first capacitor is connected to the second terminal of the corresponding secondary winding; The second terminal of the second capacitor is connected to the first terminal of the third capacitor, and the second terminal of the third capacitor is connected to the second terminal of the first capacitor. The second end of the second resistor is connected to the second end of the second capacitor and the cathode of the second diode; The positive terminal of the second diode is connected to the second terminal of the third capacitor, and the second diode is a voltage clamping diode; The positive terminal of the second diode serves as the negative voltage output terminal of the circuit topology, and the negative terminal of the second diode serves as the ground output terminal or floating ground output terminal of the circuit topology.

7. The power supply circuit according to claim 5, characterized in that, The output voltage values ​​of the positive voltage output terminals of the first voltage regulator circuit, the second voltage regulator circuit, and the third voltage regulator circuit range from 15 volts to 20 volts. The output voltages of the negative voltage output terminals of the first voltage regulator circuit, the second voltage regulator circuit, and the third voltage regulator circuit range from -2V to -5V.

8. The power supply circuit according to claim 4, characterized in that, The output terminals of the first voltage regulator circuit and the third voltage regulator circuit both include a positive voltage output terminal and a floating ground output terminal. The output terminals of the second voltage regulator circuit include a positive voltage output terminal and a grounded output terminal.

9. The power supply circuit according to claim 3, characterized in that, The power conversion circuit also includes a third full-bridge circuit on the AC side, which is used for mutual conversion between pulsating current and grid AC current. The power supply circuit also includes a third bootstrap circuit and a fourth bootstrap circuit, wherein... The third bootstrap circuit and the fourth bootstrap circuit are respectively used to power the drive circuits corresponding to the two floating ground switches in the third full-bridge circuit. The input terminals of the third bootstrap circuit and the fourth bootstrap circuit are both connected to the power supply terminals of the drive circuits corresponding to the two grounded switches in the third full-bridge circuit.

10. The power supply circuit according to claim 9, characterized in that, The third full-bridge circuit is a power frequency commutation circuit.

11. The power supply circuit according to claim 10, characterized in that, The bootstrap capacitors in the third bootstrap circuit and the fourth bootstrap circuit are implemented using electrolytic capacitors.

12. The power supply circuit according to claim 9, characterized in that, The input terminals of the third bootstrap circuit and the fourth bootstrap circuit are respectively connected to the output terminal of the second voltage regulator circuit. The second voltage regulator circuit is also used to supply power to the drive circuits corresponding to the two grounded switching transistors in the third full-bridge circuit.

13. The power supply circuit according to claim 9, characterized in that, The on-state voltage of the switching transistor in the third full-bridge circuit is less than the on-state voltage of the switching transistor in the third bridge arm circuit. The output terminal of the second voltage regulator circuit includes a positive voltage output terminal, a negative voltage output terminal and a ground output terminal. The power supply circuit also includes a second buck converter circuit, which includes an input terminal and a positive voltage output terminal. The input terminal of the second buck converter circuit is connected to the positive voltage output terminal and the ground output terminal of the second voltage regulator circuit; The input terminals of the third bootstrap circuit and the fourth bootstrap circuit are respectively connected to the positive output terminal of the second buck converter circuit. The second step-down converter circuit is used to supply power to the drive circuits corresponding to the two grounded switching transistors in the third full-bridge circuit.

14. The power supply circuit according to claim 1, characterized in that, The secondary winding is made of three layers of insulated wire.

15. A driving device, characterized in that, The driving device includes: Multiple driving circuits are used to drive the operation of each switching transistor in the power conversion circuit; The power supply circuit as described in any one of claims 1-13 is connected to each of the drive circuits and is used to supply power to each of the drive circuits.

16. A power conversion device, characterized in that, The power conversion device includes: A power conversion circuit, wherein the power conversion circuit further includes a first bridge arm circuit on the DC side; The drive device as described in claim 15.

17. The power conversion device according to claim 16, characterized in that, The power conversion circuit includes a third bridge arm circuit on the AC side, which is connected to the AC side winding in the power conversion device and is used for mutual conversion between AC current and pulsating current corresponding to the AC side winding. Each switch in the third bridge arm circuit is a silicon carbide switch or a silicon switch.

18. The power conversion device according to claim 17, characterized in that, In the operating mode, the two switching transistors of the first bridge arm circuit are turned on complementaryly at high frequency, and the driving duty cycle of each switching transistor in the first bridge arm circuit ranges from 40% to 50%. In the third bridge arm circuit, the switching transistors are complementary and conduct at high frequencies, and the driving duty cycle of each switching transistor in the third bridge arm circuit ranges from 40% to 50%. The range of the outward phase angle between the first bridge arm circuit and the third bridge arm circuit is -90 degrees to 90 degrees.

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