Bidirectional gallium nitride T-type three-level power module and circuit board

Abstract

The utility model provides a kind of bidirectional gallium nitride T type three-level power module and circuit board, wherein, upper bridge arm switch device, midpoint bidirectional switch device and lower bridge arm switch device are all bidirectional gallium nitride power switch;The first drive reference pin of upper bridge arm switch device is connected direct current positive bus;The first drive reference pin of midpoint bidirectional switch device and the first drive reference pin of lower bridge arm switch device are connected to the second drive reference pin of upper bridge arm switch device;The first drive reference pin of midpoint bidirectional switch device and the first drive reference pin of lower bridge arm switch device are also connected to the second drive reference pin of upper bridge arm switch device;The second drive reference pin of midpoint bidirectional switch device is connected direct current neutral line;The second drive reference pin of lower bridge arm switch device is connected direct current negative bus, can reduce the quantity of power tube, reduce conduction loss.

Description

Technical Field

[0001] This utility model relates to the field of power electronics technology, and in particular to a bidirectional gallium nitride T-type three-level power module and circuit board. Background Technology

[0002] Currently, in the field of power conversion, the mainstream three-level power modules still use silicon-based IGBTs (Insulated Gate Bipolar Transistors), silicon-based MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors), silicon carbide MOSFETs, and gallium nitride as core switching devices. Among them, the T-type three-level circuit is favored by new energy design engineers due to its simple structure, fewer components, and low cost. A traditional T-type three-level single-bridge power circuit includes: one upper-bridge power switch, one lower-bridge power switch, and two midpoint clamping power switches. All power switches have a body diode, and the three-level topology provides both freewheeling and conduction paths. The shortcomings of this solution are as follows: (1) It requires at least 4 power switching devices, resulting in a large power loop area and difficulties in layout and wiring; (2) Diodes have significant conduction losses, which increase with increasing conduction current; (3) Diodes have reverse recovery losses, which will increase with the increase of conduction current and switching frequency; To address the aforementioned issues, various improvement studies have been conducted on existing technologies.

[0003] An enhanced modulation scheme for multi-level T-type inverters with loss balancing and reduction has been proposed in the prior art (e.g., prior art document 1: X. Zhao et al., “An Enhanced Modulation Scheme for Multi-Level T-Type Inverter With Loss Balance and Reduction,” IEEE Transactions Power Electronic, vol. 38, no. 11, pp. 14050-14064, Nov 2023.). This scheme can balance the switching and conduction losses of all switches in the inverter without considering the influence of power factor and modulation index on losses, and has the ability to balance the midpoint potential. However, since the anti-parallel diodes are still present, it cannot fundamentally eliminate the diode reverse recovery loss.

[0004] To completely eliminate diode reverse recovery losses, a diode-free T-type three-level neutral-point clamped inverter for low-voltage renewable energy systems has been proposed in the prior art (e.g., prior art document 2: Y. Wang et al., “Diode-Free T-Type Three-Level Neutral-Point-Clamped Inverter for Low-Voltage Renewable Energy System,” IEEE Transactions on Industrial Electronics, vol.61, no. 11, pp. 14050-14064, Nov 2014.). In the proposed 3L-NPC, four MOSFETs replace the IGBT+diode bidirectional neutral-line switch. In the proposed topology, no diode is involved in the current path when the output is at zero level. Thus, compared with the conventional T-type 3L-NPC, conduction losses are reduced, especially in the low to medium power range. However, this topology uses a total of six power devices, which not only greatly increases the system cost but also adds additional switching losses.

[0005] To reduce switching losses, existing technologies have proposed a fully soft-switching T-type inverter (e.g., prior art document 3: N. Ting et al., “Design and Implementation of a Flyback-Assisted Wide-Range Fully Soft-Switched T-Type Inverter,” IEEE Transactions Power Electronic, vol. 38, no. 7, pp. 8643-8653, July 2023.). This design introduces an active buffer unit in the main circuit, enabling the main switch to achieve zero-voltage transition turn-on and zero-voltage turn-off, and the auxiliary switch to achieve zero-current turn-on and zero-voltage turn-off, thereby reducing switching losses. The buffer unit in this scheme includes an auxiliary switch, coupling inductor, diode, and buffer capacitor, enabling soft-switching operation at higher switching frequencies. However, this additional auxiliary switch complicates the circuit structure and control relationships, making high-power integration difficult and limiting its applicability.

[0006] In summary, although existing technologies have achieved certain results in reducing switching losses, suppressing reverse recovery losses, and achieving loss balancing through improved control strategies, modified converter topologies, and the addition of soft switching, it is still difficult to simultaneously achieve the comprehensive goals of simplifying bridge arm structures, reducing the number of devices, reducing conduction losses, suppressing reverse recovery losses, and realizing highly integrated power modules. Utility Model Content

[0007] This invention provides a bidirectional gallium nitride T-type three-level power module and circuit board, which reduces the number of power transistors, lowers the conduction loss of the zero vector path, and suppresses voltage spikes and electromagnetic interference.

[0008] This utility model provides a bidirectional gallium nitride T-type three-level power module, comprising: Upper bridge arm switching device, midpoint bidirectional switching device, and lower bridge arm switching device; Among them, the upper bridge arm switching device, the midpoint bidirectional switching device and the lower bridge arm switching device are all bidirectional gallium nitride power switches; The first drive reference pin of the upper bridge arm switching device is connected to the DC positive bus. The second drive reference pin of the upper bridge arm switching device is connected to the first drive reference pin of the midpoint bidirectional switching device and the first drive reference pin of the lower bridge arm switching device; the second drive reference pin of the upper bridge arm switching device, the first drive reference pin of the midpoint bidirectional switching device and the first drive reference pin of the lower bridge arm switching device are also connected to the signal output terminal; The second drive reference pin of the midpoint bidirectional switch device is connected to the DC neutral line; The second drive reference pin of the lower bridge arm switching device is connected to the DC negative bus.

[0009] On the other hand, this utility model discloses a circuit board, wherein a heat dissipation coverage area, multiple isolated power supply areas, and multiple drive signal areas are provided on the first surface of the circuit board; the heat dissipation coverage area is provided with the aforementioned bidirectional gallium nitride T-type three-level power module; the isolated power supply area is provided with an isolated power supply; and the drive signal area is provided with a gate drive unit. The isolation power supply is connected to the gate driving unit, and the isolation power supply is used to provide electrically isolated floating ground power to the gate driving unit; The gate driving unit is used to generate a gate driving signal according to the control signal and input the gate driving signal into the upper bridge arm switching device, the midpoint bidirectional switching device or the lower bridge arm switching device.

[0010] Furthermore, the heat dissipation coverage area is disposed opposite to the isolation power supply area and the drive signal area; the isolation power supply area and the drive signal area are disposed sequentially at intervals along the first direction; the upper bridge arm switching device, the midpoint bidirectional switching device and the lower bridge arm switching device are arranged sequentially along the first direction.

[0011] Furthermore, a gate resistor is also provided; one end of the gate resistor is connected to the drive pin of the upper bridge arm switch device, the midpoint bidirectional switch device, or the lower bridge arm switch device, and the other end is connected to the output terminal of the gate drive unit corresponding to the upper bridge arm switch device, the midpoint bidirectional switch device, or the lower bridge arm switch device.

[0012] Furthermore, a plurality of the gate resistors are disposed within the heat dissipation coverage area, and are respectively arranged in an array on one side of the upper bridge arm switching device, one side of the midpoint bidirectional switching device, and one side of the lower bridge arm switching device.

[0013] Furthermore, on the other side of the circuit board, there are a DC positive bus input terminal, a signal output terminal, and a DC negative bus input terminal arranged sequentially along the first direction; The DC positive bus access terminal is used to connect to the DC positive bus; The signal output terminal is used to connect to a load or an AC signal output terminal; The DC negative bus access terminal is used to connect to the DC negative bus.

[0014] Furthermore, the power supply terminal and the plurality of control signal input terminals are located on the side of the circuit board away from the heat dissipation coverage area; The DC positive bus input terminal, the signal output terminal, and the DC negative bus input terminal are located on one side of the circuit board away from the isolated power supply area and the drive signal area.

[0015] Furthermore, a DC neutral line access point is also provided on the first surface; The DC neutral line access point is located between the midpoint bidirectional switching device and the gate driving unit connected to the midpoint bidirectional switching device, and is located close to the midpoint bidirectional switching device. The DC neutral line access point is used to connect the midpoint potential or the DC neutral line.

[0016] Furthermore, the isolated power supply area is also provided with decoupling capacitors, which are connected to the isolated power supply and are arranged on both sides of the isolated power supply.

[0017] Compared with the prior art, the present invention has at least the following technical effects: By applying bidirectional gallium nitride devices to the main power bridge arm of a T-type three-level power module, firstly, the number of power devices used is reduced, lowering the on-state voltage drop of the zero-level and freewheeling circuits; secondly, the scenarios in which traditional diodes participate in conduction are reduced, effectively avoiding diode reverse recovery problems; in addition, this solution can also reduce the conduction loss of the zero vector path, suppress voltage spikes and electromagnetic interference, thereby improving the overall efficiency and reliability of the circuit.

[0018] Furthermore, the isolated power supply is located within the isolated power supply area, the gate driving unit is located within the driving signal area, and the bidirectional gallium nitride T-type three-level power module is located within the heat dissipation coverage area. These three components are independently configured, meeting the high-speed and reliable driving requirements of three-level multi-floating-point gallium nitride devices. Additionally, the isolated power supply area and driving signal area are located outside the heat dissipation coverage area, keeping the gate driving unit and isolated power supply away from major heat sources and preventing long-term high temperatures from adversely affecting the gate driving unit, power module, and small-signal devices. Moreover, by centrally arranging the bidirectional gallium nitride T-type three-level power module within the heat dissipation coverage area, the length of the main power commutation loop and midpoint loop can be shortened, reducing the power loop area and connection inductance. This also improves thermal design conditions and enhances module power density, reliability, and engineering application value. Furthermore, the bidirectional gallium nitride T-type three-level power module, the isolated power supply, and the gate driving unit are all located on the same surface of the circuit board, forming a shorter local power supply loop, reducing power supply loop impedance, and improving the stability of the driving power supply. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the circuit structure of the bidirectional gallium nitride T-type three-level power module in Embodiment 1 of this utility model; Figure 2 This is a layout diagram of each module on the first surface of the circuit board in Embodiments 1 and 2 of this utility model; Figure 3 This is a schematic diagram of the circuit structure after the isolation power supply and the decoupling capacitor are connected in Embodiment 2 of this utility model; Figure 4 This is a schematic diagram of the circuit structure after the gate driving unit is connected to the gate resistor in Embodiment 2 of this utility model. Detailed Implementation

[0020] The following description, with reference to schematic diagrams, illustrates a bidirectional gallium nitride T-type three-level power module and circuit board according to the present invention. The diagrams represent preferred embodiments of the present invention. It should be understood that those skilled in the art can modify the present invention described herein while still achieving its advantageous effects. Therefore, the following description should be understood as being of general knowledge to those skilled in the art and is not intended to limit the present invention.

[0021] The present invention will be described more specifically by way of example with reference to the accompanying drawings in the following paragraphs. The advantages and features of the present invention will become clearer from the following description. It should be noted that the drawings are all in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the present invention.

[0022] Example 1 Please refer to Figure 1 and Figure 2 This embodiment discloses a bidirectional gallium nitride T-type three-level power module, comprising: Upper bridge arm switching device S1, midpoint bidirectional switching device S2, and lower bridge arm switching device S3.

[0023] Among them, the upper bridge arm switching device S1, the midpoint bidirectional switching device S2, and the lower bridge arm switching device S3 are all bidirectional gallium nitride power switches.

[0024] The first drive reference pin SK1 of the upper bridge arm switching device S1 is connected to the DC positive bus.

[0025] The second drive reference pin SK2 of the upper arm switch device S1 is connected to the first drive reference pin SK4 of the midpoint bidirectional switch device S2 and the first drive reference pin SK5 of the lower arm switch device S3; the second drive reference pin SK2 of the upper arm switch device S1, the first drive reference pin SK4 of the midpoint bidirectional switch device S2 and the first drive reference pin SK5 of the lower arm switch device S3 are also connected to the signal output terminal Vout.

[0026] The second drive reference pin SK3 of the midpoint bidirectional switching device S2 is connected to the DC neutral line.

[0027] The second drive reference pin SK6 of the lower bridge arm switching device S3 is connected to the DC negative bus.

[0028] Please continue to refer to this. Figure 1 and Figure 2 In this embodiment, the DC positive bus is connected to the DC positive bus access terminal Vbus+, the DC neutral line is connected to the DC neutral line access point Vn, and the DC negative bus is connected to the DC negative bus access terminal Vbus-.

[0029] In this embodiment, the upper bridge arm switching device S1, the midpoint bidirectional switching device S2, and the lower bridge arm switching device S3 are bidirectional gallium nitride (GaN) devices, and they are connected in the manner described above to form a T-type three-level main power bridge arm. By applying bidirectional GaN devices to the main power bridge arm of the T-type three-level power module, firstly, the number of power devices used is reduced, lowering the on-state voltage drop of the zero-level and freewheeling circuits; secondly, the scenarios involving traditional diodes in conduction are reduced, effectively avoiding diode reverse recovery problems; furthermore, this solution can also reduce the conduction loss of the zero-vector path, suppress voltage spikes and electromagnetic interference, thereby improving the overall efficiency and reliability of the circuit.

[0030] Please continue to refer to this. Figure 1In this embodiment, the upper bridge arm switching device S1 further includes a first driving pin G1 and a second driving pin G2; the midpoint bidirectional switching device S2 further includes a first driving pin G3 and a second driving pin G4; and the lower bridge arm switching device S3 further includes a first driving pin G5 and a second driving pin G6.

[0031] In this embodiment, the aforementioned drive pins (G1-G6) are used to receive PWM control signals to perform timing control on the aforementioned six control signals, enabling the output terminal to form three output states: positive level, zero level, and negative level, thereby realizing the T-type three-level inverter function.

[0032] The working principle of the above bidirectional gallium nitride T-type three-level power module is as follows: When the upper bridge arm switch S1 is turned on, the output terminal is close to the DC positive bus, forming a positive level output; when the lower bridge arm switch S3 is turned on, the output terminal is close to the DC negative bus, forming a negative level output; when the midpoint bidirectional switch S2 is turned on, the output terminal establishes a zero-level path through the midpoint branch, forming a zero-level output.

[0033] Example 2 Please refer to Figure 2 This embodiment discloses a circuit board, which includes a heat dissipation coverage area, multiple isolated power supply areas, and multiple drive signal areas; the heat dissipation coverage area is provided with a bidirectional gallium nitride T-type three-level power module as disclosed in Embodiment 1; the isolated power supply area is provided with an isolated power supply; and the drive signal area is provided with a gate drive unit.

[0034] The isolation power supply is connected to the gate driving unit, and the isolation power supply is used to provide electrically isolated floating ground power to the gate driving unit.

[0035] The gate driving unit is used to generate a gate driving signal according to the control signal, and input the gate driving signal into the upper bridge arm switching device S1, the midpoint bidirectional switching device S2, or the lower bridge arm switching device S3.

[0036] Specifically, when the upper bridge arm switching device S1 is turned on, the output terminal is close to the DC positive bus, forming a positive level output; when the lower bridge arm switching device S3 is turned on, the output terminal is close to the DC negative bus, forming a negative level output; when the midpoint bidirectional switching device S2 is turned on, the output terminal establishes a zero-level path through the midpoint branch, forming a zero-level output. During load current commutation and freewheeling, the midpoint bidirectional gallium nitride switching unit can also provide a low-loss bidirectional current path, thereby improving the losses and commutation quality of traditional T-type three-level inverters in the zero-level range.

[0037] In this embodiment, the isolated power supply is located within the isolated power supply area, the gate driving unit is located within the driving signal area, and the bidirectional gallium nitride T-type three-level power module is located within the heat dissipation coverage area. These three components are independently configured, meeting the high-speed and reliable driving requirements of three-level multi-floating-point gallium nitride devices. Furthermore, the isolated power supply area and driving signal area are located outside the heat dissipation coverage area, keeping the gate driving unit and isolated power supply away from the main heat source area, preventing long-term high temperatures from adversely affecting the gate driving unit, power module, and small-signal devices. Moreover, by centrally arranging the bidirectional gallium nitride T-type three-level power module within the heat dissipation coverage area, the length of the main power commutation loop and midpoint loop can be shortened, reducing the power loop area and connection inductance. This also improves thermal design conditions and enhances module power density, reliability, and engineering application value. Furthermore, the bidirectional gallium nitride T-type three-level power module, the isolated power supply, and the gate driving unit are all located on the same surface of the circuit board, forming a shorter local power supply loop, reducing power supply loop impedance, and improving the stability of the driving power supply.

[0038] Furthermore, in this embodiment, the gate driving unit can also simultaneously perform level conversion, isolated reference matching, gate charging and discharging capability enhancement, and necessary anti-interference processing.

[0039] In this embodiment, the circuit board has six isolated power supply areas and six drive signal areas. Each isolated power supply area contains one isolated power supply, and each drive signal area contains one gate drive unit. Each gate drive unit controls one drive pin of the upper bridge arm switching device S1, the midpoint bidirectional switching device S2, or the lower bridge arm switching device S3. This ultimately forms six gate drive signals, which drive the upper bridge arm switching device S1, the midpoint bidirectional switching device S2, and the lower bridge arm switching device S3, respectively.

[0040] By coordinating the turn-on and turn-off timing of the upper bridge arm switch S1, the midpoint bidirectional switch S2, and the lower bridge arm switch S3, three states—positive level, zero level, and negative level—can be formed at the signal output terminal Vout, thereby realizing T-type three-level inverter output.

[0041] Correspondingly, the circuit board contains six independent isolated power supply modules. Each of the six isolated power supply modules is connected to one of the six gate drive units. Since the upper arm switch S1, the midpoint bidirectional switch S2, and the lower arm switch S3 in the T-type three-level power module operate at different potentials, especially the midpoint bidirectional switch S2 which changes with its switching state, the use of six independent isolated power supplies can meet the independent drive requirements of bidirectional gallium nitride devices under multi-floating-point conditions.

[0042] Please continue to refer to this. Figure 2In this embodiment, the isolated power supply area is further provided with decoupling capacitors, which are connected to the isolated power supply and are arranged on both sides of the isolated power supply.

[0043] In this embodiment, the decoupling capacitor and the gate driving unit are disposed on the same side of the printed circuit board to form the shortest possible local power supply loop, reduce the power supply loop impedance, and improve the stability of the driving power supply.

[0044] Specifically, isolation power supply 1 has a first decoupling capacitor C1 and a second decoupling capacitor C2 on both sides; isolation power supply 2 has a third decoupling capacitor C3 and a fourth decoupling capacitor C4 on both sides; isolation power supply 3 has a fifth decoupling capacitor C5 and a sixth decoupling capacitor C6 on both sides; isolation power supply 4 has a seventh decoupling capacitor C7 and an eighth decoupling capacitor C8 on both sides; isolation power supply 5 has a ninth decoupling capacitor C9 and a tenth decoupling capacitor C10 on both sides; and isolation power supply 6 has an eleventh decoupling capacitor C11 and a twelfth decoupling capacitor C12 on both sides.

[0045] For a specific example, please refer to Figure 3 Taking the isolation power supply 1 corresponding to the upper bridge arm switching device S1 as an example, the specific working principle of the isolation power supply after being connected to the decoupling capacitor is as follows: After the DC signal is filtered by the first inductor L3 and the first decoupling capacitor C1 to suppress interference, it is sent into the isolated DC-DC (DC to DC) module U14 to achieve electrical isolation between the primary and secondary sides and output isolated power. The isolated output is then filtered by the inductor L1 and the second decoupling capacitor C2 to reduce ripple and provide a stable input for the subsequent low-voltage linear regulator U12. The low-voltage linear regulator U12 sets the output voltage through the voltage divider network composed of resistors R17 and R13, and further filters out noise with capacitors C13 and C35. Finally, the power supply signal is input to the first drive reference pin SK1 of the upper bridge arm switching device S1.

[0046] Furthermore, in this embodiment, a gate resistor is also provided within the heat dissipation coverage area.

[0047] One end of the gate resistor is connected to the drive pin of the upper bridge arm switch S1, the midpoint bidirectional switch S2, or the lower bridge arm switch S3; the other end is connected to the output terminal of the gate drive unit corresponding to the upper bridge arm switch S1, the midpoint bidirectional switch S2, or the lower bridge arm switch S3.

[0048] In this embodiment, a plurality of gate resistors are disposed within the heat dissipation coverage area and are arranged in an array on one side of the upper bridge arm switching device S1, the midpoint bidirectional switching device S2, and the lower bridge arm switching device S3, respectively.

[0049] In this embodiment, the advantages of using the above-described gate resistor layout are: reducing the parasitic inductance and parasitic coupling parameters of the gate circuit, reducing the risk of overshoot, oscillation and crosstalk generated by the upper-level drive signal under high-speed switching conditions, and suppressing the phenomenon of false turn-on.

[0050] In a specific example, please refer to [link / reference]. Figure 2 The first gate resistor R1_1, the second gate resistor R1_2, and the third gate resistor R1_3 are disposed between the upper bridge arm switching device S1 and the gate driving unit 1 and the gate driving unit 2, and along the first direction ( Figure 2 The three gate resistors (as shown in the X direction) are arranged sequentially and connected to the first drive pin G1 of the upper bridge arm switching device S1. The fourth gate resistor R2_1, the fifth gate resistor R2_2, and the sixth gate resistor R2_3 are arranged side by side with the first gate resistor R1_1, the second gate resistor R1_2, and the third gate resistor R1_3, respectively, and these three gate resistors are connected to the second drive pin G2 of the upper bridge arm switching device S1.

[0051] The seventh gate resistor R3_1, the eighth gate resistor R3_2, and the ninth gate resistor R3_3 are disposed between the midpoint bidirectional switching device S2 and the signal output terminal Vout, and are arranged sequentially along the first direction. These three gate resistors are connected to the first drive pin G3 of the midpoint bidirectional switching device S2. The tenth gate resistor R4_1, the eleventh gate resistor R4_2, and the twelfth gate resistor R4_3 are disposed side by side with the seventh gate resistor R3_1, the eighth gate resistor R3_2, and the ninth gate resistor R3_3, respectively. These three gate resistors are connected to the second drive pin G4 of the midpoint bidirectional switching device S2.

[0052] The thirteenth gate resistor R5_1, the fourteenth gate resistor R5_2, and the fifteenth gate resistor R5_3 are disposed between the lower bridge arm switching device S3 and the gate driving unit 5, and are arranged sequentially along the first direction. These three gate resistors are connected to the first driving pin G5 of the lower bridge arm switching device S3. The sixteenth gate resistor R6_1, the seventeenth gate resistor R6_2, and the eighteenth gate resistor R6_3 are disposed side by side with the thirteenth gate resistor R5_1, the fourteenth gate resistor R5_2, and the fifteenth gate resistor R5_3, respectively. These three gate resistors are connected to the second driving pin G6 of the lower bridge arm switching device S3.

[0053] For another specific example, please refer to Figure 4 Taking the gate driving unit 1 corresponding to the upper bridge arm switching device S1 as an example, the specific working principle of the gate driving unit after being connected to the gate resistor is as follows: This circuit is a power transistor gate drive circuit based on the gate drive unit U10. The power transistor gate drive circuit includes a control side. In the control side, a 5V power supply is used to power the first power input pin VDD1 of the gate drive unit U10; a capacitor C15 is used to filter out power supply noise and stabilize the input side voltage; a PWM_A1 control signal is used to input the non-inverting input pin IN+ of the gate drive unit U10, and the inverting input pin IN- is connected to the analog ground AGND, forming a single-ended input; the gate drive unit U10 achieves electrical isolation between the control side and the power side through an internal isolation structure.

[0054] The power transistor gate drive circuit also includes a power side. In the power side section, the second power supply input pin VDD0 of the gate drive unit U10 is connected to the drive power supply (not shown in the figure). Capacitors C30, C32 and C34 are connected in parallel to form a multi-stage decoupling network to filter out high-frequency interference and provide instantaneous large current and stable drive power for gate charging and discharging. The first output pin OUT_SNK of the gate drive unit U10 is connected to the first drive pin G1 of the upper bridge arm switching device S1 through the first gate resistor R1_1 to input the gate drive signal into the upper bridge arm switching device S1. The first drive reference pin SK1 of the upper bridge arm switching device S1 is connected to the ground terminal GND0 pin of the gate drive unit U10. At the same time, the first drive reference pin SK1 of the upper bridge arm switching device S1 also provides a potential reference and current return path for the drive circuit. The second output pin OUT_SRC of the gate drive unit U10 is connected to the first drive pin G1 through the second gate resistor R1_2. It is responsible for gate charge discharge to turn off the power transistor. Differentiated resistance values ​​balance the switching speed and EMI. Zener diode D1 is used to realize overvoltage clamping of the drive pin. Bidirectional TVS diode (bidirectional transient suppression diode) D3 is used to absorb surge and ESD (electrostatic discharge protection) pulses. The third gate resistor R1_3 provides a gate charge discharge path and suppresses oscillation. Together, they form a drive pin protection network.

[0055] Please continue to refer to this. Figure 2 In this embodiment, the isolated power supply area and the drive signal area are arranged sequentially at intervals along a first direction. The heat dissipation coverage area is arranged opposite to the isolated power supply area and the drive signal area. The upper bridge arm switching device S1, the midpoint bidirectional switching device S2, and the lower bridge arm switching device S3 are arranged sequentially along the first direction.

[0056] In one specific example, the first direction is along the width direction of the circuit board.

[0057] For details, please refer to [link / reference]. Figure 2The isolation power supply 1, gate drive unit 1, isolation power supply 2, and gate drive unit 2 are arranged sequentially along the width of the circuit board and are positioned opposite to the upper bridge arm bidirectional gallium nitride device. The isolation power supply 3, gate drive unit 3, isolation power supply 4, and gate drive unit 4 are arranged sequentially along the width of the circuit board and are positioned opposite to the midpoint bidirectional switching device S2. The isolation power supply 5, gate drive unit 5, isolation power supply 6, and gate drive unit 6 are arranged sequentially along the width of the circuit board and are positioned opposite to the lower bridge arm switching device S3.

[0058] In this embodiment, the aforementioned partitioned layout has the following advantages: Firstly, the drive signal area and the heat dissipation coverage area are far apart, reducing direct coupling between strong and weak currents; secondly, the drive signal area is located between the control area and the heat dissipation coverage area, facilitating signal transition and isolation conversion. Furthermore, due to the clear boundaries of each functional area, the overall module structure is more regular, making printed circuit board wiring, debugging, maintenance, and subsequent product packaging easier. Moreover, the wiring loops of the aforementioned partitioned layout are shorter, which can shorten the drive circuit and main power circuit, reduce parasitic inductance and strong / weak current coupling interference, and improve electromagnetic compatibility and switching stability.

[0059] In this embodiment, one side of the circuit board is provided with a plurality of power supply terminals and a plurality of control signal input terminals arranged sequentially along a first direction. The plurality of power supply terminals are respectively used to input external power signals to the plurality of gate driving units and the plurality of isolation power supplies; the control signal input terminals are connected one-to-one with the input terminals of the gate driving units, and the control signal input terminals are used to input the control signals into the gate driving units.

[0060] Furthermore, in this embodiment, the plurality of power supply terminals, the plurality of control signal input terminals, and the ground pin GND are located on the side of the circuit board away from the heat dissipation coverage area.

[0061] In this embodiment, the power supply terminal, control signal input terminal, and other control signal input ports are located on the left edge of the printed circuit board, which facilitates the unified access of external controllers through pin headers, connectors, or wire harnesses, while avoiding cross-coupling between control-side signals and high-current power-side traces.

[0062] Please continue to refer to this. Figure 1 and Figure 2 In a specific example, it includes 2 power supply terminals ( Figure 2 The diagram shows Vcc1 and Vcc2) and 6 control signal input terminals (PWM1-PWM6). The 6 control signal input terminals are used to control the drive pins (G1-G6) of the upper bridge arm switching device, the midpoint bidirectional switching device and the lower bridge arm switching device, respectively.

[0063] In this embodiment, the other side of the circuit board is provided with a DC positive bus input terminal Vbus+, a signal output terminal Vout, and a DC negative bus input terminal Vbus- arranged sequentially along a first direction. The DC positive bus input terminal Vbus+ is used to connect to the DC positive bus; the signal output terminal Vout is used to connect to a load or an AC signal output terminal; and the DC negative bus input terminal Vbus- is used to connect to the DC negative bus.

[0064] For further information, please refer to the following: Figure 2 In this embodiment, the DC positive bus input terminal Vbus+, the signal output terminal Vout, and the DC negative bus input terminal Vbus- are located on the side of the circuit board away from the isolated power supply area and the drive signal area.

[0065] Furthermore, a DC neutral line access point Vn is also provided on the first surface. The DC neutral line access point Vn is disposed between the midpoint bidirectional switching device S2 and the gate driving unit correspondingly connected to the midpoint bidirectional switching device S2, and is disposed close to the midpoint bidirectional switching device S2. The DC neutral line access point is used to connect the midpoint potential or the DC neutral line.

[0066] The advantages of adopting the above layout are: the DC positive bus input terminal Vbus+, DC negative bus input terminal Vbus-, DC neutral line input point Vn connecting the high-power device, together with the bidirectional gallium nitride T-type three-level power module and the signal output terminal Vout, form the shortest main commutation loop, reducing the loop area and distributed inductance under high-frequency switching conditions, and reducing voltage spikes, circulating currents and switching oscillations caused by stray parameters.

[0067] Obviously, those skilled in the art can make various modifications and variations to this utility model without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this utility model and their equivalents, this utility model also intends to include these modifications and variations.

Claims

1. A bidirectional gallium nitride T-type three-level power module, characterized in that, include: Upper bridge arm switching device, midpoint bidirectional switching device, and lower bridge arm switching device; Among them, the upper bridge arm switching device, the midpoint bidirectional switching device and the lower bridge arm switching device are all bidirectional gallium nitride power switches; The first drive reference pin of the upper bridge arm switching device is connected to the DC positive bus. The second drive reference pin of the upper bridge arm switching device is connected to the first drive reference pin of the midpoint bidirectional switching device and the first drive reference pin of the lower bridge arm switching device; the second drive reference pin of the upper bridge arm switching device, the first drive reference pin of the midpoint bidirectional switching device and the first drive reference pin of the lower bridge arm switching device are also connected to the signal output terminal; The second drive reference pin of the midpoint bidirectional switching device is connected to the DC neutral line; The second drive reference pin of the lower bridge arm switching device is connected to the DC negative bus.

2. A circuit board, characterized in that, The first surface of the circuit board is provided with a heat dissipation coverage area, multiple isolated power supply areas, and multiple drive signal areas; the heat dissipation coverage area is provided with a bidirectional gallium nitride T-type three-level power module as described in claim 1; the isolated power supply area is provided with an isolated power supply; and the drive signal area is provided with a gate drive unit. The isolation power supply is connected to the gate driving unit, and the isolation power supply is used to provide electrically isolated floating ground power to the gate driving unit; The gate driving unit is used to generate a gate driving signal according to the control signal and input the gate driving signal into the upper bridge arm switching device, the midpoint bidirectional switching device or the lower bridge arm switching device.

3. The circuit board as described in claim 2, characterized in that, The heat dissipation coverage area is positioned opposite to the isolated power supply area and the drive signal area; the isolated power supply area and the drive signal area are sequentially spaced apart along a first direction; the upper bridge arm switching device, the midpoint bidirectional switching device, and the lower bridge arm switching device are sequentially arranged along the first direction.

4. The circuit board as described in claim 3, characterized in that, It also includes a gate resistor; One end of the gate resistor is connected to the drive pin of the upper bridge arm switch, the midpoint bidirectional switch, or the lower bridge arm switch, and the other end is connected to the output terminal of the gate drive unit corresponding to the upper bridge arm switch, the midpoint bidirectional switch, or the lower bridge arm switch.

5. The circuit board as described in claim 4, characterized in that, Multiple gate resistors are disposed within the heat dissipation coverage area and are arranged in an array on one side of the upper bridge arm switching device, one side of the midpoint bidirectional switching device, and one side of the lower bridge arm switching device, respectively.

6. The circuit board as described in claim 5, characterized in that, One side of the circuit board is provided with a power supply terminal, multiple control signal input terminals and a ground pin arranged sequentially along the first direction; The power supply terminal is used to input external power signals to the multiple gate driving units and the multiple isolation power supplies; The control signal input terminal is connected to the input terminal of the gate driving unit in a one-to-one correspondence, and the control signal input terminal is used to input the control signal into the gate driving unit.

7. The circuit board as described in claim 6, characterized in that, The other side of the circuit board is provided with a DC positive bus input terminal, a signal output terminal and a DC negative bus input terminal arranged sequentially along the first direction; The DC positive bus access terminal is used to connect to the DC positive bus; The signal output terminal is used to connect to a load or an AC signal output terminal; The DC negative bus access terminal is used to connect to the DC negative bus.

8. The circuit board as described in claim 7, characterized in that, The power supply terminal, the plurality of control signal input terminals, and the grounding pin are located on the side of the circuit board away from the heat dissipation coverage area; The DC positive bus input terminal, the signal output terminal, and the DC negative bus input terminal are located on one side of the circuit board away from the isolated power supply area and the drive signal area.

9. The circuit board as described in claim 7, characterized in that, The first surface is also provided with a DC neutral line access point; The DC neutral line access point is located between the midpoint bidirectional switching device and the gate driving unit connected to the midpoint bidirectional switching device, and is located close to the midpoint bidirectional switching device. The DC neutral line access point is used to connect the midpoint potential or the DC neutral line.

10. The circuit board as described in claim 2, characterized in that, The isolated power supply area is also provided with decoupling capacitors, which are connected to the isolated power supply and are arranged on both sides of the isolated power supply.

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