Bidirectional solid state relay based on gallium nitride triodes

Abstract

The application discloses a bidirectional solid-state relay based on a gallium nitride triode, which comprises a main circuit, a gallium nitride power triode, a bidirectional rectifying module, a switching power supply unit and a control module thereof, a to-be-on-off voltage high-low detection module and an optical coupling triode isolation control module. The gallium nitride triode with bidirectional symmetric conduction is used as a switching element of the solid-state relay, so that the on-resistance can be greatly reduced, and in the case of a large current, a plurality of gallium nitride triodes with similar performance can be connected in parallel to reduce the on-voltage drop of the solid-state relay, thereby greatly reducing the power consumption and heat generation, and reducing the difference between the input and output voltages of the relay, so that the solid-state relay has the advantages of long switching life, low on-voltage drop, low on-loss, low heat dissipation requirement and the like.

Description

Technical Field

[0001] This invention relates to the field of relay devices, and more particularly to a bidirectional solid-state relay based on a gallium nitride transistor. Background Technology

[0002] Currently, most solid-state relays use a dual anti-parallel silicon controlled rectifier (SCR) structure and two anti-parallel metal-oxide-semiconductor field-effect transistors (MOSFETs) to form a fixed main circuit that allows bidirectional current flow, replacing electromechanical contact relays. These relays generally suffer from large voltage drops or high on-resistance in the main circuit. Therefore, when a large current flows through, the main circuit may overheat, requiring heat dissipation measures such as metal heat sinks, fan cooling, or water cooling systems. However, this also results in energy waste or distortion of the voltage waveform.

[0003] Currently, most bidirectional solid-state relays on the market suffer from excessive voltage drop and high power consumption in the controlled main circuit. When power consumption is too high, a metal heat sink or forced air cooling by a fan is required, which increases the size and cost of the system and reduces the reliability of the solid-state relay. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a bidirectional solid-state relay based on a gallium nitride transistor, which can effectively solve the common problems of excessive voltage drop and high power consumption in solid-state relays.

[0005] The technical solution of this invention is:

[0006] A bidirectional solid-state relay based on a gallium nitride transistor includes a main circuit, a gallium nitride power transistor, a bidirectional rectifier module, a switching power supply unit and its control module, a voltage high / low detection module at the two ends to be switched on and off, and an optocoupler transistor isolation control module.

[0007] The gallium nitride power transistor has bidirectional consistent turn-on and turn-off characteristics;

[0008] The main circuit is connected to the bidirectional rectifier module and rectifies the voltage into DC voltage to supply power to the switching power supply unit for controlling the fixed relay.

[0009] The switching power supply unit and its control module are powered by DC voltage after rectification by a bidirectional rectifier module. The switching power supply unit and its control module include a flyback transformer and a switching power supply control unit.

[0010] The voltage level detection module at both ends to be switched on and off is connected in parallel with the gallium nitride power transistor.

[0011] The optocoupler transistor isolation control module uses optocouplers to control the bidirectional main circuit on / off of the gallium nitride power transistor of the relay based on the relay's on / off control signal and the voltage levels at both ends to be switched on / off.

[0012] Preferably, the bidirectional rectifier module includes a set of bidirectional full-bridge diode rectifier units connected by six diodes, and the voltage at the end with the higher voltage between the two ends of the main circuit to be switched on and off is rectified into a DC voltage by the bidirectional full-bridge diode rectifier units.

[0013] Preferably, the switching power supply unit and its control module include a flyback transformer comprising a main coil and two secondary coils. The DC voltage is supplied to the main coil, and the two secondary coils form two power supplies. One power supply provides power to the optocoupler transistor and to the voltage high / low detection module at the two ends to be switched on / off. The other power supply provides power to the optocoupler transistor isolation control module.

[0014] Preferably, the switching power supply unit and its control module do not require an additional DC power supply to power the excitation operation. The switching power supply unit and its control module are equipped with a unit that provides a high-voltage power input voltage directly to the switching power supply control circuit to provide startup power.

[0015] Preferably, the optocoupler isolation control module includes an on-resistor, an off-resistor, a logic circuit, and a group of optocouplers controlling the on / off state of the gallium nitride power transistor voltage and current.

[0016] Preferably, the gallium nitride transistor is also connected in parallel to a bidirectional freewheeling overvoltage protection voltage regulator module that provides a freewheeling circuit for inductive current when the relay is turned off, so as to protect the gallium nitride power transistor.

[0017] Preferably, the bidirectional freewheeling overvoltage protection voltage regulator module includes two Zener diodes connected in reverse series.

[0018] The beneficial technical effects of this invention are:

[0019] I. This invention uses bidirectional gallium nitride power transistors with symmetrical conduction as the switching element of a solid-state relay, which can significantly reduce the on-resistance. Furthermore, under high current conditions, multiple gallium nitride transistors with similar performance can be connected in parallel to reduce the on-state relay voltage drop, thereby significantly reducing power consumption and heat generation, and reducing the voltage difference between the relay input and output terminals. This results in a long switching life, a high number of switching cycles, and a low on-state voltage drop for the solid-state relay.

[0020] Second, by using a single gallium nitride transistor, this invention can reduce or eliminate the heat sink in traditional relays, thereby reducing the size of high-current solid-state relays and saving the cost of heat sinks inside the relays.

[0021] Third, the switching control module of the solid-state relay of the present invention draws power from the main circuit at both ends to be switched to achieve self-powered operation through switching power supply technology, eliminating the need for an additional DC control power supply. This further reduces the system wiring and cost of the relay, and improves reliability and ease of use.

[0022] Fourth, the solid-state relay of the present invention uses a pair of reverse series Zener diodes connected in parallel with a bidirectional gallium nitride power transistor to provide an inductive current freewheeling circuit for inductive loads when the fixed relay of the present invention is turned off, thereby avoiding overvoltage when the gallium nitride transistor is turned off, improving the reliability of the solid-state relay and expanding its application range. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the gallium nitride transistor structure of the bidirectional solid-state relay based on the gallium nitride transistor of this invention;

[0024] Figure 2 This is a circuit diagram of the gallium nitride transistor in the bidirectional solid-state relay based on the gallium nitride transistor of this invention;

[0025] Figure 3 This is a detailed circuit diagram of the bidirectional solid-state relay based on gallium nitride transistors of the present invention;

[0026] Figure 4 This is a detailed circuit diagram of the bidirectional rectifier module and switching power supply unit and control module of the bidirectional solid-state relay based on gallium nitride transistor of the present invention.

[0027] Figure 5 This is a detailed circuit diagram of the optocoupler transistor isolation control module of the bidirectional solid-state relay based on gallium nitride transistors of this invention;

[0028] Figure 6 This is a schematic diagram of the switching control unit of the bidirectional solid-state relay based on gallium nitride transistors of the present invention.

[0029] Figure 7 This is a detailed circuit diagram of the bidirectional freewheeling overvoltage protection and voltage regulation module and the high / low voltage detection module at both ends of the bidirectional solid-state relay based on gallium nitride transistors of the present invention.

[0030] Figure 8 This is a typical output conduction characteristic diagram of the bidirectional gallium nitride transistor in the bidirectional solid-state relay based on gallium nitride transistors of this invention.

[0031] Figure 1 middle:

[0032] 101 - Electron generation layer, 102 - Dielectric layer, 103 - Gallium nitride layer, 104 - Aluminum nitride isolation layer, 105 - Silicon layer. Detailed Implementation

[0033] In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0034] In the description of this invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "front", "rear", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0035] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "configuration" should be interpreted broadly. For example, they can refer to a fixed connection or configuration, a detachable connection or configuration, or an integral connection or configuration. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0036] This specific embodiment discloses in detail a bidirectional solid-state relay based on a gallium nitride transistor, including a main circuit, a gallium nitride power transistor, a bidirectional rectifier module, a switching power supply unit and its control module, a voltage high / low detection module at the two ends to be switched on and off, and an optocoupler transistor isolation control module;

[0037] The gallium nitride power transistor has bidirectional consistent turn-on and turn-off characteristics;

[0038] The main circuit is connected to the bidirectional rectifier module and rectifies the voltage into DC voltage to supply power to the switching power supply unit for controlling the fixed relay.

[0039] The switching power supply unit and its control module are powered by DC voltage after rectification by a bidirectional rectifier module. The switching power supply unit and its control module include a flyback transformer and a switching power supply control unit.

[0040] The voltage level detection module at both ends to be switched on and off is connected in parallel with the gallium nitride power transistor.

[0041] The optocoupler transistor isolation control module uses optocouplers to control the bidirectional main circuit on / off of the gallium nitride power transistor of the relay based on the relay's on / off control signal and the voltage levels at both ends to be switched on / off.

[0042] like Figures 3-7As shown, it is particularly noted that in this embodiment, the input voltage V of the main circuit is... DS_in or V DS_out With V PGND The voltage between the two circuits is used to generate a high-voltage DC voltage V in the main circuit through a rectifier bridge consisting of six diodes D1 to D6. P ~V PGND Then, two DC power supplies are generated through a flyback transformer and a switching power supply control circuit, one of which is an isolated power supply V. D ~V DGND A switching power supply V used to drive or turn off the gate of a gallium nitride power transistor and another common ground line. CC ~V CGND This circuit supplies power to the switching power supply control unit, the secondary side of the fixed relay on / off control signal isolation optocoupler transistor, and the voltage level detection module at both ends of the switch. The switching power supply control circuit does not require an external power supply for operation; instead, it is powered by the high-voltage input voltage V. P The power supply is directly supplied to the switching power supply control unit for startup until the flyback switching power supply can operate normally and output a stable gate-isolated power supply V to control the gallium nitride power transistor. D ~V DGND The transistor's gate and a common ground switching power supply V CC ~V CGND V CC It is also the voltage signal for the control feedback input of the switching power supply.

[0043] The physical structure of a gallium nitride transistor is as follows: Figure 1 As shown, it is possible to manufacture transistors with consistent bidirectional conduction characteristics, low on-resistance, and no reverse parallel diodes. Figure 8 This shows the bidirectional conduction characteristics of gallium nitride transistors, indicating that the bidirectional conduction characteristics of gallium nitride are consistent.

[0044] Furthermore, the bidirectional rectifier module includes a bidirectional full-bridge diode rectifier group consisting of six diodes connected together. The voltage at the end with the higher voltage between the two ends of the main circuit to be switched on and off is rectified into a DC voltage by the bidirectional full-bridge diode rectifier group.

[0045] Furthermore, the flyback transformer includes a main coil and two secondary coils. The DC voltage is supplied to the main coil, and the two secondary coils form two power supplies. One power supply provides power to the optocoupler transistor and the voltage level detection module at the two ends to be switched on and off; the other power supply provides power to the optocoupler transistor isolation control module.

[0046] Furthermore, the switching power supply unit and its control module do not require an additional DC power supply to power the excitation operation. The switching power supply unit and its control module are equipped with a unit that directly provides the starting power to the switching power supply control circuit with a high-voltage power input voltage.

[0047] Furthermore, the optocoupler isolation control module includes an on-resistor, an off-resistor, logic circuitry, and a group of optocouplers controlling the on / off state of the gallium nitride power transistor voltage and current.

[0048] Furthermore, the gallium nitride transistor is also connected in parallel with a set of bidirectional overvoltage protection Zener diodes or similar overvoltage protection components to provide a freewheeling circuit for inductive current when the relay is turned off, in order to protect the gallium nitride power transistor.

[0049] Furthermore, the bidirectional freewheeling overvoltage protection voltage regulator module includes two Zener diodes or similar overvoltage protection components connected in reverse series.

[0050] In this embodiment, the control signal LV, indicating voltage level or current direction, is obtained from the voltage comparison circuit between the input and output terminals of the relay main circuit to be switched on and off. DS When V DS Higher than V SD LV DS When the voltage level is high, if the solid-state relay control signal is on, the current should flow from the DS terminal (input terminal of the relay main circuit) to the SD terminal (output terminal of the relay main circuit) of the gallium nitride transistor, and the corresponding V... gSD The on-resistance R of the gallium nitride transistor is positive voltage (around +5V to +15V). DS Extremely small; if the solid-state relay control signal is off, the corresponding V gSD The on-resistance R of the gallium nitride transistor is at a negative voltage (around -5V to -15V). DS Maximum, current i DS Close to 0.

[0051] When V DS Less than V SD LV DS When the voltage level is low, if the solid-state relay control signal requires the relay to be turned on or off, the current should flow from the SD terminal (output terminal of the relay main circuit) to the DS terminal (input terminal of the relay main circuit) of the gallium nitride transistor, and the corresponding V... gDS The on-resistance R of the gallium nitride transistor is positive voltage (around +5V to +15V). SD Extremely small; if the solid-state relay control signal is off, the corresponding V gDS The on-resistance R of the gallium nitride transistor is at a negative voltage (around -5V to -15V). SD Maximum, current i SDClose to 0.

[0052] In this embodiment, as Figure 5 As shown, S on / off and V SGND It is the on / off control signal of the solid-state relay. Electrical isolation is achieved between the optocoupler transistor and the main circuit of the gallium nitride transistor in the solid-state relay, thus obtaining the gallium nitride control signal L. on / off The control signal L, which determines the direction of current flow, is obtained through a voltage comparison circuit between the input and output terminals of the relay main circuit. VDS This constitutes the gallium nitride control signal. Among them, R... on and R off It is a resistor that controls the on and off gate current of gallium nitride.

[0053] The specific work situation is shown in the table below:

[0054] <![CDATA[L on / off ]]> <![CDATA[S g1 ]]> <![CDATA[S g2 ]]> <![CDATA[LV DS ]]> <![CDATA[Q1 / L SD1 ]]> <![CDATA[Q2 / L SD2 ]]> <![CDATA[Q3 / L DS1 ]]> <![CDATA[Q4 / L DS2 ]]> 1 1 0 1 1 0 0 0 1 1 0 0 0 1 0 0 0 0 1 1 0 0 1 0 0 0 1 0 0 0 0 1

[0055] The bidirectional solid-state relay based on gallium nitride transistor of this invention uses gallium nitride transistor and utilizes its V DS and V SD The bidirectional characteristics of the relay replace the mechanical contacts of the electromagnetic relay. Compared with the electromagnetic relay, the gallium nitride bidirectional solid-state relay of this invention, in addition to connecting the input and output terminals of the active power circuit, also needs to be connected to the ground wire of the controlled active power circuit, and the active power circuit provides a small amount of power to control the gallium nitride transistor. Compared with solid-state relays composed of bidirectional thyristors, the on-resistance and voltage drop of the gallium nitride transistor are significantly reduced. This ensures that the controlled voltage waveform does not change significantly and significantly reduces its heat generation and heat dissipation requirements.

[0056] This invention relates to a solid-state relay based on the bidirectional conduction characteristics of gallium nitride and the absence of a reverse parallel diode. It can control bidirectional low-power conduction of either AC or DC current, thus replacing electromagnetic mechanical relays in applications where frequent switching is common and the contacts of electromagnetic mechanical relays are prone to damage. For example... Figure 7 As shown, the solid-state relay can control the signal S according to the switching level. on / off and V SGND The high and low levels between them control the input voltage V. DS_in With output voltage V SD_out The solid-state relay of this invention operates by switching the current between input and output voltages, with the power supply coming from the input voltage V. DS_in or V DS_out and V PGND Power supply between them. On / off switch control signal S on / off and V SGNDThe current range is between 4mA and 10mA, and the voltage range is between 3.3V and 24V.

[0057] This invention employs bidirectional gallium nitride (GaN) transistors as the switching element of a solid-state relay, significantly reducing on-resistance. Furthermore, under high current conditions, multiple GaN transistors with similar performance can be connected in parallel to reduce the on-state voltage drop, thereby significantly reducing power consumption and heat generation, and minimizing the voltage difference between the relay's input and output terminals. This results in a longer switching lifespan, a higher number of switching cycles, and a lower on-state voltage drop for the solid-state relay. The use of bidirectional GaN transistors reduces or eliminates the need for heat sinks in traditional relays, thus reducing the size of the high-current solid-state relay and saving on the cost of internal heat sinks. The switching control module of this invention draws power from the main circuit using switching power supply technology, achieving self-powering without an additional DC control power supply. This further reduces the system's wiring and cost, improving reliability and ease of use. The solid-state relay of the present invention uses a pair of reverse series Zener diodes connected in parallel with a bidirectional gallium nitride transistor to provide an inductive current freewheeling circuit for inductive loads when the fixed relay is turned off, thereby avoiding overvoltage when the gallium nitride transistor is turned off, improving the stability and reliability of the relay and expanding its application range.

[0058] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A bidirectional solid-state relay based on a gallium nitride transistor, comprising a main circuit, characterized in that, It also includes gallium nitride power transistors, bidirectional rectifier modules, switching power supply units and their control modules, voltage high / low detection modules at the two ends to be switched on and off, and optocoupler transistor isolation control modules; The gallium nitride power transistor has bidirectional consistent turn-on and turn-off characteristics; The main circuit is connected to the bidirectional rectifier module and rectifies the voltage into DC voltage to supply power to the switching power supply unit for controlling the fixed relay. The switching power supply unit and its control module are powered by DC voltage after rectification by a bidirectional rectifier module. The switching power supply unit and its control module include a flyback transformer and a switching power supply control module. The voltage level detection module at both ends to be switched on and off is connected in parallel with the gallium nitride power transistor. The optocoupler transistor isolation control module uses an optocoupler transistor to control the bidirectional main circuit on and off of the gallium nitride power transistor of the relay based on the relay's on / off control signal and the voltage level at both ends to be switched on or off. The flyback transformer includes a main coil and two secondary coils. The DC voltage is supplied to the main coil, and the two secondary coils form two power supplies. One power supply provides power to the optocoupler transistor and the voltage level detection module at both ends to be switched on and off; the other power supply provides power to the optocoupler transistor isolation control module.

2. The bidirectional solid-state relay based on a gallium nitride transistor according to claim 1, characterized in that, The bidirectional rectifier module includes a set of bidirectional full-bridge diode rectifier units connected by six diodes. The voltage at the end with the higher voltage between the two ends of the main circuit to be switched on and off is rectified into a DC voltage by the bidirectional full-bridge diode rectifier units.

3. The bidirectional solid-state relay based on a gallium nitride transistor according to claim 1, characterized in that, The switching power supply unit and its control module do not require an additional DC power supply to power the excitation operation. The switching power supply unit and its control module are equipped with a unit that provides a high-voltage power input voltage directly to the switching power supply control circuit to provide startup power.

4. The bidirectional solid-state relay based on a gallium nitride transistor according to claim 1, characterized in that, The optocoupler isolation control module includes an on-resistor, an off-resistor, logic circuitry, and a group of optocouplers controlling the on / off state of gallium nitride power transistors for voltage and current switching.

5. The bidirectional solid-state relay based on a gallium nitride transistor according to claim 1, characterized in that, The gallium nitride transistor is also connected in parallel to a bidirectional overvoltage protection voltage regulator module that provides an inductive current freewheeling circuit when the relay is turned off, in order to protect the gallium nitride power transistor.

6. The bidirectional solid-state relay based on a gallium nitride transistor according to claim 5, characterized in that, The bidirectional freewheeling overvoltage protection voltage regulator module includes two Zener diodes connected in reverse series.

Images