Anti-voltage driving circuit, three-phase frequency conversion driving circuit, refrigerator and equipment

Abstract

The utility model relates to drive circuit technical field provides anti negative pressure drive circuit, three -phase frequency conversion drive circuit, refrigerator and equipment, wherein anti negative pressure drive circuit includes: half bridge drive module, including upper bridge arm pipe and lower bridge arm pipe, and the connecting point of upper bridge arm pipe and lower bridge arm pipe forms half bridge output midpoint, pre -drive module, first output end is connected with the controlled end of upper bridge arm pipe, and the second output end is connected with the controlled end of lower bridge arm pipe, bootstrap module is connected with the suspension power end, anti negative pressure module, one end is connected with the suspension reference end, and the other end is connected with bootstrap module and half bridge output midpoint respectively. Through setting up anti negative pressure module between half bridge output midpoint and suspension reference end, when generating negative voltage in half bridge output midpoint, anti negative pressure module can reduce the peak value of negative voltage generated in half bridge output midpoint, thereby preventing the pre -drive module from happening latch -up because of the suspension reference end bears too high negative pressure, and the reliability and safety of drive circuit are improved.

Description

Technical Field

[0001] This utility model relates to the field of drive circuit technology, and in particular to anti-negative pressure drive circuit, three-phase frequency conversion drive circuit, refrigerator and equipment. Background Technology

[0002] The drive circuit uses a half-bridge circuit structure. When driving inductive loads such as compressors, abnormal operating conditions such as overload and stall can cause instantaneous changes in drive power and current. The sudden current change, combined with the effect of loop parasitic inductance, can cause the floating reference terminal (VS pin) of the pre-drive chip to be subjected to excessively high negative voltage, which can easily lead to latch-up of the pre-drive chip. When latch-up occurs, it will abnormally drive the upper transistor of the half-bridge circuit to remain in a conducting state, resulting in the upper and lower transistors of the half-bridge circuit being simultaneously conducting, i.e., shoot-through. Shoot-through of the upper and lower transistors will generate a large current, which can burn out the upper and lower transistors, sampling resistors, and other critical components in a short time, and even damage the entire circuit board, affecting the reliability and safety of the product.

[0003] Therefore, how to suppress the negative voltage across the floating reference terminal and prevent the latch-up effect is a technical problem that urgently needs to be solved. Utility Model Content

[0004] This invention aims to solve at least one of the technical problems existing in related technologies. To this end, this invention proposes an anti-negative voltage drive circuit to reduce the magnitude of the negative voltage borne by the floating reference terminal.

[0005] This utility model also proposes a three-phase frequency conversion drive circuit, a refrigerator, and related equipment.

[0006] The anti-negative pressure driving circuit according to the first aspect of the present invention includes: A half-bridge drive module includes an upper bridge arm transistor and a lower bridge arm transistor. The upper bridge arm transistor and the lower bridge arm transistor are connected to form a half-bridge circuit. The connection point between the upper bridge arm transistor and the lower bridge arm transistor forms the midpoint of the half-bridge output. The pre-drive module is provided with a first output terminal, a second output terminal, a floating power supply terminal and a floating reference terminal. The first output terminal is connected to the controlled terminal of the upper bridge arm tube, and the second output terminal is connected to the controlled terminal of the lower bridge arm tube. The bootstrap module is connected to the floating power supply terminal; An anti-negative voltage module is provided, with one end connected to the floating reference terminal and the other end connected to the bootstrap module and the midpoint of the half-bridge output, respectively. The anti-negative voltage module is used to reduce the peak value of the negative voltage generated at the midpoint of the half-bridge output.

[0007] The anti-negative voltage drive circuit according to the embodiment of this utility model has at least the following beneficial effects: After amplifying the input control signal, the pre-drive module outputs it to the controlled terminals of the upper and lower bridge arm transistors via the first and second output terminals, respectively, to control the upper and lower bridge arm transistors to turn on or off, thereby controlling the drive signal generated at the midpoint of the half-bridge output. The bootstrap module is connected to the floating power supply terminal and the floating reference terminal via the anti-negative voltage module to raise the voltage of the floating power supply terminal based on the voltage of the floating reference terminal, thereby enabling the first output terminal of the pre-drive module to reliably control the upper bridge arm transistor to turn on. By setting the anti-negative voltage module between the midpoint of the half-bridge output and the floating reference terminal, when a negative voltage is generated at the midpoint of the half-bridge output, the anti-negative voltage module can reduce the peak value of the negative voltage generated at the midpoint of the half-bridge output, thereby preventing the pre-drive module from latching up due to excessive negative voltage at the floating reference terminal, and improving the reliability and safety of the drive circuit.

[0008] According to one embodiment of the present invention, the anti-negative pressure module includes an anti-negative pressure resistor, one end of which is connected to the floating reference terminal, and the other end of which is connected to the bootstrap module and the midpoint of the half-bridge output.

[0009] According to one embodiment of the present invention, the resistance value of the anti-negative voltage resistor is in the range of 5Ω to 10Ω.

[0010] According to one embodiment of the present invention, the half-bridge drive module further includes a first on / off unit and a second on / off unit. The first output terminal is connected to the controlled terminal of the upper bridge arm tube through the first on / off unit, and the second output terminal is connected to the controlled terminal of the lower bridge arm tube through the second on / off unit. The first on / off unit is used to adjust the on / off speed of the upper bridge arm tube, and the second on / off unit is used to adjust the on / off speed of the lower bridge arm tube.

[0011] According to one embodiment of the present invention, the first switching unit includes a first resistor, a second resistor, a first capacitor, a first diode, and a first Zener diode. One end of the first resistor is connected to the first output terminal and the cathode of the first diode. The anode of the first diode is connected to one end of the second resistor. The other end of the first resistor is connected to the other end of the second resistor, the controlled terminal of the upper bridge arm transistor, one end of the first capacitor, and the cathode of the first Zener diode. The other end of the first capacitor is connected to the anode of the first Zener diode, the anti-negative voltage module, and the midpoint of the half-bridge output. And / or, the second switching unit includes a third resistor, a fourth resistor, a second capacitor, a second diode, and a second Zener diode. One end of the third resistor is connected to the second output terminal and the cathode of the second diode, respectively. The anode of the second diode is connected to one end of the fourth resistor. The other end of the third resistor is connected to the other end of the fourth resistor, the controlled terminal of the lower bridge arm transistor, one end of the second capacitor, and the cathode of the second Zener diode, respectively. The other end of the second capacitor and the anode of the second Zener diode are both grounded.

[0012] According to one embodiment of the present invention, the resistance value of the second resistor is in the range of 100Ω to 200Ω, and / or the resistance value of the fourth resistor is in the range of 100Ω to 200Ω.

[0013] According to one embodiment of the present invention, the upper bridge arm transistor is a first IGBT transistor, the lower bridge arm transistor is a second IGBT transistor, and the half-bridge drive module further includes a first freewheeling diode and a second freewheeling diode. The collector of the first IGBT transistor is connected to the power supply terminal and the cathode of the first freewheeling diode, respectively. The gate of the first IGBT transistor is connected to the first output terminal. The anode of the first freewheeling diode is connected to the emitter of the first IGBT transistor. The emitter of the first IGBT transistor and the collector of the second IGBT transistor are connected to form the midpoint of the bridge arm emitter. The cathode of the second freewheeling diode is connected to the collector of the second IGBT transistor. The gate of the second IGBT transistor is connected to the second output terminal. The emitter of the second IGBT transistor and the anode of the second freewheeling diode are both grounded.

[0014] According to one embodiment of the present invention, the bootstrap module includes a bootstrap resistor, a bootstrap diode, and a bootstrap capacitor. One end of the bootstrap resistor is connected to a power supply terminal, and the other end of the bootstrap resistor is connected to the anode of the bootstrap diode. The cathode of the bootstrap diode is connected to the floating power supply terminal and one end of the bootstrap capacitor, respectively. The other end of the bootstrap capacitor is connected to the floating reference terminal through the anti-negative voltage module.

[0015] According to a second aspect embodiment of the present invention, a three-phase frequency converter drive circuit includes three of the above-mentioned anti-negative voltage drive circuits, and the three half-bridge output midpoints form a three-phase output terminal.

[0016] According to a third aspect of the present invention, a refrigerator includes a body, the body being provided with a control module, a three-phase compressor and the aforementioned three-phase variable frequency drive circuit, the control module being connected to three of the aforementioned pre-drive modules respectively, and the midpoints of the three half-bridge outputs being connected to the three-phase compressor.

[0017] The device according to the fourth aspect of the present invention includes the above-described negative pressure drive circuit, or includes the above-described three-phase frequency conversion drive circuit.

[0018] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this utility model or related technologies, the drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a circuit diagram of the anti-negative pressure drive circuit provided in an embodiment of this utility model.

[0021] Figure 2 This is a schematic diagram illustrating the mechanism by which a negative voltage is generated at the midpoint of the half-bridge output.

[0022] Figure 3 This is a circuit diagram of the three-phase frequency converter drive circuit provided in this embodiment of the utility model.

[0023] Figure label: 100: Half-bridge drive module; 110: Upper bridge arm transistor; 120: Lower bridge arm transistor; 130: First switching unit; 131: First resistor; 132: Second resistor; 133: First capacitor; 134: First diode; 135: First Zener diode; 140: Second switching unit; 141: Third resistor; 142: Fourth resistor; 143: Second capacitor; 144: Second diode; 145: Second Zener diode; 200: Pre-drive module; 300: Bootstrap module; 310: Bootstrap resistor; 320: Bootstrap diode; 330: Bootstrap capacitor; 400: Negative voltage protection module. Detailed Implementation

[0024] The embodiments of this utility model will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and should not be construed as limiting the scope of this utility model.

[0025] In the description of the embodiments of this utility model, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this utility model 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 the embodiments of this utility model. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0026] In the description of the embodiments of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this utility model based on the specific circumstances.

[0027] In this embodiment of the utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0028] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0029] refer to Figure 1 The negative pressure driving circuit provided by this utility model includes: The half-bridge drive module 100 includes an upper bridge arm tube 110 and a lower bridge arm tube 120. The upper bridge arm tube 110 and the lower bridge arm tube 120 are connected to form a half-bridge circuit. The connection point between the upper bridge arm tube 110 and the lower bridge arm tube 120 forms the midpoint of the half-bridge output. The pre-drive module 200 is provided with a first output terminal HO, a second output terminal LO, a floating power supply terminal VB, and a floating reference terminal VS. The first output terminal HO is connected to the controlled terminal of the upper bridge arm tube 110, and the second output terminal LO is connected to the controlled terminal of the lower bridge arm tube 120. The bootstrap module 300 is connected to the floating power supply terminal VB; An anti-negative voltage module 400 is provided, one end of which is connected to the floating reference terminal VS, and the other end of which is connected to the bootstrap module 300 and the midpoint of the half-bridge output, respectively. The anti-negative voltage module 400 is used to reduce the peak value of the negative voltage generated at the midpoint of the half-bridge output.

[0030] After amplifying the input control signal, the pre-drive module 200 outputs the signal to the controlled terminals of the upper bridge arm transistor 110 and the lower bridge arm transistor 120 via the first output terminal HO and the second output terminal LO, respectively, to control the upper bridge arm transistor 110 and the lower bridge arm transistor 120 to turn on or off, thereby controlling the drive signal generated at the midpoint of the half-bridge output. The bootstrap module 300 is connected to the floating power supply terminal VB and the floating reference terminal VS via the anti-negative voltage module 400, so as to raise the voltage of the floating power supply terminal VB based on the voltage of the floating reference terminal VS, thereby enabling the first output terminal HO of the pre-drive module 200 to reliably control the upper bridge arm transistor 110 to turn on.

[0031] By setting an anti-negative voltage module 400 between the midpoint of the half-bridge output and the floating reference terminal VS, when a negative voltage is generated at the midpoint of the half-bridge output, the anti-negative voltage module 400 can reduce the peak value of the negative voltage generated at the midpoint of the half-bridge output, thereby preventing the floating reference terminal VS from latching up due to excessive negative voltage, and improving the reliability and safety of the drive circuit.

[0032] It should be noted that the output voltage of the first output terminal HO is determined by the voltage of the floating power supply terminal VB and the voltage of the floating reference terminal VS. When the upper bridge arm transistor 110 is turned on, since the lower bridge arm transistor 120 is turned off, the voltage at the midpoint of the half-bridge output is floating. However, to turn on the upper bridge arm transistor 110, the voltage of the controlled terminal of the upper bridge arm transistor 110 needs to meet the voltage threshold condition. For example, when the upper bridge arm transistor 110 is an IGBT, the voltage difference between the gate and emitter of the controlled terminal needs to be greater than the voltage threshold to turn it on. Therefore, by connecting the floating reference terminal VS of the pre-drive module 200 to the midpoint of the half-bridge output through the anti-negative voltage module 400, the floating voltage of the upper bridge arm transistor 110 can be obtained. Combined with the bootstrap module 300 raising the voltage of the floating power supply terminal VB based on the voltage of the floating reference terminal VS, the floating power supply terminal VB has sufficient voltage, thereby allowing the first output terminal HO to output a voltage that stably controls the upper bridge arm transistor 110 to turn on.

[0033] In some embodiments of this utility model, the pre-drive module 200 may include implementations of devices or circuits such as a pre-drive chip and a pre-drive circuit. Electrical equipment typically includes a control module. Since the control signals generated by the control module cannot directly control the on / off state of the upper bridge arm transistor 110 and the lower bridge arm transistor 120, the pre-drive module 200 amplifies the control module signal, enabling the control signal to control the on / off state of the upper bridge arm transistor 110 and the lower bridge arm transistor 120 without affecting the control logic.

[0034] In some embodiments of this invention, the upper bridge arm transistor 110 and the lower bridge arm transistor 120 may be IGBT transistors. In some embodiments, the upper bridge arm transistor 110 and the lower bridge arm transistor 120 may also be embodiments of devices such as MOSFETs.

[0035] In some cases, the mechanism by which a negative voltage is generated at the midpoint of the half-bridge output may be: (Refer to...) Figure 2 During the operation of the half-bridge drive module 100, initially, when both the upper bridge arm transistor 110 and the lower bridge arm transistor 120 are turned off, the midpoint of the half-bridge output can be considered to have no current output. When the upper bridge arm transistor 110 is turned on and the lower bridge arm transistor 120 is turned off, current flows through the upper bridge arm transistor 110 and is output from the midpoint of the half-bridge output. Subsequently, when both the upper bridge arm transistor 110 and the lower bridge arm transistor 120 are turned off, the current freewheels through the diode connected in reverse parallel to the lower bridge arm transistor 120. At this time, due to the current change, the parasitic inductances LC2 and LE2 will generate a reverse voltage, which will form a negative voltage at the half-bridge output point, affecting the floating reference terminal VS. The negative voltage at the midpoint of the half-bridge output may also be caused by inductive loads, such as a motor stalling, which causes transient changes in current, resulting in a negative voltage generated by the parasitic inductance in the circuit.

[0036] refer to Figure 1In some embodiments of the anti-negative pressure drive circuit of this utility model, the anti-negative pressure module 400 includes an anti-negative pressure resistor R1. One end of the anti-negative pressure resistor R1 is connected to the floating reference terminal VS, and the other end of the anti-negative pressure resistor R1 is connected to the bootstrap module 300 and the midpoint of the half-bridge output, respectively.

[0037] By placing an anti-negative voltage resistor R1 between the floating reference terminal VS and the midpoint of the half-bridge output, the voltage drop generated by the resistor during current flow can reduce the peak negative voltage generated at the midpoint of the half-bridge output, thereby reducing the magnitude of the negative voltage across the floating reference terminal VS. Thus, based on the structure of the anti-negative voltage module 400 including the anti-negative voltage resistor R1, latch-up of the pre-drive module 200 due to excessive negative voltage is avoided. The structure is simple and easy to implement, which helps improve the reliability of the circuit.

[0038] In some embodiments of this utility model, the anti-negative voltage module 400 can also form a series circuit with multiple resistors, one end of which is connected to the floating reference terminal VS, and the other end of which is connected to the midpoint of the half-bridge output. In some embodiments, the anti-negative voltage module 400 can also include a resistor and a Zener diode, with the Zener diode and the resistor connected in parallel to form a parallel circuit, one end of which is connected to the floating reference terminal VS, and the other end of which is connected to the midpoint of the half-bridge output. The cathode of the Zener diode is connected to the midpoint of the half-bridge output. In this way, the Zener diode clamps the voltage when the negative voltage is too high, preventing the floating reference terminal VS from bearing an excessively high negative voltage.

[0039] In some embodiments of the anti-negative pressure drive circuit of this utility model, the resistance value of the anti-negative pressure resistor R1 ranges from 5Ω to 10Ω.

[0040] The resistance value of the anti-negative voltage resistor R1 is selected within the range of 5Ω to 10Ω to suppress the impact of the negative voltage peak at the midpoint of the half-bridge output on the floating reference terminal VS, effectively avoiding latch-up effects. Furthermore, it prevents the anti-negative voltage resistor R1 from having an excessively high resistance value, which could affect the normal operation of the bootstrap module 300. Therefore, a resistance value of 5Ω to 10Ω for the anti-negative voltage resistor R1 provides a better performance balance, which is beneficial to improving the stability of the circuit operation.

[0041] It should be noted that the bootstrap module 300 is connected to the floating reference terminal VS via the anti-negative voltage resistor R1. The voltage at the first output terminal HO raised by the bootstrap module 300 is based on the voltage at the anti-negative voltage resistor R1 connected to the floating reference terminal VS. If the resistance value of the anti-negative voltage resistor R1 is too large, it will slow down the turn-off speed of the upper bridge arm transistor 110, thereby increasing the turn-off loss. Therefore, the resistance value of the anti-negative voltage resistor R1 cannot be too large.

[0042] refer to Figure 1In some embodiments of the negative pressure drive circuit of this utility model, the half-bridge drive module 100 further includes a first switching unit 130 and a second switching unit 140. The first output terminal HO is connected to the controlled terminal of the upper bridge arm tube 110 through the first switching unit 130, and the second output terminal LO is connected to the controlled terminal of the lower bridge arm tube 120 through the second switching unit 140. The first switching unit 130 is used to adjust the switching speed of the upper bridge arm tube 110, and the second switching unit 140 is used to adjust the switching speed of the lower bridge arm tube 120.

[0043] By setting a first switching unit 130 between the first output terminal HO of the pre-drive module 200 and the controlled terminal of the upper bridge arm transistor 110, and setting a second switching unit 140 between the second output terminal LO and the lower bridge arm transistor 120, the switching speeds of the upper bridge arm transistor 110 and the lower bridge arm transistor 120 can be adjusted respectively based on the first switching unit 130 and the second switching unit 140, thereby achieving fine control over the transient characteristics of turn-on and turn-off. By delaying the turn-off speed of the upper bridge arm transistor 110, the instantaneous current change of the inductive load can be effectively reduced, thereby reducing the induced voltage generated by the parasitic inductance, and achieving the effect of reducing the negative voltage peak generated at the midpoint of the half-bridge output. Thus, based on the structure of the first switching unit 130 and the second switching unit 140, the switching speeds of the upper bridge arm transistor 110 and the lower bridge arm transistor 120 can be flexibly adjusted, which is beneficial to adapting to different application scenarios and making the circuit performance more in line with requirements.

[0044] refer to Figure 1 In some embodiments of the anti-negative pressure drive circuit of this utility model, the first switching unit 130 includes a first resistor 131, a second resistor 132, a first capacitor 133, a first diode 134, and a first Zener diode 135. One end of the first resistor 131 is connected to the first output terminal HO and the cathode of the first diode 134, respectively. The anode of the first diode 134 is connected to one end of the second resistor 132, and the other end of the first resistor 131 is connected to the other end of the second resistor 132, the controlled terminal of the upper bridge arm transistor 110, one end of the first capacitor 133, and the cathode of the first Zener diode 135, respectively. The other end of the first capacitor 133 is connected to the anode of the first Zener diode 135, the anti-negative pressure module 400, and the midpoint of the half-bridge output, respectively.

[0045] The first diode 134 and the second resistor 132 are connected in series and then in parallel with the first resistor 131. When the first output terminal HO of the pre-drive module 200 controls the upper bridge arm transistor 110 to conduct, based on the unidirectional conduction characteristic of the first diode 134, the current generated at the first output terminal HO flows through the first resistor 131 to the controlled terminal of the upper bridge arm transistor 110. That is, the first resistor 131 is the on-resistance of the upper bridge arm transistor 110. By adjusting the resistance value of the first resistor 131, the conduction speed of the upper bridge arm transistor 110 can be accurately adjusted. When the first output terminal HO of the pre-drive module 200 controls the upper bridge arm transistor 110 to turn off, the turn-off current of the upper bridge arm transistor 110 can be discharged through the second resistor 132. By adjusting the resistance value of the second resistor 132, the turn-off speed of the upper bridge arm transistor 110 can be accurately adjusted. At the same time, the first capacitor 133 and the first resistor 131 can form an RC filter circuit, which can filter out interference fluctuations and make the conduction of the upper bridge arm transistor 110 more reliable. The first Zener diode 135 is connected to the controlled terminal of the upper bridge arm diode 110, which can clamp the voltage when the voltage is too high, prevent the controlled terminal of the upper bridge arm diode 110 from bearing too high voltage, and improve the reliability of the circuit.

[0046] Therefore, by designing the resistance values ​​of the first resistor 131 and the second resistor 132 according to application requirements, the turn-on speed and turn-off speed of the upper bridge arm transistor 110, i.e., the switching speed, can be adjusted. At the same time, the structure of the first capacitor 133 and the first Zener diode 135 can further improve the reliability of controlling the turn-on and turn-off of the upper bridge arm transistor 110.

[0047] refer to Figure 1 In some embodiments of the negative pressure driving circuit of this utility model, the second switching unit 140 includes a third resistor 141, a fourth resistor 142, a second capacitor 143, a second diode 144, and a second Zener diode 145. One end of the third resistor 141 is connected to the second output terminal LO and the cathode of the second diode 144, respectively. The anode of the second diode 144 is connected to one end of the fourth resistor 142. The other end of the third resistor 141 is connected to the other end of the fourth resistor 142, the controlled terminal of the lower bridge arm transistor 120, one end of the second capacitor 143, and the cathode of the second Zener diode 145, respectively. The other end of the second capacitor 143 and the anode of the second Zener diode 145 are both grounded.

[0048] The second diode 144 is connected in series with the fourth resistor 142 and then in parallel with the third resistor 141. When the second output terminal LO of the pre-drive module 200 controls the lower bridge arm transistor 120 to conduct, based on the unidirectional conduction characteristic of the second diode 144, the current generated by the second output terminal LO flows through the third resistor 141 to the controlled terminal of the lower bridge arm transistor 120. That is, the third resistor 141 is the on-resistance of the lower bridge arm transistor 120. By adjusting the resistance value of the third resistor 141, the conduction speed of the lower bridge arm transistor 120 can be accurately adjusted. When the second output terminal LO of the pre-drive module 200 controls the lower bridge arm transistor 120 to turn off, the turn-off current of the lower bridge arm transistor 120 can be discharged through the fourth resistor 142. By adjusting the resistance value of the fourth resistor 142, the turn-off speed of the lower bridge arm transistor 120 can be accurately adjusted. At the same time, the second capacitor 143 and the third resistor 141 can form an RC filter circuit, which can filter out interference fluctuations and make the conduction of the lower bridge arm transistor 120 more reliable. The second Zener diode 145 is connected to the controlled terminal of the lower bridge arm diode 120, which can clamp the voltage when the voltage is too high, prevent the controlled terminal of the lower bridge arm diode 120 from bearing too high a voltage, and improve the reliability of the circuit.

[0049] Therefore, the resistance values ​​of the third resistor 141 and the fourth resistor 142 are designed according to the application requirements, which can realize the adjustment of the turn-on speed and turn-off speed of the lower bridge arm transistor 120, i.e., the switching speed. At the same time, the structure of the second capacitor 143 and the second Zener diode 145 can further improve the reliability of controlling the turn-on and turn-off of the lower bridge arm transistor 120.

[0050] refer to Figure 1 In some embodiments of this utility model, the lower bridge arm transistor 120, the second capacitor 143, and the second Zener diode 145 can be grounded via the sampling resistor Rs1.

[0051] In some embodiments of the anti-negative pressure drive circuit of this utility model, the resistance value of the second resistor 132 is in the range of 100Ω to 200Ω, and / or the resistance value of the fourth resistor 142 is in the range of 100Ω to 200Ω.

[0052] The resistance values ​​of the second resistor 132 and the fourth resistor 142, which adjust the turn-off speed, are set to a range of 100Ω to 200Ω. This resistance range appropriately increases the impedance of the discharge circuit during turn-off, thus delaying the turn-off speed of the upper bridge arm transistor 110 and the lower bridge arm transistor 120. This reduces the rate of change of current during turn-off, thereby reducing the magnitude of the induced voltage generated by the parasitic capacitance in the circuit. In this way, the peak negative voltage at the floating reference terminal VS is reduced from its source, which helps to further prevent the pre-drive module 200 from latching up due to excessive negative voltage at the floating reference terminal VS, improving the reliability and safety of the drive circuit.

[0053] It is important to emphasize that by incorporating the negative voltage protection module 400, the peak value of the negative voltage is suppressed after it is generated. Simultaneously, by adjusting the resistance values ​​of the second resistor 132 and the fourth resistor 142 (i.e., the resistance value of the turn-off resistor), the rate of change of the turn-off current is reduced, thus suppressing the peak value of the negative voltage at its source. In this way, by suppressing the negative voltage both after its generation and at its source, excessively high negative voltages are reliably prevented from being applied to the floating reference terminal VS of the pre-drive module 200, avoiding latch-up effects in the pre-drive module 200 and improving the reliability and safety of the circuit.

[0054] refer to Figure 1 In some embodiments of the negative pressure drive circuit of this utility model, the upper bridge arm transistor 110 is a first IGBT transistor, the lower bridge arm transistor 120 is a second IGBT transistor, and the half-bridge drive module 100 further includes a first freewheeling diode and a second freewheeling diode. The collector of the first IGBT transistor is connected to the power supply terminal and the cathode of the first freewheeling diode, respectively. The gate of the first IGBT transistor is connected to the first output terminal HO. The anode of the first freewheeling diode is connected to the emitter of the first IGBT transistor. The emitter of the first IGBT transistor and the collector of the second IGBT transistor are connected to form the midpoint of the bridge arm emitter. The cathode of the second freewheeling diode is connected to the collector of the second IGBT transistor. The gate of the second IGBT transistor is connected to the second output terminal LO. The emitter of the second IGBT transistor and the anode of the second freewheeling diode are both grounded.

[0055] The upper bridge arm transistor 110 and the lower bridge arm transistor 120 are IGBT transistors, i.e., a first IGBT transistor and a second IGBT transistor structure, which has excellent voltage and current withstand capability and switching characteristics, which is beneficial to improving driving performance. The structure of the first freewheeling diode connected in reverse parallel with the first IGBT transistor and the second freewheeling diode connected in reverse parallel with the second IGBT transistor is suitable for driving inductive loads. It can provide the necessary current freewheeling path when turned off, prevent the generation of overvoltage spikes, and help ensure the stable operation of the circuit.

[0056] refer to Figure 1 In some embodiments of the anti-negative pressure drive circuit of this utility model, the bootstrap module 300 includes a bootstrap resistor 310, a bootstrap diode 320, and a bootstrap capacitor 330. One end of the bootstrap resistor 310 is connected to the power supply terminal, and the other end of the bootstrap resistor 310 is connected to the anode of the bootstrap diode 320. The cathode of the bootstrap diode 320 is connected to the floating power supply terminal VB and one end of the bootstrap capacitor 330, respectively. The other end of the bootstrap capacitor 330 is connected to the floating reference terminal VS through the anti-negative pressure module 400.

[0057] The bootstrap module 300 is based on a structure of bootstrap resistor 310, bootstrap diode 320, and bootstrap capacitor 330. When the lower bridge arm transistor 120 is turned on, the floating reference terminal VS is effectively grounded through the negative voltage protection module 400, i.e., the negative voltage protection resistor R1. Current flows through the bootstrap resistor 310 and bootstrap diode 320 to charge the bootstrap capacitor 330, forming a bootstrap voltage across the bootstrap capacitor 330. When the lower bridge arm transistor 120 is turned off, the bootstrap voltage of the bootstrap capacitor 330 is applied between the floating power supply terminal VB and the floating reference terminal VS, making the voltage at the floating power supply terminal VB the supply voltage plus the bootstrap voltage. This allows the first output terminal HO to output a sufficient voltage to ensure that the upper bridge arm transistor 110 can be reliably controlled to conduct on the high side. The bootstrap diode 320, based on its unidirectional conduction characteristic, prevents the bootstrap voltage from affecting the supply voltage, achieving an isolation effect.

[0058] In some embodiments of this utility model, two or more bootstrap capacitors 330 may be provided, and the bootstrap capacitors 330 are connected in parallel to improve the equivalent capacitance value.

[0059] The following section introduces the three-phase frequency converter drive circuit provided by this utility model. The three-phase frequency converter drive circuit described below can be used as a reference with the negative voltage anti-drive circuit described above.

[0060] refer to Figure 3 This utility model also provides a three-phase frequency conversion drive circuit, including three of the above-mentioned anti-negative voltage drive circuits, and the three half-bridge output midpoints form a three-phase output terminal.

[0061] In three-phase drive applications, a single negative voltage anti-drive circuit described above can be expanded into a three-phase frequency converter drive circuit. By combining three of the above negative voltage anti-drive circuits, each negative voltage anti-drive circuit corresponds to one phase of the three phases. Specifically, the midpoint of the half-bridge output of each half-bridge drive module 100 serves as the drive output terminal for one phase. The midpoints of the half-bridge outputs of the three half-bridge drive modules 100 form a three-phase output terminal, satisfying the drive requirements of the three-phase load.

[0062] In each corresponding negative voltage drive circuit, by setting a negative voltage module 400 between the midpoint of the half-bridge output and the floating reference terminal VS, when a negative voltage is generated at the midpoint of the half-bridge output, the negative voltage module 400 can reduce the peak value of the negative voltage generated at the midpoint of the half-bridge output, thereby preventing the floating reference terminal VS from latching up due to excessive negative voltage, and improving the reliability and safety of the overall three-phase frequency converter drive circuit.

[0063] Understandably, the three half-bridge drive modules 100 can form a three-phase inverter to achieve the effect of frequency conversion drive, thereby driving loads such as three-phase motors.

[0064] refer to Figure 3The present invention also provides a refrigerator, including a body, wherein the body is provided with a control module, a three-phase compressor and the aforementioned three-phase frequency conversion drive circuit, the control module is connected to three of the aforementioned pre-drive modules 200 respectively, and the midpoints of the three half-bridge outputs are connected to the three-phase compressor.

[0065] The refrigerator body is equipped with a control module, a three-phase compressor, and the aforementioned three-phase inverter drive circuit. The control module is connected to three pre-drive modules 200 in the three-phase inverter drive circuit to transmit control signals to the pre-drive modules 200, thereby controlling the on / off state of the upper bridge arm tube 110 and lower bridge arm tube 120 in each half-bridge drive module 100 to drive the three-phase compressor. During operation, by setting an anti-negative voltage module 400 between the midpoint of the half-bridge output of each phase and the floating reference terminal VS, when a negative voltage is generated at the midpoint of the half-bridge output, the anti-negative voltage module 400 can reduce the peak value of the negative voltage generated at the midpoint of the half-bridge output, thereby preventing the pre-drive module 200 from latching up due to excessive negative voltage on the floating reference terminal VS, which helps to improve the reliability and durability of the refrigerator.

[0066] The device provided by this utility model is described below. The device described below can be referenced in conjunction with the anti-negative pressure drive circuit and the three-phase frequency conversion drive circuit described above.

[0067] refer to Figure 1 and Figure 3 The present invention also provides a device, including the above-mentioned negative pressure drive circuit, or including the above-mentioned three-phase frequency conversion drive circuit.

[0068] By setting an anti-negative voltage module 400 between the midpoint of the half-bridge output and the floating reference terminal VS, when a negative voltage is generated at the midpoint of the half-bridge output, the anti-negative voltage module 400 can reduce the peak value of the negative voltage generated at the midpoint of the half-bridge output, thereby preventing the floating reference terminal VS from latching up due to excessive negative voltage, and improving the reliability and safety of the equipment.

[0069] Finally, it should be noted that the above embodiments are only used to illustrate the present utility model and are not intended to limit the present utility model. Although the present utility model has been described in detail with reference to the embodiments, those skilled in the art should understand that various combinations, modifications, or equivalent substitutions of the technical solutions of the present utility model do not depart from the spirit and scope of the technical solutions of the present utility model and should be covered within the protection scope of the present utility model.

Claims

1. An anti-negative voltage drive circuit, characterized in that, include: The half-bridge drive module (100) includes an upper bridge arm tube (110) and a lower bridge arm tube (120). The upper bridge arm tube (110) and the lower bridge arm tube (120) are connected to form a half-bridge circuit. The connection point between the upper bridge arm tube (110) and the lower bridge arm tube (120) forms the midpoint of the half-bridge output. The pre-drive module (200) is provided with a first output terminal, a second output terminal, a floating power supply terminal and a floating reference terminal. The first output terminal is connected to the controlled terminal of the upper bridge arm tube (110), and the second output terminal is connected to the controlled terminal of the lower bridge arm tube (120). The bootstrap module (300) is connected to the floating power supply terminal; An anti-negative voltage module (400) is provided, one end of which is connected to the floating reference terminal, and the other end of which is connected to the bootstrap module (300) and the midpoint of the half-bridge output, respectively. The anti-negative voltage module (400) is used to reduce the peak value of the negative voltage generated at the midpoint of the half-bridge output.

2. The anti-negative voltage drive circuit according to claim 1, characterized in that, The anti-negative pressure module (400) includes an anti-negative pressure resistor, one end of which is connected to the floating reference terminal, and the other end of which is connected to the bootstrap module (300) and the midpoint of the half-bridge output.

3. The anti-negative voltage drive circuit according to claim 2, characterized in that, The resistance value of the anti-negative voltage resistor ranges from 5Ω to 10Ω.

4. The anti-negative voltage drive circuit according to claim 1, characterized in that, The half-bridge drive module (100) further includes a first on / off unit (130) and a second on / off unit (140). The first output terminal is connected to the controlled terminal of the upper bridge arm tube (110) through the first on / off unit (130), and the second output terminal is connected to the controlled terminal of the lower bridge arm tube (120) through the second on / off unit (140). The first on / off unit (130) is used to adjust the on / off speed of the upper bridge arm tube (110), and the second on / off unit (140) is used to adjust the on / off speed of the lower bridge arm tube (120).

5. The anti-negative voltage drive circuit according to claim 4, characterized in that, The first switching unit (130) includes a first resistor (131), a second resistor (132), a first capacitor (133), a first diode (134), and a first Zener diode (135). One end of the first resistor (131) is connected to the first output terminal and the cathode of the first diode (134). The anode of the first diode (134) is connected to one end of the second resistor (132). The other end of the first resistor (131) is connected to the other end of the second resistor (132), the controlled terminal of the upper bridge arm transistor (110), one end of the first capacitor (133), and the cathode of the first Zener diode (135). The other end of the first capacitor (133) is connected to the anode of the first Zener diode (135), the anti-negative voltage module (400), and the midpoint of the half-bridge output. And / or, the second switching unit (140) includes a third resistor (141), a fourth resistor (142), a second capacitor (143), a second diode (144), and a second Zener diode (145). One end of the third resistor (141) is connected to the second output terminal and the cathode of the second diode (144), respectively. The anode of the second diode (144) is connected to one end of the fourth resistor (142), and the other end of the third resistor (141) is connected to the other end of the fourth resistor (142), the controlled terminal of the lower bridge arm transistor (120), one end of the second capacitor (143), and the cathode of the second Zener diode (145), respectively. The other end of the second capacitor (143) and the anode of the second Zener diode (145) are both grounded.

6. The anti-negative voltage drive circuit according to claim 5, characterized in that, The resistance value of the second resistor (132) is in the range of 100Ω to 200Ω, and / or the resistance value of the fourth resistor (142) is in the range of 100Ω to 200Ω.

7. The anti-negative voltage drive circuit according to claim 1, characterized in that, The upper bridge arm transistor (110) is a first IGBT transistor, and the lower bridge arm transistor (120) is a second IGBT transistor. The half-bridge drive module (100) also includes a first freewheeling diode and a second freewheeling diode. The collector of the first IGBT transistor is connected to the power supply terminal and the cathode of the first freewheeling diode, respectively. The gate of the first IGBT transistor is connected to the first output terminal. The anode of the first freewheeling diode is connected to the emitter of the first IGBT transistor. The emitter of the first IGBT transistor and the collector of the second IGBT transistor are connected to form the midpoint of the bridge arm emitter. The cathode of the second freewheeling diode is connected to the collector of the second IGBT transistor. The gate of the second IGBT transistor is connected to the second output terminal. The emitter of the second IGBT transistor and the anode of the second freewheeling diode are both grounded.

8. The anti-negative voltage drive circuit according to claim 1, characterized in that, The bootstrap module (300) includes a bootstrap resistor (310), a bootstrap diode (320), and a bootstrap capacitor (330). One end of the bootstrap resistor (310) is connected to the power supply terminal, and the other end of the bootstrap resistor (310) is connected to the anode of the bootstrap diode (320). The cathode of the bootstrap diode (320) is connected to the floating power supply terminal and one end of the bootstrap capacitor (330), respectively. The other end of the bootstrap capacitor (330) is connected to the floating reference terminal through the anti-negative voltage module (400).

9. A three-phase frequency converter drive circuit, characterized in that, It includes three anti-negative-pressure drive circuits as described in any one of claims 1 to 8, wherein the three half-bridge output midpoints form a three-phase output terminal.

10. A refrigerator, characterized in that, The system includes a housing, which is equipped with a control module, a three-phase compressor, and a three-phase frequency converter drive circuit as described in claim 9. The control module is connected to three pre-drive modules (200) respectively, and the midpoints of the three half-bridge outputs are connected to the three-phase compressor.

11. The equipment, characterized in that, It includes the anti-negative pressure drive circuit as described in any one of claims 1 to 8, or the three-phase frequency conversion drive circuit as described in claim 8.

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