Fast reaction high-voltage protection device of frequency converter

Abstract

The utility model relates to the technical field of frequency converters, in particular to a quick response high-voltage protection device of a frequency converter, which comprises a control module, a PWM (Pulse Width Modulation) driving module, a high-voltage switch triggering module, an overcurrent protection module and a level overturning module, the control module is provided with a first switch port and a PWM output port. The input end of the PWM driving module is connected with the PWM output port; the PWM driving module is provided with a second switch port; the input end of the high-voltage switch trigger module is connected with a high-voltage switch; the output end of the high-voltage switch triggering module is connected with the input end of the level overturning module; and the output end of the overcurrent protection module is connected with the input end of the level overturning module. According to the utility model, the high-voltage switch is directly integrated on the frequency converter, so that the system can normally respond and process high-voltage protection faults; in addition, the response time of the whole machine to high-voltage protection can be greatly shortened.

Description

Technical Field

[0001] The utility model relates to the technical field of frequency converters, and particularly relates to a fast-response high-voltage protection device for a frequency converter. Background Art

[0002] In an air-conditioning system, high-voltage protection is an important safety measure to prevent the refrigerant pressure from exceeding the safe range, thereby avoiding equipment damage or safety accidents. As a key component of this protection mechanism, the high-voltage switch is used to monitor the pressure in the system and trigger corresponding protection measures when the preset safety threshold is reached.

[0003] In the current method, by using a high-voltage switch device connected to the main board or the main logic control part in the control system, whether the high-voltage protection set value is reached is distinguished by the connection / disconnection of the high-voltage switch device. Then, the logic control part informs the frequency converter to stop operating due to a fault through communication, and only then can the entire heat exchange system cycle stop working. If there is an abnormality in the communication between the logic control system and the frequency converter, it will cause the high-voltage protection fault information not to be transmitted to the frequency converter, unable to correctly stop the compressor from working, resulting in a continuous increase in system pressure and possible safety hazards. Summary of the Utility Model

[0004] The purpose of the utility model is to provide a fast-response high-voltage protection device for a frequency converter aiming at the above deficiencies in the prior art.

[0005] The purpose of the utility model is achieved through the following technical solutions: A fast-response high-voltage protection device for a frequency converter includes a control module, a PWM drive module, a high-voltage switch trigger module, an overcurrent protection module, and a level inversion module;

[0006] The control module is provided with a first switch port and a PWM output port;

[0007] The input end of the PWM drive module is connected to the PWM output port; the PWM drive module is provided with a second switch port;

[0008] The input end of the high-voltage switch trigger module is connected to the high-voltage switch; the output end of the high-voltage switch trigger module is connected to the input end of the level inversion module;

[0009] The output end of the overcurrent protection module is connected to the input end of the level inversion module;

[0010] The level inversion module is provided with a first output port and a second output port; the first output port is connected to the first switch port; the second output port is connected to the second switch port.

[0011] The present utility model is further configured such that the PWM driving module includes a buffer chip U5; the second switch port is provided on the buffer chip U5; the input end of the buffer chip U5 is connected to the PWM output port; and the output end of the buffer chip U5 is used to be connected to the frequency conversion execution device.

[0012] The present utility model is further configured such that the high-voltage switch triggering module includes a resistor R138, a resistor R137, a resistor R136, and a triode Q2;

[0013] The emitter of the triode Q2 is grounded; the collector of the triode Q2 is connected to the input end of the level inversion module; the base of the triode Q2 is grounded through the resistor R136; one end of the base of the triode Q2 is connected to one end of the resistor R137; one end of the resistor R138 is connected to the power supply; the other end of the resistor R138 is connected to the other end of the resistor R137; and the other end of the resistor R137 is used to be connected to the high-voltage switch.

[0014] The present utility model is further configured such that the high-voltage switch triggering module further includes a connector; the connector is used to be connected to the high-voltage switch; one end of the connector is connected to the other end of the resistor R137; and the other end of the connector is grounded.

[0015] The present utility model is further configured such that the high-voltage switch triggering module further includes a capacitor C53 and a capacitor C52 connected in parallel with each other; and the capacitor C52 is connected in parallel with the resistor R136.

[0016] The present utility model is further configured such that the overcurrent protection module includes a first input port, a resistor R63, a comparator U6, a comparator U7, and a capacitor C48;

[0017] The first input port is connected to one end of the resistor R63; the other end of the resistor R63 is grounded through the capacitor C48; the other end of the resistor R63 is respectively connected to the negative input end of the comparator U6 and the positive input end of the comparator U7; the output ends of the comparator U6 and the comparator U7 are respectively connected to the input end of the level inversion module; the positive input end of the comparator U6 is provided with a first comparison port; and the negative input end of the comparator U7 is provided with a second comparison port.

[0018] The present utility model is further configured such that the overcurrent protection module further includes a second input port, a resistor R68, a comparator U8, a comparator U9, and a capacitor C51;

[0019] The second input port is connected to one end of a resistor R68; the other end of the resistor R68 is grounded through a capacitor C51; the other end of the resistor R68 is respectively connected to the negative input terminal of a comparator U8 and the positive input terminal of a comparator U9; the output terminals of the comparator U8 and the comparator U9 are respectively connected to the input terminal of a level inversion module; the positive input terminal of the comparator U8 is provided with a third comparison port; the negative input terminal of the comparator U9 is provided with a fourth comparison port.

[0020] The present utility model is further configured such that the level inversion module includes a resistor R64, a capacitor C50, a resistor R67, a triode Q4, a resistor R61, a resistor R65, a capacitor C49, a resistor R60, a capacitor C98, and a capacitor C99;

[0021] One end of the resistor R67 is connected to a power supply through the resistor R64; one end of the resistor R67 is grounded through the capacitor C50; one end of the resistor R67 is respectively connected to the output terminal of an overcurrent protection module and the output terminal of a high-voltage switch trigger module;

[0022] The other end of the resistor R67 is connected to the base of the triode Q4; the emitter of the triode Q4 is grounded; the collector of the triode Q4 is connected to the power supply through the resistor R61; the collector of the triode Q4 is connected to one end of the resistor R65; the other end of the resistor R65 is grounded through the capacitor C49; the other end of the resistor R65 is connected to a second output port; the other end of the resistor R65 is connected to one end of the resistor R60; one end of the resistor R60 is grounded through the capacitor C98; the other end of the resistor R60 is grounded through the capacitor C99; the other end of the resistor R60 is connected to a first output port.

[0023] The beneficial effects of the present utility model: By directly integrating a high-voltage switch on the frequency converter, the present utility model can prevent normal response and handling of high-voltage protection faults even under the condition of communication failure between the logic control system and the frequency converter; in addition, it can greatly reduce the response time of the whole machine to high-voltage protection. Description of the Drawings

[0024] The utility model is further described with reference to the accompanying drawings, but the embodiments in the drawings do not constitute any limitation to the present utility model. For those of ordinary skill in the art, other drawings can be obtained according to the following drawings without creative efforts.

[0025] Figure 1 is a block diagram of the present utility model;

[0026] Figure 2 is a circuit schematic diagram of the control module of the present utility model;

[0027] Figure 3 is the circuit schematic diagram of the PWM drive module of the present utility model;

[0028] Figure 4 is the circuit schematic diagram of the high-voltage switch trigger module of the present utility model;

[0029] Figure 5 is the circuit schematic diagram of the overcurrent protection module of the present utility model;

[0030] Figure 6 is the circuit schematic diagram of the level inversion module of the present utility model;

[0031] Wherein: 11, the first switch port; 12, the PWM output port; 2, the second switch port; 31, the first output port; 32, the second output port; 4, the connector; 51, the first input port; 52, the second input port; 61, the first comparison port; 62, the second comparison port; 63, the third comparison port; 64, the fourth comparison port. Specific embodiments

[0032] The present utility model will be further described in conjunction with the following embodiments.

[0033] As Figures 1 to 6 can be seen, a fast-response high-voltage protection device for an inverter described in this embodiment includes a control module, a PWM drive module, a high-voltage switch trigger module, an overcurrent protection module, and a level inversion module;

[0034] The control module is provided with a first switch port 11 and a PWM output port 12;

[0035] The input end of the PWM drive module is connected to the PWM output port 12; the PWM drive module is provided with a second switch port 2;

[0036] The input end of the high-voltage switch trigger module is connected to the high-voltage switch; the output end of the high-voltage switch trigger module is connected to the input end of the level inversion module;

[0037] The output end of the overcurrent protection module is connected to the input end of the level inversion module;

[0038] The level inversion module is provided with a first output port 31 and a second output port 32; the first output port 31 is connected to the first switch port 11; the second output port 32 is connected to the second switch port 2.

[0039] Specifically, the fast-response high-voltage protection device for an inverter described in this embodiment can prevent normal reaction and handling of high-voltage protection faults even under the condition of communication failure between the logic control system and the inverter by directly integrating the high-voltage switch on the inverter; in addition, it can greatly reduce the response time of the whole machine to high-voltage protection.

[0040] When the high-voltage switch operates, it can change the output level of the high-voltage switch trigger module, and thus feedback to the level inversion module to change the output levels of the first output port 31 and the second output port 32 of the level inversion module, so that the first switch port 11 of the control module of the frequency converter and the second switch port 2 of the PWM drive module stop working.

[0041] Meanwhile, when the current exceeds the threshold, it can change the output level of the overcurrent protection module, and thus feedback to the level inversion module to change the output levels of the first output port 31 and the second output port 32 of the level inversion module, so that the first switch port 11 of the control module of the frequency converter and the second switch port 2 of the PWM drive module stop working; thereby realizing overcurrent protection.

[0042] For a fast-response high-voltage protection device of a frequency converter described in this embodiment, the PWM drive module includes a buffer chip U5; the second switch port 2 is arranged on the buffer chip U5; the input end of the buffer chip U5 is connected to the PWM output port 12; the output end of the buffer chip U5 is used to be connected to a variable-frequency execution device such as a compressor, a fan or a pump.

[0043] Specifically, the model of the buffer chip U5 can be 74AC541. The MCU_H INU1 port on the left side of the buffer chip U5 is used to receive the PWM control signal from the PWM output port 12 of the control module, and the buffer chip U5 can enhance the current of the drive signal to provide to the variable-frequency execution device such as a compressor, so as to improve the stability of the compressor control circuit module; in addition, the buffer chip U5 will also form a gate. The buffer chip U5 will output a working signal only when the pins 1 and 19 are enabled normally, that is, only when the second switch port 2 is at a high level can it output the corresponding PWM control signal at the MCU_P I M_H I NU1 port on the right side.

[0044] For a fast-response high-voltage protection device of a frequency converter described in this embodiment, the high-voltage switch trigger module includes a resistor R138, a resistor R137, a resistor R136 and a triode Q2;

[0045] The emitter of the triode Q2 is grounded; the collector of the triode Q2 is connected to the input end of the level inversion module; the base of the triode Q2 is grounded through the resistor R136; one end of the base of the triode Q2 is connected to one end of the resistor R137; one end of the resistor R138 is connected to the power supply; the other end of the resistor R138 is connected to the other end of the resistor R137; the other end of the resistor R137 is used to be connected to the high-voltage switch.

[0046] Specifically, due to the change in the connection / disconnection state of the high-voltage switch, the triode Q2 will form a cut-off / conductive state change. For the output terminal of the high-voltage switch trigger module, that is, the signal of the MCU_P I M_BKI N port forms a high-low level flip change, thereby causing the response of the corresponding level flip module. The triode Q2 shows a cut-off state when the high-voltage switch does not trigger a state change.

[0047] For the fast-response high-voltage protection device of an inverter described in this embodiment, the high-voltage switch trigger module further includes a connector 4; the connector 4 is used to connect to the high-voltage switch; one end of the connector 4 is connected to the other end of the resistor R137; the other end of the connector 4 is grounded. By setting the connector 4, it is convenient to connect to the high-voltage switch.

[0048] For the fast-response high-voltage protection device of an inverter described in this embodiment, the high-voltage switch trigger module further includes a capacitor C53 and a capacitor C52 connected in parallel; the capacitor C52 is connected in parallel with the resistor R136. The above setting plays a role in filtering.

[0049] For the fast-response high-voltage protection device of an inverter described in this embodiment, the overcurrent protection module includes a first input port 51, a resistor R63, a comparator U6, a comparator U7, and a capacitor C48; the first input port 51 is connected to one end of the resistor R63; the other end of the resistor R63 is grounded through the capacitor C48; the other end of the resistor R63 is respectively connected to the negative input terminal of the comparator U6 and the positive input terminal of the comparator U7; the output terminals of the comparator U6 and the comparator U7 are respectively connected to the input terminal of the level flip module; the positive input terminal of the comparator U6 is provided with a first comparison port 61; the negative input terminal of the comparator U7 is provided with a second comparison port 62. For the fast-response high-voltage protection device of an inverter described in this embodiment, the overcurrent protection module further includes a second input port 52, a resistor R68, a comparator U8, a comparator U9, and a capacitor C51; the second input port 52 is connected to one end of the resistor R68; the other end of the resistor R68 is grounded through the capacitor C51; the other end of the resistor R68 is respectively connected to the negative input terminal of the comparator U8 and the positive input terminal of the comparator U9; the output terminals of the comparator U8 and the comparator U9 are respectively connected to the input terminal of the level flip module; the positive input terminal of the comparator U8 is provided with a third comparison port 63; the negative input terminal of the comparator U9 is provided with a fourth comparison port 64.

[0050] Specifically, the comparators U6, U7, U8, and U9 are all voltage comparators, and their main function is to compare the voltage values of the + / - two pins and then output high and low levels.

[0051] The first comparison port 61, the second comparison port 62, the third comparison port 63, and the fourth comparison port 64 are set limit voltages for determining the overcurrent value of the overcurrent protection. The two signals of the first input port 51 and the second input port 52 are real-time current sampling values for the comparator chip to determine whether the limit voltage is exceeded.

[0052] The MCU_PIM_BKIN port in the overcurrent protection module and the MCU_PIM_BKIN port in the high-voltage switch trigger module in the figure are the same port and are connected together. When the overcurrent protection is not triggered, the comparators U6, U7, U8, and U9 exhibit a high-impedance output state, similar to the cut-off state of a triode.

[0053] In the fast-response high-voltage protection device of an inverter according to this embodiment, the level inversion module includes a resistor R64, a capacitor C50, a resistor R67, a triode Q4, a resistor R61, a resistor R65, a capacitor C49, a resistor R60, a capacitor C98, and a capacitor C99;

[0054] One end of the resistor R67 is connected to the power supply through the resistor R64; one end of the resistor R67 is grounded through the capacitor C50; one end of the resistor R67 is respectively connected to the output end of the overcurrent protection module and the output end of the high-voltage switch trigger module;

[0055] The other end of the resistor R67 is connected to the base of the triode Q4; the emitter of the triode Q4 is grounded; the collector of the triode Q4 is connected to the power supply through the resistor R61; the collector of the triode Q4 is connected to one end of the resistor R65; the other end of the resistor R65 is grounded through the capacitor C49; the other end of the resistor R65 is connected to the second output port 32; the other end of the resistor R65 is connected to one end of the resistor R60; one end of the resistor R60 is grounded through the capacitor C98; the other end of the resistor R60 is grounded through the capacitor C99; the other end of the resistor R60 is connected to the first output port 31.

[0056] Specifically, due to the level inversion of the signal of the MCU_PIM_BKIN port, the on and off states of the triode Q4 change, causing a level inversion between the two signals of the first output port 31 and the second output port 32. Among them, the signal of the second output port 32 is connected to the second switch port 2 of the buffer chip U5, causing a change in the enable of the buffer chip U5, resulting in the gate closing and unable to continue outputting the drive control signal. And the signal of the first output port 31 is directly connected to the first switch port 11 of the control module to confirm to the control module that the overcurrent protection or high-voltage protection has been triggered.

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present utility model, rather than limiting the protection scope of the present utility model. Although the present utility model has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present utility model can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present utility model.

Claims

1. A fast-response high-voltage protection device for a frequency converter, characterized by: It includes a control module, a PWM driving module, a high-voltage switch triggering module, an overcurrent protection module, and a level inversion module; The control module is provided with a first switch port (11) and a PWM output port (12); The input end of the PWM driving module is connected to the PWM output port (12); the PWM driving module is provided with a second switch port (2); The input end of the high-voltage switch triggering module is connected to a high-voltage switch; the output end of the high-voltage switch triggering module is connected to the input end of the level inversion module; The output end of the overcurrent protection module is connected to the input end of the level inversion module; The level inversion module is provided with a first output port (31) and a second output port (32); the first output port (31) is connected to the first switch port (11); the second output port (32) is connected to the second switch port (2).

2. The fast-response high-voltage protection device for a frequency converter according to claim 1, characterized in that: The PWM driving module includes a buffer chip U5; the second switch port (2) is provided on the buffer chip U5; the input end of the buffer chip U5 is connected to the PWM output port (12); the output end of the buffer chip U5 is used to be connected to a frequency conversion execution device.

3. The fast-response high-voltage protection device for an inverter according to claim 1, wherein: The high-voltage switch triggering module includes a resistor R138, a resistor R137, a resistor R136, and a triode Q2; The emitter of the triode Q2 is grounded; the collector of the triode Q2 is connected to the input end of the level inversion module; the base of the triode Q2 is grounded through the resistor R136; one end of the base of the triode Q2 is connected to one end of the resistor R137; one end of the resistor R138 is connected to a power supply; the other end of the resistor R138 is connected to the other end of the resistor R137; the other end of the resistor R137 is used to be connected to a high-voltage switch.

4. The fast-response high-voltage protection device for a frequency converter according to claim 3, characterized in that: The high-voltage switch triggering module further includes a connector (4); the connector (4) is used to be connected to a high-voltage switch; one end of the connector (4) is connected to the other end of the resistor R137; the other end of the connector (4) is grounded.

5. The fast-response high-voltage protection device for a frequency converter according to claim 3, characterized in that: The high-voltage switch triggering module further includes a capacitor C53 and a capacitor C52 connected in parallel; the capacitor C52 is connected in parallel with the resistor R136.

6. The fast-response high-voltage protection device for an inverter according to claim 1, wherein: The overcurrent protection module includes a first input port (51), a resistor R63, a comparator U6, a comparator U7, and a capacitor C48; The first input port (51) is connected to one end of the resistor R63; the other end of the resistor R63 is grounded through the capacitor C48; the other end of the resistor R63 is respectively connected to the negative input end of the comparator U6 and the positive input end of the comparator U7; the output ends of the comparator U6 and the comparator U7 are respectively connected to the input end of the level inversion module; the positive input end of the comparator U6 is provided with a first comparison port (61); the negative input end of the comparator U7 is provided with a second comparison port (62).

7. The fast response high voltage protection device for a frequency converter according to claim 6, characterized in that: The overcurrent protection module further includes a second input port (52), a resistor R68, a comparator U8, a comparator U9, and a capacitor C51; The second input port (52) is connected to one end of a resistor R68; the other end of the resistor R68 is grounded via a capacitor C51; the other end of the resistor R68 is respectively connected to the negative input end of a comparator U8 and the positive input end of a comparator U9; the output end of the comparator U8 and the output end of the comparator U9 are respectively connected to the input end of a level flip module; the positive input end of the comparator U8 is provided with a third comparison port (63); the negative input end of the comparator U9 is provided with a fourth comparison port (64).

8. The fast-response high-voltage protection device for an inverter according to claim 1, wherein: The level flip module includes a resistor R64, a capacitor C50, a resistor R67, a transistor Q4, a resistor R61, a resistor R65, a capacitor C49, a resistor R60, a capacitor C98 and a capacitor C99; One end of the resistor R67 is connected to the power supply through the resistor R64; one end of the resistor R67 is grounded through the capacitor C50; one end of the resistor R67 is connected to the output end of the overcurrent protection module and the output end of the high-voltage switch trigger module respectively; The other end of the resistor R67 is connected to the base of the transistor Q4; the emitter of the transistor Q4 is grounded; the collector of the transistor Q4 is connected to the power supply through the resistor R61; the collector of the transistor Q4 is connected to one end of the resistor R65; the other end of the resistor R65 is grounded through the capacitor C49; the other end of the resistor R65 is connected to the second output port (32); the other end of the resistor R65 is connected to one end of the resistor R60; one end of the resistor R60 is grounded through the capacitor C98; the other end of the resistor R60 is grounded through the capacitor C99; and the other end of the resistor R60 is connected to the first output port (31).

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