WO2018149034A1 - Compressor protection circuit and air conditioner - Google Patents

Abstract

A compressor protection circuit and an air conditioner. The compressor protection circuit comprises a current sampling module (10), a voltage comparison module (20), an MCU (50), and an intelligent power module (60). A feedback module (30) and an unlocking module (40) are further added in the compressor protection circuit. The feedback module (30) is connected to an input end and an output end of the voltage comparison module (20); and the unlocking module (40) is connected to the input end of the voltage comparison module (20). The structure of the circuit is simple, and an individual latch circuit is not required, so that the cost can be reduced.

Description

 Compressor protection circuit and air conditioner

Technical field

The present invention relates to the field of compressor protection circuits, and more particularly to a compressor protection circuit and an air conditioner.

Background technique

At present, the driving scheme of the outdoor compressor of the inverter air conditioner is usually obtained by rectifying and filtering the AC power source to obtain the DC bus power supply, and the DC bus power source is subjected to the power factor correction processing by the power factor correction circuit, and then the power is supplied to the intelligent power module, and finally The intelligent power module directly drives the compressor to work. At the same time, the MCU in the inverter air conditioner outputs a driving signal to enable the intelligent power module to drive the compressor according to the corresponding phase current.

In order to protect the compressor from overcurrent, the prior art provides a compressor current protection circuit that can sample the phase current of the compressor and control the switching of the intelligent power module according to the sampling voltage. When the current is too large, the intelligent power module turns off its phase current output to protect the compressor, and in order to cope with the problem that the compressor cannot be effectively protected due to the interference signal during the overcurrent protection of the compressor. The prior art provides a compressor overcurrent protection circuit with a latch, which adds a latch circuit between the output of the compressor overcurrent protection circuit and the intelligent power module, mainly by a latch such as a D flip-flop. The latch function can effectively latch the overcurrent protection signal until the overcurrent fault is completely eliminated, and then the multi-overcurrent protection signal is cancelled by the latch, so that the MCU can output the driving signal to the intelligent power module to control the compressor to work normally. Because of the need to add a separate latch circuit, the circuit is relatively complicated and the cost is high in the actual application process. question.

Summary of the invention

The main object of the present invention is to provide a compressor protection circuit and an air conditioner, which aim to solve the problem of high circuit complexity and high cost when the latch circuit is added to the compressor overcurrent protection circuit.

To achieve the above object, the present invention provides a compressor protection circuit including a current sampling module, a voltage comparison module, an MCU, and an intelligent power module; the intelligent power module is driven according to the output of the MCU. The signal outputs a phase current to drive the compressor to operate; the current sampling module samples the phase current of the compressor and outputs a corresponding sampled voltage signal to the voltage comparison module; the voltage comparison module compares the sampled voltage signal with a reference The voltage signal is compared, and when the sampled voltage signal is greater than the reference voltage signal, a protection signal is output to the smart power module; the smart power module turns off the output phase current according to the protection signal to stop the compressor operation, Simultaneously outputting a fault protection signal to cause the MCU to stop outputting the driving signal; wherein the compressor protection circuit further comprises:

a feedback module, the input end is connected to the output end of the voltage comparison module, and the output end is connected to the input end of the voltage comparison module; when the voltage comparison module outputs a protection signal when the compressor phase current is too large, the The protection signal outputted by the voltage comparison module is fed back to the input end of the voltage comparison module, so that the voltage comparison module continuously outputs the protection signal;

An unlocking module, the control end is connected to the MCU, and the output end is connected to the input end of the voltage comparison module; after the intelligent power module turns off the output phase current, the MCU outputs a control signal to the unlocking module, The unlocking module outputs an unlocking signal to the voltage comparison module, so that the voltage comparison module outputs a normal signal to the smart power module, and the smart power module outputs a phase according to the normal signal and the driving signal output by the MCU. The current is driven to drive the compressor.

Preferably, the feedback module includes a first resistor and a first diode;

An anode of the first diode is an input end of the feedback module, a cathode of the first diode is connected to one end of the first resistor, and another end of the first resistor is a feedback module Output.

Preferably, the feedback module includes a second resistor and a second diode;

One end of the second resistor is an input end of the feedback module, the other end of the second resistor is connected to an anode of the second diode, and a cathode of the second diode is a feedback module Output.

Preferably, the unlocking module includes a third resistor and a fifth NPN transistor;

The base of the fifth NPN transistor is connected to one end of the third resistor, the other end of the third resistor is a control end of the unlocking module, and the emitter of the fifth NPN transistor is grounded, The collector of the fifth NPN type transistor is the output end of the unlocking module.

Preferably, the unlocking module includes an eleventh resistor and a sixth PNP type triode;

The base of the sixth PNP type transistor is connected to one end of the eleventh resistor, the other end of the eleventh resistor is a control end of the unlocking module, and the collector of the sixth PNP type transistor is grounded. The emission of the sixth PNP type transistor is extremely the output end of the unlocking module.

Preferably, the compressor protection circuit further includes a signal shaping module, an input end of the signal shaping module is connected to an output end of the voltage comparison module, and an output end of the signal shaping module is connected to an input end of the feedback module The smart power module is configured to process the signal output by the voltage comparison module to the smart power module and the feedback module.

Preferably, the voltage comparison module includes a reference voltage generating unit and a first comparator, the reference voltage generating unit generates the reference voltage, and an input end of the voltage comparison module is connected to the non-inverting input end of the first comparator The voltage generating unit is connected to the inverting input end of the first comparator

Preferably, the signal shaping module comprises a fourth resistor and a first PNP type transistor;

The base of the first PNP type transistor is substantially the input end of the signal shaping module, the collector of the first PNP type transistor is grounded, and the emitter of the first PNP type transistor is shared with one end of the fourth resistor The junction is an output of the signal shaping module, and the other end of the fourth resistor is connected to a DC power source.

Preferably, the signal shaping module comprises a fifth resistor and a second NPN transistor;

The base of the second NPN transistor is substantially the input end of the signal shaping module, the collector of the second NPN transistor is connected to a DC power source, and the emitter of the second NPN transistor and the fifth resistor are connected The common junction is the output of the signal shaping module, and the other end of the fifth resistor is grounded.

Preferably, the voltage comparison module includes a reference voltage generating unit and a second comparator, the reference voltage generating unit generates the reference voltage, and the first input end of the voltage comparing module is connected to the opposite of the second comparator At the phase input, the voltage generating unit is coupled to the non-inverting input of the second comparator.

Preferably, the signal shaping module comprises a sixth resistor and a third PNP type transistor;

The base of the third PNP type transistor is substantially the input end of the signal shaping module, the emitter of the third PNP type transistor is connected to a DC power source, and the collector of the third PNP type transistor and the sixth resistor end are The common junction is the output of the signal shaping module, and the other end of the sixth resistor is grounded.

Preferably, the signal shaping module comprises a seventh resistor and a fourth NPN transistor;

The base of the fourth NPN transistor is substantially the input end of the signal shaping module, the emitter of the fourth NPN transistor is grounded, and the collector of the fourth NPN transistor is connected to one end of the seventh resistor The junction is an output of the signal shaping module, and the other end of the seventh resistor is connected to a DC power source.

Preferably, the compressor protection circuit further includes a temperature protection module, an input end of the temperature protection module is connected to the smart power module, and an output end of the temperature protection module is connected to an input end of the voltage comparison module;

When the temperature of the smart power module is too high, the smart power module outputs a temperature protection signal to the input end of the voltage comparison module through the temperature protection module, so that the voltage comparison module outputs a protection signal to the smart power module. The intelligent power module turns off the output phase current according to the protection signal to stop the compressor operation.

Preferably, the temperature protection module includes an eighth resistor, a ninth resistor, and a third diode;

One end of the eighth resistor is an input end of the temperature protection module, and the other end of the eighth resistor and one end of the ninth resistor are connected to an anode of the third diode, the third The cathode of the diode is the output of the temperature protection module, and the other end of the ninth resistor is grounded.

Preferably, the voltage comparison module further includes a tenth resistor, one end of the tenth resistor is connected to the output end of the voltage comparison module, and the other end is connected to a DC power source.

In order to achieve the above object, the present invention also provides an air conditioner including the compressor protection circuit.

The compressor protection circuit provided by the invention adds a feedback module and an unlocking module by having a current sampling module, a voltage comparison module, an MCU and an intelligent power module. Since the feedback module is connected to the input and output ends of the voltage comparison module, the unlocking module is connected to the voltage. Comparing the input end of the module, the circuit structure can be made relatively simple. Compared with the prior art, a separate latch circuit is required. The solution provided by the embodiment of the invention is simple and can reduce the cost.

DRAWINGS

1 is a schematic structural view of a compressor protection circuit module of the present invention;

2 is a circuit structural diagram of a second embodiment of a compressor protection circuit of the present invention;

3 is a circuit structural diagram of a third embodiment of a compressor protection circuit of the present invention;

4 is a circuit structural diagram of a fourth embodiment of a compressor protection circuit of the present invention;

5 is a schematic structural view of a module of a fifth embodiment of a compressor protection circuit according to the present invention;

6 is a circuit structural diagram of a fifth embodiment of a compressor protection circuit of the present invention;

Figure 7 is a circuit diagram showing another circuit of the fifth embodiment of the compressor protection circuit of the present invention;

Figure 8 is a circuit structural view of a sixth embodiment of a compressor protection circuit of the present invention;

Figure 9 is a block diagram showing another circuit of the sixth embodiment of the compressor protection circuit of the present invention;

Figure 10 is a circuit configuration diagram of a seventh embodiment of a compressor protection circuit of the present invention;

11 is a schematic structural view of a module of an eighth embodiment of a compressor protection circuit according to the present invention;

Figure 12 is a circuit structural view of an eighth embodiment of a compressor protection circuit of the present invention;

Figure 13 is a block diagram showing another circuit of the eighth embodiment of the compressor protection circuit of the present invention.

detailed description

The embodiments of the present invention are described in detail below, and the examples of the embodiments are illustrated in the drawings, wherein the same or similar reference numerals are used to refer to the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the drawings are intended to be illustrative of the invention and are not to be construed as limiting.

1 is a block diagram of a compressor protection circuit according to an embodiment of the present invention. For convenience of description, only parts related to the embodiment of the present invention are shown, which are described in detail as follows:

The compressor protection circuit provided by the embodiment of the invention includes a current sampling module 10, a voltage comparison module 20, an MCU 50 and an intelligent power module 60; the intelligent power 60 module outputs a phase current according to a driving signal output by the MCU 50 to drive the compressor 70 to operate; The sampling module 10 samples the phase current of the compressor 70 and outputs a corresponding sampling voltage signal to the voltage comparison module 20; the voltage comparison module 20 compares the sampling voltage signal with the reference voltage signal, when the sampling voltage signal is greater than the reference voltage signal, The protection signal is output to the intelligent power module 60. The intelligent power module 60 turns off the output phase current according to the protection signal to stop the compressor 70 from running, and outputs the fault protection signal to stop the MCU 50 from outputting the driving signal. The compressor protection circuit further includes:

The feedback module 30 is connected to the output end of the voltage comparison module 20, and the output end is connected to the input end of the voltage comparison module 20; when the voltage comparison module 20 outputs a protection signal when the phase current of the compressor 70 is too large, the voltage comparison module is The output signal of the 20 output is fed back to the input end of the voltage comparison module 20, so that the voltage comparison module 20 continuously outputs the protection signal;

The unlocking module 40 is connected to the MCU 50, and the output end is connected to the input end of the voltage comparison module 20; after the intelligent power module 60 turns off the output phase current, the MCU 50 outputs a control signal to the unlocking module 40, and the unlocking module 40 outputs an unlocking signal to The voltage comparison module 20 is configured to cause the voltage comparison module 20 to output a normal signal to the smart power module 60. The smart power module 60 outputs a phase current according to the normal signal and the driving signal output by the MCU 50 to drive the compressor 70 to operate.

The compressor protection circuit provided by the embodiment of the present invention adds the feedback module 30 and the unlocking module 40 by having the current sampling module 10, the voltage comparison module 20, the MCU 50, and the intelligent power module 60, because the feedback module 30 is connected to the input of the voltage comparison module 20. And the output terminal, the unlocking module 40 is connected to the input end of the voltage comparison module 20, so that the circuit structure can be made relatively simple. Compared with the prior art, a separate latch circuit is required, and the solution provided by the embodiment of the present invention is simple and capable. cut costs.

2, FIG. 2 is a circuit structural diagram of a second embodiment of a compressor protection circuit according to the present invention. Based on the first embodiment of the compressor protection circuit of the present invention, only parts related to the embodiment of the present invention are shown for convenience of description. ,details as follows:

The current sampling module 10 is mainly composed of a resistor RS. One end of the resistor RS is connected to the intelligent power module 60 to drive the lower arm switching tubes U, V, and W of the compressor 70 to the three-phase emitter output pins Iu, Iv, and Iw. The pin output current is the three-phase current of the IPM module driving the compressor 70. The connection point is simultaneously connected to the input end of the voltage comparison module 20. The other end of the resistor RS is connected to the same potential, and the resistance RS is generally small. A power resistor, such as a milliohm-grade ceramic resistor, is used by the IPM module to drive the three-phase current of the compressor 70 to generate a voltage across the resistor RS to generate a sampled voltage signal.

The voltage comparison module 20 includes a first comparator IC1. The input terminal of the voltage comparison module 20 is connected to the non-inverting input terminal of the first comparator IC1. The voltage comparison module 20 further includes a reference voltage generating unit 21, and the reference voltage generating unit 21 is connected to the first The reference voltage generating unit 21 generates a reference voltage of the voltage comparison module 20, and the reference voltage generating unit 21 is composed of a twelfth resistor R1 and a thirteenth resistor R4, wherein one end of the twelfth resistor R1 is formed at the inverting input terminal of the comparator IC1. Connected to the DC power supply, the other end is connected to the thirteenth resistor R4, the other end of the thirteenth resistor R4 is grounded, and the reference voltage signal is output from the connection point of the twelfth resistor R1 and the thirteenth resistor R4 and is connected to the first comparator IC1 Inverting input;

The input end of the voltage comparison module 20 can also be connected to the non-inverting input end of the first comparator IC1 through the fourteenth resistor R2. As shown in FIG. 2, the fourteenth resistor R2 functions as a sampling voltage signal outputted by the current sampling module 10. Isolation and current limiting protect the input pin of the first comparator IC1.

The feedback module 30 includes a first resistor R5 and a first diode D1; an anode of the first diode D1 is an input end of the feedback module 30, and a cathode of the first diode D1 is connected to one end of the first resistor R5, first The other end of the resistor R5 is the output of the feedback module 30.

The unlocking module 40 includes a third resistor R7 and a fifth NPN transistor Q1; a base of the fifth NPN transistor Q1 is connected to one end of the third resistor R7, and the other end of the third resistor R7 is a control terminal of the unlocking module 40, and a fifth The emitter of the NPN transistor Q1 is grounded, and the collector of the fifth NPN transistor Q1 is the output terminal of the unlocking module 40.

The intelligent power module 60 is an existing intelligent power module 60 including a controller and upper and lower arm switch tubes (ie, IPM, Intelligent) Power Module), where Iu, Iv, Iw are the U, V, W three-phase emitter output pins of the lower arm switch tube, and Cin is the fault and protection signal detection pin. When this pin has a high level signal, it is faulty. And the protection signal is valid, the intelligent power module 60 internally turns off the U, V, W three-phase pin output to close the load, where the U, V, W three-phase output pins are connected to the compressor 70, where the compressor 70 It is an inverter compressor; the F0 pin is a fault signal output pin. When the fault of the Cin pin and the protection signal are valid, the F0 pin outputs a valid fault signal; The UP, VP, WP, UN, VN, and WN are upper and lower arm switch tube drive signal input pins, and the six drive signals are input to the smart power module 60 to cause the smart power module 60 to drive the compressor 70 to operate.

The MCU 50 is a signal processing chip, and includes a software algorithm program for driving the intelligent power module 60 to operate, so that the load compressor 70 operates according to the driving signal output by the MCU 50, wherein the output control terminal is connected to the control end of the unlocking module 40, and the overcurrent protection detecting end is connected to The output of the voltage comparison module 20, the IPM module fault detection pin is connected to the F0 pin of the smart power module 60.

The working principle of the compressor protection circuit will be further described below with reference to FIG. 2:

When the compressor 70 is working normally, the three-phase current of the compressor 70 is normal. At this time, the U, V, W three-phase emitter output pins Iu, Iv, Iw current of the lower arm switch tube of the intelligent power module 60 The voltage on the RS is less than the reference voltage of the first comparator IC1 from the inverting input terminal. At this time, the first comparator IC1 outputs a low level, and the first diode D1 of the feedback module 30 is not turned on; when due to the compressor 70 When the fault of the body or the internal fault of the intelligent power module 60 causes the operating current of the compressor 70 to increase, that is, the phase current output by the smart power module 60 increases, the U, V, W three-phase emitter outputs of the lower arm switch tube When the currents of the pins Iu, Iv, and Iw are correspondingly increased, and the voltage on the resistor RS is greater than the voltage of the inverting input terminal of the first comparator IC1, the first comparator IC1 outputs a high level signal, that is, the compressor 70 phase current. If the signal is too large, the first diode D1 of the feedback module 30 is turned on, and the first comparator IC1 outputs a high level signal to the non-inverting input of the first comparator IC1 through the first diode D1 and the first resistor. End, so that the non-inverting input of the first comparator IC1 is always in high power a state, which in turn causes the voltage of the non-inverting input terminal of the first comparator IC1 to be maintained at a higher state than the reference voltage of the inverting input terminal, even if the voltage on the RS is less than the reference voltage of the first comparator IC1 from the inverting input terminal, and thus The output of the first comparator IC1 is locked in an output high state; the high level signal output by the first comparator IC1 is simultaneously output to the fault and protection signal detecting pin Cin of the smart power module 60, and the smart power module 60 is valid according to The fault and protection signals then turn off their phase current output to control compressor 70 shutdown, although smart power module 60 turns off its phase current output causing Iu, Iv, Iw current to be zero such that the voltage on RS is less than that of first comparator IC1 The reference voltage of the inverting input terminal, but since the output of the first comparator IC1 is locked in the output high state state at this time, the intelligent power module 60 continuously turns off its phase current output to control the compressor 70 to stop, while at the smart power When the fault of the module 60 and the protection signal detecting pin Cin detect a valid fault and protection signal, a fault is outputted at the fault signal output pin F0. The pulse signal is sent to the MCU 50, and the MCU 50 stops outputting the driving signals of the six smart power modules 60 according to the detected fault signal. During this period, even if the 6 strong driving signals of the MCU 50 encounter external strong interference signals, The smart power module 60 is in the continuous off output state, and does not cause the smart power module 60 to generate a large current output during the drive signal interference, thereby effectively protecting the compressor 70. Wait until the relevant circuit of the compressor 70 works normally or the compressor 70 is faulty (for example, if the MCU50 obtains the stable state parameter of the compressor 70 through the relevant detection current or the state parameter of the MCU50 reads the IPM module is stable), the MCU50 outputs the control terminal to output high power. The flat pulse signal turns on the fifth NPN transistor Q1 of the unlocking module 40, and the non-inverting input terminal of the first comparator IC1 is pulled to a low level, so that the first comparator IC1 outputs a low level signal, and the feedback module 30 A diode D1 is turned off, and the low level signal is input to the Cin pin of the smart power module 60, the fault and the protection signal are released, the intelligent power module 60 works normally, and the fault signal outputted at the F0 pin is contacted, and the MCU 50 is based on The fault release signal output drive signal controls the smart power module 60 to output a phase current to drive the compressor 70 to operate normally. It should be noted that, when the output control terminal of the MCU 50 outputs a high-level pulse signal to the unlocking module 40 so that the fault and the protection signal of the smart power module 60 pin Cin are released, the MCU50 output control terminal cannot output a high level signal, and must be a high level. The pulse signal, because the output of the MCU50 output control terminal is high, the fifth NPN transistor Q1 is turned on so that the non-inverting input terminal of the first comparator IC1 is pulled low, and finally the smart power module 60 pin Cin The fault and protection signal are released. Thereafter, the MCU 50 outputs a driving signal to control the smart power module 60 to output the phase current to drive the compressor 70 to operate normally. If the fifth NPN transistor Q1 is still turned on, the first comparator IC1 is always pulled down. At the non-inverting input terminal, the sampling voltage signal outputted by the current sampling module 10 cannot be normally input to the non-inverting input terminal of the first comparator IC1, so that the first comparator IC1 plays a normal current comparison, so the output power of the output terminal of the MCU 50 is high. After the flat pulse signal is sent to the unlocking module 40, the fault and the protection signal of the smart power module 60 pin Cin are released, and the low level is required to be output. A fifth NPN transistor Q1 is turned off, so that the first comparator IC1 to work properly.

In this embodiment, the unlocking module 40 may further include a fifteenth resistor R9. One end of the fifteenth resistor R9 is connected to the base of the NPN transistor Q1, and is connected to one end of the third resistor R7, and the fifteenth resistor R9 is another. One end is grounded, that is, the fifteenth resistor R9 is connected across the base and the emitter of the NPN transistor Q1, so that the NPN transistor Q1 can reliably cut off when the MCU 50 outputs a low level. The output of the first comparator IC1 can also be connected to the fault and protection signal detection pin Cin of the smart power module 60 through the sixteenth resistor R3, and the sixteenth resistor R3 acts as a current limiting to protect the pin of the smart power module 60. Cin, for the same reason, the output of the first comparator IC1 can also be connected to the MCU 50 through the seventeenth resistor R6, and the seventeenth resistor R6 functions the same as the sixteenth resistor R3.

The compressor protection circuit provided by the embodiment of the present invention adds the feedback module 30 and the unlocking module 40 to the input and output of the feedback module 30 by having the current sampling module 10, the reference voltage generating module 30, the voltage comparing module 20, the MCU 50, and the intelligent power module 60. The terminals are respectively connected to the output end and the input end of the voltage comparison module 20, and the control end and the output end of the unlocking module are respectively connected to the input ends of the MCU and the voltage comparison module 20. Since the feedback module 30 is realized only by one diode and a resistor, the unlocking module 40 only The circuit is realized by a triode and a resistor, and the circuit thereof is much simpler than the prior art latch circuit, and the latch chip is not required to be added. Therefore, the cost of the embodiment of the present invention is lower than that of the existing latch circuit and the operation is reliable. Conducive to a large number of popularization and application of compressor protection circuits.

3 is a circuit configuration diagram of a third embodiment of a compressor protection circuit according to the present invention. The first embodiment of the compressor protection circuit according to the present invention is different from the compressor protection circuit of FIG. 2 in that the feedback module is different from the feedback module. 30, other modules are the same as those shown in FIG. 2, and therefore will not be described again.

The feedback module 30 includes a second resistor R17 and a second diode D2; an anode of the second diode D2 is an input end of the feedback module 30, a cathode of the second diode D2 is connected to one end of the second resistor R17, and a second The other end of the resistor R17 is the output of the feedback module 41. The circuit structure of the feedback module 30 of FIG. 1 is different in that the connection position of the resistor and the diode is changed, and the function of the feedback module is not affected.

4 is a circuit configuration diagram of a compressor protection circuit according to a fourth embodiment of the present invention. The first embodiment of the compressor protection circuit according to the present invention is different from the compressor protection circuit of FIG. 2 in that the unlocking module is 40, other modules are the same as shown in FIG. 2, and therefore will not be described again.

The unlocking module 40 includes an eleventh resistor R21 and a sixth PNP transistor Q6; a base of the sixth PNP transistor Q6 is connected to one end of the eleventh resistor R21, and the other end of the eleventh resistor R21 is a control end of the unlocking module 40. The collector of the sixth PNP type transistor Q6 is grounded, and the emission of the sixth PNP type transistor Q6 is extremely unlocked at the output end of the module.

Unlike the operation of the unlocking module circuit in the second embodiment, when the compressor 70 is operating normally, the MCU 50 outputs a high level signal such that the sixth PNP type transistor Q6 is turned off, so that the first comparator IC1 can operate normally; When the phase current output by the smart power module 60 is increased, causing the output of the first comparator IC1 to be locked to output a high level protection signal, so that the smart power module 60 has a protection off output, after the compressor 70 is faulty, the MCU 50 outputs low. The level pulse signal causes the sixth PNP type transistor Q6 to be turned on for a short time, unlocking the output of the first comparator IC1, thereby enabling the smart power module 60 and the MCU 50 to control the normal operation of the compressor.

The unlocking module 40 may further include an eighteenth resistor R20. One end of the eighteenth resistor R20 is connected to the base of the sixth PNP transistor Q6, and is connected to one end of the eleventh resistor R21, and the other end of the eighteenth resistor R20 is connected. The collector of the sixth PNP type transistor Q6, that is, the eighteenth resistor R20 is connected across the base and the collector of the sixth PNP type transistor Q6, and the sixth PNP type transistor Q6 can be reliably cut off when the MCU50 outputs a high level. effect.

5 is a block diagram of a fifth embodiment of a compressor protection circuit according to the present invention. According to the first embodiment of the compressor protection circuit of the present invention, the compressor protection circuit further includes a signal shaping module 80, and the signal shaping module 80 The input end is connected to the output end of the voltage comparison module 20. The output end of the signal shaping module 80 is connected to the input end of the feedback module 30 and the intelligent power module 60. The signal shaping module 80 shapes the signal output by the voltage comparison module 20 and outputs the signal to the smart power. Module 60 and feedback module 30.

The signal shaping module 80 shapes and isolates the protection signal output by the voltage comparison module 20 when the phase current of the compressor 70 is excessive, or the normal signal output by the voltage comparison module 20 when the compressor 70 is working normally, and outputs the input to the input of the feedback module 30. The fault and protection signal of the end and intelligent power module 60 detects the pin Cin.

The specific circuit structure of the signal shaping module 80 differs depending on the circuit configuration of the voltage comparison module 20.

In the circuit configuration of the voltage comparison module 20 shown in FIG. 2, that is, the input terminal of the voltage comparison module 20 is connected to the non-inverting input terminal of the first comparator IC1, and the reference voltage generating unit 21 of the voltage comparison module 20 is connected to the first comparison. The inverting input of the IC1, the signal shaping module 80 can have two different circuit structures, as follows:

Referring to FIG. 6, FIG. 6 is a circuit structural diagram of a signal shaping module 80 of a compressor protection circuit according to the present invention. The signal shaping module 80 includes a fourth resistor R10 and a first PNP transistor Q2, and a base of the first PNP transistor Q2. At the input end of the signal shaping module, the collector of the first PNP transistor Q2 is grounded, the common junction of the emitter of the first PNP transistor Q2 and the end of the fourth resistor R10 is the output of the signal shaping module, and the fourth resistor R10 Connect DC power supply VCC to one end. The signal shaping module 80 may further include a nineteenth resistor R11. One end of the nineteenth resistor R11 is connected to the base of the first PNP transistor Q2, and the other end of the nineteenth resistor R11 is grounded, that is, the nineteenth resistor R11 is connected. The base and the emitter of the first PNP transistor Q2 function as a first PNP transistor Q2 that can reliably turn off when the first comparator IC1 outputs a low level.

When the compressor 70 and the intelligent power module 60 are working normally, the first comparator IC1 outputs a low level, and the first PNP type transistor Q2 is turned on, so that the emitter outputs a low level to the fault and protection signal of the smart power module 60. The pin Cin and the feedback module 30 are detected. At this time, the fault and the protection signal are invalid, and the first diode D1 of the feedback module 30 is turned off; when the phase current of the compressor 70 is too large, the first comparator IC1 outputs a high level, A PNP type transistor Q2 is turned off, so that its emitter outputs a high level to the fault of the intelligent power module 60 and the protection signal detecting pin Cin and the feedback module 30, at which time the fault and protection signals are valid, and the first two poles of the feedback module 30 are simultaneously The tube D1 is turned on, and the intelligent power module 60 then turns off its phase current output according to the effective fault and protection signal to control the compressor 70 to stop, and the high level signal is fed back through the first diode D1 and the first resistor. The non-inverting input terminal of the first comparator IC1 causes the non-inverting input terminal of the first comparator IC1 to be in a high level state, so that the output of the first comparator IC1 is locked in an output high state state, so that the smart Fault detection and protection signals Cin foot fault rate and the protection signal module 60 has been effective. Other working principles are the same as those of the circuit shown in FIG. 2 of the second embodiment, and are not described herein.

Referring to FIG. 7, FIG. 7 is another circuit structure diagram of the signal shaping module 80 of the compressor protection circuit of the present invention. The other circuit structure is the same as that of FIG. 6. The shaping module includes a fifth resistor R13 and a second NPN transistor Q3. The input end of the signal shaping module of the second NPN transistor Q3 is connected to the voltage comparison module 20, the collector of the second NPN transistor Q3 is connected to the DC power source, and the emitter of the second NPN transistor is connected to the fifth resistor R13. The common contact at one end is the output end of the signal shaping module, the output end of which is connected to the intelligent power module 60 and the feedback module 30, and the other end of the fifth resistor R13 is grounded. Similar to the nineteenth resistor R11 in FIG. 6, a tens resistor R12 may be further included, one end of the twentieth resistor R12 is connected to the base of the second NPN transistor Q3, and the other end of the twentieth resistor R12 is grounded.

When the compressor 70 and the intelligent power module 60 are working normally, the first comparator IC1 outputs a low level, and the second NPN transistor Q3 is turned off, so that the emitter outputs a low level to the intelligent power module 60 for fault and protection signal detection. The pin Cin and the feedback module 30, at this time, the fault and the protection signal are invalid; when the phase current of the compressor 70 is too large, the first comparator IC1 outputs a high level, and the second NPN transistor Q3 is turned on, so that the emitter output thereof is high. Level to the fault of the intelligent power module 60 and the protection signal detection pin Cin and the feedback module 30, at which time the fault and protection signals are valid, while the first diode D1 of the feedback module 30 is turned on, and the intelligent power module 60 is based on an effective fault. And the protection signal then turns off its phase current output to control the compressor 70 to stop, and the high level signal passes through the feedback module 30 to the non-inverting input of the first comparator IC1, so that the non-inverting input of the first comparator IC1 is always In a high state, the output of the first comparator IC1 is locked in an output high state, so that the fault of the intelligent power module 60 and the protection signal detection pin Cin fault and protection signal Straight valid. Other working principles are the same as those of the circuit shown in FIG. 2 of the second embodiment, and are not described herein.

Referring to FIG. 8, FIG. 8 is a circuit structural diagram of a sixth embodiment of a compressor protection circuit according to the present invention. The first embodiment of the compressor protection circuit according to the present invention is different from the compressor protection circuit of FIG. 20 and signal shaping module 80, the other modules are the same as shown in FIG.

The voltage comparison module 20 includes a second comparator IC2. The input terminal of the voltage comparison module 30 is connected to the inverting input terminal of the second comparator IC2, and the reference voltage generating unit 22 of the voltage comparison module 20 is connected to the non-inverting input terminal of the second comparator IC2. . The reference voltage generating unit 22 has the same circuit connection and function as the reference voltage generating unit 21 of the fifth embodiment.

The signal shaping module 80 includes a sixth resistor R14 and a third PNP transistor Q4. The base of the third PNP transistor Q4 is the input terminal of the signal shaping module 80, and the emitter of the third PNP transistor Q4 is connected to the DC power source, and the third PNP. The common junction of the collector of the transistor Q4 and the one end of the sixth resistor R14 is the output terminal of the signal shaping module 80, and the other end of the sixth resistor R14 is grounded. Similar to the nineteenth resistor R11 in FIG. 6, the signal shaping module 80 may further include a twenty-first resistor R13. One end of the twenty-first resistor R13 is connected to the base of the third PNP transistor Q4, and the twenty-first resistor The other end of R13 is connected to the collector of the third PNP type transistor Q4, that is, the twenty-first resistor R13 is connected across the base and collector of the third PNP type transistor Q4, and the third PNP type transistor Q4 is in the second Comparator IC2 can reliably cut off when it outputs a high level.

When the compressor 70 and the smart power module 60 are working normally, the second comparator IC2 outputs a high level, and the third PNP type transistor Q4 is turned off, so that the collector outputs a low level to the fault and protection signal detection of the smart power module 60. The pin Cin and the feedback module 30, at this time, the fault and the protection signal are invalid, and the first diode D1 of the feedback module 30 is turned off; when the phase current of the compressor 70 is too large, the second comparator IC2 outputs a high level, and the third The PNP type transistor Q4 is turned on, so its collector outputs a high level to the fault of the intelligent power module 60 and the protection signal detecting pin Cin and the feedback module 30, at which time the fault and the protection signal are valid, and the first two poles of the feedback module 30 are simultaneously The tube D1 is turned on, and the intelligent power module 60 then turns off its phase current output according to the effective fault and protection signal to control the compressor 70 to stop, and the high level signal is fed back through the first diode D1 and the first resistor. The inverting input terminal of the second comparator IC2 is such that the inverting input terminal of the second comparator IC2 is always in a high state, so that the output of the second comparator IC2 is locked in an output low state state, so that the smart Fault detection and protection signals Cin foot fault rate and the protection signal module 60 has been effective. Other working principles are the same as those of the circuit shown in FIG. 2 of the second embodiment, and are not described herein.

Referring to FIG. 9, FIG. 9 is another circuit structure diagram of the signal shaping module 80 of the compressor protection circuit of the present invention. The other circuit structure is the same as that of FIG. 7. The shaping module includes a seventh resistor R16 and a fourth NPN transistor Q5. The input end of the signal shaping module of the fourth NPN transistor Q5 is connected to the voltage comparison module 20, and the common junction of the collector of the fourth NPN transistor Q5 and the seventh resistor R16 is the output of the signal shaping module. The other end of the seventh resistor R16 is connected to the DC power source VCC. Similar to the twenty-first resistor R13 in FIG. 8, a second resistor R15 may be further included. One end of the resistor R15 is connected to the base of the fourth NPN transistor Q5, and the other end of the twenty-second resistor R15 is grounded.

When the compressor 70 and the smart power module 60 are working normally, the second comparator IC2 outputs a high level, and the fourth NPN transistor Q5 is turned on, so that the collector outputs a low level to the fault and protection signal of the smart power module 60. The pin Cin and the feedback module 30 are detected, and the fault and the protection signal are invalid at this time; when the phase current of the compressor 70 is too large, the second comparator IC1 outputs a low level, and the fourth NPN transistor Q5 is turned off, so that the collector output is high. Level to the fault of the intelligent power module 60 and the protection signal detection pin Cin and the feedback module 30, at which time the fault and protection signals are valid, while the first diode D1 of the feedback module 30 is turned on, and the intelligent power module 60 is based on an effective fault. And the protection signal then turns off its phase current output to control compressor 70 shutdown, while the high level signal passes through feedback module 30 to the inverting input of second comparator IC2, causing the inverting input of second comparator IC2 The terminal is always in a high state, so that the output of the second comparator IC2 is locked in the output low state, so that the fault of the intelligent power module 60 and the protection signal detection pin Cin fault and protection signal Straight valid. Other working principles are the same as those of the circuit shown in FIG. 2 of the second embodiment, and are not described herein.

10 is a circuit configuration diagram of a seventh embodiment of a compressor protection circuit according to the present invention. According to the second or sixth embodiment of the compressor protection circuit of the present invention, with respect to the compressor protection circuit of FIG. 2 or FIG. The difference is that the voltage comparison module 20 further includes a tenth resistor R17. One end of the tenth resistor is connected to the output end of the voltage comparison module, and the other end is connected to the DC power source VCC.

The third comparator IC3 in FIG. 10 may be different from the first comparator IC1 in FIG. 2 or the second comparator IC2 in FIG. 8, and the third comparator IC3 may adopt an internal output transistor open collector output type comparison. The device itself cannot directly output a high level, and needs to be pulled up to the VCC output high level through the tenth resistor R17; and the output ends of the first comparator IC1 and the second comparator IC2 are not similar to the tenth resistor R17. For pull-up resistors, the comparator must use an internal output transistor push-pull output type, and its comparator must be capable of outputting a high level. Of course, the third comparator IC3 can also use an internal output transistor push-pull output type comparator. Therefore, the comparator can be adapted to a wider range of comparator types by the tenth resistor R17 that is pulled up.

Referring to FIG. 11, FIG. 11 is a block diagram of a first embodiment of a compressor protection circuit according to the present invention. According to a first embodiment of the compressor protection circuit of the present invention, the compressor protection circuit further includes a temperature protection module 90, and the temperature protection module 90 The input end is connected to the smart power module 60, and the output end of the temperature protection module 90 is connected to the input end of the voltage comparison module 20.

When the temperature of the smart power module 60 is too high, the smart power module 60 outputs a temperature protection signal to the input end of the voltage comparison module 20 through the temperature protection module 90, so that the voltage comparison module 20 outputs a protection signal to the smart power module 60, and the smart power module 60 turns off the output phase current according to the protection signal to stop the compressor operation.

12 is a circuit configuration diagram of the temperature protection module 90 of the compressor protection circuit of the present invention, the temperature protection module includes an eighth resistor R18, a ninth resistor R19 and a third diode D3;

One end of the eighth resistor R18 is an input end of the temperature protection module, the other end of the eighth resistor R18 and one end of the ninth resistor R19 are connected to the anode of the third diode D3, and the cathode of the third diode D3 is a temperature. At the output of the protection module, the other end of the ninth resistor R19 is grounded.

The intelligent power module 60 used in the embodiment of the present invention is an intelligent power module with a temperature signal output function, which detects the internal temperature of the intelligent power module 60, and outputs a signal reflecting the temperature through the TO pin of the intelligent power module 60 in FIG. If the different internal voltages of the smart power module 60 are reflected by different voltage values, when the operating current of the compressor is too high, the phase current output by the smart power module 60 is too large, and the temperature rise of the body of the smart power module 60 increases rapidly. At this time, if the effective protection is not obtained, the module is easily damaged. The voltage signal of the TO power output of the smart power module 60 reflects the temperature and generates a voltage value of a suitable voltage range through the voltage dividing circuit constituting the eighth resistor R18 and the ninth resistor R19, and outputs the voltage value to the voltage comparison module 20 through the third diode D3. The non-inverting input terminal of the first comparator IC1; the third diode D3 acts as an isolation to isolate the interference signal generated by the non-inverting input terminal of the first comparator IC1, preventing the three-phase currents Iu, Iv, Iw due to the compressor The interference signal is generated to the non-inverting input terminal of the first comparator IC1, and finally causes the TO pin of the intelligent power module 60 to be damaged; when the temperature of the smart power module 60 is too high, the output voltage signal of the TO pin is raised, and finally the resistor RS is When the voltage is greater than the voltage of the inverting input terminal of the first comparator IC1, the first comparator IC1 outputs a high level signal, that is, the compressor 70 phase current excessive signal, and other working principles are the same as those shown in FIG. 2, so Narration.

The temperature protection module 90 is added by the compressor protection circuit of the present invention, so that when the operating temperature of the intelligent power module 70 is too high, reliable protection is obtained to prevent the heat from being severely damaged.

Referring to Figure 13, Figure 13 is a structural diagram of an application circuit related to the complete compressor control of the compressor protection circuit of the present invention based on Figure 12, the working principle of which is as follows:

Diode D4-D7 constitutes the rectifier circuit of the AC input terminal, rectifies the AC input voltage and converts it into DC ripple voltage. L, D8 and C4 form a passive PFC circuit, and correct the DC ripple voltage output by the rectifier circuit. C5 is The high-capacity high-voltage filter capacitor smoothly filters the DC ripple voltage into a stable DC voltage, and provides the DC power supply for the intelligent power module IC5. The intelligent power module IC5 outputs the U, V, W three-phase current-driven inverter compressor. M work.

The intelligent power module IC5 includes an upper bridge arm IGBT composed of S1, S3, and S5 (Insulated Gate Bipolar) Transistor) switch tube and S2, S4, S6 lower arm IGBT switch tube and controller; the controller is HVIC (High Voltage Integrated Circuit) high voltage integrated circuit and LVIC (Low Voltage Integrated) Circuit) is a low-voltage integrated circuit, HVIC is used to drive the upper bridge IGBT switch tube, LVIC is used to drive the lower bridge IGBT switch tube and includes related control and status signal pins, including fault signal output pin F0, fault and protection signal The detection pin Cin, the intelligent power module internal temperature detection signal output pin TO, and the U, V, W three-phase emitter output pins Iu, Iv, Iw of the lower arm switch tube.

MCU IC4 is a signal processing chip, which contains the software algorithm program for driving the intelligent power module IC5 and its state detection, state detection related program of the inverter compressor M, etc.; the P3-P7 six pins of the MCU are respectively connected to the intelligent power module IC5. The Wn, Vn, Un, Wp, Vp, and Up input pins are connected to the LVIC and HVIC to drive the IGBT switch of the upper and lower arms through the LVIC and HVIC.

The other part of the circuit and the circuit including the current sampling module, the voltage comparison module, the feedback module, the unlocking module, and the temperature protection module shown in FIG. 12 have the same working principle as that of FIG. 12 and will not be further described herein.

The present invention also provides an air conditioner, including the above-mentioned compressor protection circuit, and the air conditioner thereof is an inverter air conditioner. For the specific embodiment, reference may be made to the above embodiment, and details are not described herein again.

The above are only the preferred embodiments of the present invention, and are not intended to limit the scope of the invention, and the equivalent structure or equivalent process transformations made by the description of the present invention and the drawings are directly or indirectly applied to other related technical fields. The same is included in the scope of patent protection of the present invention.

Claims (15)

1. A compressor protection circuit includes a current sampling module, a voltage comparison module, an MCU and an intelligent power module; the intelligent power module outputs a phase current according to a driving signal output by the MCU to drive a compressor to operate; the current sampling module Sampling a phase current of the compressor and outputting a corresponding sampled voltage signal to the voltage comparison module; the voltage comparison module comparing the sampled voltage signal with a reference voltage signal, wherein the sampled voltage signal is greater than the reference And outputting a protection signal to the smart power module when the voltage signal is; the smart power module turns off the output phase current according to the protection signal to stop the compressor operation, and outputs a fault protection signal to stop the MCU from outputting the drive. a signal; wherein the compressor protection circuit further comprises:

   a feedback module, the input end is connected to the output end of the voltage comparison module, and the output end is connected to the input end of the voltage comparison module; when the voltage comparison module outputs a protection signal when the compressor phase current is too large, the The protection signal outputted by the voltage comparison module is fed back to the input end of the voltage comparison module, so that the voltage comparison module continuously outputs the protection signal;

   An unlocking module, the control end is connected to the MCU, and the output end is connected to the input end of the voltage comparison module; after the intelligent power module turns off the output phase current, the MCU outputs a control signal to the unlocking module, The unlocking module outputs an unlocking signal to the voltage comparison module, so that the voltage comparison module outputs a normal signal to the smart power module, and the smart power module outputs a phase according to the normal signal and the driving signal output by the MCU. The current is driven to drive the compressor.
2. The compressor protection circuit of claim 1 wherein said feedback module comprises a first resistor and a first diode;

   An anode of the first diode is an input end of the feedback module, a cathode of the first diode is connected to one end of the first resistor, and another end of the first resistor is a feedback module Output.
3. The compressor protection circuit according to claim 1, wherein said feedback module comprises a second resistor and a second diode;

   One end of the second resistor is an input end of the feedback module, the other end of the second resistor is connected to an anode of the second diode, and a cathode of the second diode is a feedback module Output.
4. The compressor protection circuit according to claim 1, wherein said unlocking module comprises a third resistor and a fifth NPN type triode;

   The base of the fifth NPN transistor is connected to one end of the third resistor, the other end of the third resistor is a control end of the unlocking module, and the emitter of the fifth NPN transistor is grounded, The collector of the fifth NPN type transistor is the output end of the unlocking module.
5. The compressor protection circuit according to claim 1, wherein said unlocking module comprises an eleventh resistor and a sixth PNP type triode;

   The base of the sixth PNP type transistor is connected to one end of the eleventh resistor, the other end of the eleventh resistor is a control end of the unlocking module, and the collector of the sixth PNP type transistor is grounded. The emission of the sixth PNP type transistor is extremely the output end of the unlocking module.
6. The compressor protection circuit according to claim 1, wherein said compressor protection circuit further comprises a signal shaping module, wherein an input end of said signal shaping module is coupled to an output of said voltage comparison module, said signal shaping The module output is connected to the input end of the feedback module and the intelligent power module, and the signal shaping module shapes the signal output by the voltage comparison module and outputs the signal to the intelligent power module and the feedback module.
7. The compressor protection circuit according to claim 6, wherein said voltage comparison module comprises a reference voltage generating unit and a first comparator, said reference voltage generating unit generates said reference voltage, said voltage comparison module The input terminal is coupled to the non-inverting input of the first comparator, and the voltage generating unit is coupled to the inverting input of the first comparator.
8. The compressor protection circuit according to claim 7, wherein said signal shaping module comprises a fourth resistor and a first PNP type transistor;

   The base of the first PNP type transistor is substantially the input end of the signal shaping module, the collector of the first PNP type transistor is grounded, and the emitter of the first PNP type transistor is shared with one end of the fourth resistor The junction is an output of the signal shaping module, and the other end of the fourth resistor is connected to a DC power source.
9. The compressor protection circuit according to claim 7, wherein said signal shaping module comprises a fifth resistor and a second NPN type transistor;

   The base of the second NPN transistor is substantially the input end of the signal shaping module, the collector of the second NPN transistor is connected to a DC power source, and the emitter of the second NPN transistor and the fifth resistor are connected The common junction is the output of the signal shaping module, and the other end of the fifth resistor is grounded.
10. The compressor protection circuit according to claim 6, wherein said voltage comparison module comprises a reference voltage generating unit and a second comparator, said reference voltage generating unit generates said reference voltage, said voltage comparison module The first input is coupled to the inverting input of the second comparator, and the voltage generating unit is coupled to the non-inverting input of the second comparator.
11. The compressor protection circuit according to claim 10, wherein said signal shaping module comprises a sixth resistor and a third PNP type transistor;

    The base of the third PNP type transistor is substantially the input end of the signal shaping module, the emitter of the third PNP type transistor is connected to a DC power source, and the collector of the third PNP type transistor and the sixth resistor end are The common junction is the output of the signal shaping module, and the other end of the sixth resistor is grounded.
12. The compressor protection circuit according to claim 10, wherein said signal shaping module comprises a seventh resistor and a fourth NPN transistor;

    The base of the fourth NPN transistor is substantially the input end of the signal shaping module, the emitter of the fourth NPN transistor is grounded, and the collector of the fourth NPN transistor is connected to one end of the seventh resistor The junction is an output of the signal shaping module, and the other end of the seventh resistor is connected to a DC power source.
13. The compressor protection circuit according to claim 1, wherein the compressor protection circuit further comprises a temperature protection module, wherein an input end of the temperature protection module is connected to the smart power module, and an output of the temperature protection module Connecting an input end of the voltage comparison module;

    When the temperature of the smart power module is too high, the smart power module outputs a temperature protection signal to the input end of the voltage comparison module through the temperature protection module, so that the voltage comparison module outputs a protection signal to the smart power module. The intelligent power module turns off the output phase current according to the protection signal to stop the compressor operation.
14. The compressor protection circuit according to claim 13, wherein said temperature protection module comprises an eighth resistor, a ninth resistor and a third diode;

    One end of the eighth resistor is an input end of the temperature protection module, and the other end of the eighth resistor and one end of the ninth resistor are connected to an anode of the third diode, the third The cathode of the diode is the output of the temperature protection module, and the other end of the ninth resistor is grounded.
15. An air conditioner, comprising the compressor protection circuit according to claim 1.