An air conditioner

Abstract

The present invention relates to an air conditioner. A current detection circuit is used to detect current and output an overcurrent signal to a controller when the current exceeds a set current value. The controller outputs a control signal to a driver chip. The driver chip drives a compressor. A comparator has a first input connected to a reference voltage, and an output outputting a signal to the driver chip via a diode D2. A diode D1 is used to connect the overcurrent signal output of the current detection circuit to the second input of the comparator. An overcurrent extinction delay circuit includes a capacitor C8 and a resistor R17 connected in series between a power supply and ground, with the second input of the comparator connected between capacitor C8 and resistor R17. A reset signal output by the controller is connected between diode D2 and the driver chip via a diode D3, with the input or output of diodes D2 and D3 connected to a high or low level. The present invention prevents repeated faults from occurring within a short period of time and damaging the substrate through dual protection of software and hardware.

Description

Technical Field

[0001] The present invention relates to the technical field of air conditioners, in particular to an air conditioner with a software and hardware dual-delay reset circuit. Background Art

[0002] During operation, the air-conditioning compressor variable frequency drive may have problems such as module damage, load short circuit, etc., causing excessive output current and output power short circuit, threatening the safety of the substrate.

[0003] When a VFD overcurrent fault occurs, the VFD's hardware protection circuit activates and outputs a fault signal. Upon receiving this signal, the driver chip and controller initiate protection by cutting off the output signal. At this point, the VFD's current dissipates, the hardware overcurrent fault is eliminated, and the circuit returns to normal, ready for restart. However, if the module suffers irreversible damage or a short circuit caused by accumulated thermal stress, immediately re-energizing the power supply can cause the overcurrent fault to recur. Multiple overcurrent faults within a short period of time can severely damage the driver board. Therefore, after a hardware overcurrent fault occurs, it is necessary to lock the output for a period of time before re-enabling the output to prevent the fault from recurring within a short period of time.

[0004] Existing variable frequency drives rely on software protection. This prevents repeated overcurrent events by adding a delay after a fault occurs, before outputting a reset signal to the driver chip. However, this relies on the proper functioning of the software. If the control chip resets, loses power, or experiences a loss of control, the software delay becomes ineffective, and the delay function disappears.

[0005] The above information disclosed in this background technology is only used to increase the understanding of the background technology of this application. Therefore, it may contain information that does not constitute the prior art known to ordinary technicians in this field. Summary of the Invention

[0006] The present invention provides an air conditioner, which solves the technical problem of poor reliability of air conditioners in the prior art due to software-delayed resetting.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] An air conditioner, comprising:

[0009] a current detection circuit, configured to detect current and output an overcurrent signal to a controller when the current exceeds a set current value;

[0010] a controller, configured to output a driver chip control signal when not receiving the overcurrent signal, and stop outputting the driver chip control signal when receiving the overcurrent signal;

[0011] A driver chip, configured to receive a control signal from the driver chip and drive the compressor;

[0012] The air conditioner further comprises:

[0013] A comparator, wherein a first input terminal thereof is connected to a reference voltage, and an output terminal thereof outputs a signal to the driver chip via a diode D2;

[0014] A diode D1 is used to connect the overcurrent signal output terminal of the current detection circuit and the second input terminal of the comparator;

[0015] An overcurrent disappearance delay circuit includes a capacitor C8 and a resistor R17 connected in series between a power supply and a ground, wherein the capacitor C8 and the resistor R17 are connected to the second input terminal of the comparator;

[0016] The reset signal output by the controller is connected between the diode D2 and the driver chip through the diode D3, and the input end or output end of the diodes D2 and D3 is connected to a high level or a low level.

[0017] In some embodiments, the capacitor C8 and the resistor R17 form a charging circuit, and the time constant of the capacitor C8 and the resistor R17 is in the order of seconds.

[0018] In some embodiments, the air conditioner includes a resistor R16, the resistor R16 is connected between the diode D1 and the second input terminal of the comparator, the capacitor C8 and the resistor R16 form a discharge circuit, and the time constant of the capacitor C8 and the resistor R16 is in microseconds. When the resistance R16 is 0, the time constant of the capacitor C8 and the resistor R16 is 0.

[0019] In some embodiments, the air conditioner includes a resistor R18 and a resistor R19 connected in series, the reference voltage is obtained by dividing the resistor R18 and the resistor R19, one end of the resistor R18 and the resistor R19 connected in series is connected to a power supply, and the other end is grounded, and the first input end of the comparator is connected between the resistor R18 and the resistor R19, wherein R19 / (R18+R19) is between 60%-65%.

[0020] In some embodiments, the air conditioner includes a resistor R20 , the resistor R20 is connected between the first input terminal and the output terminal of the comparator, and the resistor R20 is used to provide a hysteresis voltage for the comparator.

[0021] In some embodiments, the output terminal of the comparator is connected to a pull-up resistor R21 or a pull-down resistor, the pull-up resistor R21 is connected to a power supply, and the pull-down resistor is grounded.

[0022] In some embodiments, the overcurrent signal output terminal of the current detection circuit is connected to a pull-up resistor R15 or a pull-down resistor, the pull-up resistor R15 is connected to a power supply, and the pull-down resistor is grounded.

[0023] In some embodiments, the air conditioner includes a charging and discharging circuit consisting of a capacitor C7 and a resistor R14, the overcurrent signal output end of the current detection circuit is connected to the charging and discharging circuit consisting of the capacitor C7 and the resistor R14, the resistor R14 is connected in series to the overcurrent signal output end of the current detection circuit, and the capacitor C7 is grounded.

[0024] In some embodiments, the time constant of the capacitor C7 and the resistor R14 is in microseconds.

[0025] In some embodiments, the current detection circuit includes:

[0026] a signal amplifying circuit, configured to amplify the current;

[0027] A second voltage divider circuit includes a resistor R13 and a resistor R11 connected in series, wherein the resistor R13 is connected to a power supply and the resistor R11 is grounded;

[0028] The second comparator has a first input terminal connected between the resistor R13 and the resistor R11, a second input terminal connected to the signal amplifying circuit, and an output terminal serving as an overcurrent signal output terminal of the current detection circuit.

[0029] The technical solution of the present invention has the following technical effects compared to the prior art: the air conditioner of the present invention includes a current detection circuit, a controller, a driver chip, a diode, a comparator, and an overcurrent disappearance delay circuit. The current detection circuit is used to detect current and output an overcurrent signal to the controller when the current exceeds a set current value; the controller is used to output a driver chip control signal when not receiving an overcurrent signal, and stop outputting the driver chip control signal when receiving an overcurrent signal; the driver chip is used to receive the driver chip control signal and drive the compressor; the first input terminal of the comparator is connected to a reference voltage, and the output terminal outputs a signal to the driver chip through a diode D2;

[0030] The diode D1 is used to connect the overcurrent signal output end of the current detection circuit and the second input end of the comparator; the overcurrent disappearance delay circuit includes a capacitor C8 and a resistor R17 connected in series between the power supply and the ground, and the second input end of the comparator is connected between the capacitor C8 and the resistor R17; the reset signal output by the controller is connected between the diode D2 and the driver chip through the diode D3, and the input end or output end of the diodes D2 and D3 is connected to a high level or a low level. The hardware overcurrent protection circuit of the present invention adds a hardware delay function, which works together with the software delay signal to provide dual-effect protection. When a hardware overcurrent occurs, the hardware delay is first used, and the hardware reset signal and the software reset signal are connected together through the diode, and the delay is logically "OR". Any signal can prevent the driver chip from working. When the software and hardware delay time are both met, the driver chip reset signal is released, and the driver circuit can re-enter the working state. The present invention uses the dual protection of software and hardware. Even if the software fails, the hardware can be reset and delayed for a period of time to prevent the failure from recurring in a short period of time and damaging the substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0032] Figure 1 This is a principle block diagram of an air conditioner delay reset circuit according to a specific embodiment of the present invention.

[0033] Figure 2 This is a circuit diagram of the software and hardware dual control signals of an air conditioner according to a specific embodiment of the present invention.

[0034] Figure 3 It is a principle block diagram of an air conditioner according to a specific embodiment of the present invention.

[0035] Figure 4 The figure is a principle block diagram of an air conditioner delay reset circuit according to another specific embodiment of the present invention.

[0036] Figure 5 This is a circuit diagram of a software and hardware dual control signal for an air conditioner according to another specific embodiment of the present invention.

[0037] Figure 6 This is a functional block diagram of an air conditioner according to another specific embodiment of the present invention.

[0038] Figure 7 This is a principle block diagram of a current detection circuit according to a specific embodiment of the present invention.

[0039] Figure 8FIG. 4 is a circuit diagram of a current detection circuit according to a specific embodiment of the present invention.

[0040] Figure 9 1 is a circuit diagram of an air conditioner according to a specific embodiment of the present invention.

[0041] Figure 10 This is a circuit diagram of a driving chip for an air conditioner according to a specific embodiment of the present invention. DETAILED DESCRIPTION

[0042] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0043] In the description of this application, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0044] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of such features. Throughout this application, unless otherwise specified, "plurality" means two or more.

[0045] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0046] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0047] The disclosure below provides many different embodiments or examples for realizing different structures of the present invention. In order to simplify the disclosure of the present invention, the components and settings of specific examples are described below. Of course, they are merely examples and are not intended to limit the present invention. In addition, the present invention may repeat reference numbers and / or reference letters in different examples. Such repetition is for the purpose of simplicity and clarity and does not in itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present invention provides examples of various specific processes and materials, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0048] In this application, the air conditioner performs a refrigeration cycle of the air conditioner by using a compressor, a condenser, a throttling device and an evaporator. The refrigeration cycle includes a series of processes involving compression, condensation, expansion and evaporation to cool or heat the indoor space.

[0049] Low-temperature, low-pressure refrigerant enters the compressor, which compresses it into high-temperature, high-pressure refrigerant gas and discharges the compressed refrigerant gas. The discharged refrigerant gas flows into the condenser. The condenser condenses the compressed refrigerant into a liquid phase, releasing heat into the surrounding environment through the condensation process.

[0050] The throttling device expands the high-temperature, high-pressure liquid refrigerant condensed in the condenser into a low-pressure liquid. The evaporator evaporates the refrigerant expanded in the throttling device and returns the low-temperature, low-pressure refrigerant gas to the compressor. The evaporator achieves a cooling effect by utilizing the latent heat of evaporation to exchange heat with the material being cooled. Throughout this cycle, the air conditioner regulates the temperature of the indoor space.

[0051] The outdoor unit of the air conditioner refers to a portion of a refrigeration cycle including a compressor and an outdoor heat exchanger, the indoor unit of the air conditioner includes an indoor heat exchanger, and a throttling device may be provided in the indoor unit or the outdoor unit.

[0052] The indoor heat exchanger and the outdoor heat exchanger function as a condenser or an evaporator. When the indoor heat exchanger functions as a condenser, the air conditioner functions as a heater in a heating state, and when the indoor heat exchanger functions as an evaporator, the air conditioner functions as a cooler in a cooling state.

[0053] When a hardware overcurrent fault occurs in the air conditioner of the present application, the hardware fault delayed reset signal and the software fault delayed reset signal work together to provide dual protection, thereby realizing a delayed recovery function after a hardware overcurrent fault, preventing the variable frequency drive from restarting in a short period of time, repeatedly triggering the hardware overcurrent protection, and damaging the substrate.

[0054] This solution can realize overcurrent protection and perform software / hardware recovery delay function. After the overcurrent fault disappears, the fault signal is kept delayed for a period of time to realize the hardware protection delay function.

[0055] like Figure 3 、 6 As shown, the air conditioner includes a time-delay reset circuit, a controller, a driver chip (gate driver chip) and a software and hardware dual-control signal circuit.

[0056] In some embodiments, as Figure 1 As shown, the time-delay reset circuit includes a current detection circuit, a diode D1, a comparator and an overcurrent disappearance delay circuit.

[0057] The current detection circuit is used to detect the current and output an overcurrent signal to the controller when the current exceeds the set current value.

[0058] like Figure 7 、 8 As shown, the current detection circuit includes:

[0059] The signal amplifier circuit is used to amplify the current. It mainly uses the operational amplifier IC2A to achieve current amplification.

[0060] The second voltage divider circuit includes a resistor R13 and a resistor R11 connected in series, wherein the resistor R13 is connected to a power supply and the resistor R11 is grounded.

[0061] The second comparator IC1B has a first input terminal connected between the resistor R13 and the resistor R11 , a second input terminal connected to the signal amplifying circuit, and an output terminal serving as an overcurrent signal output terminal of the current detection circuit.

[0062] The overcurrent signal output terminal of the current detection circuit is connected to a pull-up resistor R15 or a pull-down resistor. The pull-up resistor R15 is connected to a power supply, and the pull-down resistor is grounded.

[0063] The air conditioner includes a charge and discharge circuit consisting of a capacitor C7 and a resistor R14. The overcurrent signal output end of the current detection circuit is connected to the charge and discharge circuit consisting of the capacitor C7 and the resistor R14. The resistor R14 is connected in series to the overcurrent signal output end of the current detection circuit. The capacitor C7 is grounded.

[0064] The time constant of capacitor C7 and resistor R14 is in the microsecond level to ensure a quick response when an overcurrent signal is generated.

[0065] The comparator IC1A has a first input terminal connected to a reference voltage, a second input terminal connected to a diode D1 , and in some embodiments, the second input terminal is connected to the input terminal of the diode D1 . The output terminal outputs a signal to the driver chip.

[0066] The diode D1 is used to connect the overcurrent signal output terminal of the current detection circuit and the second input terminal of the comparator IC1A.

[0067] In some embodiments, the output terminal of diode D1 is connected to the overcurrent signal output terminal of the current detection circuit. A reference voltage is provided by a voltage divider circuit. The air conditioner includes resistors R18 and R19 connected in series. The reference voltage is obtained by voltage division by resistors R18 and R19. One end of the series resistors R18 and R19 is connected to a power supply, and the other end is grounded. The first input terminal of comparator IC1A is connected between resistors R18 and R19. R19 / (R18 + R19) is between 60% and 65%, which is close to the RC constant value. The filter time constant can be directly used to calculate the recovery time of the overcurrent protection signal.

[0068] The air conditioner includes a resistor R20 . The resistor R20 is connected between the first input terminal and the output terminal of the comparator IC1A. The resistor R20 is used to provide a hysteresis voltage for the comparator IC1A.

[0069] The output end of the comparator IC1A is connected to a pull-up resistor R21 or a pull-down resistor. The pull-up resistor R21 is connected to a power supply, and the pull-down resistor is grounded.

[0070] The overcurrent disappearance delay circuit includes a capacitor C8 and a resistor R17 connected in series between the power supply and the ground. The second input terminal of the comparator IC1A is connected between the capacitor C8 and the resistor R17.

[0071] The capacitor C8 and the resistor R17 form a charging circuit, and the time constant of the capacitor C8 and the resistor R17 is in the order of seconds, so as to provide a delay in the order of seconds.

[0072] The controller is used to output the driver chip control signal when not receiving the overcurrent signal, and stop outputting the driver chip control signal when receiving the overcurrent signal.

[0073] The driver chip is used to receive the driver chip control signal and drive the compressor.

[0074] like Figure 2 As shown, the software and hardware dual control signal circuit includes a diode D3 and a diode D2. The reset signal output by the controller is connected between the diode D2 and the driver chip through the diode D3. The input or output of the diodes D2 and D3 are connected to a high level or a low level. Figure 2 In the figure, the input ends of diodes D3 and D2 are connected to a high level through resistor R22. The input ends of diodes D3 and D2 are also connected to the reset pin of the gate driver chip. The output end of diode D2 is connected to the output of comparator IC1A, and the output end of diode D3 is connected to the reset pin of the control chip.

[0075] In some embodiments, as Figure 4 As shown, the time-delay reset circuit includes a resistor R16. The resistor R16 is connected between the diode D1 (in some embodiments, the input terminal of the diode D1) and the second input terminal of the comparator IC1A. The capacitor C8 and the resistor R16 form a discharge circuit. The time constant of the capacitor C8 and the resistor R16 is in the microsecond level to ensure a fast response when an overcurrent signal is generated.

[0076] When the resistance R6 is 0, Figure 1-Figure 3 In the case shown, the time constant of capacitor C8 and resistor R16 is zero.

[0077] like Figure 9-10 As shown, the circuit of this embodiment includes a dual constant voltage positive power supply for providing chip power, a constant voltage negative power supply and a reference ground GND. A 3.3V power supply is used to supply the comparator IC1A, IC1B, op amp IC2A and the control side of the gate driver chip IC1. Two 15V / -8V power supplies are used to supply the high voltage drive side of the gate driver chip IC1.

[0078] An operational amplifier IC2A capable of signal conditioning and amplification, such as Figure 9As shown, a differential amplifier circuit is constructed. The measured current is converted into a voltage signal by sampling resistor R1. This signal is then conditioned by a multi-stage filter circuit consisting of resistors R3, R4, R5, R6, and R7, and capacitors C1 and C2, before being sent to the inverting input (pin 2) and the non-inverting input (pin 3) of the operational amplifier. To achieve impedance matching in the differential circuit, the resistance values ​​of R3, R5, and R7 are equal to those of R2, R4, and R6. By splitting the two input resistors at the non-inverting and inverting inputs into six, a capacitor can be placed between each pair of resistors to achieve filtering, removing interference from the collected signal. Resistors R8 and R9 form a voltage divider circuit, providing a bias voltage for the differential signal. The measured signal is selected to be raised to half the supply voltage, so the resistance values ​​of R8 and R9 are equal. To ensure impedance matching in the differential circuit, the parallel value of R8 and R9 is equal to that of R10. Capacitor C3 filters the bias voltage signal, ensuring a stable and reliable bias voltage. Its small value prevents input signal distortion caused by the filtering effect. Resistors R10 and C4 form an amplifier circuit, amplifying the collected signal to an appropriate ratio for subsequent applications. The ratio of R10's resistance to the resistance of R2+R4+R6 represents the amplification factor of the differential circuit. To ensure impedance matching in the differential circuit, capacitors C4 and C3 have the same value. Capacitor C5 stores energy and filters out interference from the power supply, providing clean power to the operational amplifier chip IC2A. This differential amplifier circuit operates in an inverse differential operation mode, meaning that the greater the current, the lower the output level.

[0079] Comparator IC1B performs overcurrent signal comparison. The operational amplifier output signal is fed into the positive input of comparator IC1B, pin 5, through an RC filter circuit consisting of resistor R12 and capacitor C6. To ensure a fast response, the filter time constant is in the microsecond range. Resistors R11 and R13 form a voltage divider circuit to set the comparator threshold. After filtering through the larger capacitor C11, the signal is fed into the negative input of comparator IC1B, pin 6. The comparison result between pins 5 and 6 is output at pin 7. If the level at pin 5 is higher than that at pin 6, pin 7 outputs a high level. If the level at pin 6 is higher than that at pin 5, pin 7 outputs a low level, indicating excessive current and triggering the overcurrent protection function. The output signal at pin 7 is pulled up by resistor R15 to ensure that the output is high even when no signal is present, preventing the overcurrent protection function from being falsely triggered. Resistor R14 and capacitor C7 form an RC filter circuit with a filtering time of microseconds. The signal output from pin 7 is filtered and sent to the controller after removing the interference signal. When a fault occurs, a low level is sent to notify the controller that an overcurrent signal has been generated and the output needs to be stopped for software protection.

[0080] Comparator IC1A implements delayed fault signal recovery and triggers gate driver hardware protection. The output signal from pin 7 is also fed to the hardware driver protection circuit via the circuit containing diode D1 and resistor R16. Pin 3 of comparator IC1A is pulled up by resistor R17 and remains high when no fault occurs. When an overcurrent fault occurs, pin 7 is pulled low, and the charge on capacitor C8 is released through diode D1 and resistor R16. R16 has a very low resistance and only serves to limit current and protect the comparator pin. This allows the charge on C8 to be released quickly, quickly pulling pin 3 low. Resistors R18 and R19 divide the voltage to create a fixed voltage, which serves as the threshold voltage for comparator IC1A. This voltage is filtered by the larger capacitor C9 and fed to the comparator's negative input, pin 2. The comparison result between pins 2 and 3 is output via pin 1. If the voltage level at pin 3 is higher than that at pin 2, pin 1 outputs a high level. If the voltage level at pin 2 is higher than that at pin 3, pin 1 outputs a low level, indicating excessive current, triggering the overcurrent protection function for shutdown. The output signal from pin 1 is pulled up via resistor R21, ensuring that the output from pin 1 remains high even when no signal is present, preventing the overcurrent protection function from being falsely triggered. Resistor R20 has a high resistance value and provides a hysteresis voltage for comparator IC1A, preventing voltage fluctuations at critical levels. Capacitor C10 stores energy and filters out power supply interference, providing clean power to comparator IC1A. The overcurrent signal from comparator IC1A is fed to the fault signal pin of the gate driver chip. When the fault current disappears, pin 7 outputs a high level again, and diode D1 acts as a cutoff. The level of pin 3 can only be restored to a high level through resistor R17 to charge capacitor C8. The values ​​of resistor R17 and capacitor C8 are both large, which can achieve a charging recovery time of seconds, delaying the disappearance of the hardware protection signal. By adjusting the values ​​of resistor R17 and capacitor C8, the time it takes for the gate driver chip's fault signal to disappear can be adjusted to achieve the purpose of hardware delayed recovery. The threshold value of pin 2, obtained by voltage division by R18 and R19, must ensure that this level is close to the RC constant value of 63.2%. This allows the filter time constant to be directly used to calculate the recovery time of the gate driver overcurrent protection signal. The function of resistor R22 is to pull up the enable reset pin of the gate driver chip, so that the pin receives a fixed level signal, preventing the level uncertainty that causes unstable operation of the gate driver chip. At the same time, after the disable enable signals of both the software and hardware disappear, it provides a stable enable signal to the gate driver chip. Diode D2 is connected to the hardware overcurrent protection fault signal, and diode D3 is connected to the controller's software overcurrent protection disable enable signal. The diode isolation isolates the hardware and software fault disable enable signals from each other without affecting each other, realizing the logic "OR" function. Any signal can lock the enable signal of the gate drive chip.

[0081] Six gate driver chips with protection signal self-locking and enabling functions are analyzed by taking one of them as an example. Figure 10 As shown in the figure, gate driver IC1 integrates the gate drive circuitry for the switching transistor. Pins 15 and 16 of the gate driver IC are power pins. Capacitors C5 and C6 connected to the gate driver IC1 store energy and filter out interference, providing clean power to the gate driver IC1. Pin 14 is the reset pin for the gate driver IC; it only activates when it receives a high-level signal. Pins 12 and 13 output fault signals. When pin 14 receives an external fault signal or detects a fault internally, the gate driver IC pulls the pin low, internally locking the output and sending a fault signal to the controller, notifying it of the fault and initiating software protection. Pins 10 and 11 carry the PWM signals for the upper and lower bridge arms from the controller. These two complementary signals interlock the output signals to prevent simultaneous activation, which could cause a short circuit in the upper and lower bridge arms and burn out the circuit. Resistor R3 and capacitor C7, as well as resistor R4 and capacitor C8, form RC filter circuits to filter out interference on the PWM signal. The filter constant is very small and does not cause PWM signal distortion. Resistor R5 acts as a pull-down circuit, ensuring that the input signal is low when no PWM signal is present, preventing the gate driver chip from operating. Pins 1, 3, 5, and 8 are the high-voltage driver power supply pins. Pin 3 is the common ground for the driver output power supply, pin 5 is the 15V positive power supply that controls the switch on, and pin 1 is the -8V power supply that controls the switch off. Capacitors C2, C3, and C4 provide energy storage and filtering on the driver power supply side. Pin 2 is the gate driver chip's built-in overcurrent protection measurement pin. It is connected to the collector of the switch through resistor R1 and high-voltage diodes D1 and D2. Overcurrent faults are detected by measuring the voltage drop across the switch. If a fault occurs, the gate driver chip immediately locks out the output and sends a signal to the controller by pulling pin 13 low. Capacitor C1 filters interference signals and prevents false triggering of the protection function. Zener diode D3 clamps the signal at pin 2 to prevent excessive signal voltages that could damage gate driver IC1. Pins 4 and 6 provide the drive signal outputs. The turn-on voltage is applied to the gate of the switching device through pin 4 and resistor RH1, turning it on. Resistor RH1 limits current to prevent damage to the switch due to turn-on signal oscillation caused by excessive turn-on. The turn-off voltage is applied to the gate of the switching device through pin 6 and resistor RL1, turning it off. Resistor RL1 prevents premature turn-off and suppresses interference. Resistor R2 pulls the gate down to prevent false turn-on.

[0082] The signal conditioning circuit primarily consists of operational amplifier IC2A, resistors R2, R3, R4, R5, R6, R7, R8, R9, R10, and capacitors C1, C2, C3, C4, and C5. Operational amplifier IC2A, along with its peripheral circuitry, forms a differential amplifier circuit. R2, R3, R4, R5, R6, R7, C1, and C2 form a current signal sampling circuit to acquire current information. R8, R9, and C3 form a bias circuit, which uses voltage division to generate a bias voltage to set the center value of the current signal. R10 and C4 form an amplifier circuit, which sets the output signal amplification factor.

[0083] The comparator overcurrent protection circuit primarily consists of comparator IC1B, resistors R11, R12, R13, R14, and R15, and capacitors C6 and C7. R12 and C6 form the current signal input filter circuit, which transmits filtered current information to the comparator. R11, R13, and C11 form a voltage divider circuit, which determines the overcurrent protection voltage threshold and sets the current level. R14, R15, and C7 form the output circuit, ensuring a stable high-level output signal when no signal is present through the pull-up function of R15. The output signal is then filtered and conditioned and transmitted to the controller to trigger software protection.

[0084] The circuit has different charge and discharge time constants, primarily composed of R16, R17, D1, and C8. The discharge circuit time constant is formed by C8 and R16. R16 has a low resistance value, allowing for a relatively short operating time constant. This allows for a quick response to overcurrent faults and triggers the gate driver's hardware protection. The charging circuit time constant is formed by R17 and C8. Their relatively large values ​​produce a recovery time constant in the second range, allowing the hardware overcurrent signal to persist for several seconds, preventing the hardware circuit from immediately resuming operation after an overcurrent fault. Diode D1's unidirectional conduction and reverse blocking characteristics ensure that the two time constants operate independently without interfering with each other.

[0085] The comparator circuit with adjustable time constants primarily consists of comparator IC1A, R18, R19, R20, R21, and C9. R18, R19, and C9 form a voltage divider circuit, which controls the recovery time. For reliable performance and simplified calculations, the threshold voltage is set to 63.2% of the chip voltage. This perfectly matches the commonly used RC filter time constant, ensuring that the hardware protection signal recovery time is equal to the filter time constant formed by R17 and C8. R20 and R21 form the output circuit, ensuring a normal high output level while also providing a hysteresis voltage to ensure a stable output signal.

[0086] This circuit primarily consists of diodes D2, D3, and R22. R22 provides a stable pull-up signal for the gate driver chip, ensuring reliable operation. D2 connects to the hardware control signal, while D3 connects to the controller's software control signal. The unidirectional conductivity of the diodes isolates the signals, allowing the software reset signal and the hardware reset signal to function independently without interfering with each other. Together, they determine whether the gate driver chip resumes normal operation. The gate driver chip only outputs a drive signal when both the inputs of diodes D2 and D3 are high, and the gate chip reset pin is high.

[0087] Six gate driver chips feature fault signal lockout and reset signal control. For example, one circuit consists of IC1, R2, R3, R4, R5, RH1, RL1, C1, C2, C3, C4, C5, C6, C7, C8, D1, D2, and D3. R3, R4, R5, C7, and C8 form the PWM signal input filter circuit, providing a pull-down signal to ensure control signal interlock and prevent false triggering. R1, C1, D1, D2, and D3 form the gate driver's built-in overcurrent protection circuit, which detects overcurrent fault signals and prevents false triggering through a filter circuit, providing self-protection. This protection level is typically high, but provides relatively low circuit protection. R2, RH1, and RL1 form the switch driver charge and discharge circuit, which first pulls down the switch gate to prevent false turn-on and then controls the switch's turn-on and turn-off speed to prevent oscillation and minimize interference. C2, C3 and C4 form the driver side power supply circuit, which uses a 15V positive voltage to drive it when turned on and an 8V negative voltage to drive it when turned off, which can effectively prevent the switch tube from being unable to be effectively turned off.

[0088] The gate driver chip itself has no delay function and requires an external signal to control the working state. When the reset pin of the gate driver chip receives a low-level signal, the output drive signal is locked, causing the drive circuit to stop working.

[0089] This solution allows the hardware overcurrent protection to be delayed after a fault has resolved. The software and hardware delay signals are connected together via a diode to function together. The hardware circuit first implements a basic delay to ensure circuit safety. The software delay signal then provides a programmable control delay based on the actual control state. When both signals are simultaneously high, the driver chip begins operating and outputs according to the control chip's drive signal. The software delay time is equal to or greater than the hardware delay time.

[0090] The above are only specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. An air conditioner, comprising: a current detection circuit, configured to detect current and output an overcurrent signal to a controller when the current exceeds a set current value; a controller, configured to output a driver chip control signal when not receiving the overcurrent signal, and stop outputting the driver chip control signal when receiving the overcurrent signal; A driver chip, configured to receive a control signal from the driver chip and drive the compressor; Characterized in that the air conditioner further comprises: A software and hardware dual-control signal circuit includes a diode D2, a diode D3, and a resistor R22; the resistor R22 is used to provide a pull-up signal for the driver chip, the diode D2 is connected to the hardware control signal, and the diode D3 is connected to the driver chip control signal output terminal of the controller; A comparator, wherein a first input terminal is connected to a reference voltage, an output terminal outputs a hardware control signal, and outputs the signal to the driver chip through a diode D2; A diode D1 is used to connect the overcurrent signal output terminal of the current detection circuit and the second input terminal of the comparator; An overcurrent disappearance delay circuit includes a capacitor C8 and a resistor R17 connected in series between a power supply and a ground, wherein the capacitor C8 and the resistor R17 are connected to the second input terminal of the comparator; The reset signal output by the controller is connected between the diode D2 and the driver chip through the diode D3, and the input end or output end of the diode D2 and the diode D3 is connected to a high level or a low level; the unidirectional conductivity of the diode D2 and the diode D3 isolates the signal, so that the software reset signal and the hardware reset signal take effect respectively, and jointly determine whether the driver chip resumes normal operation.

2. The air conditioner according to claim 1, characterized in that The capacitor C8 and the resistor R17 form a charging circuit, and the time constant of the capacitor C8 and the resistor R17 is in the order of seconds.

3. The air conditioner according to claim 1, characterized in that The air conditioner includes a resistor R16, and the resistor R16 is connected between the diode D1 and the second input terminal of the comparator. The capacitor C8 and the resistor R16 form a discharge circuit. The time constant of the capacitor C8 and the resistor R16 is in the microsecond level. When the resistance R16 is 0, the time constant of the capacitor C8 and the resistor R16 is 0.

4. The air conditioner according to claim 1, wherein: The air conditioner includes a resistor R18 and a resistor R19 connected in series. The reference voltage is obtained by dividing the resistor R18 and the resistor R19. One end of the resistor R18 and the resistor R19 in series is connected to a power supply, and the other end is grounded. The first input end of the comparator is connected between the resistor R18 and the resistor R19, wherein R19 / (R18+R19) is between 60% and 65%.

5. The air conditioner according to claim 1, characterized in that The air conditioner includes a resistor R20 , which is connected between the first input terminal and the output terminal of the comparator. The resistor R20 is used to provide a hysteresis voltage for the comparator.

6. The air conditioner according to claim 1, characterized in that The output end of the comparator is connected to a pull-up resistor R21 or a pull-down resistor. The pull-up resistor R21 is connected to a power supply, and the pull-down resistor is grounded.

7. The air conditioner according to claim 6, characterized in that The overcurrent signal output terminal of the current detection circuit is connected to a pull-up resistor R15 or a pull-down resistor. The pull-up resistor R15 is connected to a power supply, and the pull-down resistor is grounded.

8. The air conditioner according to claim 1, wherein: The air conditioner includes a charging and discharging circuit consisting of a capacitor C7 and a resistor R14. The overcurrent signal output end of the current detection circuit is connected to the charging and discharging circuit consisting of the capacitor C7 and the resistor R14. The resistor R14 is connected in series to the overcurrent signal output end of the current detection circuit. The capacitor C7 is grounded.

9. The air conditioner according to claim 8, characterized in that The time constant of the capacitor C7 and the resistor R14 is in the microsecond level.

10. The air conditioner according to claim 1, wherein The current detection circuit comprises: a signal amplifying circuit, configured to amplify the current; A second voltage divider circuit includes a resistor R13 and a resistor R11 connected in series, wherein the resistor R13 is connected to a power supply and the resistor R11 is grounded; The second comparator has a first input terminal connected between the resistor R13 and the resistor R11, a second input terminal connected to the signal amplifying circuit, and an output terminal serving as an overcurrent signal output terminal of the current detection circuit.

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