Control device of air conditioner, air conditioner and control method of air conditioner

Abstract

The invention discloses a control device of an air conditioner, the air conditioner and a control method of the air conditioner, and the device comprises a switching power supply unit which is arranged between a bus capacitor unit and an electronic expansion valve; the detection unit is used for detecting a power signal of the alternating current side of the driving system; the power supply signal of the alternating current side of the driving system comprises a power-down power supply signal after the power-down of the air conditioner under the condition that the power-down of the air conditioner occurs; the control unit is used for controlling the electronic expansion valve to act when receiving the power-down power supply signal so as to accelerate the drop rate of the bus voltage on the bus capacitor unit; and after the bus voltage on the bus capacitor unit is reduced to a direct current side output voltage threshold value, the switch unit is controlled to be switched off, so that the charging current limiting module is connected. According to the scheme, when it is detected that the alternating current side of the air conditioner driving system is not powered, the electronic expansion valve is controlled in a linkage mode to act so that the bus capacitor can be rapidly discharged, the charging current limiting module of the charging unit can be connected in time, and the reliability and safety when the air conditioner is powered on again are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of air conditioners, and specifically relates to a control device of an air conditioner, an air conditioner and a control method thereof, and more particularly to a circuit for controlling the rapid discharge of a bus capacitor of an air conditioner variable frequency drive system through the linkage of an electronic expansion valve of the air conditioner, an air conditioner having the circuit, and a control method of the air conditioner. Background Art

[0002] For air conditioners, in the air conditioner drive system (such as the variable frequency drive system), the AC power source obtains DC power through the rectifier bridge and bus capacitor. Since the motor power of the air conditioner is relatively large, the required bus capacitor is also relatively large. At the moment when the AC power source is powered on, the instantaneous current of the bus capacitor charging is relatively large, which has a great impact on the circuit where the variable frequency drive system is located, and it is easy to damage the circuit where the variable frequency drive system is located. Therefore, when designing the circuit where the variable frequency drive system is located, the engineer connects the charging current limiting resistor of the bus capacitor in series in the charging circuit. After the bus capacitor is charged, the charging current limiting resistor is bypassed by a relay. Unless the circuit where the variable frequency drive system is located loses power, the charging current limiting resistor is always bypassed.

[0003] However, in actual use, if the air conditioner unit is powered on again after an abnormal power outage, the charging current limiting resistor in the charging circuit of the bus capacitor of the variable frequency drive system will be bypassed, resulting in a large instantaneous impact current when charging the bus capacitor, which can easily cause current impact and damage to the main board and components of the circuit where the variable frequency drive system is located.

[0004] The above contents are only used to assist in understanding the technical solution of the present invention and do not constitute an admission that the above contents are prior art. Summary of the invention

[0005] The object of the present invention is to provide an air conditioner control device, an air conditioner and a control method thereof, so as to solve the problem that when the air conditioner unit is powered on again after abnormal power failure, the charging current limiting resistor in the charging circuit of the bus capacitor of the variable frequency drive system is always bypassed, resulting in a large instantaneous impact current of the bus capacitor charging, which can easily cause current impact and damage to the main board and components of the circuit where the variable frequency drive system is located. When it is detected that there is no power on the AC side of the air conditioner drive system, the electronic expansion valve is controlled to act in a linkage manner to quickly discharge the bus capacitor, so that the charging current limiting resistor of the charging circuit is connected in time, thereby improving the reliability and safety of the air conditioner when it is powered on again.

[0006] The present invention provides a control device for an air conditioner. The air conditioner has a refrigerant system and a drive system. The refrigerant system has an electronic expansion valve, and the drive system has a bus capacitor unit and a charging unit for the bus capacitor unit. The charging unit includes a charging current limiting module and a switching module, and the charging current limiting module is connected in parallel with the switching module. The control device of the air conditioner includes a detection unit, a switching power supply unit, and a control unit. The switching power supply unit is arranged between the bus capacitor unit and the electronic expansion valve. Among them, the detection unit is used to detect the power supply signal on the AC side of the drive system. The power supply signal on the AC side of the drive system includes a power-off power supply signal after the air conditioner loses power when the air conditioner loses power. The control unit is used to control the electronic expansion valve to act to accelerate the discharge rate of the bus capacitor unit, that is, to accelerate the decrease rate of the bus voltage on the bus capacitor unit if the power-off power supply signal is received. And after the bus voltage on the bus capacitor unit drops to the DC side output voltage threshold of the drive system, the control unit controls the switching unit to disconnect so that the charging current limiting module is connected.

[0007] In some embodiments, the power supply signal on the AC side of the drive system further includes a power-on power supply signal after the air conditioner is powered on when the air conditioner is powered on. The control device of the air conditioner further includes that the control unit is further used to control the switching unit to close after a set time delay if the power-on power supply signal is received so that the charging current limiting module is cut out.

[0008] In some embodiments, the situation where the air conditioner loses power is a normal power-off situation or an abnormal power-off situation of the air conditioner. Among them, when the situation where the air conditioner loses power is a normal power-off situation of the air conditioner, the control unit controls the electronic expansion valve to act, and after the bus voltage on the bus capacitor unit drops to the DC side output voltage threshold of the drive system and the control unit controls the switching unit to disconnect so that the charging current limiting module is connected, the air conditioner shuts down. When the situation where the air conditioner loses power is an abnormal power-off situation of the air conditioner, the control unit controls the electronic expansion valve to act, and after the bus voltage on the bus capacitor unit drops to the DC side output voltage threshold of the drive system and the control unit controls the switching unit to disconnect so that the charging current limiting module is connected, the air conditioner is powered on again.

[0009] In some embodiments, the control unit controls the electronic expansion valve to act, including: when the switching power supply unit supplies power to the electronic expansion valve, controlling the opening degree of the electronic expansion valve to decrease so that the opening degree of the electronic expansion valve changes.

[0010] In some embodiments, the drive system further includes a rectification unit; and the charging unit is disposed between the rectification unit and the bus capacitor unit.

[0011] In some embodiments, the AC side of the drive system includes: the AC power access terminal of the drive system; the drive system further includes a filtering unit; wherein, the filtering unit is disposed between the AC power access terminal of the drive system and the rectification unit, and is configured to filter the AC power transmitted from the AC power access terminal of the drive system and then transmit it to the rectification unit; and the detection unit is disposed between the AC power access terminal of the drive system and the filtering unit.

[0012] In some embodiments, the charging unit further includes: a driving module; the switching module includes: a relay module; wherein, the control unit is connected to the input end of the driving module; the relay module has a coil and contacts, the output end of the driving module is connected to the coil of the relay module, and the contacts of the relay module are connected in parallel with the charging current limiting module.

[0013] Matched with the above device, on the other hand, the present invention provides an air conditioner, including: the control device of the air conditioner described above.

[0014] Matched with the above air conditioner, on the other hand, the present invention provides a control method for an air conditioner, including: detecting a power signal on the AC side of the drive system; the power signal on the AC side of the drive system includes: in the case of a power failure of the air conditioner, the power failure signal after the power failure of the air conditioner; if the power failure signal is received, controlling the electronic expansion valve to act to accelerate the decline rate of the bus voltage on the bus capacitor unit; and, after the bus voltage on the bus capacitor unit drops to the DC side output voltage threshold of the drive system, controlling the switching unit to disconnect so that the charging current limiting module is connected.

[0015] In some embodiments, the power signal on the AC side of the drive system further includes: in the case of power-on of the air conditioner, the power-on signal after the power-on of the air conditioner; the control method of the air conditioner further includes: if the power-on signal is received, controlling the switching unit to close after a set time delay so that the charging current limiting module is cut out.

[0016] Therefore, the scheme of the present invention is aimed at the electronic expansion valve in the refrigerant system of the air conditioner, and the rectifier bridge, bus capacitor, the charging circuit composed of a charging current limiting resistor and a control switch (such as relay K1) connected in parallel between the rectifier bridge and the bus capacitor, and the controller (such as MCU) in the drive system (such as a variable frequency drive system). A switching power supply is set at the output end of the bus capacitor to power the electronic expansion valve, and the relay K1 and the electronic expansion valve are controlled by the MCU. A voltage detection circuit for detecting whether there is power or no power on the AC side is set on the AC side of the drive system; after the unit where the air conditioner is located is powered on, if the MCU receives a first voltage detection signal (such as voltage detection signal A1) fed back by the voltage detection circuit, the contact of the delay control relay K1 is closed to cut out the charging current limiting resistor so that the unit where the air conditioner is located can work normally; if the air conditioner is located When the unit loses power (such as normal power failure or abnormal power failure), the MCU receives a second voltage detection signal (such as voltage detection signal A2) fed back by the voltage detection circuit. The bus voltage on the bus capacitor needs to be consumed. The MCU controls the electronic expansion valve to consume the bus voltage on the bus capacitor until the electronic expansion valve stops operating when the switching power supply is out of power. When the bus voltage on the bus capacitor drops to the release voltage of the relay K1, the MCU controls the contacts of the relay K1 to close to connect the charging current limiting resistor. After the unit where the air conditioner is located is powered on again, the current is limited by the charging current limiting resistor. Therefore, when it is detected that there is no power on the AC side of the air-conditioning drive system, the electronic expansion valve is controlled to operate in a linkage manner to quickly discharge the bus capacitor, so that the charging current limiting resistor of the charging circuit is connected in time, thereby improving the reliability and safety of the air conditioner when it is powered on again.

[0017] Other features and advantages of the present invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the present invention.

[0018] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A schematic structural diagram of an embodiment of a control device for an air conditioner of the present invention;

[0020] Figure 2 It is a structural schematic diagram of an embodiment of a circuit for controlling the rapid discharge of a bus capacitor of an air conditioner variable frequency drive system through linkage with an electronic expansion valve of the air conditioner;

[0021] Figure 3 A flow chart of an embodiment of a method for controlling the rapid discharge of a bus capacitor of an air-conditioning variable frequency drive system in a related solution;

[0022] Figure 4Schematic flowchart of an embodiment of a method for controlling rapid discharge of the bus capacitor of an air conditioner's variable-frequency drive system through the electronic expansion valve of the present invention;

[0023] Figure 5 Schematic flowchart of an embodiment of a control method for an air conditioner of the present invention. Detailed implementation manners

[0024] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments of the present invention and the corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

[0025] Considering that in the case of abnormal power failure and then re-power-on of the variable-frequency device, due to the charging current-limiting resistor in the charging circuit of the bus capacitor of the variable-frequency drive system being bypassed all the time, the inrush current during the charging of the bus capacitor is relatively large, which is likely to cause current impact and damage to the main board and components of the circuit where the variable-frequency drive system is located.

[0026] In related solutions, in the circuit where the variable-frequency drive system is located, the AC power supply is output to the bus capacitor (such as the capacitor C4 shown in Figure 2 ) after passing through the rectification unit (such as the rectifier bridge shown in Figure 2 ); the positive pole of the output end of the rectifier bridge is connected to the positive pole of the capacitor C4, the negative pole of the output end of the rectifier bridge is connected to the negative pole of the capacitor C4, and the negative pole of the capacitor C4 is grounded; a charging circuit for the bus capacitor is provided between the positive pole of the output end of the rectifier bridge and the positive pole of the capacitor C4. Among them, the charging circuit of the bus capacitor includes: a charging current-limiting resistor (such as the resistor R5 shown in Figure 2 ) and a control switch (such as the relay K1 shown in Figure 2 ), and the resistor R5 is in parallel with the contact of the relay K1. The coil of the relay K1 is connected to the relay driver chip to drive the coil of the relay K1 to be energized or de-energized through the relay driver chip. The relay driver chip is connected to the Microcontroller Unit (MCU), and the MCU controls the relay driver chip to drive the coil of the relay K1 to be energized or de-energized. The power supply of the MCU can be obtained by converting the AC-side power supply through the AC-DC module and then through the switching power supply. The control power supply of the relay K1 is obtained by converting the AC-side power supply through the AC-DC module. When the AC-side power supply of the AC-DC module loses power, the DC side of the AC-DC module will also lose power.

[0027] In related solutions, for the bus capacitor discharge control of a variable-frequency drive system, after the variable-frequency drive system is powered on and the MCU works normally, it delays for a certain time t and then closes the relay K1. When powering off, unless the operating voltage of the relay K1 is abnormal, the relay K1 will disconnect. Figure 3 It is a schematic flowchart of an embodiment of a method for controlling the rapid discharge of the bus capacitor of an air-conditioning variable-frequency drive system in related solutions, which can show the process of controlling the rapid discharge of the bus capacitor of the air-conditioning variable-frequency drive system after the air conditioner is normally powered off. As Figure 3 shown, a method for controlling the rapid discharge of the bus capacitor of an air-conditioning variable-frequency drive system in related solutions includes:

[0028] Step 11: The unit where the air conditioner is located is powered on, and then step 12 is executed.

[0029] Step 12: After the MCU works normally, it delays for time t to enable the charging circuit of capacitor C4 to complete the charging of capacitor C4, and then step 13 is executed. Among them, the charging circuit of capacitor C4 includes: resistor R5 and relay K1. When capacitor C4 is charging, the contact of relay K1 is disconnected, and the direct current output by the rectifier bridge is supplied to capacitor C4 after passing through resistor R5; after time t, the charging circuit of capacitor C4 completes the charging of capacitor C4. The contact of relay K1 can be a normally open contact; when the unit where the air conditioner is located is powered on and the MCU does not control the relay.

[0030] Step 13: After delaying for time t after the MCU works normally, the MCU controls the relay driver chip to make the coil of relay K1 energized, so that the coil of relay K1 closes the contact of relay K1, making the contact of relay K1 closed, and resistor R5 is short-circuited. The direct current output by the rectifier bridge is directly supplied to capacitor C4 instead of being supplied to capacitor C4 through resistor R5, and the unit where the air conditioner is located works normally, and then step 14 can be executed.

[0031] Step 14: When the unit where the air conditioner is located is working normally, if the unit where the air conditioner is located is normally powered off, then when the voltage of the AC power supply drops to the release voltage of relay K1, the MCU cannot control the relay driver chip and the coil of relay K1 loses power, so that the coil of relay K1 releases the contact of relay K1, making the contact of relay K1 disconnected, and the unit where the air conditioner is located stops.

[0032] However, in actual use, an emergency occurs in the air-conditioning unit, such as the AC power suddenly loses power and then resumes power in a short time. Since the power outage time is not controlled, when the bus voltage at the output end of the bus capacitor does not drop below the minimum operating voltage of the switching power supply, the motherboard (such as MCU) of the variable frequency drive system controls the switching power supply to work normally during the AC power failure period, so the relay is still in the state of bypassing the charging current limiting resistor. If the AC power supply is restored at this time, but the charging circuit of the bus capacitor is not connected to the charging current limiting resistor, the bus capacitor will be charged with a large instantaneous impact current, which can easily cause current impact and damage to the motherboard and components of the circuit where the variable frequency drive system is located.

[0033] Therefore, the scheme of the present invention proposes a scheme for quickly discharging the bus capacitor of the air conditioner variable frequency drive system by controlling the linkage of the air conditioner's electronic expansion valve: when it is detected that the AC side voltage of the variable frequency drive system is powered off, the electronic expansion valve is quickly controlled to operate, so that the bus capacitor is quickly discharged, so that the charging current limiting resistor of the charging circuit is connected in time, thereby improving the reliability and safety of the air conditioner when it is powered on again.

[0034] According to an embodiment of the present invention, a control device for an air conditioner is provided. Figure 1 The schematic diagram of the structure of an embodiment of the device of the present invention is shown. The air conditioner has a refrigerant system and a drive system, the refrigerant system has an electronic expansion valve, the drive system has a bus capacitor unit, and a charging unit of the bus capacitor unit; the charging unit includes: a charging current limiting module and a switch module, the charging current limiting module is connected in parallel with the switch module; in the solution of the present invention, Figure 1 As shown, the control device of the air conditioner includes: a detection unit, a switching power supply unit and a control unit; the switching power supply unit is arranged between the bus capacitor unit and the electronic expansion valve; specifically, the rectifier unit is as shown Figure 2 The rectifier bridge shown in the figure has a bus capacitor unit such as Figure 2 The capacitor C4 shown in the figure, the switch module is as follows Figure 2 The relay K1 shown in the figure, the detection unit is as follows Figure 2 The voltage detection circuit shown in the figure is a switching power supply unit. Figure 2 IDE switch power supply, control unit as shown Figure 2 The MCU shown.

[0035] Among them, the detection unit is arranged on the AC side of the drive unit and is used to detect the power supply signal on the AC side of the drive system. Among them, the power supply signal on the AC side of the drive system includes: the voltage signal on the AC side of the drive system and / or the current signal on the AC side of the drive system. The power supply signal on the AC side of the drive system includes: in the case of power failure of the air conditioner, the power failure signal after the power failure of the air conditioner, and the power failure signal is the second voltage detection signal (such as voltage detection signal A2).

[0036] The control unit is respectively connected to the detection unit, the switch unit and the electronic expansion valve, can receive the power-on power supply signal or the power-off power supply signal, and can control the switch unit and / or the electronic expansion valve, and is used to determine whether the power-on power supply signal or the power-off power supply signal is received. If the power-off power supply signal is received, the electronic expansion valve is controlled to act to accelerate the discharge rate of the bus capacitor unit, that is, to accelerate the decline rate of the bus voltage on the bus capacitor unit. And, after the bus voltage on the bus capacitor unit drops to the DC side output voltage threshold of the drive system, the switch unit is controlled to disconnect, so that the charging current limiting module is connected to the power supply circuit of the drive system, and the charging current limiting module performs current limiting after the air conditioner is powered on again. Until the bus voltage on the bus capacitor unit drops, so that the output voltage of the switching power supply unit is lower than the target supply voltage of the electronic expansion valve, the electronic expansion valve stops acting.

[0037] Among them, the bus voltage drops to the DC side output voltage threshold of the drive system. Specifically: after the power failure on the AC side, the bus capacitor voltage drops naturally and drops to the DC side output voltage threshold of the drive system, that is, it drops to the point where the DC side (i.e., the DC side) cannot output normally, and then the DC side DC voltage drops slowly and drops to the release voltage of the relay. After the MCU controls the electronic expansion valve to act, the DC side DC voltage drops to the point where the electronic expansion valve cannot work, and then the electronic expansion valve stops acting.

[0038] A solution provided by the solution of the present invention for controlling the rapid discharge of the bus capacitor of the air conditioner variable frequency drive system through the electronic expansion valve of the air conditioner. By setting a charging current limiting resistor (such as Figure 2 the shown resistor R5) and a control switch (such as Figure 2The charging circuit is formed by connecting the relay K1 in parallel, setting a switching power supply at the output end of the bus capacitor of the air conditioner variable frequency drive system to power the electronic expansion valve of the air conditioner, and using the mainboard controller (such as MCU) of the air conditioner variable frequency drive system to control the relay K1 and the electronic expansion valve; when controlling the rapid discharge of the bus capacitor of the air conditioner variable frequency drive system, detecting whether the AC side of the variable frequency drive system is powered off, and when detecting that the AC side of the variable frequency drive system is powered off, the electronic expansion valve is controlled to act in a linkage manner to rapidly discharge the bus capacitor, which can avoid the damage caused by large current shock to the mainboard (such as the controller mainboard) and components of the circuit where the variable frequency drive system is located; it can also reduce the after-sales failure rate of the air conditioner causing damage to the mainboard and components of the circuit where the variable frequency drive system is located due to large current shock, and improve the reliability of the air conditioner unit in a complex use environment. Among them, the complex use environment is an environment with a complex power supply environment, such as the situation where the power supply suddenly loses power and suddenly powers on.

[0039] In some embodiments, the power signal on the AC side of the drive system further includes: when the air conditioner is powered on, a power-on signal after the air conditioner is powered on, the power-on signal being a first voltage detection signal (such as voltage detection signal A1). Figure 2 The schematic diagram of the structure of an embodiment of a circuit for controlling the rapid discharge of bus capacitors of an air conditioner variable frequency drive system through linkage control of an air conditioner electronic expansion valve. The air conditioner variable frequency drive system has an AC side and a DC side. Figure 2 In the example shown, the AC side voltage detection circuit is used to detect whether the AC side of the variable frequency drive system has power or no power. When there is power or no power, the voltage detection circuit inputs different voltage signals to the MCU. Among them, there are many detection methods for the voltage detection circuit, such as: detection through a detection resistor, or detection through an optical coupler, so as to determine whether the AC side is powered off. The detection resistor can be a negative temperature coefficient thermistor (Negative Temperature Coefficient thermistor, NTC thermistor).

[0040] The control device of the air conditioner also includes: the control unit is also used to determine whether the power-on power signal or the power-off power signal is received. If the power-on power signal is received, the switch unit is controlled to close after a delay of a set time, so that the charging current limiting module cuts out the power supply circuit of the drive system, so that the air conditioner can work normally.

[0041] In the solution of the present invention, after the air conditioner is powered on, the charging current limiting module on the charging unit is used to limit the charging current of the bus capacitor unit, so as to avoid damage to the main board (such as the controller main board) and components of the circuit where the variable frequency drive system is located caused by the large current impact on the bus capacitor unit at the moment when the air conditioner is powered on; after the bus capacitor is fully charged, the charging current limiting module on the charging unit is cut out to save the power consumption on the charging current limiting module and enable the air conditioner to operate normally.

[0042] In some embodiments, the situation where the air conditioner loses power is the situation where the air conditioner loses power normally or the situation where the air conditioner loses power abnormally.

[0043] Among them, when the situation where the air conditioner loses power is the situation where the air conditioner loses power normally, the control unit controls the electronic expansion valve to act, and after the bus voltage on the bus capacitor unit drops to the DC side output voltage threshold of the drive system, controls the switch unit to disconnect, so that after the charging current limiting module is connected, the air conditioner shuts down.

[0044] When the situation where the air conditioner loses power is the situation where the air conditioner loses power abnormally, the control unit controls the electronic expansion valve to act, and after the bus voltage on the bus capacitor unit drops to the DC side output voltage threshold of the drive system, controls the switch unit to disconnect, so that after the charging current limiting module is connected, the air conditioner is powered on again.

[0045] Figure 4 It is a schematic flow chart of an embodiment of a method for controlling the rapid discharge of the bus capacitor of the air conditioner variable frequency drive system through the linkage of the electronic expansion valve of the air conditioner according to the present invention. Figure 4 Among them, through the voltage detection circuit that detects the presence and absence of electricity on the AC side, it can be known whether the unit where the air conditioner is located loses power. The normal power failure and abnormal power failure (that is, sudden power failure during operation) of the unit where the air conditioner is located are two power failure processes; after the normal power failure, the unit where the air conditioner is located has no power all the time, and after the abnormal power failure, the unit where the air conditioner is located is powered on again in a short time. As Figure 4 shown, a method for controlling the rapid discharge of the bus capacitor of the air conditioner variable frequency drive system through the linkage of the electronic expansion valve of the air conditioner includes:

[0046] Step 21: The unit where the air conditioner is located is powered on, and then step 22 is executed.

[0047] Step 22: The MCU receives the voltage detection signal A1 provided by the voltage detection circuit, and then step 23 is executed. The voltage detection signal A1 is a signal indicating that there is electricity on the AC side.

[0048] Step 23: Wait for time t1. The MCU controls the contact of relay K1 to close, and then Step 24 is executed. When the unit is powered on normally, the live wire and neutral wire are powered, and the AC side voltage detection circuit outputs a voltage detection signal A1 indicating power. After receiving the voltage detection signal A1, the MCU controls and drives the contact of relay K1 to close after a delay of t1.

[0049] Among them, the power-on charging time t1 of the bus capacitor = 5R*C4, where R is the load at the back end during the charging of the bus capacitor. R is the load in actual use. During actual use, engineers can calculate the load R based on the test of the charging time. That is to say, the charging time of the bus capacitor is determined by the loop resistance in the load loop.

[0050] Step 24: Resistor R5 is connected to the energized circuit of the variable frequency drive system, and the unit where the air conditioner is located operates normally, and then Step 31 or Step 41 is executed.

[0051] Step 31: The unit where the air conditioner is located is powered off normally, and then Step 32 is executed.

[0052] Step 32: The MCU receives the voltage detection signal A2 provided by the voltage detection circuit, and then Step 33 is executed. The voltage detection signal A2 is a signal indicating no power on the AC side.

[0053] Step 33: The MCU controls the electronic expansion valve to act, and then Step 34 is executed. After the AC side is powered off, in order to quickly discharge the bus capacitor (such as capacitor C4), the electronic expansion valve is controlled to act to achieve the purpose of quickly discharging capacitor C4. Among them, controlling the electronic expansion valve to act is to control the electronic expansion valve to close, such as controlling the opening degree of the electronic expansion valve to decrease. The way to control the electronic expansion valve to act is similar to the way to control a stepping motor. For example: directly drive the electronic expansion valve to act with a drive chip of model 2003. Controlling the electronic expansion valve to act can quickly reduce the voltage of the bus capacitor.

[0054] Step 34: When the bus voltage on capacitor C4 drops to a certain voltage, the contact of relay K1 disconnects, and resistor R5 is connected to the energized circuit of the variable frequency drive system, and then Step 35 is executed.

[0055] Step 41: The unit where the air conditioner is located suddenly loses power during operation, and then Step 42 is executed.

[0056] Step 42: The MCU receives the voltage detection signal A2 provided by the voltage detection circuit, and then Step 43 is executed.

[0057] Step 43: The MCU controls the electronic expansion valve to act, and then Step 44 is executed.

[0058] Step 44: When the bus voltage on capacitor C4 drops to a certain voltage, the contact of relay K1 disconnects, and resistor R5 is connected to the power-on circuit of the variable frequency drive system, and then return to Step 21 to power on again.

[0059] In the solution of the present invention, during the operation of the unit where the air conditioner is located, when the AC side suddenly loses power and then powers on again, when the power is lost, the voltage detection circuit on the AC side outputs a voltage detection signal A2 without power to the MCU. The MCU controls the electronic expansion valve to act in a linked manner, and the bus capacitor discharges quickly. The bus capacitor discharges to a certain voltage (such as the release voltage of relay K1), the contact of relay K1 disconnects, and the charging current-limiting resistor is connected to the power-on circuit of the variable frequency drive system; it is ensured that when the unit where the air conditioner is located powers on again, the charging current-limiting resistor is connected to the power-on circuit of the variable frequency drive system, so that when the unit where the air conditioner is located powers on again, the charging current-limiting resistor plays a current-limiting role, improving the reliability of the power-on circuit of the variable frequency drive system.

[0060] In some embodiments, the control unit controls the operation of the electronic expansion valve, including: specifically, the control unit is further configured to control the opening of the electronic expansion valve to decrease when the switching power supply unit supplies power to the electronic expansion valve, so as to change the opening of the electronic expansion valve.

[0061] In the solution of the present invention, by setting a switching power supply at the output end of the bus capacitor in the variable frequency drive system and using the switching power supply to supply power to the electronic expansion valve; when the voltage detection circuit for detecting power and no power on the AC side detects that there is no power on the AC side, the electronic expansion valve is controlled to act in a linked manner to quickly discharge the bus capacitor, so that the charging current-limiting resistor can be quickly connected to the charging circuit of the bus capacitor, which can avoid damage to the main board and components of the circuit where the variable frequency drive system is located caused by large current impact, and improve the reliability and safety of air conditioner operation.

[0062] In related solutions, discharging through a resistor in parallel with the bus capacitor or controlling the current of the bus capacitor to be transmitted to the stator resistor of the motor for discharging is all through the strong power end; while in the solution of the present invention, by detecting whether the alternating current loses power and the electronic expansion valve discharges in a linked manner, and it is through the weak power end. It can be seen that the solution of the present invention uses the electronic expansion valve to discharge. Since the power of the electronic expansion valve is large, rapid discharge can be achieved; and since the opening of the electronic expansion valve is adjustable, the discharge rate can be adjusted, making the discharge method more flexible and having a wider application range. These are all discharge methods completely different from related solutions; in addition, in the solution of the present invention, it is the electronic expansion valve of the air conditioner itself that discharges, and there is no need to additionally set a discharge load.

[0063] In some embodiments, the drive system further has a rectifier unit, that is, the drive system is provided with a rectifier unit, a charging unit and a bus capacitor unit in sequence; the rectifier unit is used to rectify the AC power provided by the AC side of the drive system into DC power, and then charge the bus capacitor unit; the charging unit is arranged between the rectifier unit and the bus capacitor unit, and is used to charge the bus capacitor unit after the air conditioner is powered on, so as to perform charging current limiting protection on the bus capacitor unit, which is beneficial to improving the safety of the drive system of the air conditioner itself and the reliability of power supply to subsequent loads.

[0064] In some embodiments, the AC side of the drive system includes: an AC power supply access terminal of the drive system; and the drive system further includes a filtering unit.

[0065] The filtering unit is arranged between the AC power supply access terminal of the driving system and the rectifying unit, and is used for filtering the AC power transmitted from the AC power supply access terminal of the driving system before transmitting it to the rectifying unit.

[0066] The detection unit is arranged between the AC power supply input terminal of the driving system and the filtering unit.

[0067] In the solution of the present invention, a filtering unit is provided at the AC power supply access end of the air conditioner driving system, which can filter the interference signal in the AC power supply before providing it to the rectifying unit, which is beneficial to improving the stability and reliability of the power supply of the driving system.

[0068] In some implementations, the charging unit further includes: a driving module, such as a relay driving chip; the switch module includes: a relay module, such as a relay K1.

[0069] Wherein, the control unit is connected to the input end of the driving module; the relay module has a coil and a contact, the output end of the driving module is connected to the coil of the relay module, and the contact of the relay module is connected in parallel with the charging current limiting module.

[0070] like Figure 2 As shown, a circuit for rapidly discharging the bus capacitor of an air conditioner variable frequency drive system by controlling the electronic expansion valve of the air conditioner through linkage, comprises: a zero-live line filter circuit, a rectifier bridge, a charging current limiting resistor (such as Figure 2 The resistor R5 shown in FIG. Figure 2The charging circuit formed by the parallel connection of the shown relay K1), the bus capacitor (such as capacitor C4), the switching power supply, the electronic expansion valve, the voltage detection circuit for detecting the presence and absence of electricity on the AC side, and the MCU. The zero-fire wire filtering circuit adopts a single-phase filtering circuit. The drive system can convert AC into DC. For example, 220VAC becomes a half-wave through a rectifier bridge and then becomes 310VAC through a capacitor.

[0071] Among them, the AC side has AC power access terminals (such as the access terminal for the live wire L and the access terminal for the neutral wire N). The access terminal of the live wire L is connected to the first connection end of the input end of the zero-fire wire filtering circuit, and the access terminal of the neutral wire N is connected to the second connection end of the input end of the zero-fire wire filtering circuit; the first connection end of the output end of the zero-fire wire filtering circuit is connected to the first connection end of the input end of the rectifier bridge; the second connection end of the output end of the zero-fire wire filtering circuit is connected to the second connection end of the input end of the rectifier bridge; the first connection end of the output end of the rectifier bridge is connected to the positive electrode of capacitor C4 after passing through resistor R5; the second connection end of the output end of the rectifier bridge is connected to the negative electrode of capacitor C4 after passing through resistor R5, and the negative electrode of capacitor C4 is grounded. The positive electrode of capacitor C4 is connected to the first connection end of the input end of the switching power supply, and the negative electrode of capacitor C4 is connected to the second connection end of the input end of the switching power supply; the first connection end of the output end of the switching power supply is connected to the first connection end of the power supply terminal of the electronic expansion valve; the second connection end of the output end of the switching power supply is connected to the second connection end of the power supply terminal of the electronic expansion valve; the first output end of the MCU is connected to the control end of the electronic expansion valve. The MCU is powered by another switching power supply, and the MCU can control the opening degree change of the electronic expansion valve. When the MCU is powered by the switching power supply on the output side of the bus capacitor, because the discharge of the bus capacitor is relatively slow, the MCU will not lose power until some time after the AC side loses power.

[0072] Relay K1 has a coil and contacts, and the contacts of relay K1 are connected in parallel with resistor R5; a relay driver chip (such as a driver chip with model number 2003) is provided to match relay K1. The access terminal of the live wire L is connected to the first connection end of the input terminal of the voltage detection circuit for detecting the presence and absence of electricity on the AC side, and the access terminal of the neutral wire N is connected to the second connection end of the input terminal of the voltage detection circuit for detecting the presence and absence of electricity on the AC side; the output terminal of the voltage detection circuit for detecting the presence and absence of electricity on the AC side outputs a voltage detection signal to the input terminal of the MCU; the second output terminal of the MCU is connected to the input terminal of the relay driver chip; the output terminal of the relay driver chip is connected to the coil of relay K1. The MCU controls the energization or de-energization of the coil of relay K1 by controlling the relay driver chip; the energization or de-energization of the coil of relay K1 controls the closing or opening of the contacts of relay K1. For example: if the contacts of relay K1 are normally open contacts, the contacts of relay K1 are controlled to close when the coil of relay K1 is energized; and the contacts of relay K1 return to the open state when the coil of relay K1 is de-energized. If the contacts of relay K1 are normally closed contacts, the contacts of relay K1 are controlled to open when the coil of relay K1 is energized; and the contacts of relay K1 return to the closed state when the coil of relay K1 is de-energized.

[0073] In the solution of the present invention, relay K1 is used as the switch module. Relay K1 can be powered by another switching power supply, which can ensure the reliability of control. By detecting the power-off or power-on signal of the AC side voltage of the variable frequency drive system of the air conditioner, the closing and opening time of the contacts of relay K1 is controlled, and the charging current limiting resistor of the bus capacitor is cut out or connected, so as to control the magnitude of the charging current and improve the reliability of the power-on circuit of the variable frequency drive system. Thus, by controlling the NTC resistor during power-on and power-off, the problem of the main board working when the neutral wire is disconnected in front of the single-phase filter board and the problem of the discharge of the X capacitor (such as capacitor C4) when the unit is powered off are solved.

[0074] The technical solution of the present invention is adopted, through the electronic expansion valve in the refrigerant system of the air conditioner, and the rectifier bridge, bus capacitor, the charging circuit composed of the charging current limiting resistor connected in parallel between the rectifier bridge and the bus capacitor and the control switch (such as relay K1), and the controller (such as MCU) in the drive system (such as variable frequency drive system), a switching power supply is set at the output end of the bus capacitor to power the electronic expansion valve, the relay K1 and the electronic expansion valve are controlled by the MCU, and a voltage detection circuit for detecting whether there is power or no power on the AC side is set on the AC side of the drive system; after the air conditioner unit is powered on, if the MCU receives the first voltage detection signal (such as voltage detection signal A1) fed back by the voltage detection circuit, the contact of the delay control relay K1 is closed to cut out the charging current limiting resistor so that the air conditioner unit can work normally; if the air conditioner When the unit loses power (such as normal power failure or abnormal power failure), the MCU receives a second voltage detection signal (such as voltage detection signal A2) fed back by the voltage detection circuit, and the bus voltage on the bus capacitor needs to be consumed. The MCU controls the electronic expansion valve to consume the bus voltage on the bus capacitor until the electronic expansion valve stops operating when the switching power supply is out of power. When the bus voltage on the bus capacitor drops to the release voltage of the relay K1, the MCU controls the contacts of the relay K1 to close to connect the charging current limiting resistor, and the current is limited by the charging current limiting resistor after the unit where the air conditioner is located is powered on again. Therefore, when it is detected that there is no power on the AC side of the air-conditioning drive system, the electronic expansion valve is controlled to operate in a linkage manner to quickly discharge the bus capacitor, so that the charging current limiting resistor of the charging circuit is connected in time, thereby improving the reliability and safety of the air conditioner when it is powered on again.

[0075] According to an embodiment of the present invention, an air conditioner corresponding to the control device of the air conditioner is also provided. The air conditioner may include: the control device of the air conditioner described above.

[0076] Since the processing and functions implemented by the air conditioner of this embodiment basically correspond to the embodiments, principles and examples of the device, for the details not described in this embodiment, please refer to the relevant descriptions in the aforementioned embodiments and will not be repeated here.

[0077] According to an embodiment of the present invention, a control method for an air conditioner is also provided. Figure 5 The flowchart of an embodiment of the method of the present invention is shown in FIG. The air conditioner control method may include: step S110 to step S120.

[0078] At step S110, the power signal on the AC side of the drive system is detected; wherein the power signal on the AC side of the drive system includes: a voltage signal on the AC side of the drive system, and / or a current signal on the AC side of the drive system; the power signal on the AC side of the drive system includes: in the event that the air conditioner loses power, a power-off power signal after the air conditioner loses power, the power-off power signal being a second voltage detection signal (such as voltage detection signal A2).

[0079] At step S120, it is determined whether the power-on signal or the power-off signal is received. If the power-off signal is received, the electronic expansion valve is controlled to operate to accelerate the discharge rate of the bus capacitor unit, that is, to accelerate the rate of decrease of the bus voltage on the bus capacitor unit; and, after the bus voltage on the bus capacitor unit drops to the DC side output voltage threshold of the drive system, the switch unit is controlled to be disconnected so that the charging current limiting module is connected to the power supply circuit of the drive system, so that the charging current limiting module performs current limiting after the air conditioner is powered on again; until the bus voltage on the bus capacitor unit drops so that the output voltage of the switching power supply unit is lower than the target power supply voltage of the electronic expansion valve, the electronic expansion valve stops operating.

[0080] In the solution of the present invention, a charging current limiting resistor (such as Figure 2 The resistor R5 shown in FIG. Figure 2 In the embodiment of the present invention, a charging circuit is formed by connecting a relay K1) in parallel with the relay K1 shown in the figure, a switching power supply is set at the output end of the bus capacitor of the air conditioner variable frequency drive system to power the electronic expansion valve of the air conditioner, and the mainboard controller (such as MCU) of the air conditioner variable frequency drive system is used to control the relay K1 and the electronic expansion valve; when controlling the rapid discharge of the bus capacitor of the air conditioner variable frequency drive system, it is detected whether the AC side of the variable frequency drive system is powered off. When it is detected that the AC side of the variable frequency drive system is powered off, the electronic expansion valve is controlled to act in a linkage manner to rapidly discharge the bus capacitor, which can avoid damage to the mainboard (such as the controller mainboard) and components of the circuit where the variable frequency drive system is located due to large current impact; it can also reduce the after-sales failure rate of the air conditioner due to large current impact on the mainboard and components of the circuit where the variable frequency drive system is located, thereby improving the reliability of the air conditioner unit in a complex use environment.

[0081] In some embodiments, the power signal of the AC side of the drive system further includes: when the air conditioner is powered on, the power signal after the air conditioner is powered on, the power signal is the first voltage detection signal (such as voltage detection signal A1); the air conditioner variable frequency drive system has an AC side and a DC side. Figure 2In the example shown, the AC-side voltage detection circuit is used to detect whether there is power or no power on the AC side of the variable-frequency drive system. When there is power and no power, the voltage detection circuit inputs different voltage signals to the MCU. Among them, there are many detection methods for the voltage detection circuit. For example, it can be detected through a detection resistor, or it can be detected through an optocoupler, etc., so as to determine whether the AC side has lost power. The detection resistor can use an NTC resistor.

[0082] The control method of the air conditioner further includes: determining whether the power-on power signal or the power-off power signal is received. If the power-on power signal is received, the switch unit is controlled to close after a set time delay, so that the charging current-limiting module cuts out the power supply circuit of the drive system, and the air conditioner works normally.

[0083] In the solution of the present invention, after the air conditioner is powered on, the charging current-limiting module on the charging unit is used to limit the charging current of the bus capacitor unit, so as to avoid damage to the main board (such as the controller main board) and components of the circuit where the variable-frequency drive system is located due to the large current impact on the bus capacitor unit at the moment when the air conditioner is powered on; after the bus capacitor is fully charged, the charging current-limiting module on the charging unit is cut out to save the power consumption on the charging current-limiting module and make the air conditioner work normally.

[0084] Since the processing and functions implemented by the method of this embodiment are basically corresponding to the embodiments, principles and examples of the foregoing air conditioner, the details not described in the description of this embodiment can be referred to the relevant descriptions in the foregoing embodiments and will not be elaborated here.

[0085] In summary, it is easy for those skilled in the art to understand that, on the premise of no conflict, the above-mentioned advantageous ways can be freely combined and superimposed.

[0086] The above are only the embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the scope of the claims of the present invention.

Claims

1. A control device for an air conditioner, characterized in that, The air conditioner has a refrigerant system and a drive system. The refrigerant system has an electronic expansion valve. The drive system has a bus capacitor unit and a charging unit for the bus capacitor unit; The charging unit includes: a charging current limiting module and a switching module, and the charging current limiting module is connected in parallel with the switching module; the control device of the air conditioner includes: a detection unit, a switching power supply unit and a control unit; the switching power supply unit is arranged between the bus capacitor unit and the electronic expansion valve; wherein, The detection unit is used for detecting the power supply signal on the AC side of the drive system; the power supply signal on the AC side of the drive system includes: in the case of power failure of the air conditioner, the power failure signal after the power failure of the air conditioner; The control unit is used for, if receiving the power failure signal, controlling the electronic expansion valve to act to accelerate the decrease rate of the bus voltage on the bus capacitor unit; and, after the bus voltage on the bus capacitor unit drops to the DC side output voltage threshold of the drive system, controlling the switching unit to disconnect so that the charging current limiting module is connected.

2. The control device of the air conditioner according to claim 1, characterized in that, The power supply signal on the AC side of the drive system further includes: in the case of power-on of the air conditioner, the power-on signal after the power-on of the air conditioner; The control device of the air conditioner further includes: The control unit is further used for, if receiving the power-on signal, controlling the switching unit to close after a set time delay so that the charging current limiting module is cut out.

3. The control device of the air conditioner according to claim 1 or 2, characterized in that, The case of power failure of the air conditioner is the case of normal power failure of the air conditioner or the case of abnormal power failure of the air conditioner; wherein, In the case that the power failure of the air conditioner is the case of normal power failure of the air conditioner, the control unit controls the electronic expansion valve to act, and after the bus voltage on the bus capacitor unit drops to the DC side output voltage threshold of the drive system and the control unit controls the switching unit to disconnect so that the charging current limiting module is connected, the air conditioner shuts down; In the case that the power failure of the air conditioner is the case of abnormal power failure of the air conditioner, the control unit controls the electronic expansion valve to act, and after the bus voltage on the bus capacitor unit drops to the DC side output voltage threshold of the drive system and the control unit controls the switching unit to disconnect so that the charging current limiting module is connected, the air conditioner powers on again.

4. The control device of the air conditioner according to any one of claims 1 to 3, characterized in that, The control unit controls the electronic expansion valve to act, including: In the case that the switching power supply unit supplies power to the electronic expansion valve, controlling the opening degree of the electronic expansion valve to decrease so that the opening degree of the electronic expansion valve changes.

5. The control device of the air conditioner according to claim 1 or 2, characterized in that, The drive system further has a rectifying unit; the charging unit is arranged between the rectifying unit and the bus capacitor unit.

6. The control device of the air conditioner according to claim 5, characterized in that, The AC side of the drive system includes: the AC power access end of the drive system; the drive system further has a filtering unit; wherein, The filtering unit is arranged between the AC power access end of the drive system and the rectifying unit and is used for filtering the AC power transmitted from the AC power access end of the drive system and then transmitting it to the rectifying unit; The detection unit is arranged between the AC power access end of the drive system and the filtering unit.

7. The control device of the air conditioner according to claim 1 or 2, characterized in that, The charging unit further includes: a drive module; the switching module includes: a relay module; wherein, The control unit is connected to the input end of the drive module; the relay module has a coil and contacts, the output end of the drive module is connected to the coil of the relay module, and the contacts of the relay module are connected in parallel with the charging current limiting module.

8. An air conditioner, characterized in that, Comprising: The control device of the air conditioner according to any one of claims 1 to 7.

9. A control method for an air conditioner as claimed in claim 8, characterized in that, Comprising: Detect the power signal on the AC side of the drive system; The power signal on the AC side of the drive system includes: in the case of power failure of the air conditioner, the power failure signal after the power failure of the air conditioner; If the power failure signal is received, control the electronic expansion valve to act to accelerate the falling rate of the bus voltage on the bus capacitor unit; and after the bus voltage on the bus capacitor unit drops to the DC side output voltage threshold of the drive system, control the switching unit to disconnect so that the charging current limiting module is connected.

10. The control method of the air conditioner according to claim 9, wherein The power signal on the AC side of the drive system further includes: in the case of power-on of the air conditioner, the power-on signal after the power-on of the air conditioner; The control method of the air conditioner further includes: If the power-on signal is received, control the switching unit to close after a set time delay so that the charging current limiting module is cut out.

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