A circuit for multi-split air conditioner power-off valve

Abstract

This invention discloses a circuit for power-off valve closure in multi-split air conditioners. A voltage detection and control module is connected to the indoor unit's AC-DC module and detects its output voltage, comparing it with a set value. Based on the comparison result, the voltage detection and control module controls the indoor unit to draw power or supply power to the wired controller via a relay. The input terminal of a power conversion module is connected to the output voltage terminal of the indoor unit's AC-DC module and controls the system to draw power from the bus or cut off power via a relay. The output terminal of the power conversion module is connected to the electronic expansion valve control module, and an energy storage module forms a power supply connection with both the power conversion module and the electronic expansion valve control module. This application enables one outdoor unit to control multiple indoor units, providing energy to a high-power electronic expansion valve to completely close it. It can store a large amount of energy, and the simple circuit structure improves reliability and stability.

Description

Technical Field

[0001] This invention belongs to the field of industrial applications such as commercial air conditioning, and more specifically to the field of multi-split air conditioning applications, particularly a circuit for shutting off valves when a multi-split air conditioning unit is powered off. Background Technology

[0002] In industrial applications such as commercial air conditioning, especially in multi-split systems, one outdoor unit connects to multiple indoor units, theoretically allowing for 32 or 64 indoor units, commonly referred to as 1-to-32 or 1-to-64. Typically, one indoor unit is installed per room, so 64 indoor units correspond to 64 rooms. In real-world scenarios, a power outage may occur in one or more rooms. When a room loses power, the corresponding indoor unit also loses power. Due to the sudden power outage, the electronic expansion valve controlling the refrigerant on the indoor unit may not close in time, causing the outdoor unit to continue supplying refrigerant. Since the indoor unit's fan stops due to the power outage, it cannot expel cold air, leading to frost formation on the condensate drain of the indoor unit, resulting in condensate and severely impacting the user experience. With the rapid popularization of multi-split systems, the failure to close the electronic expansion valve can cause condensation in the corresponding room's indoor unit, affecting the cooling effect of other rooms and wasting energy.

[0003] Since it's common for one outdoor unit to control multiple indoor units, and the trend is towards an increasing number of controlled indoor units, power outages of one or more indoor units may occur during practical applications. Therefore, to completely solve this problem, a power-off valve shut-off device needs to be considered. Considering the specific application area, the device must have high reliability, long lifespan, and controllable cost. Especially given its inherent characteristics, achieving both long lifespan and complete safety control is not always possible. Therefore, while meeting multiple stringent conditions, cost control is also crucial, as each indoor unit requires one set of this device.

[0004] The current approach involves programmatic detection. When it detects that n indoor units have lost network access (n can be 1, 2, 3, etc.; during the installation and commissioning of multi-split air conditioners, the system automatically detects the number of connected indoor and outdoor units. When an indoor unit loses power, the corresponding indoor unit cannot communicate normally, and the program can determine that an indoor unit has lost network access), the entire network stops working, severely impacting user experience. The existing solution, by shutting down all internal network devices, avoids issues like condensation in rooms experiencing power outages, but by shutting down outdoor units, it stops supplying refrigerant to the entire network, causing the entire network to shut down. Summary of the Invention

[0005] The purpose of this invention is to provide a circuit for shutting off valves in multi-split air conditioners when power is off, which overcomes the shortcomings of existing technologies and is a reliable, stable, and cost-controllable solution that will not produce condensate or affect the normal operation of the entire network.

[0006] To achieve the above technical objectives, the present invention provides a circuit for power-off valve closure in multi-split air conditioners, comprising an indoor / outdoor unit side powered and communicated via a bus, and a wired controller side, wherein: on the indoor unit side, a voltage detection and control module is connected to the indoor unit side AC-DC module and detects its output voltage and compares it with a set value; the voltage detection and control module controls the indoor unit side to draw power or supply power to the wired controller side accordingly via a relay based on the comparison result; the input terminal of a power conversion module is connected to the output voltage terminal of the indoor unit side AC-DC module and controls the drawing power from the bus or power-off accordingly via the relay; the output terminal of the power conversion module is connected to an electronic expansion valve control module, and an energy storage module forms a power supply connection with both the power conversion module and the electronic expansion valve control module.

[0007] This invention provides a circuit for shutting off valves in multi-split air conditioners when power is off. It is suitable for a structure where one outdoor unit controls multiple indoor units. It can still provide energy to the high-power electronic expansion valve to completely shut it off. It can store a large amount of energy, and the simple circuit structure of the device can improve reliability and stability.

[0008] As a further improvement, a voltage equalization management module connected to the energy storage module is provided to equalize the voltage of the energy storage module, thereby improving the performance and lifespan of the energy storage module; and a signal suppression module is provided to prevent the signals transmitted on the bus from being absorbed by the power supply module connected to it, which could lead to communication abnormalities.

[0009] As a further improvement, the energy storage module is composed of multiple batteries connected in series or multiple supercapacitors connected in series, and the equalization management module is composed of multiple sets of passive equalization modules connected in series. The number of the multiple sets of passive equalization modules corresponds to the number of batteries connected in series or the number of supercapacitors connected in series and is arranged in parallel with them. Each passive equalization module is composed of a Zener diode and a current-limiting resistor arranged in series.

[0010] As a further improvement, the power conversion module is a DC-DC module with a step-down topology and constant voltage and constant current functions. The output voltage VOUT of the DC-DC module is connected to the electronic expansion valve control module, and is also connected to the energy storage module through a Schottky diode DB. The supply voltage BAT of the energy storage module is lower than the output voltage VOUT of the DC-DC module. As long as the mains power supply on the indoor unit side is normal, the DC-DC module supplies power to the electronic expansion valve control module, and the energy storage module has a slightly lower voltage and does not supply power.

[0011] As a further improvement, it also includes a rectifier bridge to distinguish the polarity of the DC voltage of the bus and connect them to the fixed contacts of the relays respectively. The moving contact of the relay and the AC-DC module on the indoor unit side have a second diode D2 to isolate and prevent the power on the bus from flowing back to the AC-DC module on the indoor unit side. The numerical relationship between the ultimate withstand voltage V3, the rated operating voltage V2, the normal operating voltage V1 of each battery or each supercapacitor, and the breakdown voltage V4 of each Zener diode is: V3>V2>V4>V1.

[0012] As a further improvement, when the value is greater than the set value, the bus terminal fixed contact L of the relay is disconnected and its wire control terminal fixed contact R is connected to supply power to the wire controller side. When the value is less than the set value, the wire control terminal fixed contact R is disconnected and the bus terminal fixed contact L is connected. The indoor unit side draws power from the bus, and the electronic expansion valve control module detects that the AC power supply of the indoor unit side AC-DC module is cut off, and detects the status of the electronic expansion valve and determines whether the electronic expansion valve needs to be closed.

[0013] As a further improvement, the signal suppression module employs a differential mode inductor, which includes: a first differential mode inductor L1 located on the outdoor unit side and connected to the bus, a second differential mode inductor L2 located on the indoor unit side, the second differential mode inductor L2 being located between the moving contact of the relay and the AC-DC module on the indoor unit side, and a third differential mode inductor L3 located on the wired controller side.

[0014] As a further improvement, the input voltage terminal of the first differential mode inductor L1 is connected to a first diode D1, and the second diode D2 is located between the AC-DC module on the indoor unit side and the second differential mode inductor L2, to suppress the differential signal of the bus and prevent it from being absorbed by the capacitor in the DC-DC module. The third differential mode inductor L3 is connected to the fixed contact R terminal of the wired control terminal and the wired controller module on the wired controller side, respectively, to prevent the differential signal of the bus from being absorbed by the capacitor of the power module in the wired controller module.

[0015] As a further improvement, the signal suppression module employs active inductors located on the indoor and outdoor unit sides and the wired controller side, respectively. The active inductors are made of solid-state circuits. The active inductor on the outdoor unit side is connected to the bus for power supply. The active inductor on the indoor unit side is arranged between the moving contact of the relay and the indoor unit side AC-DC module. The active inductor on the wired controller side is arranged between the fixed contact R of the relay and the wired controller module on the wired controller side. The input voltage terminal of the active inductor on the outdoor unit side is connected to a first diode D1.

[0016] As a further improvement, HBS modules are arranged on both the indoor and outdoor units and provide the bus for communication, with a communication distance of more than 500 meters. The indoor and outdoor units are arranged so that one outdoor unit controls multiple indoor units.

[0017] As a further improvement, the voltage detection and control module has: high and low voltage detection terminals A and B connected to the indoor unit side AC-DC module, a signal terminal E connected to the electronic expansion valve control module, and high and low voltage control terminals C and D connected to the relay control. The voltage detection and control module controls the high and low voltage control terminals C and D according to the signals from the high and low voltage detection terminals A and B and the signal terminal E. The supply voltage BAT is connected to the base of the fourth transistor Q4 via the second Zener diode DZB. The supply voltage BAT is connected to the collector of the fourth transistor Q4 and the base of the fifth transistor Q5 via the ninth resistor R9. The collector of the fifth transistor Q5 is connected to the high voltage control terminal C of the high and low voltage control terminals C and D.

[0018] This invention solves the technical problem of valve shut-off upon power failure and provides a solution that is long-lasting, highly reliable, safe, stable, and low-cost. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the circuit principle of the differential-mode inductor scheme used in this invention;

[0020] Figure 2 This is a schematic diagram of the circuit principle of the energy storage module and the equalization management module of the present invention;

[0021] Figure 3 This is a schematic diagram of the DC-DC module circuit of the present invention;

[0022] Figure 4 This is a schematic diagram of the circuit principle of the active inductor scheme used in this invention;

[0023] Figure 5 This is a schematic diagram of the circuit principle of the voltage detection and control module of the present invention. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] like Figures 1 to 4As shown, the present invention provides a circuit for power-off valve shut-off in a multi-split air conditioner, comprising an indoor and outdoor unit side powered and communicated by a bus, and a wired controller side, wherein: on the indoor unit side, a voltage detection and control module is connected to the indoor unit side AC-DC module and detects its output voltage and compares it with a set value; the voltage detection and control module controls the indoor unit side to draw power or supply power to the wired controller side accordingly through a relay based on the comparison result; the input terminal of a power conversion module is connected to the output voltage terminal of the indoor unit side AC-DC module and controls the drawing power from the bus or power-off accordingly through the relay; the output terminal of the power conversion module is connected to an electronic expansion valve control module, and an energy storage module forms a power supply connection with the power conversion module and the electronic expansion valve control module respectively.

[0026] This invention provides a circuit for shutting off valves in multi-split air conditioners when power is off. It is suitable for a layout where one outdoor unit controls multiple indoor units. It can still provide energy to the high-power electronic expansion valve to completely shut it off. It can store a large amount of energy, and the simple circuit structure of the device can improve reliability and stability.

[0027] As a further improvement, a voltage equalization management module connected to the energy storage module is provided to equalize the voltage of the energy storage module, thereby improving the performance and lifespan of the energy storage module; and a signal suppression module is provided to prevent the signals transmitted on the bus from being absorbed by the power supply module connected to it, which could lead to communication abnormalities.

[0028] As a further improvement, the energy storage module is composed of multiple batteries connected in series or multiple supercapacitors connected in series, and the equalization management module is composed of multiple sets of passive equalization modules connected in series. The number of the multiple sets of passive equalization modules corresponds to the number of batteries connected in series or the number of supercapacitors connected in series and is arranged in parallel with them. Each passive equalization module is composed of a Zener diode and a current-limiting resistor arranged in series.

[0029] As a further improvement, the power conversion module is a DC-DC module with a step-down topology and constant voltage and constant current functions. The output voltage VOUT of the DC-DC module is connected to the electronic expansion valve control module, and is also connected to the energy storage module through a Schottky diode DB. The supply voltage BAT of the energy storage module is lower than the output voltage VOUT of the DC-DC module. As long as the mains power supply on the indoor unit side is normal, the DC-DC module supplies power to the electronic expansion valve control module, and the energy storage module has a slightly lower voltage and does not supply power.

[0030] As a further improvement, it also includes a rectifier bridge to distinguish the polarity of the DC voltage of the bus and connect them to the fixed contacts of the relays respectively. The moving contact of the relay and the AC-DC module on the indoor unit side have a second diode D2 to isolate and prevent the power on the bus from flowing back to the AC-DC module on the indoor unit side. The numerical relationship between the ultimate withstand voltage V3, the rated operating voltage V2, the normal operating voltage V1 of each battery or each supercapacitor, and the breakdown voltage V4 of each Zener diode is: V3>V2>V4>V1.

[0031] As a further improvement, when the value is greater than the set value, the bus terminal fixed contact L of the relay is disconnected and its wire control terminal fixed contact R is connected to supply power to the wire controller side. When the value is less than the set value, the wire control terminal fixed contact R is disconnected and the bus terminal fixed contact L is connected. The indoor unit side draws power from the bus, and the electronic expansion valve control module detects that the AC power supply of the indoor unit side AC-DC module is cut off, and detects the status of the electronic expansion valve and determines whether the electronic expansion valve needs to be closed.

[0032] As a further improvement, the signal suppression module employs a differential mode inductor, which includes: a first differential mode inductor L1 located on the outdoor unit side and connected to the bus, a second differential mode inductor L2 located on the indoor unit side, the second differential mode inductor L2 being located between the moving contact of the relay and the AC-DC module on the indoor unit side, and a third differential mode inductor L3 located on the wired controller side.

[0033] As a further improvement, the input voltage terminal of the first differential mode inductor L1 is connected to a first diode D1, and the second diode D2 is located between the AC-DC module on the indoor unit side and the second differential mode inductor L2, to suppress the differential signal of the bus and prevent it from being absorbed by the capacitor in the DC-DC module. The third differential mode inductor L3 is connected to the fixed contact R terminal of the wired control terminal and the wired controller module on the wired controller side, respectively, to prevent the differential signal of the bus from being absorbed by the capacitor of the power module in the wired controller module.

[0034] As a further improvement, the signal suppression module employs active inductors located on the indoor and outdoor unit sides and the wired controller side, respectively. The active inductors are made of solid-state circuits. The active inductor on the outdoor unit side is connected to the bus for power supply. The active inductor on the indoor unit side is arranged between the moving contact of the relay and the indoor unit side AC-DC module. The active inductor on the wired controller side is arranged between the fixed contact R of the relay and the wired controller module on the wired controller side. The input voltage terminal of the active inductor on the outdoor unit side is connected to a first diode D1.

[0035] As a further improvement, HBS modules are arranged on both the indoor and outdoor units and provide the bus for communication, with a communication distance of more than 500 meters. The indoor and outdoor units are arranged so that one outdoor unit controls multiple indoor units.

[0036] like Figure 5 As shown, as a further improvement, the voltage detection and control module has: high and low voltage detection terminals A and B connected to the indoor unit side AC-DC module, signal terminal E connected to the electronic expansion valve control module, and high and low voltage control terminals C and D connected to the relay control. The voltage detection and control module controls the high and low voltage control terminals C and D according to the signals from the high and low voltage detection terminals A and B and the signal terminal E.

[0037] As a further improvement, the signal terminal E is connected between the high and low voltage detection terminals A and B and the base of the first transistor Q1 through the third diode D3. The high voltage detection terminal A is connected to the first Zener diode DZA. The collector of the first transistor Q1 is connected to the power supply voltage BAT of the energy storage module and the base of the second transistor Q2. The collector of the second transistor Q2 is connected to the gate of the third PMOS transistor Q3. The source and drain of the third PMOS transistor Q3 are connected to the power supply voltage BAT and the high voltage control terminal C, respectively.

[0038] As a further improvement, when the AC mains power on the indoor unit side is interrupted, the voltage difference between the high and low voltage detection terminals A and B decreases rapidly. When the voltage difference is less than the value of the first Zener diode DZA, the first transistor Q1 turns off, the second transistor Q2 turns on, the third PMOS transistor Q3 turns on, and the high and low voltage control terminals C and D supply a high voltage to the relay, so that it can draw power from the bus. Preferably, the drain of the third PMOS transistor Q3 is connected to the high voltage control terminal C via the seventh resistor R7.

[0039] As a further improvement, the supply voltage BAT is connected to the base of the fourth transistor Q4 via the second Zener diode DZB, and the supply voltage BAT is connected to the collector of the fourth transistor Q4 and the base of the fifth transistor Q5 via the ninth resistor R9. The collector of the fifth transistor Q5 is connected to the high-voltage control terminal C. Preferably, the second Zener diode DZB is connected to the base of the fourth transistor Q4 via the tenth resistor R10.

[0040] As a further improvement, when the electronic expansion valve control module detects that the electronic expansion valve has been completely closed, it outputs a high electrical signal to the signal terminal E, controls the first transistor Q1 to turn on through the third diode D3, and turns off the second transistor Q2 and the third PMOS transistor Q3. The voltage at the high and low voltage control terminals C and D is 0 to the relay, and the power is cut off from the bus accordingly through the relay.

[0041] As a further improvement, as the supply voltage BAT continuously decreases and falls below the value of the second Zener diode DZB, the fourth transistor Q4 turns off and the fifth transistor Q5 turns on, continuing to short-circuit the high and low voltage control terminals C and D together, locking the relay state, and preventing the signal terminal E from disappearing after the supply voltage BAT falls below a certain value. The second transistor Q2 and the third PMOS transistor Q3 then turn on again and close the relay, drawing power from the bus to drive it again.

[0042] As a further improvement, a second resistor R2 is arranged and connected to the low voltage detection terminal B side, a third resistor R3 is arranged and connected to the base side of the first transistor Q1, and its collector is arranged and connected to the supply voltage BAT via a first resistor R1. The collector of the second transistor Q2 is connected to the supply voltage BAT via the fifth and sixth resistors R5 and R6 connected in series, and is connected to the gate of the third PMOS transistor Q3 via the fifth resistor R5. The drain of the third PMOS transistor Q3 is connected to the high voltage control terminal C via a seventh resistor R7.

[0043] As a further improvement, the second Zener diode DZB is connected to the base of the fourth transistor Q4 via the tenth resistor R10, and connected to the low voltage detection terminal B and the low voltage control terminal D via the eighth resistor R8 and grounded. The emitters of the first, second, fourth, and fifth transistors Q1, Q2, Q4, and Q5 are grounded. The collectors of the second and fifth transistors Q2 and Q5 are grounded via the fourth and eleventh resistors R4 and R11, respectively. The collector of the second transistor Q2 is also grounded via the third capacitor C3.

[0044] This invention solves the technical problem of valve shut-off during power outages and provides a long-life, highly reliable, safe, stable, and low-cost solution. It enables the indoor unit to still provide energy to the high-power electronic expansion valve to completely shut it off when the power is off. The device can store a large amount of energy, and its simple circuit structure improves reliability and stability, achieving a long lifespan and safe and controllable operation while reducing costs under multiple stringent conditions.

[0045] In a preferred embodiment of the invention, the invention comprises an energy storage module, a power conversion module (DC-DC module), a voltage detection and control module (including a relay), a signal suppression module (differential-mode inductor or active inductor), and an equalization management module. The energy storage module can use a supercapacitor, which stores energy and provides transient power to the electronic expansion valve during power outages. The power conversion module charges the supercapacitor and maintains it within a reasonable voltage range. The voltage detection and control module determines whether the indoor unit is powered off and whether the energy storage module is undervoltage or overcharged. The signal suppression module prevents signals transmitted on the bus from being absorbed by the connected power module, causing communication abnormalities. When the voltage detection and control module detects a power outage in the indoor unit, it quickly controls the energy storage module to supply power to the electronic expansion valve control module of the indoor unit, achieving step-by-step closure of the expansion valve. The equalization management module equalizes the voltage of individual batteries or supercapacitors in the energy storage module, improving the performance and lifespan of the energy storage module. The device comprised of the above modules immediately switches power to the electronic expansion valve control module when a power outage is detected in the indoor unit. The expansion valve on the indoor unit side gradually closes to prevent frost and condensation. When the indoor unit is powered normally by mains electricity, the above modules are in normal standby mode.

[0046] When the indoor unit loses power, the charge stored in the supercapacitor may not be sufficient to completely close the electronic expansion valve (the expansion valve requires a lot of energy due to its multiple steps), necessitating power from the outdoor unit. The HBS protocol chip used in this invention has DC carrier communication functionality, meaning that power supply and communication signals share a bus consisting of two wires, and polarity is not required. To prevent the differential signal on the bus from being absorbed by the power module's capacitor, the outdoor unit's power module needs to transmit DC power to the bus via a differential-mode inductor. Upon detecting an AC power outage, the indoor unit draws power from the bus via the differential-mode inductor.

[0047] As a preferred embodiment, the connection relationship of each module is as follows: Figure 1 As shown, the outdoor unit supplies power to the bus via differential inductor L1, and the HBS module-outdoor unit is responsible for transmitting and receiving signals; the communication distance between the indoor and outdoor units is 500m or more. The indoor unit's voltage detection and control module is responsible for detecting the AC-DC output voltage and controlling the relay. When the voltage at points A and B is detected to be greater than a certain value, it indicates that the indoor unit's AC power supply is normal, and the relay is connected to terminal "R". At this time, the AC-DC output voltage supplies power to the wired controller module. When the voltage difference between points A and B is detected to be less than a certain value, it indicates that the indoor unit's AC power supply is cut off, and the relay is connected to terminal "L". At this time, the indoor unit draws power from the bus via differential inductor L2. The indoor unit's electronic expansion valve control module detects the AC power failure and checks the status of the electronic expansion valve to determine whether the expansion valve needs to be closed.

[0048] Because the amount of charge stored in a supercapacitor is relatively limited, it may not be able to support the continuous operation of the electronic expansion valve. Furthermore, the current capability of the DC power supply on the bus is limited and cannot directly drive the electronic expansion valve. Therefore, the operating state at this time is:

[0049] 1. The AC power supply to the indoor unit is detected to be cut off, and the electronic expansion valve is detected to be open at this time. The electronic expansion valve needs to be closed.

[0050] 2. The energy storage module supplies power to the electronic expansion valve control module and gradually closes the electronic expansion valve (at this time, the DC-DC module has actually drawn power from the bus and supplies power to the electronic expansion valve control module together with the energy storage module).

[0051] 3. When the electronic expansion valve control module detects that the power supply of the energy storage module is lower than a certain value, it pauses the action of closing the expansion valve. At this time, the DC-DC module can draw power from the bus and charge the energy storage module.

[0052] 4. After the energy storage module is fully charged, the electronic expansion valve control module continues to repeat step 2 to gradually close the electronic expansion valve;

[0053] 5. Repeat steps 2, 3, and 4 above until the electronic expansion valve is completely closed.

[0054] The energy storage module consists of supercapacitors. Because supercapacitors have relatively low rated voltages, multiple supercapacitors need to be connected in series. However, due to differences in capacitance, the voltages between capacitors will differ under the same charging and discharging current. For supercapacitors with relatively smaller capacitances, the voltage is highest during charging but drops the fastest during discharging. Without control, after multiple charge-discharge cycles, the voltage difference between individual supercapacitors gradually increases, potentially causing a capacitor's voltage to exceed its rated value, affecting its performance and lifespan. Based on practical applications, this invention patent uses a Zener diode and a current-limiting resistor to create a passive balancing module, the principle of which is as follows:

[0055] 1. Based on the operating voltage of the electronic expansion valve, select an appropriate number of supercapacitors to form an energy storage module in series;

[0056] 2. Based on the voltage of the energy storage module, the operating voltage of each supercapacitor is calculated to be V1, which is the theoretical value under ideal conditions;

[0057] 3. The rated operating voltage of the supercapacitor is V2, and the ultimate withstand voltage is V3;

[0058] 4. Select a Zener diode with a breakdown voltage of V4 and connect it in series with a current-limiting resistor R to control the current;

[0059] 5. Voltage order: V3 > V2 > V4 > V1; After multiple charge-discharge cycles, the voltage of a certain capacitor will be higher than V1. When the voltage reaches V4, the Zener diode connected in parallel breaks down. The discharge circuit formed by the Zener diode and the resistor discharges the capacitor until the voltage is lower than V4. As long as the voltage of one capacitor drops, the DC-DC module will charge the entire energy storage module. This ensures that the voltage of the energy storage module is within a reasonable range and that the voltage of each supercapacitor cell does not reach V2.

[0060] Because there is a voltage difference between V1 and V4, the resulting voltage variation in each supercapacitor within the energy storage module is slight. However, each supercapacitor operates within its rated voltage range, so this does not affect its performance, lifespan, or reliability. Since the equalization module only contains Zener diodes and resistors, its circuit structure is simple and highly reliable. Furthermore, after equalization, the capacitor voltage is below the Zener diode's breakdown value, meaning the equalization module experiences no losses. In contrast, while conventional equalization modules use dedicated chips with high precision, their circuit structure is complex, costly, and they continuously consume power.

[0061] like Figure 2 As shown, the energy storage module can be multiple batteries connected in series or multiple supercapacitors connected in series. This invention patent preferably uses a supercapacitor module. Supercapacitors include lithium-ion supercapacitors and conventional supercapacitors. Lithium-ion supercapacitors have the advantage of high energy density (large capacity). Similar to batteries, they have a minimum voltage requirement. When the voltage of a lithium-ion supercapacitor falls below its specified minimum voltage, it will fail. Considering practical situations, if a supercapacitor module is paired with a conventional balancing module, and is not used for a long time, the charge of the supercapacitor may be consumed by the balancing module, causing the entire module to fail. Therefore, the balancing module in this invention patent has obvious advantages due to its no power consumption and can be applied to energy storage modules composed of lithium-ion supercapacitors. Conventional supercapacitors have similar characteristics to ordinary capacitors. Even if the voltage is 0, it can be restored to normal after recharging, so there is no need to worry about the entire module being damaged due to prolonged disuse.

[0062] like Figure 3 In the preferred embodiment shown, the DC-DC module has a step-down topology and constant voltage / constant current functions. Its output terminal VOUT is connected to the electronic expansion valve control module, and then connected to the energy storage module via a Schottky diode. The energy storage module's voltage BAT is approximately 0.4V lower than VOUT. Therefore, as long as the mains power supply on the indoor unit side is normal, the DC-DC module supplies power to the electronic expansion valve control module, while the energy storage module, with its slightly lower voltage, will not supply power. Those skilled in the art will understand that, based on the technical features and objectives disclosed in this invention, the same circuit principle structure can be used to achieve the same DC-DC module function.

[0063] Because it is a nonpolar connection, it requires Figure 1The rectifier bridge in the circuit distinguishes the polarity of the DC voltage on the bus. D2 is used for isolation to prevent backflow of power from the bus to the AC-DC module on the indoor unit side. L2 is used to suppress the differential signal on the bus to prevent it from being absorbed by the capacitors in the DC-DC module. Similarly, L3 prevents the differential signal on the bus from being absorbed by the capacitors in the power module of the wired controller module.

[0064] As another embodiment of the present invention, such as Figure 4 The diagram shows the use of active inductors to replace the previous differential-mode inductors. Active inductors are manufactured using solid-state circuitry, offering advantages such as small size, high current capacity, light weight, no mechanical vibration, and long lifespan. This further overcomes the problems of differential-mode inductors, which are large, have low current capacity, and generate mechanical oscillations and periodic noise during communication (due to periodic communication between devices).

[0065] Figure 5 The voltage detection and control module works as follows: when the AC mains power on the indoor unit side is cut off, the voltage difference between points A and B decreases rapidly. When the voltage difference is less than DZA, Q1 is turned off, and Q2 is turned on. Q3 is a PMOS transistor. After Q2 is turned on, Q3 is also turned on, supplying power to the relay coil through the current-limiting resistor R7. At this time, the relay is activated, connecting the "L" contact, and the device begins to draw power from the bus.

[0066] When the electronic expansion valve control module detects that the electronic expansion valve has been completely closed, it outputs a high electrical signal E, which controls Q1 to open via D3. After Q1 opens, Q2 and Q3 close, the voltage at point CD is 0, and the relay connects to contact "R". The entire indoor unit no longer draws power from the bus. As the BAT voltage continues to decrease and falls below DZB, Q4 closes, Q5 turns on, and points CD remain shorted together, locking the relay state. This prevents the signal at point E from disappearing when the BAT voltage drops below a certain value, allowing Q2 and Q3 to reopen and close the relay, thus resuming bus-driven operation.

[0067] This circuit can detect a mains power failure, control a relay to draw power from the bus, and after the valve is completely closed, prevent the device from drawing power from the bus, so that the bus voltage can supply power to other similar "power-off devices".

[0068] It should be understood that the scope of protection sought by this invention is not limited to the non-limiting embodiments, which are merely illustrative examples. The substantive scope of protection claimed in this application is further embodied in the scope provided by the independent claims and their dependent claims.

Claims

1. A circuit for shutting off valves in a multi-split air conditioner upon power failure, comprising an indoor / outdoor unit side powered and communicated via a bus, and a wired controller side, characterized in that: On the indoor unit side, the voltage detection and control module is connected to the indoor unit side AC-DC module and detects its output voltage and compares it with a set value. Based on the comparison result, the voltage detection and control module controls the indoor unit side to draw power or supply power to the wired controller side via a relay. The input terminal of the power conversion module is connected to the output voltage terminal of the indoor unit side AC-DC module and controls the power to draw power from the bus or disconnect power via the relay. The output terminal of the power conversion module is connected to the electronic expansion valve control module, and the energy storage module forms a power supply connection with the power conversion module and the electronic expansion valve control module respectively.

2. The circuit for power-off valve closure in a multi-split air conditioning system according to claim 1, characterized in that: It also includes: a voltage equalization management module connected to the energy storage module to equalize the voltage of the energy storage module and improve the performance and lifespan of the energy storage module; and a signal suppression module to prevent the signals transmitted on the bus from being absorbed by the power supply module connected to it, which could lead to communication abnormalities.

3. The circuit for power-off valve closure in a multi-split air conditioning system according to claim 2, characterized in that: The energy storage module is composed of multiple batteries connected in series or multiple supercapacitors connected in series. The equalization management module is composed of multiple sets of passive equalization modules connected in series. The number of the multiple sets of passive equalization modules corresponds to the number of batteries connected in series or the number of supercapacitors connected in series and they are arranged in parallel. Each passive equalization module consists of a Zener diode and a current-limiting resistor arranged in series.

4. The circuit for power-off valve closure in a multi-split air conditioning system according to claim 3, characterized in that: The power conversion module is a DC-DC module with a step-down topology and constant voltage and constant current functions. The output voltage VOUT of the DC-DC module is connected to the electronic expansion valve control module and is also connected to the energy storage module through a Schottky diode DB. The supply voltage BAT of the energy storage module is lower than the output voltage VOUT of the DC-DC module. As long as the mains power supply on the indoor unit side is normal, the DC-DC module supplies power to the electronic expansion valve control module, and the energy storage module has a slightly lower voltage and does not supply power.

5. A circuit for shutting off a valve in a multi-split air conditioner upon power failure, as described in claim 4, characterized in that: It also includes a rectifier bridge to distinguish the polarity of the DC voltage of the bus and connect them to the fixed contacts of the relays respectively. The moving contact of the relay and the AC-DC module on the indoor unit side have a second diode D2 to isolate and prevent the power on the bus from flowing back to the AC-DC module on the indoor unit side. The numerical relationship between the ultimate withstand voltage V3, the rated operating voltage V2, the normal operating voltage V1 of each battery or each supercapacitor, and the breakdown voltage V4 of each Zener diode is: V3>V2>V4>V1.

6. A circuit for shutting off a valve in a multi-split air conditioner upon power failure, as described in claim 5, characterized in that: When the value is greater than the set value, the fixed contact L of the bus terminal of the relay is disconnected and its fixed contact R of the wired control terminal is connected to supply power to the wired controller side. When the value is less than the set value, the fixed contact R of the wired control terminal is disconnected and the fixed contact L of the bus terminal is connected. The indoor unit side draws power from the bus, and the electronic expansion valve control module detects that the AC power supply of the indoor unit side AC-DC module is cut off, and detects the status of the electronic expansion valve and determines whether the electronic expansion valve needs to be closed.

7. A circuit for shutting off a valve in a multi-split air conditioner upon power failure, as described in claim 6, characterized in that: The signal suppression module uses a differential mode inductor, which includes: a first differential mode inductor L1 located on the outdoor unit side and connected to the bus, a second differential mode inductor L2 located on the indoor unit side, the second differential mode inductor L2 being located between the moving contact of the relay and the AC-DC module on the indoor unit side, and a third differential mode inductor L3 located on the wired controller side.

8. A circuit for shutting off a valve in a multi-split air conditioner upon power failure, as described in claim 7, characterized in that: The input voltage terminal of the first differential inductor L1 is connected to a first diode D1. The second diode D2 is located between the AC-DC module on the indoor unit side and the second differential inductor L2, and is used to suppress the differential signal of the bus to prevent it from being absorbed by the capacitor in the DC-DC module. The third differential inductor L3 is connected to the fixed contact R terminal of the wired control terminal and the wired controller module on the wired controller side, respectively, to prevent the differential signal of the bus from being absorbed by the capacitor of the power module in the wired controller module.

9. A circuit for shutting off a valve in a multi-split air conditioner upon power failure, as described in claim 6, characterized in that: The signal suppression module employs active inductors located on the indoor and outdoor unit sides and the wired controller side, respectively. The active inductors are made of solid-state circuits. The active inductor on the outdoor unit side is connected to the bus for power supply. The active inductor on the indoor unit side is arranged between the moving contact of the relay and the indoor unit side AC-DC module. The active inductor on the wired controller side is arranged between the fixed contact R of the relay and the wired controller module on the wired controller side. The input voltage terminal of the active inductor on the outdoor unit side is connected to a first diode D1.

10. A circuit for shutting off a valve in a multi-split air conditioning unit when power is off, as described in claim 1, characterized in that: Both the indoor and outdoor units are equipped with HBS modules and provide the bus for communication. The communication distance is more than 500 meters. The indoor and outdoor units are arranged in a way that one outdoor unit controls multiple indoor units.

11. A circuit for shutting off a valve in a multi-split air conditioning unit upon power failure, as described in claim 1, characterized in that: The voltage detection and control module has: high and low voltage detection terminals A and B connected to the indoor unit side AC-DC module, signal terminal E connected to the electronic expansion valve control module, and high and low voltage control terminals C and D connected to the relay control. The voltage detection and control module controls the high and low voltage control terminals C and D according to the signals from the high and low voltage detection terminals A and B and the signal terminal E. The power supply voltage BAT is connected to the base of the fourth transistor Q4 through the second Zener diode DZB. The power supply voltage BAT is connected to the collector of the fourth transistor Q4 and the base of the fifth transistor Q5 through the ninth resistor R9. The collector of the fifth transistor Q5 is connected to the high voltage control terminal C of the high and low voltage control terminals C and D.

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