Power supply protection circuit and air conditioner

Abstract

The utility model provides a power supply protection circuit and an air conditioner, and relates to the technical field of power supply detection. The power supply protection circuit comprises a three-phase detection circuit, a misconnection detection circuit, a controller and a relay, and the three-phase detection circuit detects the voltage of each phase of the input end of a three-phase power supply and outputs a voltage detection signal of each phase to the controller; the misconnection detection circuit samples the voltage of one phase of the input end of the three-phase power supply and outputs a voltage sampling signal to the controller; the controller controls the relay to disconnect the three-phase power supply and the load under the condition that the voltage sampling signal represents that the power line of the three-phase power supply is misconnected or the voltage detection signal represents that the three-phase power supply has phase loss or phase sequence error. Effective detection of three-phase power supply phase loss, phase sequence errors, power line misconnection and other abnormal conditions is realized, and power supply of the load is cut off in time when the abnormal conditions are detected, so that safe operation of the load is guaranteed, and loss is reduced.

Description

Technical Field

[0001] This utility model relates to the field of power supply detection technology, and more specifically, to a power supply protection circuit and an air conditioner. Background Technology

[0002] With the increasing electricity demand from household and commercial air conditioners, the 380V three-phase four-wire power supply is gradually becoming the mainstream. Three-phase power has advantages such as stable power supply and high transmission efficiency, but in practical applications, it also presents certain safety hazards, specifically in the following three aspects:

[0003] Three-phase power supply phase loss problem: In a three-phase power supply system, if a phase fails and causes a phase loss, it will lead to an unbalanced load voltage, affecting the normal operation of the equipment, and may even cause equipment damage.

[0004] Phase sequence error: The correct phase sequence of three-phase electricity is crucial for the operation of equipment. Incorrect phase sequence may cause equipment to reverse, be damaged, or fail to start.

[0005] Incorrect wiring problem: In actual wiring process, it is easy to connect the phase voltage as the line voltage, resulting in excessive voltage, which can burn out components and cause safety hazards. Utility Model Content

[0006] The problem solved by this invention is that the existing technology cannot effectively detect abnormalities such as phase loss, phase sequence error, and incorrect connection of power lines in a three-phase power supply, thus failing to ensure the safe operation of the load.

[0007] To solve the above problems, this utility model provides a power supply protection circuit and an air conditioner.

[0008] In a first aspect, this utility model provides a power supply protection circuit, including a three-phase detection circuit, a misconnection detection circuit, a controller, and a relay. The three-phase detection circuit, the misconnection detection circuit, and the relay are all electrically connected to the controller. The three-phase detection circuit and the misconnection detection circuit are both electrically connected to the input terminal of the three-phase power supply. The relay is electrically connected between the output terminal of the three-phase power supply and the load.

[0009] The three-phase detection circuit is used to detect the voltage of each phase at the input terminal of the three-phase power supply and output the voltage detection signal of each phase to the controller.

[0010] The misconnection detection circuit is used to sample the voltage of one phase of the input terminal of the three-phase power supply and output the voltage sampling signal to the controller.

[0011] The controller is used to control the relay to disconnect the three-phase power supply from the load when the voltage sampling signal indicates that the three-phase power supply has a power line misconnection, or when the voltage detection signal indicates that the three-phase power supply has a phase loss or phase sequence error.

[0012] The power supply protection circuit provided by this utility model detects the voltage of each phase at the input of a three-phase power supply using a three-phase detection circuit and samples the voltage of one phase at the input of the three-phase power supply using a misconnection detection circuit. The controller determines whether there is a phase loss or phase sequence error in the three-phase power supply based on the voltage detection signals of each phase fed back by the three-phase detection circuit, and determines whether there is a power line misconnection based on the voltage sampling signal fed back by the misconnection detection circuit. When there is a power line misconnection, phase loss, or phase sequence error in the three-phase power supply, the controller controls the relay to disconnect the connection between the three-phase power supply and the load. This achieves effective detection of abnormal conditions such as phase loss, phase sequence error, and power line misconnection in the three-phase power supply, and promptly cuts off the power supply to the load when an abnormality is detected, thereby ensuring the safe operation of the load and reducing losses.

[0013] In an optional implementation, the three-phase detection circuit includes a first-phase detection module, a second-phase detection module, and a third-phase detection module. One end of each of the first-phase detection module, the second-phase detection module, and the third-phase detection module is electrically connected to the first phase line, the second phase line, and the third phase line of the input terminal of the three-phase power supply, respectively. The other end of each of the first-phase detection module, the second-phase detection module, and the third-phase detection module is electrically connected to the first detection terminal, the second detection terminal, and the third detection terminal of the controller, respectively.

[0014] The first phase detection module is used to detect the voltage of the first phase of the three-phase power supply and output the voltage detection signal of the first phase to the first detection terminal of the controller.

[0015] The second phase detection module is used to detect the voltage of the second phase of the three-phase power supply and output the voltage detection signal of the second phase to the second detection terminal of the controller;

[0016] The third-phase detection module is used to detect the voltage of the third phase of the three-phase power supply and output the voltage detection signal of the third phase to the third detection terminal of the controller.

[0017] The power supply protection circuit provided by this utility model, for the first, second and third phases of a three-phase power supply, respectively sets up a first phase detection module, a second phase detection module and a third phase detection module in the three-phase detection circuit, and then detects the voltage of the first, second and third phases of the three-phase power supply through the first phase detection module, the second phase detection module and the third phase detection module respectively.

[0018] In an optional implementation, the first phase detection module includes a first optocoupler, a first resistor, a first diode, and a first pull-up resistor; the second phase detection module includes a second optocoupler, a second resistor, a second diode, and a second pull-up resistor; and the third phase detection module includes a third optocoupler, a third resistor, a third diode, and a third pull-up resistor.

[0019] The first diode and the first resistor are connected in series between the anode of the light-emitting diode of the first optocoupler and the first phase line of the input terminal of the three-phase power supply. The cathode of the light-emitting diode of the first optocoupler is electrically connected to the neutral line of the three-phase power supply through the fourth resistor. The collector of the phototransistor of the first optocoupler is electrically connected to the first detection terminal of the controller and the first pull-up resistor. The emitter of the phototransistor of the first optocoupler is grounded.

[0020] The second diode and the second resistor are connected in series between the anode of the light-emitting diode of the second optocoupler and the second phase line of the input terminal of the three-phase power supply. The cathode of the light-emitting diode of the second optocoupler is electrically connected to the neutral line of the three-phase power supply through the fourth resistor. The collector of the phototransistor of the second optocoupler is electrically connected to the second detection terminal of the controller and the second pull-up resistor. The emitter of the phototransistor of the second optocoupler is grounded.

[0021] The third diode and the third resistor are connected in series between the anode of the light-emitting diode of the third optocoupler and the third phase line of the input terminal of the three-phase power supply. The cathode of the light-emitting diode of the third optocoupler is electrically connected to the neutral line of the three-phase power supply through the fourth resistor. The collector of the phototransistor of the third optocoupler is electrically connected to the third detection terminal of the controller and the third pull-up resistor. The emitter of the phototransistor of the third optocoupler is grounded.

[0022] In an optional implementation, the first phase detection module further includes a fifth resistor and a fourth diode, the second phase detection module further includes a sixth resistor and a fifth diode, and the third phase detection module further includes a seventh resistor and a sixth diode;

[0023] The cathode of the fourth diode is electrically connected to the anode of the light-emitting diode of the first optocoupler, the anode of the fourth diode is electrically connected to the neutral line of the three-phase power supply through the fourth resistor, and the fifth resistor is connected in parallel with the fourth diode;

[0024] The cathode of the fifth diode is electrically connected to the anode of the light-emitting diode of the second optocoupler, the anode of the fifth diode is electrically connected to the neutral line of the three-phase power supply through the fourth resistor, and the sixth resistor is connected in parallel with the fifth diode;

[0025] The cathode of the sixth diode is electrically connected to the anode of the light-emitting diode of the third optocoupler, the anode of the sixth diode is electrically connected to the neutral line of the three-phase power supply through the fourth resistor, and the seventh resistor is connected in parallel with the sixth diode.

[0026] In an optional implementation, the first phase detection module further includes an eighth resistor and a first capacitor, the second phase detection module further includes a ninth resistor and a second capacitor, and the third phase detection module further includes a tenth resistor and a third capacitor.

[0027] The eighth resistor is electrically connected between the collector of the phototransistor of the first optocoupler and the first detection terminal of the controller; one end of the first capacitor is electrically connected between the eighth resistor and the first detection terminal of the controller; and the other end of the first capacitor is grounded.

[0028] The ninth resistor is electrically connected between the collector of the phototransistor of the second optocoupler and the second detection terminal of the controller; one end of the second capacitor is electrically connected between the ninth resistor and the second detection terminal of the controller; and the other end of the second capacitor is grounded.

[0029] The tenth resistor is electrically connected between the collector of the phototransistor of the third optocoupler and the third detection terminal of the controller. One end of the third capacitor is electrically connected between the tenth resistor and the third detection terminal of the controller, and the other end of the third capacitor is grounded.

[0030] In an optional implementation, the misconnection detection circuit includes a transformer, a rectifier module, and a voltage divider module. The input terminal of the transformer is electrically connected to the input terminal of the three-phase power supply, the output terminal of the transformer is electrically connected to the rectifier module, the rectifier module is also electrically connected to the voltage divider module, and the voltage divider module is also electrically connected to the fourth detection terminal of the controller.

[0031] The transformer is used to step down the voltage of one phase of the input terminal of the three-phase power supply.

[0032] The rectifier module is used to rectify the AC voltage output by the transformer into DC voltage;

[0033] The voltage divider module is used to divide the DC voltage to obtain the voltage sampling signal, and output the voltage sampling signal to the fourth detection terminal of the controller.

[0034] The power supply protection circuit provided by this utility model achieves high-voltage and low-voltage separation by setting a transformer in the misconnection detection circuit, effectively identifying the circuit voltage and improving the circuit safety.

[0035] In an optional implementation, the voltage divider module includes a first voltage divider resistor and a second voltage divider resistor, which are connected in series between the rectifier module and ground. The fourth detection terminal of the controller is electrically connected between the first voltage divider resistor and the second voltage divider resistor.

[0036] In an optional embodiment, the misconnection detection circuit further includes an eleventh resistor, a fourth capacitor, and a pull-up diode. One end of the eleventh resistor is electrically connected between the first voltage divider resistor and the second voltage divider resistor, and the other end of the eleventh resistor is electrically connected to the fourth detection terminal of the controller. One end of the fourth capacitor is electrically connected to the other end of the eleventh resistor, and the other end of the fourth capacitor is grounded. The anode of the pull-up diode is electrically connected to the other end of the eleventh resistor, and the cathode of the pull-up diode is electrically connected to the first power supply.

[0037] In an optional embodiment, the misconnection detection circuit further includes a shorting cap, which includes a first end, a second end, and a third end. The first end of the shorting cap is electrically connected between the first voltage divider resistor and the second voltage divider resistor, and the second end of the shorting cap is grounded. The shorting cap is used to control whether the misconnection detection circuit enables the detection function.

[0038] Secondly, this utility model provides an air conditioner, including a three-phase power supply, a load, and a power supply protection circuit as described in any of the foregoing embodiments. Attached Figure Description

[0039] Figure 1 A structural block diagram of an air conditioner provided by this utility model;

[0040] Figure 2 A schematic diagram of a power supply protection circuit provided by this utility model;

[0041] Figure 3 A functional module diagram of a three-phase detection circuit for a power supply protection circuit provided by this utility model;

[0042] Figure 4 A circuit connection diagram of a three-phase detection circuit for the power supply protection circuit provided by this utility model;

[0043] Figure 5 A functional module diagram of a misconnection detection circuit for a power supply protection circuit provided by this utility model;

[0044] Figure 6 A circuit connection diagram of the misconnection detection circuit for the power supply protection circuit provided by this utility model;

[0045] Figure 7A circuit connection diagram of a relay for the power supply protection circuit provided by this utility model.

[0046] Figure Label Explanation: 10-Air conditioner; 100-Power supply protection circuit; 200-Three-phase power supply; 300-Load; 110-Three-phase detection circuit; 120-Incorrect connection detection circuit; 130-Controller; 140-Relay; 111-First phase detection module; 112-Second phase detection module; 113-Third phase detection module; 121-Transformer; 122-Rectifier module; 123-Voltage divider module; 141-First insert; 142-Second insert; 143-Coil; R1-First resistor; R2-Second resistor; R3-Third resistor; R4-Fourth resistor; R5-Fifth resistor; R6-Sixth resistor; R7-Seventh resistor; R8-Eighth resistor; R9-Ninth resistor; R10-Tenth resistor; R11-Eleventh resistor; R12 R13 - First pull-up resistor; R14 - Second pull-up resistor; R15 - Third pull-up resistor; R16 - First voltage divider resistor; D1 - First diode; D2 - Second diode; D3 - Third diode; D4 - Fourth diode; D5 - Fifth diode; D6 - Sixth diode; D7 - Seventh diode; D8 - Eighth diode; D9 - Ninth diode; D10 - Tenth diode; D11 - Pull-up diode; C1 - First capacitor; C2 - Second capacitor; C3 - Third capacitor; C4 - Fourth capacitor; P1 - First output terminal; P2 - Second output terminal; K1 - First terminal; K2 - Second terminal; K3 - Third terminal; DR - First detection terminal; DS - Second detection terminal; DT - Third detection terminal; Vad - Fourth detection terminal. Detailed Implementation

[0047] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings.

[0048] Please refer to Figure 1 This is a structural block diagram of an air conditioner 10 provided by this utility model. The air conditioner 10 includes a three-phase power supply 200, a load 300, and a power supply protection circuit 100. The power supply protection circuit 100 is electrically connected to both the three-phase power supply 200 and the load 300. The power supply protection circuit 100 can effectively detect abnormalities such as phase loss, phase sequence error, and incorrect power line connection in the three-phase power supply 200. When it detects that the three-phase power supply 200 has incorrect power line connection, phase loss, or phase sequence error, it disconnects the connection between the three-phase power supply 200 and the load 300, thereby timely cutting off the power supply to the load 300, ensuring the safe operation of the load 300, and reducing losses.

[0049] Please refer to Figure 2This is a schematic diagram of one possible composition of the power supply protection circuit 100 provided by this utility model. The power supply protection circuit 100 includes a three-phase detection circuit 110, a misconnection detection circuit 120, a controller 130, and a relay 140. The three-phase detection circuit 110, the misconnection detection circuit 120, and the relay 140 are all electrically connected to the controller 130. The three-phase detection circuit 110 and the misconnection detection circuit 120 are both electrically connected to the input terminal of the three-phase power supply 200. The relay 140 is electrically connected between the output terminal of the three-phase power supply 200 and the load 300.

[0050] The three-phase detection circuit 110 is used to detect the voltage of each phase at the input terminal of the three-phase power supply 200 and output the voltage detection signal of each phase to the controller 130; the misconnection detection circuit 120 is used to sample the voltage of one phase at the input terminal of the three-phase power supply 200 and output the voltage sampling signal to the controller 130; the controller 130 is used to control the relay 140 to disconnect the connection between the three-phase power supply 200 and the load 300 when the voltage sampling signal indicates that there is a power line misconnection in the three-phase power supply 200, or the voltage detection signal indicates that there is a phase loss or phase sequence error in the three-phase power supply 200.

[0051] In this embodiment, when the controller 130 fails to acquire a voltage detection signal for any phase, it determines that the three-phase power supply 200 is missing a phase. Simultaneously, since the phase difference between the three phases of the three-phase power supply 200 is 120°, if the voltage detection signals acquired by the controller 130 do not change sequentially according to the 120° phase difference, it determines that the input phase sequence of the three-phase power supply 200 is incorrect. By sampling the voltage of one phase at the input terminal of the three-phase power supply 200 through the misconnection detection circuit 120, the controller 130 can determine whether the input is line voltage or phase voltage based on the acquired voltage sampling signal, and thus determine whether there is a power line misconnection.

[0052] In this embodiment, if the controller 130 determines that there is a power line misconnection, phase loss, or phase sequence error in the three-phase power supply 200, it can also simultaneously control the display to output a fault code to trigger an alarm, so that the user can check the power supply in a timely manner.

[0053] As can be seen, the power supply protection circuit 100 provided by this utility model detects the voltage of each phase at the input terminal of the three-phase power supply 200 by setting a three-phase detection circuit 110 and samples the voltage of one phase at the input terminal of the three-phase power supply 200 by setting a misconnection detection circuit 120. The controller 130 determines whether there is a phase loss or phase sequence error in the three-phase power supply 200 based on the voltage detection signals of each phase fed back by the three-phase detection circuit 110, and determines whether there is a power line misconnection in the three-phase power supply 200 based on the voltage sampling signal fed back by the misconnection detection circuit 120. When there is a power line misconnection, phase loss, or phase sequence error in the three-phase power supply 200, the control relay 140 disconnects the connection between the three-phase power supply 200 and the load 300, thereby achieving effective detection of abnormal conditions such as phase loss, phase sequence error, and power line misconnection in the three-phase power supply 200, and timely cutting off the power supply to the load 300 when an abnormality is detected, thereby ensuring the safe operation of the load 300 and reducing losses.

[0054] In one implementation, please refer to Figure 3 The three-phase detection circuit 110 includes a first-phase detection module 111, a second-phase detection module 112, and a third-phase detection module 113. One end of each of the first-phase detection module 111, the second-phase detection module 112, and the third-phase detection module 113 is electrically connected to the first phase line, the second phase line, and the third phase line of the input terminal of the three-phase power supply 200, respectively. The other end of each of the first-phase detection module 111, the second-phase detection module 112, and the third-phase detection module 113 is electrically connected to the first detection terminal DR, the second detection terminal DS, and the third detection terminal DT of the controller 130, respectively.

[0055] The first phase detection module 111 is used to detect the voltage of the first phase of the three-phase power supply 200 and output the voltage detection signal of the first phase to the first detection terminal DR of the controller 130; the second phase detection module 112 is used to detect the voltage of the second phase of the three-phase power supply 200 and output the voltage detection signal of the second phase to the second detection terminal DS of the controller 130; the third phase detection module 113 is used to detect the voltage of the third phase of the three-phase power supply 200 and output the voltage detection signal of the third phase to the third detection terminal DT of the controller 130.

[0056] In this embodiment, for the first, second, and third phases of the three-phase power supply 200, a first-phase detection module 111, a second-phase detection module 112, and a third-phase detection module 113 are respectively set in the three-phase detection circuit 110, so that the voltages of the first, second, and third phases of the three-phase power supply 200 are detected by the first-phase detection module 111, the second-phase detection module 112, and the third-phase detection module 113 respectively.

[0057] In one implementation, please refer to Figure 4 The first phase detection module 111 includes a first optocoupler, a first resistor R1, a first diode D1, and a first pull-up resistor R12. The second phase detection module 112 includes a second optocoupler, a second resistor R2, a second diode D2, and a second pull-up resistor R13. The third phase detection module 113 includes a third optocoupler, a third resistor R3, a third diode D3, and a third pull-up resistor R14. In the three-phase power supply 200, R represents the first phase line at the input terminal, S represents the second phase line at the input terminal, T represents the third phase line at the input terminal, and N represents the neutral line.

[0058] In this configuration, the first diode D1 and the first resistor R1 are connected in series between the anode of the first optocoupler's light-emitting diode and the first phase line of the input terminal of the three-phase power supply 200. The cathode of the first optocoupler's light-emitting diode is electrically connected to the neutral line of the three-phase power supply 200 through the fourth resistor R4. The collector of the first optocoupler's phototransistor is electrically connected to the first detection terminal DR of the controller 130 and the first pull-up resistor R12. The emitter of the first optocoupler's phototransistor is grounded.

[0059] The second diode D2 and the second resistor R2 are connected in series between the anode of the light-emitting diode of the second optocoupler and the second phase line of the input terminal of the three-phase power supply 200. The cathode of the light-emitting diode of the second optocoupler is electrically connected to the neutral line of the three-phase power supply 200 through the fourth resistor R4. The collector of the phototransistor of the second optocoupler is electrically connected to the second detection terminal DS of the controller 130 and the second pull-up resistor R13. The emitter of the phototransistor of the second optocoupler is grounded.

[0060] The third diode D3 and the third resistor R3 are connected in series between the anode of the LED of the third optocoupler and the third phase line of the input terminal of the three-phase power supply 200. The cathode of the LED of the third optocoupler is electrically connected to the neutral line of the three-phase power supply 200 through the fourth resistor R4. The collector of the phototransistor of the third optocoupler is electrically connected to the third detection terminal DT of the controller 130 and the third pull-up resistor R14. The emitter of the phototransistor of the third optocoupler is grounded.

[0061] In this embodiment, the three-phase power supply 200 adopts a three-phase four-wire system. The voltage of each phase (the voltage between the R, S, T phases and the neutral line, 220VAC) is applied to the optocouplers (IC1, IC2, IC3) through diodes (D1, D2, D3) and high-power resistors (R1, R2, R3, R4). The optocouplers conduct during the positive half-cycle of the voltage signal and are cut off during the negative half-cycle. Since the output terminals of the optocouplers (IC1, IC2, IC3) have pull-up resistors (R12, R13, R14), when the optocouplers (IC1, IC2, IC3) are on, the controller 130 detects a low level, and when the optocouplers (IC1, IC2, IC3) are off, the controller 130 detects a high level. The phase difference between the R, S, and T phases is 120°, and the three detection terminals (DR, DS, DT) of the controller 130 detect the waveforms of the R, S, and T phases. If a square wave signal is not detected at a certain detection terminal of the controller 130, it indicates a phase loss; if the three-phase signals are detected not changing sequentially according to a 120° phase difference, it indicates an incorrect phase sequence.

[0062] Please continue to refer to Figure 4 The first phase detection module 111 also includes a fifth resistor R5 and a fourth diode D4, the second phase detection module 112 also includes a sixth resistor R6 and a fifth diode D5, and the third phase detection module 113 also includes a seventh resistor R7 and a sixth diode D6.

[0063] In this configuration, the cathode of the fourth diode D4 is electrically connected to the anode of the LED of the first optocoupler, and the anode of the fourth diode D4 is electrically connected to the neutral wire of the three-phase power supply 200 through the fourth resistor R4. The fifth resistor R5 is connected in parallel with the fourth diode D4. The cathode of the fifth diode D5 is electrically connected to the anode of the LED of the second optocoupler, and the anode of the fifth diode D5 is connected to the neutral wire of the three-phase power supply 200 through the fourth resistor R4. The sixth resistor R6 is connected in parallel with the fifth diode D5. The cathode of the sixth diode D6 is electrically connected to the anode of the LED of the third optocoupler, and the anode of the sixth diode D6 is connected to the neutral wire of the three-phase power supply 200 through the fourth resistor R4. The seventh resistor R7 is connected in parallel with the sixth diode D6.

[0064] In this embodiment, by setting the fifth resistor R5 and the fourth diode D4, the fourth diode D4 conducts when the input voltage is reversed, thus protecting the light-emitting diode of the first optocoupler. Similarly, by setting the sixth resistor R6 and the fifth diode D5, the fifth diode D5 conducts when the input voltage is reversed, thus protecting the light-emitting diode of the second optocoupler. By setting the seventh resistor R7 and the sixth diode D6, the sixth diode D6 conducts when the input voltage is reversed, thus protecting the light-emitting diode of the third optocoupler.

[0065] Please continue to refer to Figure 4The first phase detection module 111 also includes an eighth resistor R8 and a first capacitor C1, the second phase detection module 112 also includes a ninth resistor R9 and a second capacitor C2, and the third phase detection module 113 also includes a tenth resistor R10 and a third capacitor C3.

[0066] Specifically, the eighth resistor R8 is electrically connected between the collector of the phototransistor of the first optocoupler and the first detection terminal DR of the controller 130; one end of the first capacitor C1 is electrically connected between the eighth resistor R8 and the first detection terminal DR of the controller 130, and the other end of the first capacitor C1 is grounded. The ninth resistor R9 is electrically connected between the collector of the phototransistor of the second optocoupler and the second detection terminal DS of the controller 130; one end of the second capacitor C2 is electrically connected between the ninth resistor R9 and the second detection terminal DS of the controller 130, and the other end of the second capacitor C2 is grounded. The tenth resistor R10 is electrically connected between the collector of the phototransistor of the third optocoupler and the third detection terminal DT of the controller 130; one end of the third capacitor C3 is electrically connected between the tenth resistor R10 and the third detection terminal DT of the controller 130, and the other end of the third capacitor C3 is grounded.

[0067] In this embodiment, by setting an eighth resistor R8 and a first capacitor C1, a ninth resistor R9 and a second capacitor C2, and a tenth resistor R10 and a third capacitor C3 in the first phase detection module 111, the second phase detection module 112 and the third phase detection module 113 respectively, current limiting and filtering can be achieved, preventing excessive current from damaging the circuit, filtering high-frequency noise, and ensuring that the signal received by the controller 130 is stable and noise-free.

[0068] In one implementation, please refer to Figure 5 The misconnection detection circuit 120 includes a transformer 121, a rectifier module 122, and a voltage divider module 123. The input terminal of the transformer 121 is electrically connected to the input terminal of the three-phase power supply 200, and the output terminal of the transformer 121 is electrically connected to the rectifier module 122. The rectifier module 122 is also electrically connected to the voltage divider module 123, and the voltage divider module 123 is also electrically connected to the fourth detection terminal Vad of the controller 130.

[0069] The transformer 121 is used to step down the voltage of one phase of the input terminal of the three-phase power supply 200; the rectifier module 122 is used to rectify the AC voltage output by the transformer 121 into a DC voltage; the voltage divider module 123 is used to divide the DC voltage to obtain a voltage sampling signal and output the voltage sampling signal to the fourth detection terminal Vad of the controller 130.

[0070] As can be seen, the power supply protection circuit 100 provided by this utility model achieves high voltage and low voltage separation by setting a transformer 121 in the misconnection detection circuit 120, effectively identifies the circuit voltage, and improves the safety of the circuit.

[0071] In one implementation, please refer to Figure 6 The rectifier module 122 includes a seventh diode D7, an eighth diode D8, a ninth diode D9, and a tenth diode D10. The cathode of the seventh diode D7 is electrically connected to the first output terminal P1 of the transformer 121, and the cathode of the eighth diode D8 is electrically connected to the second output terminal P2 of the transformer 121. The anode of the seventh diode D7 is electrically connected to the anode of the eighth diode D8 and grounded. The anode of the ninth diode D9 is electrically connected to the first output terminal P1 of the transformer 121, and the anode of the tenth diode D10 is electrically connected to the second output terminal P2 of the transformer 121. The cathode of the ninth diode D9 is electrically connected to the cathode of the tenth diode D10, and both the cathodes of the ninth diode D9 and the tenth diode D10 are electrically connected to the voltage divider module 123. For example, when the input terminal of the transformer 121 is 220VAC, the output voltage of the transformer 121 is 14.5VAC. Through full-bridge rectification by the seventh diode D7, the eighth diode D8, the ninth diode D9, and the tenth diode D10, the AC voltage is rectified into a DC voltage.

[0072] Please continue to refer to Figure 6 The voltage divider module 123 includes a first voltage divider resistor R15 and a second voltage divider resistor R16. The first voltage divider resistor R15 and the second voltage divider resistor R16 are connected in series between the rectifier module 122 and ground. The fourth detection terminal Vad of the controller 130 is electrically connected between the first voltage divider resistor R15 and the second voltage divider resistor R16.

[0073] In this embodiment, the DC voltage output by the rectifier module 122 is divided by the first voltage divider resistor R15 and the second voltage divider resistor R16 to obtain a voltage sampling signal, which is then output to the fourth detection terminal Vad of the controller 130.

[0074] Please continue to refer to Figure 6 The misconnection detection circuit 120 also includes an eleventh resistor R11, a fourth capacitor C4, and a pull-up diode D11. One end of the eleventh resistor R11 is electrically connected between the first voltage divider resistor R15 and the second voltage divider resistor R16, and the other end of the eleventh resistor R11 is electrically connected to the fourth detection terminal Vad of the controller 130. One end of the fourth capacitor C4 is electrically connected to the other end of the eleventh resistor R11, and the other end of the fourth capacitor C4 is grounded. The anode of the pull-up diode D11 is electrically connected to the other end of the eleventh resistor R11, and the cathode of the pull-up diode D11 is electrically connected to the first power supply (+3.3V).

[0075] In this embodiment, the eleventh resistor R11 and the fourth capacitor C4 form a filter circuit. After filtering the voltage sampling signal obtained by the voltage divider module 123, the signal is output to the fourth detection terminal Vad of the controller 130. The pull-up diode D11 can release excessive voltage in the circuit, thus protecting the circuit.

[0076] Please continue to refer to Figure 6 The misconnection detection circuit 120 also includes a shorting cap, which includes a first end K1, a second end K2 and a third end K3. The first end K1 of the shorting cap is electrically connected between the first voltage divider resistor R15 and the second voltage divider resistor R16, and the second end K2 of the shorting cap is grounded. The shorting cap is used to control whether the misconnection detection circuit 120 enables the detection function.

[0077] In this embodiment, the activation or deactivation of the misconnection detection circuit 120 is achieved by controlling the connection status of the first end K1, the second end K2, and the third end K3 of the jumper cap. Specifically, when the third end K3 of the jumper cap is shorted to the second end K2, the misconnection detection circuit 120 functions normally; when the first end K1 of the jumper cap is shorted to the second end K2, the misconnection detection circuit 120 fails to function.

[0078] In one implementation, please refer to Figure 7 One end of the coil 143 of the relay 140 is electrically connected to the controller 130, and the other end of the coil 143 of the relay 140 is electrically connected to the second power supply (+12V power supply). The first plug 141 of the relay 140 is electrically connected to the load 300, and the second plug 142 of the relay 140 is electrically connected to the output terminal of the three-phase power supply 200.

[0079] For example, the controller 130 makes a judgment based on the voltage sampling signal obtained from the fourth detection terminal Vad. When the voltage input to the transformer 121 is between 176VAC and 264VAC, the obtained voltage sampling signal will be within the normal range. The controller 130 will output a low level through the NET_SV3 port, the coil 143 of the relay 140 will be energized, the first connector 141 and the second connector 142 will be connected, the load 300 will be energized, and the load 300 will work normally. When the voltage input to the transformer 121 is lower than 176VAC or higher than 264VAC, the obtained voltage sampling signal is not within the normal range, indicating that there may be a power line misconnection (such as phase voltage being connected as line voltage). The controller 130 will output a high level through the NET_SV3 port, the coil 143 of the relay 140 will not be energized, the first connector 141 and the second connector 142 will not be connected, and the load 300 will not be energized.

[0080] As can be seen, the power supply protection circuit 100 and air conditioner 10 provided in this embodiment of the present invention, through three-phase phase sequence and phase loss detection and transformer 121 isolation scheme, achieve high-voltage and low-voltage separation, effectively identify and detect circuit voltage, and simultaneously control whether the downstream load 300 is powered, avoiding abnormal power output that could lead to overvoltage burnout of downstream components and cause losses. This scheme effectively prevents incorrect voltage connection at the input terminal of the three-phase power supply 200, eliminates abnormal voltage that could cause the load 300 to burn out, thereby avoiding the impact of large energy on the electronic components of the load 300, improving system stability, and increasing the service life of the air conditioner.

[0081] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the present invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A power supply protection circuit, characterized in that, The system includes a three-phase detection circuit (110), a misconnection detection circuit (120), a controller (130), and a relay (140). The three-phase detection circuit (110), the misconnection detection circuit (120), and the relay (140) are all electrically connected to the controller (130). The three-phase detection circuit (110) and the misconnection detection circuit (120) are both electrically connected to the input terminal of the three-phase power supply (200). The relay (140) is electrically connected between the output terminal of the three-phase power supply (200) and the load (300). The three-phase detection circuit (110) is used to detect the voltage of each phase at the input terminal of the three-phase power supply (200) and output the voltage detection signal of each phase to the controller (130). The misconnection detection circuit (120) is used to sample the voltage of one phase of the input terminal of the three-phase power supply (200) and output the voltage sampling signal to the controller (130). The controller (130) is used to control the relay (140) to disconnect the connection between the three-phase power supply (200) and the load (300) when the voltage sampling signal indicates that the three-phase power supply (200) has a power line misconnection, or the voltage detection signal indicates that the three-phase power supply (200) has a phase loss or phase sequence error.

2. The power supply protection circuit according to claim 1, characterized in that, The three-phase detection circuit (110) includes a first-phase detection module (111), a second-phase detection module (112), and a third-phase detection module (113). One end of each of the first-phase detection module (111), the second-phase detection module (112), and the third-phase detection module (113) is electrically connected to the first phase line, the second phase line, and the third phase line of the input terminal of the three-phase power supply (200), respectively. The other end of each of the first-phase detection module (111), the second-phase detection module (112), and the third-phase detection module (113) is electrically connected to the first detection terminal (DR), the second detection terminal (DS), and the third detection terminal (DT) of the controller (130), respectively. The first-phase detection module (111) is used to detect the voltage of the first phase of the three-phase power supply (200) and output the voltage detection signal of the first phase to the first detection terminal (DR) of the controller (130). The second phase detection module (112) is used to detect the voltage of the second phase of the three-phase power supply (200) and output the voltage detection signal of the second phase to the second detection terminal (DS) of the controller (130); The third phase detection module (113) is used to detect the voltage of the third phase of the three-phase power supply (200) and output the voltage detection signal of the third phase to the third detection terminal (DT) of the controller (130).

3. The power supply protection circuit according to claim 2, characterized in that, The first phase detection module (111) includes a first optocoupler, a first resistor (R1), a first diode (D1), and a first pull-up resistor (R12); the second phase detection module (112) includes a second optocoupler, a second resistor (R2), a second diode (D2), and a second pull-up resistor (R13); and the third phase detection module (113) includes a third optocoupler, a third resistor (R3), a third diode (D3), and a third pull-up resistor (R14). The first diode (D1) and the first resistor (R1) are connected in series between the anode of the first optocoupler's light-emitting diode and the first phase line of the input terminal of the three-phase power supply (200). The cathode of the first optocoupler's light-emitting diode is electrically connected to the neutral line of the three-phase power supply (200) through the fourth resistor (R4). The collector of the first optocoupler's phototransistor is electrically connected to the first detection terminal (DR) of the controller (130) and the first pull-up resistor (R12). The emitter of the first optocoupler's phototransistor is grounded. The second diode (D2) and the second resistor (R2) are connected in series between the anode of the light-emitting diode of the second optocoupler and the second phase line of the input terminal of the three-phase power supply (200). The cathode of the light-emitting diode of the second optocoupler is electrically connected to the neutral line of the three-phase power supply (200) through the fourth resistor (R4). The collector of the phototransistor of the second optocoupler is electrically connected to the second detection terminal (DS) of the controller (130) and the second pull-up resistor (R13). The emitter of the phototransistor of the second optocoupler is grounded. The third diode (D3) and the third resistor (R3) are connected in series between the anode of the light-emitting diode of the third optocoupler and the third phase line of the input terminal of the three-phase power supply (200). The cathode of the light-emitting diode of the third optocoupler is electrically connected to the neutral line of the three-phase power supply (200) through the fourth resistor (R4). The collector of the phototransistor of the third optocoupler is electrically connected to the third detection terminal (DT) of the controller (130) and the third pull-up resistor (R14). The emitter of the phototransistor of the third optocoupler is grounded.

4. The power supply protection circuit according to claim 3, characterized in that, The first phase detection module (111) further includes a fifth resistor (R5) and a fourth diode (D4), the second phase detection module (112) further includes a sixth resistor (R6) and a fifth diode (D5), and the third phase detection module (113) further includes a seventh resistor (R7) and a sixth diode (D6). The cathode of the fourth diode (D4) is electrically connected to the anode of the light-emitting diode of the first optocoupler, and the anode of the fourth diode (D4) is electrically connected to the neutral wire of the three-phase power supply (200) through the fourth resistor (R4). The fifth resistor (R5) is connected in parallel with the fourth diode (D4). The cathode of the fifth diode (D5) is electrically connected to the anode of the light-emitting diode of the second optocoupler, and the anode of the fifth diode (D5) is electrically connected to the neutral wire of the three-phase power supply (200) through the fourth resistor (R4). The sixth resistor (R6) is connected in parallel with the fifth diode (D5). The cathode of the sixth diode (D6) is electrically connected to the anode of the light-emitting diode of the third optocoupler. The anode of the sixth diode (D6) is electrically connected to the neutral wire of the three-phase power supply (200) through the fourth resistor (R4). The seventh resistor (R7) is connected in parallel with the sixth diode (D6).

5. The power supply protection circuit according to claim 3, characterized in that, The first phase detection module (111) further includes an eighth resistor (R8) and a first capacitor (C1), the second phase detection module (112) further includes a ninth resistor (R9) and a second capacitor (C2), and the third phase detection module (113) further includes a tenth resistor (R10) and a third capacitor (C3). The eighth resistor (R8) is electrically connected between the collector of the phototransistor of the first optocoupler and the first detection terminal (DR) of the controller (130). One end of the first capacitor (C1) is electrically connected between the eighth resistor (R8) and the first detection terminal (DR) of the controller (130), and the other end of the first capacitor (C1) is grounded. The ninth resistor (R9) is electrically connected between the collector of the phototransistor of the second optocoupler and the second detection terminal (DS) of the controller (130). One end of the second capacitor (C2) is electrically connected between the ninth resistor (R9) and the second detection terminal (DS) of the controller (130), and the other end of the second capacitor (C2) is grounded. The tenth resistor (R10) is electrically connected between the collector of the phototransistor of the third optocoupler and the third detection terminal (DT) of the controller (130). One end of the third capacitor (C3) is electrically connected between the tenth resistor (R10) and the third detection terminal (DT) of the controller (130), and the other end of the third capacitor (C3) is grounded.

6. The power supply protection circuit according to claim 1, characterized in that, The misconnection detection circuit (120) includes a transformer (121), a rectifier module (122), and a voltage divider module (123). The input terminal of the transformer (121) is electrically connected to the input terminal of the three-phase power supply (200), the output terminal of the transformer (121) is electrically connected to the rectifier module (122), the rectifier module (122) is also electrically connected to the voltage divider module (123), and the voltage divider module (123) is also electrically connected to the fourth detection terminal (Vad) of the controller (130). The transformer (121) is used to step down the voltage of one phase of the input terminal of the three-phase power supply (200); The rectifier module (122) is used to rectify the AC voltage output by the transformer (121) into DC voltage; The voltage divider module (123) is used to divide the DC voltage to obtain the voltage sampling signal and output the voltage sampling signal to the fourth detection terminal (Vad) of the controller (130).

7. The power supply protection circuit according to claim 6, characterized in that, The voltage divider module (123) includes a first voltage divider resistor (R15) and a second voltage divider resistor (R16). The first voltage divider resistor (R15) and the second voltage divider resistor (R16) are connected in series between the rectifier module (122) and ground. The fourth detection terminal (Vad) of the controller (130) is electrically connected between the first voltage divider resistor (R15) and the second voltage divider resistor (R16).

8. The power supply protection circuit according to claim 7, characterized in that, The misconnection detection circuit (120) further includes an eleventh resistor (R11), a fourth capacitor (C4), and a pull-up diode (D11). One end of the eleventh resistor (R11) is electrically connected between the first voltage divider resistor (R15) and the second voltage divider resistor (R16), and the other end of the eleventh resistor (R11) is electrically connected to the fourth detection terminal (Vad) of the controller (130). One end of the fourth capacitor (C4) is electrically connected to the other end of the eleventh resistor (R11), and the other end of the fourth capacitor (C4) is grounded. The anode of the pull-up diode (D11) is electrically connected to the other end of the eleventh resistor (R11), and the cathode of the pull-up diode (D11) is electrically connected to the first power supply.

9. The power supply protection circuit according to claim 7, characterized in that, The misconnection detection circuit (120) further includes a jumper cap, which includes a first end (K1), a second end (K2), and a third end (K3). The first end (K1) of the jumper cap is electrically connected between the first voltage divider resistor (R15) and the second voltage divider resistor (R16), and the second end (K2) of the jumper cap is grounded. The jumper cap is used to control whether the misconnection detection circuit (120) enables the detection function.

10. An air conditioner, characterized in that, It includes a three-phase power supply (200), a load (300), and a power supply protection circuit as described in any one of claims 1-9.

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