Electric appliance and its protection circuit

Abstract

This application discloses an electrical device and its protection circuit. The protection circuit of the electrical device includes: an inverter circuit connected to the electrical load for converting direct current (DC) to alternating current (AC) to power the load; a rectifier bridge circuit connected to the inverter circuit for rectifying the AC to DC; and an anti-interference circuit connected to both the rectifier bridge circuit and the three-phase AC power supply for eliminating interference generated during the operation of the electrical load. By eliminating interference, the impact of interference on the operation of the electrical load can be avoided, thus solving the technical problem of poor operational stability in related technologies.

Description

Technical Field

[0001] This application relates to the field of electrical control technology, and more specifically, to an electrical device and its protection circuit. Background Technology

[0002] Inverter air conditioners can cause interference during use. Some manufacturers have two main ways of dealing with this: one is to use an active full-bridge solution, and the other is a passive solution. Regardless of which method is used, it is unavoidable that the operation will be unstable or even burn out due to power grid quality fluctuations and large interference.

[0003] There is currently no effective solution to the technical problem of poor operational stability of the electrical appliances mentioned above. Summary of the Invention

[0004] This application provides an electrical device and its protection circuit to solve the technical problem of poor operational stability of electrical devices in related technologies.

[0005] To address the aforementioned technical problems, according to one aspect of this application, a protection circuit for an electrical device is provided, comprising: an inverter circuit connected to an electrical load for converting direct current (DC) into alternating current (AC) to power the electrical load; a rectifier bridge circuit connected to the inverter circuit for rectifying AC into DC; and an anti-interference circuit connected to both the rectifier bridge circuit and the three-phase AC power supply for eliminating interference generated during the power consumption of the electrical load.

[0006] Optionally, the anti-interference circuit includes: a first inductor, a second inductor, and a third inductor, one end of the first inductor being connected to the first phase of the three-phase AC power supply, one end of the second inductor being connected to the second phase of the three-phase AC power supply, and one end of the third inductor being connected to the third phase of the three-phase AC power supply; a first control sub-circuit, a second control sub-circuit, and a third control sub-circuit, one end of the first control sub-circuit, one end of the third control sub-circuit, and the other end of the first inductor being connected to a first node; the other ends of the first control sub-circuit, one end of the second control sub-circuit, and the other end of the second inductor being connected to a second node; and the other ends of the second control sub-circuit, the third control sub-circuit, and the third inductor being connected to a third node.

[0007] Optionally, the first control sub-circuit includes a first relay, a first capacitor, a second capacitor, and a first resistor. One end of the first relay is connected to the first node, one end of the first capacitor and one end of the second capacitor are connected to the other end of the first relay, one end of the first resistor is connected to the other end of the second capacitor, and the other end of the first resistor and the other end of the first capacitor are connected to the second node. The second control sub-circuit includes a second relay, a third capacitor, a fourth capacitor, and a second resistor. One end of the second relay is connected to the second node, one end of the third capacitor and one end of the fourth capacitor are connected to the other end of the second relay, one end of the second resistor is connected to the other end of the fourth capacitor, and the other end of the second resistor and the other end of the third capacitor are connected to the third node. The third control sub-circuit includes a third relay, a fifth capacitor, a sixth capacitor, and a third resistor. One end of the third relay is connected to the first node, one end of the fifth capacitor and one end of the sixth capacitor are connected to the other end of the third relay, one end of the third resistor is connected to the other end of the sixth capacitor, and the other end of the third resistor and the other end of the fifth capacitor are connected to the third node.

[0008] Optionally, the protection circuit further includes: a voltage sampling circuit, which includes: a fourth resistor and a fifth resistor, one end of the fourth resistor and one end of the fifth resistor being connected to a fourth node, the other end of the fourth resistor being connected to the inverter circuit at the fifth node, and the other end of the fifth resistor being connected to the inverter circuit at a sixth node; and a control chip, which is connected to the first relay, the second relay, the third relay, and the fourth node respectively, for determining the operating state of the electrical load based on the voltage of the fourth node, so as to control the on / off state of the first relay, the second relay, and the third relay.

[0009] Optionally, the rectifier bridge circuit includes: a first diode, a second diode, a third diode, a fourth diode, a fifth diode, and a sixth diode; the cathodes of the first diode, the second diode, and the third diode are connected to the fifth node; the anodes of the fourth diode, the fifth diode, and the sixth diode are connected to the sixth node; the anodes of the first diode and the fourth diode are connected to the first node; the anodes of the second diode and the fifth diode are connected to the second node; and the anodes of the third diode and the sixth diode are connected to the third node; and a seventh capacitor is connected between the fifth node and the sixth node.

[0010] Optionally, when the electrical load is in standby mode, the control chip is used to output a low level to the first relay, the second relay, and the third relay to disconnect the first relay, the second relay, and the third relay.

[0011] Optionally, when the operating frequency of the electrical load is lower than a preset frequency or the operating load is lower than a first preset load, the control chip is used to output a high level to the first relay, the second relay and the third relay to close the first relay, the second relay and the third relay.

[0012] Optionally, when the operating load of the electrical load is higher than the second preset load, the control chip is used to output a high level to the first relay, the second relay and the third relay to close the first relay, the second relay and the third relay, wherein the second preset load is not less than the first preset load.

[0013] Optionally, when the operating load of the electrical load changes from higher than the second preset load to lower than the first preset load, or when it is in the process of being shut down, the control chip is used to output a low level to the first relay, the second relay and the third relay to disconnect the first relay, the second relay and the third relay.

[0014] According to another aspect of the embodiments of this application, an electrical device is also provided, including the protection circuit of the electrical device described above.

[0015] The protection circuit of the electrical equipment using the technical solution of this application includes: an inverter circuit connected to the electrical load for converting DC power into AC power to supply power to the electrical load; a rectifier bridge circuit connected to the inverter circuit for rectifying AC power into DC power; and an anti-interference circuit connected to both the rectifier bridge circuit and the three-phase AC power supply for eliminating interference generated during the use of the electrical load. By eliminating interference, the impact of interference on the operation of the electrical load can be avoided, thus solving the technical problem of poor operational stability of electrical appliances in related technologies. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of a protection circuit for an electrical device according to an embodiment of this application. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0018] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to limit the application. The singular forms “a,” “said,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms, and “multiple” generally includes at least two unless the context clearly indicates otherwise.

[0019] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0020] It should be understood that although the terms first, second, third, etc., may be used to describe certain technical features in the embodiments of this application, these technical features should not be limited to these terms. These terms are only used to distinguish these technical features.

[0021] Depending on the context, the words “if” or “suppose” as used here can be interpreted as “when” or “in response to determination” or “in response to detection.” Similarly, depending on the context, the phrases “if determination” or “if detection (of the stated condition or event)” can be interpreted as “when determination” or “in response to determination” or “when detection (of the stated condition or event)” or “in response to detection (of the stated condition or event).”

[0022] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or device. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or device that includes said element.

[0023] Example 1

[0024] This solution, through circuit improvements, effectively addresses the voltage boosting issue and enables reasonable switching under different loads, ensuring the efficient operation of electrical equipment such as air conditioners. According to one aspect of this application, an embodiment of a protection circuit for electrical equipment is provided, such as... Figure 1 As shown, the protection circuit includes: an inverter circuit 11, a rectifier bridge circuit 12, and an anti-interference circuit 13.

[0025] Inverter circuit 11 is connected to the electrical load and is used to invert DC power into AC power to supply power to the electrical load, which may be a compressor, etc.

[0026] The rectifier bridge circuit 12 is connected to the inverter circuit and is used to rectify AC power into DC power.

[0027] The aforementioned rectifier bridge circuit may include: a first diode D1, a second diode D2, a third diode D3, a fourth diode D4, a fifth diode D5, and a sixth diode D6. The cathodes of the first, second, and third diodes are connected to the fifth node J5. The anodes of the fourth, fifth, and sixth diodes are connected to the sixth node J6. The anodes of the first and fourth diodes are connected to the first node J1. The anodes of the second and fifth diodes are connected to the second node J2. The anodes of the third and sixth diodes are connected to the third node J3. A seventh capacitor C7 is connected between the fifth and sixth nodes.

[0028] The anti-interference circuit 13 is connected to the rectifier bridge circuit and the three-phase AC power supply respectively, and is used to eliminate interference generated during the power consumption of the electrical load.

[0029] In the above embodiments, the anti-interference circuit may include: a first inductor L1, a second inductor L2 and a third inductor L3, a first control sub-circuit, a second control sub-circuit and a third control sub-circuit.

[0030] For the aforementioned inductors, one end of the first inductor is connected to the first phase of the three-phase AC power supply, one end of the second inductor is connected to the second phase of the three-phase AC power supply, and one end of the third inductor is connected to the third phase of the three-phase AC power supply.

[0031] For the above control sub-circuit, one end of the first control sub-circuit, one end of the third control sub-circuit, and the other end of the first inductor are connected to the first node; the other end of the first control sub-circuit, one end of the second control sub-circuit, and the other end of the second inductor are connected to the second node; and the other end of the second control sub-circuit, the other end of the third control sub-circuit, and the other end of the third inductor are connected to the third node.

[0032] Optionally, the first control sub-circuit includes a first relay K1, a first capacitor C1, a second capacitor C2, and a first resistor R1. One end of the first relay is connected to the first node, one end of the first capacitor and one end of the second capacitor are connected to the other end of the first relay, one end of the first resistor is connected to the other end of the second capacitor, and the other ends of the first resistor and the other ends of the first capacitor are connected to the second node.

[0033] Similarly, the second control sub-circuit includes a second relay K2, a third capacitor C3, a fourth capacitor C4, and a second resistor R2. One end of the second relay is connected to the second node, one end of the third capacitor and one end of the fourth capacitor are connected to the other end of the second relay, one end of the second resistor is connected to the other end of the fourth capacitor, and the other end of the second resistor and the other end of the third capacitor are connected to the third node.

[0034] Similarly, the third control sub-circuit includes a third relay K3, a fifth capacitor C5, a sixth capacitor C6, and a third resistor R3. One end of the third relay is connected to the first node, one end of the fifth capacitor and one end of the sixth capacitor are connected to the other end of the third relay, one end of the third resistor is connected to the other end of the sixth capacitor, and the other end of the third resistor and the other end of the fifth capacitor are connected to the third node.

[0035] In embodiments of this application, the protection circuit may further include: a voltage sampling circuit, which includes: a fourth resistor R4 and a fifth resistor R5, one end of the fourth resistor and one end of the fifth resistor being connected to a fourth node J4, the other end of the fourth resistor being connected to the inverter circuit at the fifth node, and the other end of the fifth resistor being connected to the inverter circuit at the sixth node; and a control chip DSP, which is connected to the first relay, the second relay, the third relay, and the fourth node respectively, for determining the operating state of the electrical load based on the voltage of the fourth node, so as to control the on / off state of the first relay, the second relay, and the third relay.

[0036] In the above embodiments, the protection circuit includes, but is not limited to, the following operating states:

[0037] 1) When the electrical load is in standby mode, the control chip outputs a low level to the first relay, the second relay and the third relay to disconnect the first relay, the second relay and the third relay;

[0038] 2) When the operating frequency of the electrical load is lower than the preset frequency (i.e., low frequency operation) or the operating load is lower than the first preset load (i.e., low load operation), the control chip is used to output a high level to the first relay, the second relay and the third relay to close the first relay, the second relay and the third relay.

[0039] 3) When the operating load of the electrical load is higher than the second preset load (i.e., heavy load operation), the control chip is used to output a high level to the first relay, the second relay and the third relay to close the first relay, the second relay and the third relay, wherein the second preset load is not less than the first preset load;

[0040] 4) When the operating load of the electrical load changes from higher than the second preset load to lower than the first preset load (i.e., from heavy load to light load), or when it is in the process of shutting down, the control chip outputs a low level to the first relay, the second relay and the third relay to disconnect the first relay, the second relay and the third relay.

[0041] In the technical solution of this application, the protection circuit of the electrical equipment includes: an inverter circuit, connected to the electrical load, for converting DC power into AC power to supply power to the electrical load; a rectifier bridge circuit, connected to the inverter circuit, for rectifying AC power into DC power; and an anti-interference circuit, connected to the rectifier bridge circuit and the three-phase AC power supply respectively, for eliminating interference generated during the power consumption of the electrical load. By eliminating interference, the impact of interference on the operation of the electrical load can be avoided, and the technical problem of poor operational stability of electrical appliances in related technologies can be solved.

[0042] Example 2

[0043] As an optional embodiment, the following is combined with Figure 1 Further details of the technical solution of this application:

[0044] like Figure 1 As shown, L1-L3 are inductors, C1-C3 are X capacitors, C4-C6 are ordinary absorption capacitors, K1-K3 are relays, R1-R3 are absorption resistors, and R4-R5 are voltage sensing resistors.

[0045] The core circuit consists of L1-L3, C1-C6, K1-K3, R1-R5, and the DSP. R4-R5 is the DC bus sampling circuit after rectification, which sends the sampled value to the DSP. The DSP sends on / off signals to K1-K3 via designated I / O ports by setting appropriate thresholds. The control method varies depending on the operating stage:

[0046] 1) In standby mode, K1-K3 are disconnected, and L1-L3 are connected in series to the power input. Because they cannot resonate with C1-C3, the voltage across C7 is the rectified AC voltage, i.e., AC voltage * 1.414. The air conditioner's interference with the power grid is minimal. At this time, the pins connected to K1-K3 on the DSP output a low level, and relays K1-K3 are disconnected under chip control. L1-L3 cannot form an LC closed loop with C1-C3 connected in series, so the voltage across C7 has no superposition value.

[0047] 2) When the compressor operates at low frequency or low load, L1-L3 are connected in series in the three-phase input lines. Due to the characteristics of inductors, a voltage drop occurs when the AC power current flows through the inductor. If the voltage is lower than the set threshold, the DSP sends a high-level control signal to K1-K3 through the I / O port, causing all relays to engage. L1-L3 resonates with C1-C3, and the bus voltage is correspondingly increased to meet load changes. Because the capacitors connected in series with the relays act as a short circuit at the moment the relays close, the current is very large, and the voltage across C1-C3 is also very high, causing the relays to arc and stick, damaging the circuit system. Therefore, designing effective mitigation measures is crucial. By designing an absorption circuit across each capacitor of C1-C3, the current and voltage spikes during the relay opening and closing process can be effectively bypassed and absorbed, ensuring the effective operation of the circuit system.

[0048] 3) When the compressor is running under heavy load, K1-K3 are normally closed, and L1-L3 and C1-C3 continuously resonate, effectively increasing the voltage and reducing the interference of the air conditioning system to the external power grid.

[0049] 4) The relay disconnects during the transition from heavy load to light load or even during shutdown. This circuit effectively prevents external power interference from causing abnormally high C7 readings and damaging some components.

[0050] In related technologies, interference can cause the downstream bus voltage to rise, thus threatening the reliability of components; when switching into the boost system, there are issues such as voltage and current spikes. The technical solution of this application provides a boost circuit for electrical equipment such as air conditioners. By real-time monitoring of the bus voltage, it automatically switches between entering and exiting the voltage boost circuit. This solution allows for automatic detection and switching, is fast, and requires no special control, improving component tolerance and reducing maintenance costs; it also effectively reduces peak current and voltage, ensuring component reliability.

[0051] Example 3

[0052] According to another aspect of the embodiments of this application, an electrical device is also provided, including the protection circuit of the above-described electrical device, and its specific implementation is described in the foregoing embodiments.

[0053] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0054] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A protection circuit for an electrical device, characterized in that, The protection circuit includes: An inverter circuit, connected to an electrical load, is used to convert direct current into alternating current to supply power to the electrical load. A rectifier bridge circuit, connected to the inverter circuit, is used to rectify AC power into DC power. An anti-interference circuit is connected to the rectifier bridge circuit and the three-phase AC power supply respectively, and is used to eliminate interference generated during the power consumption of the electrical load; When the operating frequency of the electrical load is lower than the preset frequency or the operating load is lower than the first preset load, the control chip is used to output a high level to the first relay, the second relay and the third relay to close the first relay, the second relay and the third relay; When the operating load of the electrical load is higher than the second preset load, the control chip is used to output a high level to the first relay, the second relay and the third relay to close the first relay, the second relay and the third relay; When the operating load of the electrical load changes from higher than the second preset load to lower than the first preset load, or when it is in the process of being shut down, the control chip is used to output a low level to the first relay, the second relay and the third relay to disconnect the first relay, the second relay and the third relay, wherein the second preset load is not less than the first preset load; The first relay, the second relay, and the third relay are respectively used to control the on / off state of the first control sub-circuit, the second control sub-circuit, and the third control sub-circuit in the anti-interference circuit.

2. The protection circuit according to claim 1, characterized in that, The anti-interference circuit includes: The three inductors are a first inductor, a second inductor, and a third inductor. One end of the first inductor is connected to the first phase of the three-phase AC power supply, one end of the second inductor is connected to the second phase of the three-phase AC power supply, and one end of the third inductor is connected to the third phase of the three-phase AC power supply. The system comprises a first control subcircuit, a second control subcircuit, and a third control subcircuit. One end of the first control subcircuit, one end of the third control subcircuit, and the other end of the first inductor are connected to a first node. The other end of the first control subcircuit, one end of the second control subcircuit, and the other end of the second inductor are connected to a second node. The other end of the second control subcircuit, the other end of the third control subcircuit, and the other end of the third inductor are connected to a third node.

3. The protection circuit according to claim 2, characterized in that, The first control sub-circuit includes a first relay, a first capacitor, a second capacitor, and a first resistor. One end of the first relay is connected to the first node, one end of the first capacitor and one end of the second capacitor are connected to the other end of the first relay, one end of the first resistor is connected to the other end of the second capacitor, and the other end of the first resistor and the other end of the first capacitor are connected to the second node. The second control sub-circuit includes a second relay, a third capacitor, a fourth capacitor, and a second resistor. One end of the second relay is connected to the second node. One end of the third capacitor and one end of the fourth capacitor are connected to the other end of the second relay. One end of the second resistor is connected to the other end of the fourth capacitor. The other end of the second resistor and the other end of the third capacitor are connected to the third node. The third control sub-circuit includes a third relay, a fifth capacitor, a sixth capacitor, and a third resistor. One end of the third relay is connected to the first node, one end of the fifth capacitor and one end of the sixth capacitor are connected to the other end of the third relay, one end of the third resistor is connected to the other end of the sixth capacitor, and the other end of the third resistor and the other end of the fifth capacitor are connected to the third node.

4. The protection circuit according to claim 3, characterized in that, The protection circuit also includes: A voltage sampling circuit, comprising: a fourth resistor and a fifth resistor, one end of the fourth resistor and one end of the fifth resistor being connected to a fourth node, the other end of the fourth resistor being connected to the inverter circuit to the fifth node, and the other end of the fifth resistor being connected to the inverter circuit to a sixth node; The control chip is connected to the first relay, the second relay, the third relay and the fourth node respectively, and is used to determine the operating state of the electrical load according to the voltage of the fourth node, so as to control the on and off of the first relay, the second relay and the third relay.

5. The protection circuit according to claim 4, characterized in that, The rectifier bridge circuit includes: A first diode, a second diode, a third diode, a fourth diode, a fifth diode, and a sixth diode are connected. The cathodes of the first diode, the second diode, and the third diode are connected to the fifth node. The anodes of the fourth diode, the fifth diode, and the sixth diode are connected to the sixth node. The anodes of the first diode and the fourth diode are connected to the first node. The anodes of the second diode and the fifth diode are connected to the second node. The anodes of the third diode and the sixth diode are connected to the third node. The seventh capacitor is connected between the fifth node and the sixth node.

6. The protection circuit according to claim 4, characterized in that, When the electrical load is in standby mode, the control chip outputs a low level to the first relay, the second relay, and the third relay to disconnect the first relay, the second relay, and the third relay.

7. An electrical appliance, characterized in that, The protection circuit of the electrical equipment as described in any one of claims 1 to 6.

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