Voltage drive circuits, systems and home appliances

Abstract

The present application relates to a voltage drive circuit, system and household appliance. When the working current of the load connected to the inverter circuit exceeds the preset current, the resonant circuit can enter a non-resonant operating state, and the control device will also input a pulse width modulation signal to the switch device. At this time, the inductance in the resonant circuit will store energy. Under the action of the input pulse width modulation signal, the switch device is switched on and off in an orderly manner, thereby transmitting the excess energy stored in the resonant circuit to both ends of the film capacitor. However, since the film capacitor does not have an energy storage function, the voltage at both ends of the film capacitor increases under the action of the energy transmitted to both ends of the film capacitor. When the working current of the load exceeds the preset current, the voltage of the resonant circuit increases, and the voltage at both ends of the film capacitor can be increased by the orderly switching of the switch device, thereby increasing the available voltage of the inverter, ensuring the stable operation of the inverter, and avoiding the situation where the bus voltage is too low and affects the normal operation of the load.

Description

Technical Field

[0001] The present application relates to the field of voltage driving technology, and in particular to a voltage driving circuit, system and household appliance. Background Art

[0002] With the rapid development of science and technology, more and more types of electrical appliances are used in people's daily life, which has brought great convenience to daily life. Among them, the voltage driving circuit of low-power electrical equipment (that is, electrical equipment with power current below 16A, including air conditioners, refrigerators, washing machines, etc.) generally adopts a resonant scheme for variable frequency driving during operation, so as to ensure the reliable operation of low-power electrical equipment.

[0003] However, during the operation of the voltage drive circuit, when the power current exceeds a certain level (eg, 16A), as the voltage division of the internal reactor increases, the available voltage of the inverter of the voltage drive circuit will decrease, making the operation of the inverter unstable. Summary of the invention

[0004] Based on this, it is necessary to provide a voltage driving circuit, system and household appliance to address the problem that the traditional voltage driving circuit is prone to unstable inverter operation.

[0005] A voltage drive circuit comprises: a diode; a thin film capacitor; a resonant circuit for connecting to a three-phase power supply, wherein when a load operating current is greater than a preset current, the resonant circuit enters a non-resonant operating state; a rectifier circuit, wherein an input end of the rectifier circuit is connected to the resonant circuit; a switch device, wherein a first end of the switch device is connected to a first output end of the rectifier circuit and an anode of the diode, a second end of the switch device is connected to a second output end of the rectifier circuit and a first end of the thin film capacitor, and a cathode of the diode is connected to a second end of the thin film capacitor; an inverter circuit, wherein a first end of the thin film capacitor and a second end of the thin film capacitor are respectively connected to the inverter circuit, and the inverter circuit is also used to connect to a load; a control device, wherein a control end of the switch device, the resonant circuit and the inverter circuit are respectively connected to the control device, and the control device is used to transmit a pulse width modulation signal to the switch device when the load operating current is greater than the preset current.

[0006] In one embodiment, the resonant circuit includes a first inductor, a second inductor, a third inductor, a first capacitor, a second capacitor, a third capacitor, a first switch, a second switch and a third switch; the first end of the first inductor is connected to the first phase line of a three-phase power supply, the first end of the second inductor is connected to the second phase line of the three-phase power supply, the first end of the third inductor is connected to the third phase line of the three-phase power supply, the second end of the first inductor is connected to the first end of the third switch, the second end of the third switch is connected to the first end of the third capacitor, the second end of the third capacitor is connected to the first end of the first capacitor and the first input end of the rectifier circuit, the first end of the first capacitor is connected to the second end of the second inductor, the second end of the first capacitor is connected to the first end of the first switch, the second end of the first switch is connected to the second end of the third inductor and the first end of the second switch, the first end of the second switch is connected to the second input end of the rectifier circuit, the second end of the second switch is connected to the first end of the second capacitor, the second end of the second capacitor is connected to the first end of the third switch and the third input end of the rectifier circuit, and the control ends of the first switch, the second switch and the third switch are respectively connected to the control device.

[0007] In one embodiment, the first switch, the second switch and the third switch are any one of a relay switch, a transistor, a field effect transistor or an insulated gate bipolar transistor.

[0008] In one embodiment, the rectifier circuit is an uncontrollable rectifier circuit.

[0009] In one embodiment, the rectifier circuit includes a first diode, a second diode, a third diode, a fourth diode, a fifth diode and a sixth diode; the anode of the first diode is connected to the resonant circuit and the cathode of the fourth diode, the cathode of the third diode is connected to the cathode of the first diode and the cathode of the fifth diode, the cathode of the fifth diode is connected to the first end of the switching device and the anode of the diode, the anode of the third diode is connected to the resonant circuit and the cathode of the sixth diode, the anode of the sixth diode is connected to the anode of the fourth diode and the anode of the second diode, the anode of the second diode is connected to the second end of the switching device, and the anode of the fifth diode is connected to the resonant circuit and the cathode of the second diode.

[0010] In one embodiment, the switching device includes a fourth switch and a first switching device, the first end of the fourth switch is connected to the first output end of the rectifier circuit and the anode of the diode, the second end of the fourth switch is connected to the first end of the first switching device, the second end of the first switching device is connected to the second output end of the rectifier circuit and the first end of the thin film capacitor, the control end of the fourth switch and the control end of the first switching device are respectively connected to the control device, and the control end of the first switching device is used to input a pulse width modulation signal.

[0011] In one embodiment, the inverter circuit includes a second switching device, a third switching device, a fourth switching device, a fifth switching device, a sixth switching device, a seventh switching device, a seventh diode, an eighth diode, a ninth diode, a tenth diode, an eleventh diode and a twelfth diode; the control ends of the second switching device, the third switching device, the fourth switching device, the fifth switching device, the sixth switching device and the seventh switching device are respectively connected to the control device, the first end of the second switching device is connected to the cathode of the seventh diode and the second end of the thin film capacitor, the second end of the second switching device is connected to the anode of the seventh diode and the first end of the third switching device, the first end of the third switching device is connected to the cathode of the eighth diode and the load, the second end of the third switching device is connected to the anode of the eighth diode and the thin film capacitor. a first end of the capacitor, a first end of the fourth switching device connected to the cathode of the ninth diode and the first end of the second switching device, a second end of the fourth switching device connected to the anode of the ninth diode and the first end of the fifth switching device, a first end of the fifth switching device connected to the cathode of the tenth diode and a load, a second end of the fifth switching device connected to the anode of the tenth diode and the second end of the third switching device, a first end of the sixth switching device connected to the cathode of the eleventh diode and the first end of the fourth switching device, a second end of the sixth switching device connected to the anode of the eleventh diode and the first end of the seventh switching device, a first end of the seventh switching device connected to the cathode of the twelfth diode and the load, and a second end of the seventh switching device connected to the anode of the twelfth diode and the second end of the fifth switching device.

[0012] In one embodiment, the first switching device is a metal-oxide semiconductor field effect transistor, and the second switching device, the third switching device, the fourth switching device, the fifth switching device, the sixth switching device and the seventh switching device are transistors.

[0013] A voltage driving system comprises a three-phase resistive-inductive load and the above-mentioned voltage driving circuit.

[0014] A household appliance comprises the above-mentioned voltage driving system.

[0015] The voltage drive circuit, system and household appliance are provided with a film capacitor, a switch device and a diode between the rectifier circuit and the inverter circuit. When the working current of the load connected to the inverter circuit exceeds the preset current, the resonant circuit can enter the non-resonant operation state, and the control device will also input a pulse width modulation signal to the switch device. In this state, there is no capacitor connected to the resonant circuit. At this time, the inductance in the resonant circuit will store energy. Under the action of the input pulse width modulation signal, the switch device is turned on and off in an orderly manner, so as to transfer the excess energy stored in the resonant circuit to both ends of the film capacitor. However, since the film capacitor does not have an energy storage function, the voltage at both ends of the film capacitor increases under the action of the energy delivered to both ends of the film capacitor. Through this scheme, when the working current of the load exceeds the preset current and the voltage division of the resonant circuit increases, the voltage at both ends of the film capacitor can be increased by the orderly switching of the switch device, thereby increasing the available voltage of the inverter, ensuring the stable operation of the inverter, and avoiding the situation where the bus voltage is too low and affects the normal operation of the load. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the conventional technology, the drawings required for use in the embodiments or the conventional technology descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0017] Figure 1 This is a schematic diagram of the structure of a voltage driving circuit in an embodiment;

[0018] Figure 2 A schematic diagram of the structure of a voltage driving circuit in another embodiment;

[0019] Figure 3 Schematic diagram of the three-phase voltage and current waveforms output by the resonant circuit in one embodiment. DETAILED DESCRIPTION

[0020] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present application are provided in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present application more thorough and comprehensive.

[0021] See also Figure 1, a voltage drive circuit, comprising: a diode; a film capacitor C0; a resonant circuit 10, used to connect to a three-phase power supply, when the load working current is greater than a preset current, the resonant circuit 10 enters a non-resonant operating state; a rectifier circuit 20, the input end of the rectifier circuit 20 is connected to the resonant circuit 10; a switch device 30, a first end of the switch device 30 is connected to a first output end of the rectifier circuit 20 and an anode of the diode, a second end of the switch device 30 is connected to a second end of the rectifier circuit 20 and a first end of the film capacitor C0, and a cathode of the diode is connected to the second end of the film capacitor C0; an inverter circuit 40, a first end of the film capacitor C0 and a second end of the film capacitor C0 are respectively connected to the inverter circuit 40, and the inverter circuit 40 is also used to connect a load; a control device (not shown), the control end of the switch device 30, the resonant circuit 10 and the inverter circuit 40 are respectively connected to the control device, and the control device is used to transmit a pulse width modulation signal to the switch device 30 when the load working current is greater than the preset current.

[0022] Specifically, a film capacitor is a capacitor that uses metal foil as an electrode, overlaps it with plastic films such as polyethylene, polypropylene, polystyrene or polycarbonate, and is wound into a cylindrical structure. Depending on the type of plastic film, it is called polyethylene capacitor (also known as Mylar capacitor), polypropylene capacitor (also known as PP capacitor), polystyrene capacitor (also known as PS capacitor) and polycarbonate capacitor. It has the advantages of non-polarity, high insulation impedance, excellent frequency characteristics (wide frequency response), and small dielectric loss.

[0023] For a passive one-port network including capacitors, inductors (reactors) and resistors, its ports may be capacitive, inductive and resistive. When the voltage and current at the circuit port are in phase and the circuit is resistive, it is called a resonance phenomenon. Such a circuit is called a resonant circuit 10. The essence of resonance is the mutual conversion of the electric field energy in the capacitor and the magnetic field energy in the inductor, with one increasing and the other decreasing, and complete compensation. The sum of the electric field energy and the magnetic field energy remains unchanged at all times. The power supply does not need to convert energy back and forth with the capacitor or inductor, but only needs to supply the electric energy consumed by the resistor in the circuit.

[0024] According to the technical solution of the present application, when the working current of the load connected to the inverter circuit 40 is less than the preset current, the input voltage of the inverter circuit 40 can meet the operation requirements through the resonance of the resonant circuit 10. Therefore, when the control device detects that the working current of the load is less than the preset current, it only needs to control the resonant circuit 10 to be in the capacitor connection operation state, that is, in the resonant operation state, and the inverter input voltage is effectively increased through the resonance of the resonant circuit 10.

[0025] When the working current of the load connected to the inverter circuit 40 is greater than the preset current, the voltage division of the reactor in the resonant circuit 10 will increase, which will eventually reduce the voltage input to the inverter circuit 40, affecting the operating reliability of the inverter circuit 40. At this time, the control device will send a corresponding control instruction to the resonant circuit 10, so that the resonant circuit 10 enters a non-capacitor connected operating state, that is, the connection between the capacitor in the resonant circuit 10 and the reactor of the resonant circuit 10 is disconnected, so that the resonant circuit 10 stops resonant operation and enters a non-resonant operating state. At the same time, the control device will also transmit a pulse width modulation signal to the switch device 30. Under the action of the modulated PWM wave, the switch device 30 is turned on and off in an orderly manner, so that the excess energy at the resonant circuit 10 is transmitted to both ends of the film capacitor C0. The film capacitor itself does not have an energy storage function. Under the transmission of energy, the voltage at both ends of the film capacitor C0 will increase, so as to achieve a voltage boost on the input voltage of the inverter circuit 40 to ensure the operating reliability of the inverter circuit 40.

[0026] It is understood that the magnitude of the preset current is not unique, and in a more detailed embodiment, the preset current can be set to 16 A. In other embodiments, the preset current can be set to other magnitudes in combination with the actual situation of the unit where the load is located, as long as it indicates that when it is greater than the preset current, the partial voltage of the resonant circuit 10 will increase, affecting the normal operation of the inverter circuit 40.

[0027] The specific type of the resonant circuit 10 is not limited to a single type, and any resonant circuit 10 can be used as long as it can adjust the connection and disconnection state of the capacitor that resonates with the reactor according to the relationship between the working power of the load and the preset current. Figure 2In one embodiment, the resonant circuit 10 includes a first reactor L1, a second reactor L2, a third reactor L3, a first capacitor C1, a second capacitor C2, a third capacitor C3, a first switch K1, a second switch K2 and a third switch K3; a first end of the first reactor L1 is connected to a first phase line of a three-phase power supply, a first end of the second reactor L2 is connected to a second phase line of the three-phase power supply, a first end of the third reactor L3 is connected to a third phase line of the three-phase power supply, a second end of the first reactor L1 is connected to a first end of the third switch K3, a second end of the third switch K3 is connected to a first end of the third capacitor C3, and a second end of the third capacitor C3 is connected to a first end of the first capacitor C1. The first end of the first capacitor C1 is connected to the second end of the second inductor L2, the second end of the first capacitor C1 is connected to the first end of the first switch K1, the second end of the first switch K1 is connected to the second end of the third inductor L3 and the first end of the second switch K2, the first end of the second switch K2 is connected to the second input end of the rectifier circuit 20, the second end of the second switch K2 is connected to the first end of the second capacitor C2, the second end of the second capacitor C2 is connected to the first end of the third switch K3 and the third input end of the rectifier circuit 20, and the control ends of the first switch K1, the second switch K2 and the third switch K3 are respectively connected to the control device (not shown).

[0028] Specifically, in the scheme of this embodiment, the first end of each reactor is connected to a three-phase power supply, and a capacitor and a switch are connected between any two reactors, and the control device realizes the connection and disconnection of the capacitor by controlling the switch. When the unit where the load is located is working at a working current lower than the preset current, the first switch K1, the second switch K2 and the third switch K3 are all closed, and the switch device 30 is in an open state at this time, and no pulse width modulation signal input is required. In this state, the voltage drive circuit reactor L1-L3, capacitor C1-C3, rectifier circuit 20 and inverter circuit 40 are composed, and the resonance generated by L1-L3 and C1-C3 can effectively increase the inverter input voltage (that is, the voltage at a in the figure), that is, at this time, the voltage drive circuit is in a normal driving operation state.

[0029] It is understood that the specific types of the first switch K1, the second switch K2 and the third switch K3 are not limited, and any device having a switch function can be used. For example, in one embodiment, the first switch K1, the second switch K2 and the third switch K3 are any one of a relay switch, a transistor, a field effect transistor or an insulated gate bipolar transistor.

[0030] Specifically, a relay switch is a relay (English name: relay), which is an electrical control device. When the change of the input quantity (excitation quantity) reaches the specified requirements, it causes the controlled quantity to undergo a predetermined step change in the electrical output circuit. A transistor is a transistor, also known as a bipolar transistor or a transistor. It is a semiconductor device that controls current. Its function is to amplify weak signals into electrical signals with larger amplitude values. It is also used as a contactless switch. Field effect laser is also a field effect transistor (Field Effect Transistor abbreviated as FET). There are two main types: junction field effect transistor (junction FET—JFET) and metal-oxide-semiconductor field effect transistor (metal-oxide semiconductor FET, referred to as MOS-FET). The insulated gate bipolar transistor (IGBT) is a composite fully controlled voltage-driven power semiconductor device composed of BJT (bipolar transistor) and MOS (insulated gate field effect transistor). It has the advantages of both the high input impedance of MOSFET and the low on-state voltage drop of GTR. The above-mentioned switching devices can all be used to control whether the capacitor is connected to the resonant circuit 10. In actual use, different selections can be made according to the scenario.

[0031] It can be understood that, in one embodiment, the first switch K1, the second switch K2 and the third switch K3 can be of the same type, that is, all are relay switches, or all are transistors, or all are field effect transistors, or all are insulated gate bipolar transistors. In another embodiment, different types of devices can be selected for the first switch K1, the second switch K2 and the third switch K3, for example, the first switch K1 is a relay switch, and the second switch K2 and the third switch K3 are transistors.

[0032] It should be noted that the specific type of the rectifier circuit 20 is not unique, and any circuit that can convert AC power into DC power for stable transmission can be used. For example, in one embodiment, the rectifier circuit 20 is an uncontrollable rectifier circuit 20.

[0033] Specifically, the uncontrolled rectifier circuit 20 is a rectifier circuit 20 composed of rectifier diodes without control function. When the input AC voltage is constant, the DC voltage obtained on the load is a circuit that cannot be adjusted. It uses the unidirectional conductivity of the rectifier diode to convert the external AC voltage into a DC voltage. For the ideal case, that is, the rectifier diode has neither inertia nor loss, because the opening and closing of the diode only takes a few microseconds, for the half cycle of the 50Hz current, it can be regarded as instantaneous. This embodiment uses an uncontrolled rectifier circuit 20 in the voltage drive circuit. After the circuit structure is certain, the ratio of its DC rectifier voltage to the AC power supply voltage value is fixed and unchanged, and has good working reliability.

[0034] Further, in one embodiment, the rectifier circuit 20 includes 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 anode of the first diode D1 is connected to the resonant circuit 10 and the cathode of the fourth diode D4, the cathode of the third diode D3 is connected to the cathode of the first diode D1 and the cathode of the fifth diode D5, the cathode of the fifth diode D5 is connected to the first end of the switching device 30 and the anode of the diode, the anode of the third diode D3 is connected to the resonant circuit 10 and the cathode of the sixth diode D6, the anode of the sixth diode D6 is connected to the anode of the fourth diode D4 and the anode of the second diode D2, the anode of the second diode D2 is connected to the second end of the switching device 30, and the anode of the fifth diode D5 is connected to the cathode of the resonant circuit 10 and the second diode D2.

[0035] Specifically, under the structure of the rectifier circuit 20, when the unit where the load is located is operating at a working current lower than the preset current, the first switch K1, the second switch K2 and the third switch K3 are all closed, and the switch device 30 is in an open state at this time, and no pulse width modulation signal input is required. In this state, the voltage drive circuit reactor L1-L3, capacitor C1-C3, rectifier circuit 20 and inverter circuit 40 are formed, and the inverter input voltage can be effectively increased through the resonance generated by L1-L3 and C1-C3.

[0036] The specific working method is as follows: Figure 3, when the circuit works under rated conditions (heavy load), assuming that the current lags behind the voltage by an angle of θ (the leading situation is similar to the lagging situation), the cut-off angle β is less than π / 3 (60 degrees), and it is repeated every 1 / 6 cycle. Capacitors C1-C3 start to charge or discharge by an angle of β at the moment when each phase current passes through zero, and the conduction angle of each diode in the rectifier circuit 20 is π-β. In the range of ωt from θ-β to θ: D5 and D6 are turned on, C2 and C3 are charged, and the load voltage is across C1; in the range of ωt from θ to θ-β+π / 3: D1, D5 and D6 are turned on. Because the film capacitor C0 has no energy storage function, after the inverter DC pulse voltage is increased through the above steps, it can be used reliably by the inverter.

[0037] See also Figure 2 In one embodiment, the switch device 30 includes a fourth switch K4 and a first switch device Q1, the first end of the fourth switch K4 is connected to the first output end of the rectifier circuit 20 and the anode of the diode, the second end of the fourth switch K4 is connected to the first end of the first switch device Q1, the second end of the first switch device Q1 is connected to the second output end of the rectifier circuit 20 and the first end of the film capacitor C0, the control end of the fourth switch K4 and the control end of the first switch device Q1 are respectively connected to a control device (not shown), and the control end of the first switch device Q1 is used to input a pulse width modulation signal.

[0038] Specifically, the switch device 30 specifically includes two switch devices, wherein the fourth switch K4 is used as a control device for whether the diode, the film capacitor C0 and the first switch device Q1 are connected to the loop. When the load working current is greater than the preset current, the control device first controls the fourth switch K4 to close. The control device has a PWM pulse generation function. After the fourth switch K4 is closed, the control device will input a modulated PWM wave to the first switch device Q1 to increase the voltage across the film capacitor C0. This embodiment uses two switch devices as the switch device 30 to realize the working state switching operation of the voltage drive circuit, which has the advantage of strong control reliability.

[0039] Please refer to Figure 2In one embodiment, the inverter circuit 40 includes a second switch device Q2, a third switch device Q3, a fourth switch device Q4, a fifth switch device Q5, a sixth switch device Q6, a seventh switch device Q7, a seventh diode D7, an eighth diode D8, a ninth diode D9, a tenth diode D10, an eleventh diode D11 and a twelfth diode D12; control ends of the second switch device Q2, the third switch device Q3, the fourth switch device Q4, the fifth switch device Q5, the sixth switch device Q6 and the seventh switch device Q7 are respectively connected to a control device (not shown in the figure), a first end of the second switch device Q2 is connected to a cathode of the seventh diode D7 and a second end of the film capacitor C0, a second end of the second switch device Q2 is connected to an anode of the seventh diode D7 and a first end of the third switch device Q3, a first end of the third switch device Q3 is connected to a cathode of the eighth diode D8 and a load, and a second end of the third switch device Q3 is connected to the eighth diode D8. The anode of the diode D8 and the first end of the film capacitor C0, the first end of the fourth switching device Q4 is connected to the cathode of the ninth diode D9 and the first end of the second switching device Q2, the second end of the fourth switching device Q4 is connected to the anode of the ninth diode D9 and the first end of the fifth switching device Q5, the first end of the fifth switching device Q5 is connected to the cathode of the tenth diode D10 and the load, the second end of the fifth switching device Q5 is connected to the anode of the tenth diode D10 and the second end of the third switching device Q3, the first end of the sixth switching device Q6 is connected to the cathode of the eleventh diode D11 and the first end of the fourth switching device Q4, the second end of the sixth switching device Q6 is connected to the anode of the eleventh diode D11 and the first end of the seventh switching device Q7, the first end of the seventh switching device Q7 is connected to the cathode of the twelfth diode D12 and the load, and the second end of the seventh switching device Q7 is connected to the anode of the twelfth diode D12 and the second end of the fifth switching device Q5.

[0040] Specifically, the type of the inverter circuit 40 is not limited, as long as it can convert DC power into AC power to power AC loads. In this embodiment, a three-phase bridge inverter circuit 40 is used to convert the DC power flowing out of the rectifier circuit 20 to power various AC loads.

[0041] It should be noted that the specific types of the first switching device Q1 in the switching apparatus and the various switching devices in the inverter circuit 40 are not unique. In one embodiment, the first switching device Q1 is a metal-oxide semiconductor field effect transistor, and the second switching device Q2, the third switching device Q3, the fourth switching device Q4, the fifth switching device Q5, the sixth switching device Q6 and the seventh switching device Q7 are transistors.

[0042] In the voltage driving circuit, a film capacitor C0, a switch device 30 and a diode are arranged between the rectifier circuit 20 and the inverter circuit 40. When the working current of the load connected to the inverter circuit 40 exceeds the preset current, the resonant circuit 10 can enter the non-resonant operation state, and the control device will also input a pulse width modulation signal to the switch device 30. In this state, there is no capacitor connected to the resonant circuit 10. At this time, the inductance in the resonant circuit 10 will store energy. Under the action of the input pulse width modulation signal, the switch device 30 is turned on and off in an orderly manner, so that the excess energy stored in the resonant circuit 10 is transmitted to both ends of the film capacitor C0. Since the film capacitor C0 does not have an energy storage function, the voltage at both ends of the film capacitor C0 increases under the action of the energy transmitted to both ends of the film capacitor C0. Through this scheme, when the working current of the load exceeds the preset current and the partial pressure of the resonant circuit 10 increases, the voltage at both ends of the film capacitor C0 can be increased by the orderly switching of the switch device 30, thereby increasing the available voltage of the inverter, ensuring the stable operation of the inverter, and avoiding the situation where the bus voltage is too low and affects the normal operation of the load.

[0043] A voltage driving system comprises a three-phase resistive-inductive load and the above-mentioned voltage driving circuit.

[0044] Specifically, the voltage driving circuit is as shown in the above-mentioned embodiments and the accompanying drawings. The three-phase resistive-inductive load is a resistive load or an inductive load that uses three-phase alternating current as a power source. The resistive load is a load that is resistive when there is no phase difference between the load current and the load voltage compared to the power source, such as an incandescent lamp, an electric furnace, etc.; an inductive load refers to a load with an inductance parameter, that is, a load current that lags behind the load voltage by a phase difference is an inductive load, such as a transformer, a motor, and other loads.

[0045] When the working current of the load connected to the inverter circuit 40 is less than the preset current, the input voltage of the inverter circuit 40 can meet the operation requirements through the resonance of the resonant circuit 10. Therefore, when the control device detects that the working current of the load is less than the preset current, it only needs to control the resonant circuit 10 to be in the capacitor connection operation state, that is, in the resonant operation state, and the inverter input voltage is effectively increased through the resonance of the resonant circuit 10.

[0046] When the working current of the load connected to the inverter circuit 40 is greater than the preset current, the voltage division of the reactor in the resonant circuit 10 will increase, which will eventually lead to a decrease in the voltage input to the inverter circuit 40, affecting the operating reliability of the inverter circuit 40. At this time, the control device will send a corresponding control instruction to the resonant circuit 10, so that the resonant circuit 10 enters a non-capacitor connected operating state, that is, the capacitor in the resonant circuit 10 is cut out of the circuit, so that the resonant circuit 10 stops resonant operation and enters a non-resonant operating state. At the same time, the control device will also transmit a pulse width modulation signal to the switch device 30. Under the action of the modulated PWM wave, the switch device 30 is turned on and off in an orderly manner, so that the excess energy at the resonant circuit 10 is transmitted to both ends of the film capacitor C0. The film capacitor itself does not have an energy storage function. Under the transmission of energy, the voltage at both ends of the film capacitor C0 will increase, so as to achieve a voltage boost on the input voltage of the inverter circuit 40 to ensure the operating reliability of the inverter circuit 40.

[0047] In the above voltage drive system, the voltage drive circuit is provided with a film capacitor C0, a switch device 30 and a diode between the rectifier circuit 20 and the inverter circuit 40. When the working current of the load connected to the inverter circuit 40 exceeds the preset current, the resonant circuit 10 can enter the non-resonant operation state, and the control device will also input a pulse width modulation signal to the switch device 30. In this state, there is no capacitor connected to the resonant circuit 10. At this time, the resonant circuit 10 will store energy. Under the action of the input pulse width modulation signal, the switch device 30 is turned on and off in an orderly manner, so as to transfer the excess energy stored in the resonant circuit 10 to both ends of the film capacitor C0. Since the film capacitor C0 does not have an energy storage function, the voltage at both ends of the film capacitor C0 increases under the action of the energy transferred to both ends of the film capacitor C0. Through this solution, when the working current of the load exceeds the preset current and the voltage division of the resonant circuit 10 increases, the voltage across the film capacitor C0 can be increased through the orderly on and off of the switching device 30, thereby increasing the available voltage of the inverter, ensuring the stable operation of the inverter, and avoiding the situation where the bus voltage is too low and affects the normal operation of the three-phase inductive load.

[0048] A household appliance comprises the above-mentioned voltage driving system.

[0049] Specifically, the voltage drive system is as shown in the above embodiments and the accompanying drawings. When the working current of the load connected to the inverter circuit 40 is less than the preset current, the input voltage of the inverter circuit 40 can meet the operating requirements through the resonance of the resonant circuit 10. Therefore, when the control device detects that the working current of the load is less than the preset current, it only needs to control the resonant circuit 10 to be in the capacitor connection operating state, that is, in the resonant working state, and the inverter input voltage is effectively increased through the resonance of the resonant circuit 10.

[0050] When the working current of the load connected to the inverter circuit 40 is greater than the preset current, the voltage division of the reactor in the resonant circuit 10 will increase, which will eventually lead to a decrease in the voltage input to the inverter circuit 40, affecting the operational reliability of the inverter circuit 40. At this time, the control device will send a corresponding control instruction to the resonant circuit 10, so that the resonant circuit 10 enters a non-capacitor connected operating state, that is, the capacitor in the resonant circuit 10 is cut out of the circuit, so that the resonant circuit 10 stops resonating. At the same time, the control device will also transmit a pulse width modulation signal to the switch device 30. Under the action of the modulated PWM wave, the switch device 30 is turned on and off in an orderly manner, so that the excess energy at the resonant circuit 10 is transmitted to both ends of the film capacitor C0. The film capacitor itself does not have an energy storage function. Under the transmission of energy, the voltage at both ends of the film capacitor C0 will increase, so as to achieve a voltage boost on the input voltage of the inverter circuit 40 to ensure the operational reliability of the inverter circuit 40.

[0051] It is understandable that the specific type of household electrical appliances is not unique, as long as it is a household electrical appliance with a three-phase resistive inductive load type, for example, in one embodiment, it is specifically an air conditioner, a refrigerator, a washing machine, etc.

[0052] In the above household appliance, a film capacitor C0, a switch device 30 and a diode are arranged between the rectifier circuit 20 and the inverter circuit 40. When the working current of the load connected to the inverter circuit 40 exceeds the preset current, the resonant circuit 10 can enter the non-resonant operation state, and the control device will also input a pulse width modulation signal to the switch device 30. In this state, there is no capacitor connected to the resonant circuit 10. At this time, the inductance in the resonant circuit 10 will store energy. Under the action of the input pulse width modulation signal, the switch device 30 is turned on and off in an orderly manner, so that the excess energy stored in the resonant circuit 10 is transmitted to both ends of the film capacitor C0. Since the film capacitor C0 does not have an energy storage function, the voltage at both ends of the film capacitor C0 increases under the action of the energy transmitted to both ends of the film capacitor C0. Through this scheme, when the working current of the load exceeds the preset current and the partial voltage of the resonant circuit 10 increases, the voltage at both ends of the film capacitor C0 can be increased by the orderly switching of the switch device 30, thereby increasing the available voltage of the inverter, ensuring the stable operation of the inverter, and avoiding the situation where the bus voltage is too low and affects the normal operation of the household appliance.

[0053] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0054] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A voltage driving circuit, characterized in that: include: diode; Film capacitors; A resonant circuit, used to connect to a three-phase power supply, when the load working current is greater than a preset current, the resonant circuit enters a non-resonant operating state; A rectifier circuit, wherein an input end of the rectifier circuit is connected to the resonant circuit; A switch device, wherein a first end of the switch device is connected to a first output end of the rectifier circuit and an anode of the diode, a second end of the switch device is connected to a second output end of the rectifier circuit and a first end of the film capacitor, and a cathode of the diode is connected to a second end of the film capacitor; An inverter circuit, wherein the first end of the thin film capacitor and the second end of the thin film capacitor are respectively connected to the inverter circuit, and the inverter circuit is also used to connect a load; A control device, wherein the control end of the switch device, the resonant circuit and the inverter circuit are respectively connected to the control device, and the control device is used to transmit a pulse width modulation signal to the switch device when the load working current is greater than a preset current.

2. The voltage driving circuit according to claim 1, characterized in that: The resonant circuit includes a first inductor, a second inductor, a third inductor, a first capacitor, a second capacitor, a third capacitor, a first switch, a second switch and a third switch; A first end of the first reactor is connected to a first phase line of a three-phase power supply, a first end of the second reactor is connected to a second phase line of the three-phase power supply, a first end of the third reactor is connected to a third phase line of the three-phase power supply, a second end of the first reactor is connected to a first end of the third switch, a second end of the third switch is connected to a first end of the third capacitor, a second end of the third capacitor is connected to a first end of the first capacitor and a first input end of the rectifier circuit, a first end of the first capacitor is connected to a second end of the second reactor, a second end of the first capacitor is connected to a first end of the first switch, a second end of the first switch is connected to a second end of the third reactor and a first end of the second switch, a first end of the second switch is connected to a second input end of the rectifier circuit, a second end of the second switch is connected to a first end of the second capacitor, a second end of the second capacitor is connected to a first end of the third switch and a third input end of the rectifier circuit, and control ends of the first switch, the second switch and the third switch are respectively connected to the control device.

3. The voltage driving circuit according to claim 2, characterized in that: The first switch, the second switch and the third switch are any one of a relay switch, a transistor, a field effect transistor or an insulated gate bipolar transistor.

4. The voltage driving circuit according to claim 1, characterized in that: The rectifier circuit is an uncontrollable rectifier circuit.

5. The voltage driving circuit according to claim 4, characterized in that: The rectifier circuit includes a first diode, a second diode, a third diode, a fourth diode, a fifth diode and a sixth diode; The anode of the first diode is connected to the resonant circuit and the cathode of the fourth diode, the cathode of the third diode is connected to the cathode of the first diode and the cathode of the fifth diode, the cathode of the fifth diode is connected to the first end of the switching device and the anode of the diode, the anode of the third diode is connected to the resonant circuit and the cathode of the sixth diode, the anode of the sixth diode is connected to the anode of the fourth diode and the anode of the second diode, the anode of the second diode is connected to the second end of the switching device, and the anode of the fifth diode is connected to the resonant circuit and the cathode of the second diode.

6. The voltage driving circuit according to any one of claims 1 to 5, characterized in that: The switching device includes a fourth switch and a first switching device, the first end of the fourth switch is connected to the first output end of the rectifier circuit and the anode of the diode, the second end of the fourth switch is connected to the first end of the first switching device, the second end of the first switching device is connected to the second output end of the rectifier circuit and the first end of the film capacitor, the control end of the fourth switch and the control end of the first switching device are respectively connected to the control device, and the control end of the first switching device is used to input a pulse width modulation signal.

7. The voltage driving circuit according to claim 6, characterized in that: The inverter circuit includes a second switching device, a third switching device, a fourth switching device, a fifth switching device, a sixth switching device, a seventh switching device, a seventh diode, an eighth diode, a ninth diode, a tenth diode, an eleventh diode and a twelfth diode; The control ends of the second switch device, the third switch device, the fourth switch device, the fifth switch device, the sixth switch device and the seventh switch device are respectively connected to the control device, the first end of the second switch device is connected to the cathode of the seventh diode and the second end of the thin film capacitor, the second end of the second switch device is connected to the anode of the seventh diode and the first end of the third switch device, the first end of the third switch device is connected to the cathode of the eighth diode and the load, the second end of the third switch device is connected to the anode of the eighth diode and the first end of the thin film capacitor, the first end of the fourth switch device is connected to the cathode of the ninth diode and the first end of the second switch device, The second end of the four switching devices is connected to the anode of the ninth diode and the first end of the fifth switching device, the first end of the fifth switching device is connected to the cathode of the tenth diode and the load, the second end of the fifth switching device is connected to the anode of the tenth diode and the second end of the third switching device, the first end of the sixth switching device is connected to the cathode of the eleventh diode and the first end of the fourth switching device, the second end of the sixth switching device is connected to the anode of the eleventh diode and the first end of the seventh switching device, the first end of the seventh switching device is connected to the cathode of the twelfth diode and the load, and the second end of the seventh switching device is connected to the anode of the twelfth diode and the second end of the fifth switching device.

8. The voltage driving circuit according to claim 7, characterized in that: The first switching device is a metal-oxide semiconductor field effect transistor, and the second switching device, the third switching device, the fourth switching device, the fifth switching device, the sixth switching device and the seventh switching device are transistors.

9. A voltage drive system, characterized in that: It comprises a three-phase resistive-inductive load and the voltage driving circuit according to any one of claims 1 to 8.

10. A household appliance, characterized in that: Includes the voltage drive system as described in claim 9.

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