Alternating current input control circuit, variable frequency driver and electric appliance

Abstract

The application relates to an alternating current input control circuit, a variable frequency driver and an electric device. The alternating current input control circuit comprises a rectifier, an intermediate circuit, a voltage conversion circuit, a sampling circuit, a comparison circuit and a control module. The sampling circuit collects a current signal from an output end of the voltage conversion circuit, converts the collected current signal into a voltage sampling signal and sends the voltage sampling signal to the comparison circuit. The comparison circuit compares the voltage sampling signal with a reference voltage signal, outputs a comparison result signal to the control module. The control module outputs a control signal to the voltage conversion circuit according to the comparison result signal, and controls the access state of the voltage conversion circuit. The alternating current input control circuit of the application judges whether the voltage conversion circuit will affect the inverter at the rear end according to the size of the current at the output end of the voltage conversion circuit, thereby controlling the access state of the voltage conversion circuit, avoiding the influence of the voltage conversion circuit on the normal work of the rear-stage circuit after voltage division, and solving the power limitation of the resonant circuit.

Description

Technical Field

[0001] This application relates to the field of frequency converter drive technology, specifically to an AC input control circuit, a frequency converter driver, and electrical equipment. Background Technology

[0002] A variable frequency drive (VFD) is a motor controller that controls the speed of an AC motor by changing the frequency and voltage supplied to it, thereby ensuring the motor's output meets speed and torque requirements. Specifically, to control the motor's speed, the VFD controls the frequency of the electrical energy supplied to it. Frequency is directly related to motor speed: the higher the frequency, the faster the motor rotates. As application requirements change, the VFD can easily adjust the motor speed up or down to meet those requirements, thus saving energy.

[0003] A variable frequency drive typically includes a rectifier, intermediate circuitry, and an inverter. The rectifier allows current to flow in only one direction, converting the input AC power supply into a unidirectional sine wave; the intermediate circuitry regulates and rectifies the unidirectional sine wave, converting it into DC power; the DC power is then fed to the inverter, which converts the DC back into AC power with the required frequency and voltage.

[0004] In related technologies, when designing frequency converters using resonant schemes, the power output is often affected. When used in high-power situations (power current exceeding 16A), the output voltage may be too low due to voltage division by the reactor, resulting in unstable inverter operation or even damage. Summary of the Invention

[0005] To address the problem of low output voltage caused by reactor voltage division under high power conditions, which leads to unstable inverter operation, this application provides an AC input control circuit, a frequency converter driver, and electrical equipment.

[0006] According to a first aspect of the embodiments of this application, an AC input control circuit is provided, including a rectifier, an intermediate circuit, a voltage conversion circuit, a sampling circuit, a comparison circuit, and a control module;

[0007] An AC power source is connected to the input terminal of the voltage conversion circuit; the electrical energy output by the voltage conversion circuit is processed sequentially by the rectifier and the intermediate circuit before being output.

[0008] The sampling circuit acquires a current signal from the output of the voltage conversion circuit, converts the acquired current signal into a voltage sampling signal, and sends it to the comparison circuit. The comparison circuit compares the voltage sampling signal with a reference voltage signal and outputs a comparison result signal to the control module.

[0009] The control module outputs a control signal to the voltage conversion circuit based on the comparison result signal, thereby controlling the connection status of the voltage conversion circuit.

[0010] Furthermore, the voltage conversion circuit includes a first voltage conversion device and a first controllable switch;

[0011] The input terminal of the first voltage conversion device is connected to an AC power supply, and the output terminal is connected to the rectifier;

[0012] The first controllable switch is connected in parallel with the first voltage conversion device, and the control terminal of the first controllable switch is connected to the output terminal of the control module; the first controllable switch is turned on or off under the action of the control signal.

[0013] Furthermore, the AC power supply is a three-phase AC power supply; the voltage conversion circuit includes three sets of first voltage conversion devices and corresponding first controllable switches; the three sets of first voltage conversion devices and the first controllable switches are respectively arranged on the three phase lines of the three-phase AC power supply.

[0014] Furthermore, the first voltage conversion device is a reactor; the first controllable switch is a relay, MOSFET, IGBT, transistor or thyristor.

[0015] Furthermore, the voltage conversion circuit includes reactors L1, L2, and L3, as well as relays K1, K2, and L3 connected in parallel with reactor L1, K2, and K3 respectively.

[0016] Furthermore, the sampling circuit includes multiple sampling resistors connected in series; one end of the sampling circuit is connected to the output terminal of the voltage conversion circuit, and the other end is grounded.

[0017] Furthermore, the sampling circuit includes resistors R1, R2, R3 and R4 connected in series, with one end of resistor R1 connected to the output terminal of the voltage conversion circuit and one end of resistor R4 grounded.

[0018] The common terminal of resistors R3 and R4 is the voltage sampling point, and the voltage signal at this point is sent to the comparator circuit.

[0019] Furthermore, the intermediate circuit includes a second voltage conversion device, a second controllable switch, and an energy storage device;

[0020] The first terminal of the second voltage conversion device is connected to the first terminal of the energy storage device; the second terminal of the second voltage conversion device and the second terminal of the energy storage device are connected to the output terminal of the rectifier; the two ends of the energy storage device are used to connect to the input terminal of the inverter.

[0021] The second controllable switch is connected in parallel with the second voltage conversion device, and the control terminal of the second controllable switch is connected to the output terminal of the control module.

[0022] Furthermore, the second voltage conversion device is a reactor L4, the second controllable switch is a relay K4, and the energy storage device is a capacitor C1.

[0023] Furthermore, the control module outputs two opposite control signals, which act on the first controllable switch and the second controllable switch respectively, so that the conduction states of the first controllable switch and the second controllable switch are opposite.

[0024] Furthermore, the control module includes a control unit and an inverter; the input terminal of the control unit is connected to the output terminal of the comparator circuit; the output terminal of the control unit is directly connected to the first controllable switch, and the output terminal of the control unit is also connected to the second controllable switch through the inverter.

[0025] According to a second aspect of the present application, a variable frequency drive is provided, including the AC input control circuit described in any of the above embodiments; it also includes an inverter, the input terminal of which is connected to the output terminal of the intermediate circuit, and the output terminal of the inverter supplies power to a motor.

[0026] According to a third aspect of the embodiments of this application, an electrical device is provided, including the frequency converter driver described in the above embodiments.

[0027] The technical solutions provided by the embodiments of this application have the following beneficial effects:

[0028] The AC input control circuit of this application collects the current at the output terminal of the voltage conversion circuit through a sampling circuit. Based on the magnitude of the current, it determines whether the voltage conversion circuit will affect the downstream inverter, thereby controlling the connection state of the voltage conversion circuit. This avoids the voltage conversion circuit from affecting the normal operation of the downstream circuit after voltage division, thus improving the reliability of the inverter and solving the limitation of the power application of the resonant circuit.

[0029] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0030] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0031] Figure 1 This is a conventional frequency converter driver circuit illustrated according to an exemplary embodiment.

[0032] Figure 2 This is a block diagram illustrating a three-phase AC input control circuit according to an exemplary embodiment.

[0033] Figure 3 This is a circuit block diagram of a frequency converter driver according to an exemplary embodiment.

[0034] Figure 4 This is a circuit diagram of a frequency converter driver according to an exemplary embodiment.

[0035] In the diagram: 101-Rectifier; 102-Intermediate circuit; 103-Inverter; 201-Rectifier; 202-Intermediate circuit; 203-Inverter; 204-Voltage conversion circuit; 205-Sampling circuit; 206-Comparison circuit; 207-Control module. Detailed Implementation

[0036] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of circuits consistent with some aspects of this application as detailed in the appended claims.

[0037] To further elaborate on the technical solution of this application, the working mode of the frequency converter drive will be explained in detail first.

[0038] like Figure 1 The diagram shows a variable frequency drive circuit, comprising a rectifier 101, an intermediate circuit 102, and an inverter 103. This circuit can only be used in low-power units (input current less than 16A). If applied to high-power applications, the voltage drop caused by the reactor will result in an excessively low load voltage, reducing voltage utilization. It should be noted that industry standards define current less than 16A as low-power.

[0039] To address the aforementioned issues, this application proposes a three-phase AC input control circuit that improves the voltage division problem by controlling the reactor connection method, thereby making the resonant scheme applicable to high-power products.

[0040] Figure 2This is a block diagram illustrating an AC input control circuit according to an exemplary embodiment. The AC input control circuit includes a rectifier 201, an intermediate circuit 202, a voltage conversion circuit 204, a sampling circuit 205, a comparator circuit 206, and a control module 207. AC power is connected to the input terminal of the voltage conversion circuit 204; the electrical energy output by the voltage conversion circuit 204 is processed sequentially by the rectifier 201 and the intermediate circuit 202 before being output. The sampling circuit 205 collects a current signal from the output terminal of the voltage conversion circuit 204, converts the collected current signal into a voltage sampling signal, and sends it to the comparator circuit 206; the comparator circuit 206 compares the voltage sampling signal with a reference voltage signal and outputs a comparison result signal to the control module 207. The control module 207 outputs a control signal to the voltage conversion circuit 204 based on the comparison result signal to control the connection state of the voltage conversion circuit 204.

[0041] like Figure 3 As shown, the output of the intermediate circuit 202 is used to connect to the inverter 203, which is used to convert DC power into AC power with the frequency and voltage required by the motor M.

[0042] The AC input control circuit of this application collects the current at the output terminal of the voltage conversion circuit through a sampling circuit. Based on the magnitude of the current, it determines whether the voltage conversion circuit will affect the downstream inverter, thereby controlling the connection state of the voltage conversion circuit. This avoids the voltage conversion circuit from affecting the normal operation of the downstream circuit after voltage division, thus improving the reliability of the inverter and solving the limitation of the power application of the resonant circuit.

[0043] In some embodiments, the voltage conversion circuit 204 includes a first voltage conversion device and a first controllable switch. The input terminal of the first voltage conversion device is connected to an AC power supply, and the output terminal is connected to the rectifier 201. The first controllable switch is connected in parallel with the first voltage conversion device, and the control terminal of the first controllable switch is connected to the output terminal of the control module 207; the first controllable switch is turned on or off under the action of the control signal.

[0044] In specific application scenarios, the first controllable switch can be made of various types of electronic switching devices, such as relays, MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors), IGBTs (Insulated Gate Bipolar Transistors), transistors, and thyristors, all of which can realize the solution of this application. The first voltage conversion device is connected in parallel with the first controllable switch, and the first controllable switch is controlled by the control signal output by the control module 207. When the first controllable switch is turned on, the first voltage conversion device is short-circuited, thus eliminating the voltage division effect of the first voltage converter. When the first controllable switch is turned off, the first voltage conversion device operates normally, generating a certain voltage division effect.

[0045] In some embodiments, the AC power supply is a three-phase AC power supply; the voltage conversion circuit 204 includes three sets of first voltage conversion devices and corresponding first controllable switches; the three sets of first voltage conversion devices and the first controllable switches are respectively disposed on the three phase lines of the three-phase AC power supply.

[0046] The AC input control circuit of this application is typically used with three-phase AC power. The input terminal of the voltage conversion circuit 204 is connected to the three-phase AC power supply. Therefore, the voltage conversion circuit 204 needs to be set with three parallel branches, each corresponding to the voltage conversion of the three-phase power. Each of the three first voltage conversion devices is connected in parallel with a first controllable switch, and the three first controllable switches are synchronously controlled by the control module 207, turning on or off simultaneously. Therefore, the three first voltage conversion devices work synchronously or are short-circuited.

[0047] In some embodiments, the first voltage conversion device is a reactor; the first controllable switch is a relay, MOSFET, IGBT, transistor, or thyristor. In the embodiments of this application, the primary function of the first voltage conversion device is to boost the voltage, hence the use of a reactor.

[0048] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0049] like Figure 4 As shown, in some embodiments, the voltage conversion circuit 204 includes reactors L1, L2, and L3, as well as relays K1, K2, and L3 connected in parallel with reactors L1, K2, and L3.

[0050] The switching contacts of relay K1 are connected in parallel with reactor L1, and the coil of relay K1 is connected to the output of the control unit. Relays K2 and K3 are connected in parallel with reactors L2 and L3 respectively in the same way. It is easy to understand that relays K1, K2, and K3 are of the same type, either normally open or normally closed, thus achieving synchronous control. Taking the normally open type as an example, when the control unit outputs a high level, the coils of relays K1, K2, and K3 are energized, and the corresponding contacts close, short-circuiting reactors L1, L2, and L3; when the control unit outputs a low level, the coils of relays K1, K2, and K3 are de-energized, the corresponding contacts open, and reactors L1, L2, and L3 are connected to the circuit and begin operation.

[0051] In some embodiments, the sampling circuit 205 includes multiple sampling resistors connected in series; one end of the sampling circuit 205 is connected to the output terminal of the voltage conversion circuit 204, and the other end is grounded. The sampling circuit 205 acquires the output current of the voltage conversion circuit 204, converts it into a voltage signal after passing through several resistors, and outputs it to the comparator circuit 206.

[0052] like Figure 4 As shown, the sampling circuit 205 includes resistors R1, R2, R3, and R4 connected in series. One end of resistor R1 is connected to the output terminal of the voltage conversion circuit 204, and one end of resistor R4 is grounded. The common terminal of resistors R3 and R4 is the voltage sampling point, and the voltage signal at this point is sent to the comparator circuit 206.

[0053] It should be noted that in specific application scenarios, the number and value of resistors are set according to actual needs and are not limited to four resistors; the voltage sampling point is also not limited to a single point, and the common terminal of any two resistors can be selected as the voltage sampling point. The sampling circuit 205 can be connected to any one of the three branches in the voltage conversion circuit 204.

[0054] In some embodiments, the intermediate circuit 202 includes a second voltage conversion device, a second controllable switch, and an energy storage device. A first terminal of the second voltage conversion device is connected to a first terminal of the energy storage device; a second terminal of the second voltage conversion device and a second terminal of the energy storage device are connected to the output terminal of the rectifier; the two ends of the energy storage device are used to connect to the input terminals of the inverter. The second controllable switch is connected in parallel with the second voltage conversion device, and the control terminal of the second controllable switch is connected to the output terminal of the control module 207.

[0055] like Figure 4As shown, the second voltage conversion device is a reactor L4, the second controllable switch is a relay K4, and the energy storage device is a capacitor C1. It is easy to understand that the first controllable switch can also be other types of electronic switching devices, such as MOSFETs, IGBTs, transistors, and thyristors, all of which can achieve the solution of this application. The main function of the second voltage conversion device is to boost the voltage, hence the use of a reactor.

[0056] In some embodiments, the control module 207 outputs two opposite control signals, which act on the first controllable switch and the second controllable switch respectively, so that the conduction states of the first controllable switch and the second controllable switch are opposite.

[0057] It should be noted that in specific application scenarios, if both the first and second controllable switches use MOSFETs, IGBTs, transistors, or SCRs, then the control module 207 needs to output two opposite control signals to reverse the conduction states of the first and second controllable switches. If both the first and second controllable switches use relays, and both are normally open or normally closed, the control module 207 also needs to output two opposite control signals. However, when the first controllable switch uses a normally open relay and the second controllable switch uses a normally closed relay, then the control module 207 only needs to output one control signal to reverse the conduction states of the first and second controllable switches.

[0058] like Figure 4 As shown, the control module 207 includes a control unit and an inverter; the input terminal of the control unit is connected to the output terminal of the comparator circuit 206; the output terminal of the control unit is directly connected to the first controllable switch, and the output terminal of the control unit is also connected to the second controllable switch through the inverter. It is easy to understand that the control unit can be a control chip, such as an MCU chip or a DSP chip.

[0059] Since the control signals required by the first and second controllable switches are exactly opposite, the embodiments of this application use the output signal of one control unit as one control signal, and then process the output signal through an inverter to use it as the other control signal. This satisfies the requirements and the circuit structure is relatively simple. Of course, two control units can also be used to generate two opposite control signals, but this would result in a more complex circuit structure and higher cost.

[0060] The working principle of this application solution will be further explained below in conjunction with specific application scenarios.

[0061] like Figure 4As shown, in a three-phase AC input control circuit, L1-L4 are reactors, K1-K4 are relays, R1-R6 are resistors, U1 is a comparator circuit, U2 is an inverter, and VCC is DC voltage. Compared to a conventional three-phase AC input circuit, a relay and its control module 207 are added. The relay and reactor are connected in parallel. When the input power is low (input current less than 16A), the relay is open and does not short-circuit the reactor. At this time, the voltage drop of the reactor is small and does not affect the load voltage. When the input power is high (input current greater than 16A), the presence of the reactor will cause voltage drop, resulting in a low load voltage and triggering protection. Therefore, by controlling the relay to close and short-circuit the reactor, it can prevent voltage drop and does not affect the load voltage, thus not affecting its normal operation.

[0062] The sampling circuit 205 consists of sampling resistors R1 to R4 and comparator U1. Sampling resistors R1 to R4 sample the current of a certain phase of the three-phase input and convert it into a voltage signal, which is then sent to comparator U1. After comparison with the reference voltage Vref of comparator U1, a signal is output to the control unit. The control unit modulates the PWM wave according to this control signal to control the working state of relays K1 to K4. Vref is determined by the DC voltage VCC and resistors R5 and R6. Vref = VCC × R6 / (R5 + R6). VCC can be powered by DC voltage sources such as +3.3V, +5V, and +12V.

[0063] When the unit operates in the low-power range (input current less than 16A): Sampling resistors R1 to R4 collect the input current signal and convert it into a voltage signal, which is then sent to comparator U1. After comparing it with the reference voltage, the comparator outputs a high level to the control unit. The control unit then modulates a PWM wave according to the sampled signal (output signal of comparator U1) and outputs a control signal to the relays. At this time, relays K1 to K3 are turned off. Since the control signal is inverted by inverter U2, the switching state of relay K4 is different from that of relays K1 to K3. Relay K4 is turned on. At this time, reactors L1 to L3 are used to boost the voltage, and reactor L4 is short-circuited and does not work.

[0064] When the unit operates at high power (input current greater than 16A): Sampling resistors R1 to R4 collect the input current signal and convert it into a voltage signal, which is then sent to comparator U1. After comparing it with the reference voltage, the comparator outputs a low level to the control unit. The control unit then modulates a PWM wave according to the sampling signal and outputs a control signal to the relays, controlling relays K1 to K3 to turn on. Since the control signal is inverted by inverter U2, the switching state of relay K4 is different from that of relays K1 to K3. Relay K4 is turned off. At this time, reactors L1 to L3 are short-circuited and do not work. Reactor L4 is used to boost the voltage.

[0065] This application adopts the solution described in the above embodiments. By adding a control device to the three-phase AC input circuit to control the connection method of the reactor, it solves the problem of the inverter's normal operation being affected by excessively low output voltage caused by the reactor, thus improving the inverter's reliability. This solution can broaden the applicable power range of the resonant circuit and increase its compatibility; it solves the problem of the reactor's voltage division affecting the normal operation of subsequent circuits under high power input conditions; and it overcomes the limitation of the resonant circuit's applied power through a simple sampling control module.

[0066] like Figure 3 As shown, this application also provides a variable frequency drive, including an AC input control circuit and an inverter 203. The specific structure of the AC input control circuit is the same as that described in any of the above embodiments, and will not be repeated here. The input terminal of the inverter 203 is connected to the output terminal of the intermediate circuit, and the output terminal of the inverter 203 supplies power to the motor.

[0067] This application also provides an electrical device including a frequency converter and a motor. The frequency converter converts a three-phase AC power supply into AC power with the required frequency and voltage, thereby driving the motor to operate at the required speed. The specific structure of the frequency converter is the same as that described in the above embodiments, and will not be repeated here.

[0068] It is understood that the same or similar parts in the above embodiments can be referred to each other, and the contents not described in detail in some embodiments can be referred to the same or similar contents in other embodiments.

[0069] It should be noted that in the description of this application, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Furthermore, in the description of this application, unless otherwise stated, "a plurality of" means at least two.

[0070] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0071] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. An AC input control circuit, characterized in that, include: Rectifier, intermediate circuit, voltage conversion circuit, sampling circuit, comparator circuit and control module; An AC power supply is connected to the input terminal of the voltage conversion circuit; The electrical energy output from the voltage conversion circuit is processed sequentially by the rectifier and the intermediate circuit before being output. The sampling circuit acquires a current signal from the output of the voltage conversion circuit, converts the acquired current signal into a voltage sampling signal, and sends it to the comparison circuit. The comparison circuit compares the voltage sampling signal with the reference voltage signal and outputs the comparison result signal to the control module. The control module outputs a control signal to the voltage conversion circuit based on the comparison result signal, thereby controlling the connection state of the voltage conversion circuit; The voltage conversion circuit includes a first voltage conversion device and a first controllable switch; The input terminal of the first voltage conversion device is connected to an AC power source, and the output terminal is connected to the rectifier; The first controllable switch is connected in parallel with the first voltage conversion device, and the control terminal of the first controllable switch is connected to the output terminal of the control module; the first controllable switch is turned on or off under the action of the control signal. The intermediate circuit includes a second voltage conversion device, a second controllable switch, and an energy storage device. The first terminal of the second voltage conversion device is connected to the first terminal of the energy storage device; the second terminal of the second voltage conversion device and the second terminal of the energy storage device are respectively connected to two different output terminals of the rectifier; the two ends of the energy storage device are used to connect to the input terminals of the inverter. The second controllable switch is connected in parallel with the second voltage conversion device, and the control terminal of the second controllable switch is connected to the output terminal of the control module; The second voltage conversion device is a reactor L4, the second controllable switch is a relay K4, and the energy storage device is a capacitor C1; The control module outputs two opposite control signals, which act on the first controllable switch and the second controllable switch respectively, so that the conduction states of the first controllable switch and the second controllable switch are opposite.

2. The AC input control circuit according to claim 1, characterized in that, The AC power supply is a three-phase AC power supply; the voltage conversion circuit includes three sets of first voltage conversion devices and corresponding first controllable switches; the three sets of first voltage conversion devices and the first controllable switches are respectively arranged on the three phase lines of the three-phase AC power supply.

3. The AC input control circuit according to claim 2, characterized in that, The first voltage conversion device is a reactor; the first controllable switch is a relay, MOSFET, IGBT, transistor or thyristor.

4. The AC input control circuit according to claim 3, characterized in that, The voltage conversion circuit includes reactors L1, L2, and L3, as well as relays K1, K2, and L3 connected in parallel with reactor L1, K2, and K3 respectively.

5. The AC input control circuit according to any one of claims 1-4, characterized in that, The sampling circuit includes multiple sampling resistors connected in series; one end of the sampling circuit is connected to the output terminal of the voltage conversion circuit, and the other end is grounded.

6. The AC input control circuit according to claim 5, characterized in that, The sampling circuit includes resistors R1, R2, R3 and R4 connected in series. One end of resistor R1 is connected to the output terminal of the voltage conversion circuit, and one end of resistor R4 is grounded. The common terminal of resistors R3 and R4 is the voltage sampling point, and the voltage signal at this point is sent to the comparator circuit.

7. The AC input control circuit according to claim 1, characterized in that, The control module includes a control unit and an inverter; the input terminal of the control unit is connected to the output terminal of the comparator circuit; the output terminal of the control unit is directly connected to the first controllable switch, and the output terminal of the control unit is also connected to the second controllable switch through the inverter.

8. A variable frequency drive, characterized in that, include: The AC input control circuit according to any one of claims 1-7; It also includes an inverter, the input of which is connected to the output of the intermediate circuit, and the output of which supplies power to the motor.

9. An electrical appliance, characterized in that, include: The frequency converter driver according to claim 8.

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