CN108631688B

CN108631688B - AC motor speed regulation circuit and air conditioner

Info

Publication number: CN108631688B
Application number: CN201710182274.0A
Authority: CN
Inventors: 李洪涛
Original assignee: GD Midea Air Conditioning Equipment Co Ltd
Current assignee: GD Midea Air Conditioning Equipment Co Ltd
Priority date: 2017-03-23
Filing date: 2017-03-23
Publication date: 2021-02-09
Anticipated expiration: 2037-03-23
Also published as: CN108631688A

Abstract

The invention provides an alternating current motor speed regulation circuit and an air conditioner, which comprise an alternating current input end, a first rectification module, a load, a second rectification module, a switch module, a first follow current module, a second follow current module and an MCU (micro control unit), wherein a follow current loop is provided for induced electromotive force on an alternating current motor winding coil through the first follow current module or the second follow current module, the follow current loop passes through the existing first rectification module and the load in the circuit and does not need to additionally increase electronic switch follow current, and the first follow current module and the second follow current module are formed by devices with a one-way conduction function, so that the cost can be greatly reduced, the MCU is not needed to control during follow current, and the MCU is completely realized by a simple hardware circuit, therefore, the working reliability is high, the problem of device damage caused by control in the prior art is avoided, and the EMC (electro magnetic compatibility) performance.

Description

AC motor speed regulation circuit and air conditioner

Technical Field

The invention relates to the field of alternating current motor control, in particular to an alternating current motor speed regulation circuit and an air conditioner.

Background

An existing speed regulation circuit for an alternating current motor is shown in fig. 1, an alternating current motor is connected in series with an L or N line of an alternating current power supply, the alternating current motor is input into a rectification module, an electronic switch K1 is connected in series in two output end loops of the rectification module, meanwhile, the two ends of the motor are connected in parallel with another electronic switch K2, an MCU outputs a PWM (pulse width modulation) signal to control the on and off of an electronic switch K1, when the K1 is switched on, the alternating current power supply forms a current path through the alternating current motor, the rectification module and the K1 to provide a working current for the alternating current motor, when the K1 is switched off, the MCU controls the K2 to be switched on, and when the K1 is switched off, the induced electromotive force generated on a winding of the alternating current motor is subjected:

firstly, the method comprises the following steps: the separate electronic switch K2 is required to realize the electric energy follow current of the alternating current motor, and the electronic switch K2 is composed of a high-power switch tube, so that the cost is increased, and the cost is high.

Secondly, the method comprises the following steps: the dead time of K1 and K2 switches, namely the time of K1 switching to K2 switching and the time of K2 switching to K1 switching, needs to be considered during control, high voltage and large high-frequency electromagnetic noise are easily generated at two ends of a motor winding coil and two ends of an electronic switch K1 in the dead time, switching tubes of the electronic switches K1 and K2 are easily consumed, and the EMC performance of the circuit is reduced.

Disclosure of Invention

The invention mainly aims to provide an alternating current motor speed regulating circuit and an air conditioner, and aims to solve the problems that the existing alternating current motor speed regulating circuit is high in cost and circuit devices are damaged during control.

In order to achieve the above object, the present invention provides an ac motor speed regulation circuit, which includes an ac input terminal, a first rectification module, a load, a second rectification module, a switch module, a first follow current module, a second follow current module, and an MCU;

the first rectifying module rectifies alternating current of an alternating current power supply input by the alternating current input end and outputs direct current, and two output ends of the first rectifying module are connected with a direct current bus to provide power for load work;

the second rectifying module rectifies alternating current of an alternating current power supply input by the alternating current input end and outputs direct current, and two output ends of the second rectifying module are connected with the switch module to provide power for the switch module to work;

the switch module realizes switching of a switch state under the control of the MCU, when the switch module is conducted, alternating current of the alternating current power supply flows through the alternating current motor, the second rectification module and the switch module to supply power to the alternating current motor, and electric energy is stored on a winding coil of the alternating current motor;

the first follow current module and the second follow current module comprise an input end and an output end, the first follow current module and the second follow current module are conducted in a unidirectional mode, current is input from the input end of the first follow current module or the second follow current module, and current is output from the output end of the first follow current module or the second follow current module; when the switch module is turned off, induced electromotive force generated on a winding coil of the alternating current motor performs follow current release through a follow current loop, and a circuit forming the follow current loop comprises the first follow current module or the second follow current module, the first rectification module, the second rectification module and the load.

Preferably, the input end of the first freewheeling module is connected to the positive electrode of the output end of the second rectifying module, and the output end of the first freewheeling module is connected to the positive electrode of the output end of the first rectifying module;

the input end of the second follow current module is connected with the negative electrode of the output end of the first rectifying module, and the output end of the second follow current module is connected with the negative electrode of the output end of the second rectifying module.

Preferably, the input end of the first freewheeling module is connected to the positive electrode of the output end of the second rectifying module, and the output end of the first freewheeling module is connected to the positive electrode of the output end of the first rectifying module.

The output end of the second follow current module and one input end of the motor are connected to one input end of the second rectifying module in a shared mode, and the input end of the second follow current module is connected with the negative electrode of the output end of the first rectifying module;

preferably, the output end of the second freewheeling module, the input end of the first freewheeling module and one end of the motor are connected to one input end of the second rectifying module, the input end of the second freewheeling module is connected to the negative electrode of the output end of the first rectifying module, and the output end of the first freewheeling module is connected to the positive electrode of the output end of the first rectifying module.

Preferably, an input end of the first freewheeling module and one end of the motor are commonly connected to an input end of the second rectifying module, and an output end of the first freewheeling module is connected to the positive electrode of the output end of the first rectifying module;

Preferably, the speed regulating circuit of the alternating current motor further comprises a PFC module;

the PFC module is connected in series between the first rectifying module and a load through the direct current bus to correct power factors of the direct current voltage output by the first rectifying module.

Preferably, the input end of the second freewheeling module is connected to the negative electrode of the output end of the PFC module, and the output end of the second freewheeling module is connected to the negative electrode of the output end of the second rectification module;

the input end of the first follow current module is connected with the positive electrode of the output end of the second rectifying module, and the output end of the first follow current module is connected with the positive electrode of the output end of the PFC module.

Preferably, the input end of the second freewheeling module is connected to the negative electrode of the output end of the first rectifying module, and the output end of the second freewheeling module is connected to the negative electrode of the output end of the second rectifying module;

Preferably, the speed regulating circuit of the alternating current motor further comprises a filtering module;

the PFC module is connected in series between the PFC module and a load through the direct current bus to carry out smooth filtering on the direct current voltage output by the PFC module.

Preferably, the speed regulating circuit of the alternating current motor further comprises a reactor, and the reactor is connected in series between the alternating current input end and the input end of the first rectification module.

Preferably, the first freewheel module comprises a first diode and the second freewheel module comprises a second diode;

the anode of the first diode is the input end of the first follow current module, and the cathode of the first diode is the output end of the first follow current module;

the anode of the second diode is the input end of the second freewheeling module, and the cathode of the second diode is the output end of the second freewheeling module.

Preferably, the speed regulating circuit of the alternating current motor further comprises a first capacitor;

and two ends of the first capacitor are respectively connected with the output end of the first follow current module and the input end of the second follow current module.

Preferably, the switch module includes a first switch unit and a first RC absorbing unit;

the first switch unit realizes the switch switching of the switch module;

the first RC absorption unit is connected in parallel to two ends of the first switch unit and used for absorbing high voltage generated at two ends of the first switch unit when the first switch unit is switched.

Preferably, the first RC absorbing unit comprises a second capacitor and a second resistor;

one end of the second capacitor is connected with one end of the second resistor, the other end of the second capacitor is connected with one end of the first switch unit, and the other end of the second resistor is connected with the other end of the first switch unit.

Preferably, the speed regulating circuit of the alternating current motor further comprises a second RC absorbing module;

the second RC absorption module is connected in parallel to two ends of the main winding of the alternating current motor set and used for absorbing high voltage generated at two ends of the main winding of the alternating current motor set when the switch of the switch module is switched.

In order to achieve the purpose, the invention also provides an air conditioner which comprises the alternating current motor speed regulating circuit.

The speed regulating circuit of the alternating current motor provided by the embodiment of the invention provides a follow current loop for storing electric energy on a winding coil of the alternating current motor through the first follow current module or the second follow current module, the follow current loop passes through the existing rectifying module and load in the circuit, and no additional electronic switch follow current is needed, and the first follow current module and the second follow current module are formed by devices with a one-way conduction function, so that the cost can be greatly reduced, the control of an MCU is not needed during follow current, and the control is completely realized by a simple hardware circuit, so that the working reliability is high, the problem of device damage caused by control in the prior art is avoided, and the EMC performance of current is improved.

Drawings

FIG. 1 is a block diagram of a prior art AC motor speed regulation circuit module;

FIG. 2 is a block diagram of a first embodiment of the AC motor speed regulation circuit of the present invention;

FIG. 3 is a schematic diagram of a freewheel circuit according to a first embodiment of the AC motor speed regulation circuit of the present invention;

FIG. 4 is a schematic diagram of another freewheel circuit of the first embodiment of the AC motor speed regulation circuit according to the present invention;

FIG. 5 is a circuit diagram of a second embodiment of the AC motor speed regulation circuit of the present invention;

FIG. 6 is a block diagram of a third embodiment of the AC motor speed regulation circuit of the present invention;

FIG. 7 is a circuit diagram of a third embodiment of the AC motor speed regulation circuit of the present invention;

FIG. 8 is a block diagram of another embodiment of the AC motor speed regulation circuit of the present invention;

FIG. 9 is another circuit configuration diagram of the third embodiment of the AC motor speed regulating circuit of the present invention;

FIG. 10 is a block diagram of a fourth embodiment of the AC motor speed control circuit according to the present invention

FIG. 11 is a circuit diagram of a fourth embodiment of the AC motor speed regulation circuit of the present invention;

FIG. 12 is a block diagram of a fifth embodiment of the AC motor speed regulation circuit of the present invention;

FIG. 13 is a circuit configuration diagram of a fifth embodiment of the AC motor speed regulation circuit of the present invention;

FIG. 14 is a block diagram of a sixth embodiment of the AC motor speed regulation circuit of the present invention;

FIG. 15 is a circuit diagram of a sixth embodiment of the AC motor speed regulation circuit of the present invention;

FIG. 16 is a block diagram of a seventh embodiment of the AC motor speed regulation circuit of the present invention;

FIG. 17 is a circuit configuration diagram of a seventh embodiment of the AC motor speed adjusting circuit of the present invention;

FIG. 18 is a block diagram of an eighth embodiment of the AC motor speed regulation circuit of the present invention;

FIG. 19 is a circuit configuration diagram of an eighth embodiment of the AC motor speed adjusting circuit of the present invention;

FIG. 20 is a block diagram of an alternate current motor speed control circuit according to an eighth embodiment of the present invention;

FIG. 21 is another circuit configuration diagram of an eighth embodiment of the AC motor speed regulation circuit of the present invention;

FIG. 22 is a block diagram of a ninth embodiment of the AC motor speed regulation circuit of the present invention;

FIG. 23 is a circuit configuration diagram of a ninth embodiment of the AC motor speed adjusting circuit of the present invention;

fig. 24 is a block diagram showing a speed regulating circuit of an ac motor according to a tenth embodiment of the present invention;

FIG. 25 is a circuit configuration diagram of a tenth embodiment of the AC motor speed adjusting circuit of the present invention;

fig. 26 is a block configuration diagram of an eleventh embodiment of the speed regulating circuit of the ac motor of the present invention;

FIG. 27 is a circuit configuration diagram of an eleventh embodiment of the speed adjusting circuit of the AC motor of the present invention;

FIG. 28 is a block diagram of a twelfth embodiment of the AC motor speed regulation circuit of the present invention;

FIG. 29 is a circuit configuration diagram of a twelfth embodiment of the speed adjusting circuit of the AC motor according to the present invention;

fig. 30 is a block configuration diagram of a thirteenth embodiment of the speed regulating circuit of the ac motor of the present invention;

fig. 31 is a circuit configuration diagram of a thirteenth embodiment of the ac motor speed adjusting circuit of the present invention;

fig. 32 is a block diagram of another thirteenth embodiment of the ac motor speed adjusting circuit according to the present invention;

FIG. 33 is another circuit configuration diagram of a thirteenth embodiment of the AC motor speed regulating circuit of the present invention;

FIG. 34 is a block diagram of a fourteenth embodiment of an AC motor speed control circuit according to the present invention;

FIG. 35 is a circuit diagram of a fourteenth embodiment of the speed adjusting circuit of the AC motor according to the present invention;

fig. 36 is a block configuration diagram of a fifteenth embodiment of the speed regulating circuit of the ac motor according to the present invention;

FIG. 37 is a circuit configuration diagram of a fifteenth embodiment of a speed regulating circuit of an AC motor according to the present invention;

fig. 38 is a block diagram of a sixteenth embodiment of an ac motor speed control circuit according to the present invention;

FIG. 39 is a circuit configuration diagram of a sixteenth embodiment of an AC motor speed adjusting circuit according to the present invention;

FIG. 40 is a block diagram of a speed regulating circuit for an AC motor in accordance with a seventeenth embodiment of the present invention;

FIG. 41 is a circuit configuration diagram of a seventeenth embodiment of a speed regulating circuit of an AC motor according to the present invention;

fig. 42 is a block configuration diagram of an eighteenth embodiment of a speed regulating circuit of an ac motor of the present invention;

fig. 43 is a circuit configuration diagram of an eighteenth embodiment of the ac motor speed adjusting circuit of the present invention;

fig. 44 is a block diagram of another eighteenth embodiment of an ac motor speed control circuit according to the present invention;

FIG. 45 is another circuit configuration diagram of an eighteenth embodiment of an AC motor speed regulating circuit of the present invention;

fig. 46 is a block configuration diagram of a nineteenth embodiment of the speed regulating circuit of the ac motor of the present invention;

FIG. 47 is a circuit configuration diagram of a nineteenth embodiment of the speed regulating circuit of the AC motor of the present invention;

FIG. 48 is a block diagram of a twentieth embodiment of the speed regulating circuit of the AC motor according to the present invention;

FIG. 49 is a circuit configuration diagram of a twentieth embodiment of the speed regulating circuit of the AC motor according to the present invention;

FIG. 50 is a block diagram of a twenty-first embodiment of an AC motor speed regulation circuit of the present invention;

fig. 51 is a circuit configuration diagram of a twenty-first embodiment of the ac motor speed control circuit according to the present invention.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.

Referring to fig. 2, fig. 2 is a block diagram of an ac motor speed regulation circuit module according to a first embodiment of the present invention, and for convenience of description, only the parts related to the embodiment of the present invention are shown, and detailed descriptions are as follows:

the speed regulating circuit of the alternating current motor provided by the embodiment of the invention comprises an alternating current input end, a first rectifying module 10, a load 20, a second rectifying module 30, a switch module 40, a first follow current module 50, a second follow current module 60 and an MCU 70.

The first rectifying module 10 rectifies the ac power of the ac power input by the ac input terminal and outputs the dc power, and two output terminals of the first rectifying module 10 are connected to a dc bus to provide power for the operation of the load 20, where the first rectifying module 10 may be a discrete full-bridge rectifying circuit or an integrated rectifying bridge stack module, and the first rectifying module 10 includes two ac input terminals, and a dc output terminal positive electrode and a dc output terminal negative electrode.

The second rectifying module 30 rectifies the ac power input from the ac input terminal and outputs the dc power, two output terminals of the second rectifying module 30 are connected to the switch module to provide power for the switch module to work, the second rectifying module 30 includes two ac input terminals, and a dc output terminal anode and a dc output terminal cathode, where the second rectifying module 30 may be a discrete full-bridge rectifying circuit or an integrated rectifying bridge stack module.

The switching module 40 is controlled by the MCU70 to switch the switching states, and when the switching module 40 is turned on, ac power of the ac power source flows through the ac motor 80, the second rectifying module 30 and the switching module 40 to supply power to the ac motor 80.

The first and

second freewheel modules

50, 60 include an input and an output, the first and

second freewheel modules

50, 60 being unidirectionally conducting, current being input from the input of the first or

second freewheel module

50, 60 and output from the output of the first or

second freewheel module

50, 60; when the switching module 40 is turned off, the induced electromotive force generated on the winding coil of the ac motor 80 is freewheeling and discharged through the freewheeling circuit, and the circuit constituting the freewheeling circuit includes the first freewheeling module 50 or the second freewheeling module 60, the first rectification module 10, and the load 20. The current in the freewheel loop may pass through other circuits such as the second rectification module 30, in addition to the first freewheel module 50 or the second freewheel module 60, the first rectification module 10 and the load 20, it should be noted that, since the ac current passing through the ac motor 80 starts from the ac input terminal L and from the ac input terminal N, the induced electromotive force polarity generated on the winding coil of the ac motor 80 when the switch module is turned off is different according to the direction of the ac current passing through the coil, and the freewheel loops corresponding to the different induced electromotive force polarities are different, as shown in fig. 3, when the ac current direction starts from the input terminal L, the current direction is the B terminal of the ac motor 80 flowing to the a terminal, and when the switch module 40 is turned off, the induced electromotive force generated on the winding coil of the ac motor 80 is negative at the B terminal, the end a is positive, and the current direction of the loop for freewheeling and releasing the induced electromotive force is specifically shown in the dotted line part in fig. 3, where the arrow direction is the current direction, and the loop specifically includes: the induced electromotive force flows through the loop to perform follow current release, namely, the current direction passing through the motor 80 in the follow current loop is the same as the current direction passing through the motor 80 before the switch module 40 is cut off, so that the current in the loop plays a role in follow current release on the induced electromotive force. When the alternating current direction starts from the input end N, the current direction is from the terminal a to the terminal B of the alternating current motor 80, as shown in fig. 4, when the switch module 40 is turned off, the direction of the induced electromotive force generated on the winding coil of the alternating current motor 80 is negative at the terminal a, and positive at the terminal B, and the loop current for freewheeling and discharging the induced electromotive force is specifically shown in the dotted line portion in fig. 4, where the arrow direction is the current direction, and the loop is specifically: the current direction passing through the motor 80 in the follow current loop is the same as the current direction passing through the motor 80 before the switch module 40 is cut off, so that the current in the loop plays a role of follow current relief on the induced electromotive force. The first follow current module and the second follow current module have a unidirectional conduction function, so that different follow current loops can be formed for the induced electromotive forces with different polarities respectively to perform follow current release on the induced electromotive forces, and the normal work of the motor is ensured; meanwhile, the unidirectional conduction also plays a role in isolation, so that when the switch module 40 is switched on to supply power to the motor 80, the direct-current high voltage output from the first rectification module 10 cannot be connected in series into the switch module, so that the switch module cannot work normally, namely, the function of isolating the direct-current voltage output by the first rectification module 10 is played.

In the above-mentioned ac motor speed regulation circuit, the first rectification module 10 and the load 20 also form a part of an existing control circuit, for example, for an air conditioner, in the control circuit of the air conditioner, the load 20 may include a circuit formed by a compressor driving circuit and a compressor load, and the first rectification module 10 outputs a dc voltage to provide a working power supply for the load 20 through a dc bus. The speed regulating circuit of the alternating current motor provided by the embodiment of the invention outputs high-speed switching signals (such as the frequency of 10-30KHz) through the MCU70 to control the switch module 40 to switch the switch state, when the switch module 40 is on, the ac power supply supplies power to the motor 80, and when the switch module 40 is off, the MCU70 regulates the speed of the ac motor 80 by freewheeling the induced electromotive force generated on the winding coil of the ac motor 80 through a freewheeling circuit comprising the first freewheeling module 50 and the second freewheeling module 60, and when the door opening module 40 is turned off in one cycle, because the frequency of the switching signal is high, an induced electromotive force is generated on the ac motor 80, and thus the induced electromotive force needs to be discharged before a switching signal cycle is completed, so that the normal operation of the motor 80 can be ensured.

The speed regulating circuit of the alternating current motor provided by the embodiment of the invention provides a follow current loop for induced electromotive force generated on a winding coil of an alternating current motor 80 through the first follow current module 50 and the second follow current module 60, the follow current loop is formed by the first follow current module 50 and the second follow current module 60, the first rectification module 20 and the load 20 existing in the control circuit participate in the follow current loop, and follow current is released from the induced electromotive force, no additional electronic switch follow current is needed, the first follow current module 50 and the second follow current module 60 are formed by devices with a unidirectional conduction function, so that the cost can be greatly reduced, the MCU control is not needed during follow current, and the MCU control is completely realized by a simple hardware circuit, therefore, the reliability of the work is high, the problem of device damage caused by control in the prior art is avoided, and the EMC performance of current is improved.

Further, referring to fig. 2, based on the first embodiment of the ac motor speed regulating circuit of the present invention, in the second embodiment of the ac motor speed regulating circuit of the present invention, the specific connection manner of the first freewheel module 50 and the second freewheel module 60 is as follows: the input end of the first follow current module 50 is connected with the positive electrode of the output end of the second rectifying module 30, and the output end of the first follow current module 50 is connected with the positive electrode of the output end of the first rectifying module 10; the input end of the second freewheeling module 60 is connected to the negative electrode of the output end of the first rectifying module 10, and the output end of the second freewheeling module 60 is connected to the negative electrode of the output end of the second rectifying module 30. Since the first freewheel module 50 and the second freewheel module 60 are connected at the output of the second rectifier module 30, their freewheel circuits require the participation of the second rectifier module 30 in addition to passing through the first rectifier module 10 and the load 20.

Referring to fig. 5, fig. 5 is a circuit structure diagram of a second embodiment of the ac motor speed regulating circuit according to the present invention, and for convenience of description, only the parts related to the embodiment of the present invention are shown, specifically as follows:

the first rectifying module 10 is composed of a rectifying bridge stack DR1, and rectifies alternating current of an alternating current power supply input from an alternating current input end and outputs direct current;

the load 20 is a dc load, and includes a common dc-powered load such as a dc-operated motor, and the dc load may also be a dc-powered specific circuit, not a simple load, such as a switching power supply circuit, a motor driving circuit, and the like.

The second rectification module 30 is composed of four diodes FD1-FD4, and includes two input ends, an output end anode and an output end cathode, wherein a connection point of an anode of a diode FD1 and a cathode of a diode FD2 is an input end, a connection point of an anode of a diode FD4 and a cathode of a diode FD3 is another input end, a connection point of a cathode of a diode FD1 and a cathode of a diode FD4 is an anode output end, a connection point of an anode of a diode FD2 and an anode of a diode FD3 is a cathode output end, the ac motor 80 is connected IN series IN an ac loop from the ac input ends ACL-IN and ACN-IN to the two input ends of the second rectification module 30, wherein the capacitor FC1 is a start capacitor of the ac motor 80 and is connected IN parallel to two ends of a start winding of the ac motor 80, IN this figure, the ac motor is connected IN series to the ACN-IN (.

The switch module 40 mainly comprises a first switch tube IGBT (insulated Gate Bipolar transistor) Q2, the switch tube Q2 forms a first switch unit 41 to realize the switch switching of the switch module, the switch module 40 further comprises an IGBT driving circuit, and the MCU70 outputs a PWM signal to the IGBT driving circuit through a pin P1 to drive the first switch tube Q2 to switch. When the IGBT is turned on, the current output from the ac power supply forms a current loop through the ac motor 80, the second rectifier module 30, and the first switching tube Q2, and provides power for the ac motor 80 to operate. The current loop is as follows: when the current of the alternating current power supply starts from ACL-IN (alternating current L line), the current returns to ACN-IN (alternating current N line) of the alternating current power supply through the anode and the cathode of the diode FD1, the collector and the emitter of the first switching tube Q2, the anode and the cathode of the diode FD3 and the alternating current motor 80; when the current of the ac power supply starts from ACN-IN, i.e., the ac N line, the current returns to ACL-IN, i.e., the ac L line of the ac power supply through the ac motor 80, the anode and cathode of the diode FD4, the collector and emitter of the first switching tube Q2, the anode and cathode of the diode FD2, and the collector-IN of the ac power supply. When the IGBT is turned off, induced electromotive force is generated in the winding coil of ac motor 80, and when the current direction of the ac power supply is different, induced electromotive force generated in the winding coil of ac motor 80 differs in polarity. Here, the first switching transistor Q2 of the switching module 40 may also be a MOS (metal oxide semiconductor) power transistor, and the IGBT driving is changed to a MOS driving circuit.

The first and

second freewheel modules

50 and 60 are respectively composed of a first diode FD5 and a second diode FD6, and perform a unidirectional conduction function, an anode FD5 of the first diode is an input terminal of the first freewheel module 50, a cathode of the first diode FD5 is an output terminal of the first freewheel module 50, an anode FD6 of the second diode is an input terminal of the second freewheel module 60, a cathode of the second diode FD6 is an output terminal of the second freewheel module 60, and the first diode FD5 and the second diode FD6 respectively provide a freewheel loop for induced electromotive forces of different polarities generated at a winding coil of the ac motor 80 when the switching module 40 is turned off. The method comprises the following specific steps: when the current direction of the alternating current power supply starts from an L line and generates induced electromotive force on a winding coil of the alternating current motor 80, a follow current loop of the alternating current power supply starts from the L line, passes through a 4 th pin which is the positive electrode output end of a rectifier bridge stack DR1, enters the direct current load 20 through the positive electrode of a direct current bus, enters the anode and the cathode of a second diode FD6 through the negative electrode of the direct current bus, enters the anode and the cathode of a diode FD3, and returns to an N line of the alternating current power supply through the alternating current motor 80; when the current direction of the alternating current power supply starts from an N line and generates induced electromotive force on a winding coil of the alternating current motor 80, a follow current loop of the alternating current power supply starts from the N line and passes through the alternating current motor 80, the anode and the cathode of the diode FD4, the anode and the cathode of the first diode FD5 and the anode of the direct current bus to enter the direct current load 20, the cathode of the direct current bus to enter the output end of the cathode of the rectifier bridge stack DR1, namely the 1 st pin, and finally returns to the L line of the alternating current power supply, the current direction of the alternating current motor 80 in the follow current loop is the same as the current direction when the switch module 40 is conducted, and the induced electromotive force of the alternating current power supply is subjected to follow current discharge by the load 80 through the.

In the speed regulating circuit of the ac motor according to the embodiment of the present invention, the switch module 40 may further include a first RC absorbing unit 40, the first RC absorbing unit includes a second capacitor FC3 and a second resistor FR4, one end of the second capacitor FC3 is connected to one end of the second resistor FR4, the other end of the second capacitor FC3 is connected to the collector of the first switch tube Q2, and the other end of the second resistor FR4 is connected to the emitter of the first switch tube Q2. When the switch tube of the switch module 40 is turned off, the first absorption unit can generate a high voltage formed by induced electromotive force in the winding coil of the ac motor 80, and the first absorption unit can form auxiliary follow current discharge to the induced electromotive force through the second rectification module 30, so as to inhibit the high voltage, and meanwhile, the induced electromotive force generated by the winding coil of the ac motor 80 can be transmitted to the switch module 40 through the second rectification module 30 to form a high voltage, so that the first absorption unit also inhibits the high voltage in the switch module 40 at the same time, and can absorb high-frequency electromagnetic noise formed when the switch module 40 switches, thereby improving EMC performance.

The speed regulating circuit of the alternating current motor provided by the embodiment of the invention may further include a second RC absorption module 90, where the second RC absorption module includes a third capacitor FC2 and a third resistor FR1, one end of the third capacitor FC2 is connected to one end of the third resistor FR1, the other end of the third capacitor FC2 is connected to one end of the main winding of the alternating current motor set 80, and the other end of the third resistor FR1 is connected to the other end of the main winding of the alternating current motor set 80. The same as the first RC absorbing unit, when the switching tube of the switching module 40 generates a high voltage formed by induced electromotive force at the winding coil of the ac motor 80 when the switch is turned off, the first RC absorbing unit forms follow current to the induced electromotive force and releases the follow current, so as to suppress the high voltage, and the second RC absorbing unit can suppress the high voltage on the switching tube of the induced electromotive force switching module 40 through the second rectifying module 30, absorb high frequency electromagnetic noise formed when the switching of the switching module 40 is switched, and improve EMC performance.

The alternating current motor speed regulation circuit provided by the embodiment of the invention also comprises a filtering module A0, wherein the filtering module A0 is composed of an electrolytic capacitor E1, the direct current bus voltage rectified by the rectifier bridge DR1 is subjected to smooth filtering, and in order to increase the filtering effect, an electrolytic capacitor E2 can be added.

The speed regulating circuit for the ac motor according to the embodiment of the present invention may further include a first capacitor C6, where two ends of the first capacitor C6 are respectively connected to the output end of the first freewheel module 50 and the input end of the second freewheel module 60, that is, a cathode of the first diode FD5 and an anode of the second diode FD 6. The first capacitor C6 functions to reduce the impedance of the freewheel circuit to facilitate the freewheel circuit to rapidly freewheel the induced electromotive force generated by the winding coil of the ac motor 80.

The alternating current motor speed regulation circuit provided by the embodiment of the invention utilizes the follow current module consisting of the diode to provide the follow current loop for generating induced electromotive force on the winding coil of the alternating current motor, the follow current loop passes through the existing rectifier bridge stack and the load in the circuit, the follow current of the electronic switch is not required to be additionally added, the cost can be greatly reduced, the MCU is not required to be controlled during follow current, and the MCU is completely realized by a simple hardware circuit, so the reliability of the work is high, the problem of device damage caused by control in the prior art is avoided, and the EMC performance of the current is improved.

Referring to fig. 6, fig. 6 is a circuit module structure diagram provided by a third embodiment of the ac motor speed regulating circuit of the present invention, and based on the first embodiment of the compressor protection circuit of the present invention, the ac motor speed regulating circuit further includes a first PFC module B0, the first PFC module B0 is connected in series between the ac input terminal and the first rectification module 10, the input terminal of the first PFC module B is connected to the ac input terminal, and the output terminal of the first PFC module B is connected to the first rectification module 10, so as to perform power factor correction on the dc voltage output by the first rectification module 10.

In this embodiment, two connection manners are specifically provided according to the difference between the connection positions of the one input end of the second rectification module 30 and the input end of the motor at the ac end with respect to the first PFC module B0, fig. 6 shows that the one input end of the second rectification module 30 and the input end of the motor are connected to the ac input end, that is, the input end side of the first PFC module B0, fig. 8 shows that the one input end of the second rectification module 30 and the input end of the motor are connected to the output end side of the first PFC module B0, and a power supply loop to the motor in fig. 8 needs to pass through the first PFC module B0. The first PFC module B0 of fig. 6 and 8 participates in a freewheeling circuit of induced electromotive force generated on the winding coil of the ac motor 80.

Fig. 7 and 9 are circuit structure diagrams of an ac motor speed regulating circuit provided in an embodiment of the present invention based on fig. 4 and 6, respectively. Compared with the ac motor speed regulation circuit shown in fig. 5, the difference is that a PFC module B0 is added, the specific circuit of the load 20 is also different, and other modules are the same as those shown in fig. 5, and therefore, the description thereof is omitted. The first PFC module B0 mainly includes a first PFC inductor L1, which is connected in series to the ac terminal, and the PFC circuit is a passive PFC circuit, and power factor correction of the dc voltage output by the first rectifier module 10 is performed through the inductor L1.

The freewheeling circuits in the circuits shown in fig. 7 and 9 are different from those in fig. 5 in that a first PFC inductor L1 is added from the ac input terminal L to the bridge rectifier DR1, so that the freewheeling circuit thereof is added near the L-line input terminal to pass through the first PFC inductor L1, and the rest is the same as that in fig. 5. In the circuit shown in fig. 9, because the power supply loop of the ac motor needs to pass through the first PFC inductor L1 at the ac input terminal, noise generated by the switching module during high-speed switching can be effectively eliminated, and EMC performance of the circuit is improved.

Referring to fig. 10, fig. 10 is a circuit module structure diagram provided by a fourth embodiment of the ac motor speed regulating circuit of the present invention, and based on the first embodiment of the compressor protection circuit of the present invention, the ac motor speed regulating circuit further includes two PFC modules C0, the second PFC module C0 is connected in series between the first rectifier module 10 and the load 20 through a dc bus, that is, an input end of the second PFC module C0 is connected to the first rectifier module 10, and an output end of the second PFC module C0 is connected to the load 20, so as to perform power factor correction on the dc voltage output by the first rectifier module 10.

The second PFC module C0 may participate in a freewheel loop in addition to the power factor correction discussed above, and may function to form a freewheel loop with the first and

second freewheel modules

50 and 60 and the first rectifier module 10. Referring to fig. 11, fig. 11 is a circuit structure diagram of an ac motor speed regulating circuit according to an embodiment of the present invention based on fig. 10. Compared with the ac motor speed regulation circuit shown in fig. 5, the difference is that a second PFC module C0 is added, the specific circuit of the load 20 is also different, and other modules are the same as those shown in fig. 5, and therefore, the description thereof is omitted.

The second PFC module C0 mainly includes an active PFC circuit including a second PFC inductor L2, an IGBT switching tube Q1, and a diode D1, the MCU70 outputs a PWM signal to the IGBT driving circuit through a pin P2 to drive the switching tube Q1 to operate, and the MCU detects an input voltage and an output voltage of the second PFC module C0 through a voltage detection current including a resistor R1 and a resistor R2, and a resistor R7 and a resistor R8, so as to output a suitable PWM signal to control the second PFC module C0 to operate.

The load 20 here mainly comprises an ipm (intelligent Power module) and a motor, and forms a driving circuit of the motor, although the motor may also be a compressor to form a driving circuit of the compressor.

When the switching transistor Q1 of the second PFC module C0 is turned on, the second PFC module C0 may also participate in forming a freewheeling loop at this time. When the current direction of the alternating current power supply is from the L line to generate induced electromotive force on the winding coil of the alternating current motor 80, the freewheeling circuit of the alternating current power supply passes from the L line through the 4 th pin which is the output end of the positive pole of the rectifier bridge stack DR1, the positive pole of the direct current bus, the second PFC inductor L2, the collector and the emitter of the switching tube Q1, the negative pole of the direct current bus, the resistor R0, the anode and the cathode of the second diode FD6, the anode and the cathode of the diode FD3, and the N line from the alternating current motor 80 back to the alternating current power supply; when the current direction of the alternating current power supply is from the N line to generate induced electromotive force on a winding coil of the alternating current motor 80, a follow current loop of the alternating current power supply enters from the N line to the second PFC inductor L2 through the alternating current motor 80, the anode and the cathode of the diode FD4, the anode and the cathode of the first diode FD5, the anode of the direct current bus, the collector and the emitter of the switching tube Q1, the cathode of the direct current bus, the resistor R0, the cathode output end, namely the 1 st pin, of the rectifier bridge stack DR1, and finally returns to the L line of the alternating current power supply.

If the switch Q1 of the second PFC module C0 is not turned on, the freewheeling circuit is different from the switch Q1 in that the freewheeling circuit is turned on not via the switch Q1 but via the IPM module and the motor of the load 20, and the other circuit components are the same as those described above.

Because the bleeder circuit directly passes through the switch tube without passing through a load when the switch tube of the PFC module is switched on, the bleeder circuit is shortened, and the line impedance can be reduced, thereby being more favorable for the quick bleeder of the induced electromotive force when the PFC module participates in the formation of the bleeder circuit.

The second PFC module, in addition to participating in the freewheeling circuit, can also participate in the power supply of ac motor 80, and together with switching module 40, provides current for the operation of ac motor 80. IN fig. 11, IN the current loop for supplying power to the motor, when the current of the ac power supply starts from ACN-IN, i.e. the ac N line, the current returns to ACL-IN, i.e. the ac L line of the ac power supply through the motor 80, the diode FD4, the collector and emitter of the first switching tube Q2, and the diode FD2, the other branch is separated at the cathode of the diode FD4 and returns to ACL-IN, i.e. the ac L line of the ac power supply through the first diode FD5, the positive electrode of the dc bus, the second PFC inductor L2, the collector and emitter of the switching tube Q1, the negative electrode of the dc bus, the resistor R0, and the negative electrode of the output end of the rectifier bridge DR 1. The two current loops are branched from the positive pole of the output end of the second rectifying module 30, one current loop passes through the switch module 40, the other current loop passes through the second PFC module C0, and finally returns to the alternating current L line, so that when the switching tube of the second PFC module C0 is switched on, the current passing through the switching tube Q2 of the switch module 40 is reduced, the heat generated during the work of the switching tube Q2 is reduced, the working reliability of the switch module is improved, meanwhile, the switching tube Q2 can adopt a relatively low-power device before being switched off, the cost of the switch module is reduced, and the cost of the whole alternating current motor speed regulation circuit is reduced.

Referring to fig. 12, fig. 12 is a circuit module structure diagram provided by a fifth embodiment of the ac motor speed regulating circuit of the present invention, and based on the first embodiment of the compressor protection circuit of the present invention, compared with the ac motor speed regulating circuit of fig. 10, the difference is that the connection lines of the first freewheel module 50 and the second freewheel module 60 are different, and the other modules are the same as those shown in fig. 10, and therefore, the description thereof is omitted.

The input end of the second freewheeling module 60 is connected to the negative electrode of the output end of the second PFC module C0, and the output end of the second freewheeling module 60 is connected to the negative electrode of the output end of the second rectification module 30; the input end of the first freewheeling module 50 is connected to the positive electrode of the output end of the second rectifying module 30, and the output end of the first freewheeling module 50 is connected to the positive electrode of the output end of the second PFC module C0.

Fig. 13 is a circuit structure diagram based on fig. 11 of an ac motor speed regulating circuit according to an embodiment of the present invention. The difference from fig. 11 is that the connection lines of the first diode FD5 constituting the first freewheel module 50 and the second diode FD6 constituting the second freewheel module 60 are different, and specifically, the difference is that the cathode of the first diode FD5 is connected to the cathode of the diode D1 of the second PFC module C0, and the anode of the second diode FD6 is connected to the emitter of the IGBT switching tube Q1 of the second PFC module C0. The cathode of the first diode FD5 and the anode of the second diode FD6 are connected to the output terminal of the second PFC module C0, so that the freewheeling circuit thereof is isolated by the diode D1, which requires the load to participate, and does not pass through the IGBT switching tube Q1 of the second PFC module C0, and the IPM module and the motor of the load 20 need to pass through, and the rest is the same as that in fig. 11.

Referring to fig. 14, fig. 14 is a circuit module structure diagram provided by a sixth embodiment of the ac motor speed regulating circuit of the present invention, and based on the first embodiment of the compressor protection circuit of the present invention, compared with the ac motor speed regulating circuit of fig. 10, the difference is that the connection lines of the first freewheel module 50 and the second freewheel module 60 are different, and other modules are the same as those shown in fig. 10, and therefore, the description thereof is omitted.

The input end of the second follow current module 60 is connected with the negative electrode of the output end of the first rectifying module 10, and the output end of the second follow current module 60 is connected with the negative electrode of the output end of the second rectifying module 30; the input end of the first freewheeling module 50 is connected to the positive electrode of the output end of the second rectifying module 30, and the output end of the first freewheeling module 50 is connected to the positive electrode of the output end of the second PFC module C0.

Fig. 15 is a circuit configuration diagram of an ac motor speed regulating circuit according to an embodiment of the present invention, which is based on fig. 14, and is different from fig. 11 in that connection lines of a first diode FD5 constituting the first freewheel module 50 and a second diode FD6 constituting the second freewheel module 60 are different, and specifically, a cathode of the first diode FD5 is connected to a cathode of a diode D1 of the second PFC module C0, and an anode of the second diode FD6 is connected to a cathode of an output terminal of the rectifier bridge stack DR 1.

When the switching transistor Q1 of the second PFC module C0 is turned on, the second PFC module C0 may also participate in forming a freewheeling loop at this time. When the current direction of the alternating current power supply starts from an L line and induced electromotive force is generated on a winding coil of the alternating current motor 80, a follow current loop of the alternating current power supply starts from the L line and passes through a 4 th pin which is the output end of the positive pole of the rectifier bridge stack DR1, the positive pole of a direct current bus, a second PFC inductor L2, the collector and the emitter of the switching tube Q1, the negative pole of the direct current bus, the anode and the cathode of a second diode FD6, the anode and the cathode of a diode FD3 and an N line which returns to the alternating current power supply from the alternating current motor 80; when the current direction of the ac power supply is from the N-line to generate an induced electromotive force in the winding coil of the ac motor 80, since the cathode of the first diode FD5 is connected to the cathode of the diode D1 of the second PFC module C0, the freewheeling circuit cannot pass through the switching tube Q1 at this time, and needs to pass through the IPM module of the load 20, specifically, the freewheeling circuit thereof passes through the ac motor 80 from the N-line, the anode and cathode of the diode FD4, the anode and cathode of the first diode FD5, the anode of the dc bus, the IPM module of the load 20, the dc bus, the negative electrode of the rectifier bridge DR1, the output terminal of the negative electrode, i.e., the 1 st pin, and finally the L-line returning to the ac power supply.

Similar to fig. 11, since the bleeding circuit from the ac L line directly passes through the switching tube without passing through the load when the switching tube of the PFC module is turned on, the bleeding circuit is shortened, and the line impedance can be reduced, which is more favorable for the rapid bleeding of the induced electromotive force when the PFC module participates in forming the bleeding circuit.

Referring to fig. 16, fig. 16 is a circuit module structure diagram provided by a seventh embodiment of the ac motor speed regulating circuit of the present invention, and based on the first embodiment of the ac motor speed regulating circuit of the present invention, different from fig. 2 in the connection manner of the first freewheel module 50 and the second freewheel module 60, the specific connection manner of the first freewheel module 50 and the second freewheel module 60 is as follows: the input end of the first follow current module 50 is connected with the positive electrode of the output end of the second rectifying module 30, and the output end of the first follow current module 50 is connected with the positive electrode of the output end of the first rectifying module 10; the output end of the second flywheel module 60 and an input end of the motor 80 are connected to an input end of the second rectification module 30, and the input end of the second flywheel module 60 is connected to the negative electrode of the output end of the first rectification module 10. Since the second freewheel module 60 is connected to the input terminal of the second rectifier module 30, and the first freewheel module 50 is connected to the output terminal of the second rectifier module 30, the current direction of the ac power supply in the freewheel loop needs to be participated in by the second rectifier module 30 from the N line, and the current direction of the ac power supply needs not to be participated in by the second rectifier module 30 from the L line.

Referring to fig. 17, fig. 17 is a circuit structure diagram of an ac motor speed regulating circuit according to an embodiment of the present invention based on fig. 16. Different from fig. 5, the connection mode of the second freewheel module 60 is different, the input end of the first freewheel module 50 is connected with the positive electrode of the output end of the second rectification module 30, and the output end of the first freewheel module 50 is connected with the positive electrode of the output end of the first rectification module 10; the output end of the second flywheel module 60 and an input end of the motor 80 are connected to an input end of the second rectification module 30, and the input end of the second flywheel module 60 is connected to the negative electrode of the output end of the first rectification module 10. The follow current loop is as follows: when the current direction of the alternating current power supply starts from the L line and generates induced electromotive force on the winding coil of the alternating current motor 80, the follow current loop of the alternating current power supply starts from the L line, passes through the output end of the positive pole of the rectifier bridge stack DR1, namely the 4 th pin, the positive pole of the direct current bus enters the direct current load 20, the negative pole of the direct current bus enters the anode and the cathode of the second diode FD6, and the alternating current motor 80 returns to the N line of the alternating current power supply, namely the participation of the second rectifier module 30 is not needed; when the current direction of the alternating current power supply starts from an N line and generates induced electromotive force on a winding coil of the alternating current motor 80, a follow current loop of the alternating current power supply starts from the N line and enters the direct current load 20 through the alternating current motor 80, the anode and the cathode of the diode FD4, the anode and the cathode of the first diode FD5 and the anode of the direct current bus, the cathode of the direct current bus enters the output end, namely the 1 st pin, of the cathode of the rectifier bridge stack DR1, and finally returns to the L line of the alternating current power supply, namely the participation of the second rectifier module 30 is required.

Referring to fig. 18, fig. 18 is a circuit module structure diagram provided by an ac motor speed regulating circuit according to an eighth embodiment of the present invention, and based on the seventh embodiment of the compressor protection circuit according to the present invention, the ac motor speed regulating circuit further includes a first PFC module B0, the first PFC module B0 is connected in series between the ac input terminal and the first rectification module 10, the input terminal of the first PFC module B is connected to the ac input terminal, and the output terminal of the first PFC module B is connected to the first rectification module 10, so as to perform power factor correction on the dc voltage output by the first rectification module 10.

In this embodiment, two connection manners are specifically provided according to the difference between the connection positions of the one input end of the second rectification module 30 and the input end of the motor at the ac end with respect to the first PFC module B0, fig. 18 shows that the one input end of the second rectification module 30 and the input end of the motor are connected to the ac input end, that is, the input end side of the first PFC module B0, fig. 20 shows that the one input end of the second rectification module 30 and the input end of the motor are connected to the output end side of the first PFC module B0, and a power supply loop to the motor in fig. 20 needs to pass through the first PFC module B0. The first PFC module B0 of fig. 18 and 20 participates in a freewheeling circuit of induced electromotive force generated on the winding coil of the ac motor 80.

Fig. 19 and 21 are circuit structure diagrams based on fig. 18 and 20 of an ac motor speed regulating circuit provided by an embodiment of the present invention, respectively. Compared with the ac motor speed regulation circuit shown in fig. 5, the difference is that a PFC module B0 is added, the specific circuit of the load 20 is also different, and other modules are the same as those shown in fig. 5, and therefore, the description thereof is omitted. The first PFC module B0 mainly includes a first PFC inductor L1, which is connected in series to the ac terminal, and the PFC circuit is a passive PFC circuit, and power factor correction of the dc voltage output by the first rectifier module 10 is performed through the inductor L1.

The freewheeling circuits in the circuits shown in fig. 19 and 21 are different from those in fig. 5 in that a first PFC inductor L1 is added from the ac input terminal L to the bridge rectifier DR1, so that the freewheeling circuit thereof is added near the L-line input terminal to pass through the first PFC inductor L1, and the rest is the same as that in fig. 5. In the circuit shown in fig. 21, because the power supply loop of the ac motor needs to pass through the first PFC inductor L1 at the ac input terminal, noise generated by the switching module during high-speed switching can be effectively eliminated, and EMC performance of the circuit is improved.

Referring to fig. 22, fig. 22 is a circuit module structure diagram provided by a ninth embodiment of the ac motor speed regulating circuit according to the present invention, and based on the seventh embodiment of the compressor protection circuit according to the present invention, the ac motor speed regulating circuit further includes a second PFC module C0, and the second PFC module C0 is connected in series between the first rectifier module 10 and the load 20 through a dc bus to perform power factor correction on the dc voltage output by the first rectifier module 10.

second freewheel modules

50 and 60 and the first rectifier module 10. Referring to fig. 23, fig. 21 is a circuit structure diagram of an ac motor speed regulating circuit according to an embodiment of the present invention based on fig. 21. Compared with the ac motor speed regulation circuit shown in fig. 11, the difference is that the connection lines of the first freewheel module 50 and the second freewheel module 60 are different, and the rest are the same as those shown in fig. 11, and therefore, the description is omitted.

When the switching transistor Q1 of the second PFC module C0 is turned on, the second PFC module C0 may also participate in forming a freewheeling loop at this time. When the current direction of the alternating current power supply starts from an L line and induced electromotive force is generated on a winding coil of the alternating current motor 80, a follow current loop of the alternating current power supply starts from the L line and returns to an N line of the alternating current power supply through a 4 th pin which is the output end of the positive pole of the rectifier bridge stack DR1, the positive pole of a direct current bus, a second PFC inductor L2, the collector and the emitter of the switching tube Q1, the negative pole of the direct current bus, a resistor R0, the anode and the cathode of a second diode FD6 and the alternating current motor 80; when the current direction of the alternating current power supply is from the N line to generate induced electromotive force on a winding coil of the alternating current motor 80, a follow current loop of the alternating current power supply enters from the N line to the second PFC inductor L2 through the alternating current motor 80, the anode and the cathode of the diode FD4, the anode and the cathode of the first diode FD5, the anode of the direct current bus, the collector and the emitter of the switching tube Q1, the cathode of the direct current bus, the resistor R0, the cathode output end, namely the 1 st pin, of the rectifier bridge stack DR1, and finally returns to the L line of the alternating current power supply.

The second PFC module, in addition to participating in the freewheeling circuit, can also participate in the power supply of ac motor 80, and together with switching module 40, provides current for the operation of ac motor 80. IN fig. 23, IN the current loop for supplying power to the motor, when the current of the ac power supply starts from ACN-IN, i.e. the ac N line, the current returns to ACL-IN, i.e. the ac L line of the ac power supply through the motor 80, the diode FD4, the collector and emitter of the first switching tube Q2, and the diode FD2, the other branch is separated at the cathode of the diode FD4 and returns to ACL-IN, i.e. the ac L line of the ac power supply through the first diode FD5, the positive electrode of the dc bus, the second PFC inductor L2, the collector and emitter of the switching tube Q1, the negative electrode of the dc bus, the resistor R0, and the negative electrode of the output end of the rectifier bridge DR 1. The two current loops are branched from the positive pole of the output end of the second rectifying module 30, one current loop passes through the switch module 40, the other current loop passes through the second PFC module C0, and finally returns to the alternating current L line, so that when the switching tube of the second PFC module C0 is switched on, the current passing through the switching tube Q2 of the switch module 40 is reduced, the heat generated during the work of the switching tube Q2 is reduced, the working reliability of the switch module is improved, meanwhile, the switching tube Q2 can adopt a relatively low-power device before being switched off, the cost of the switch module is reduced, and the cost of the whole alternating current motor speed regulation circuit is reduced.

Referring to fig. 24, fig. 24 is a circuit module structure diagram provided by a tenth embodiment of the ac motor speed regulating circuit according to the present invention, and based on the seventh embodiment of the compressor protection circuit according to the present invention, compared with the ac motor speed regulating circuit shown in fig. 22, the difference is that the connection lines of the first freewheel module 50 and the second freewheel module 60 are different, and the other modules are the same as those shown in fig. 22, and therefore, the description thereof is omitted.

The input end of the second freewheeling module 60 is connected to the negative electrode of the output end of the second PFC module C0, and the output end of the second freewheeling module 60 and one end of the motor 80 are commonly connected to one input end of the second rectification module 30; the input end of the first freewheeling module 50 is connected to the positive electrode of the output end of the second rectifying module 30, and the output end of the first freewheeling module 50 is connected to the positive electrode of the output end of the second PFC module C0.

Fig. 25 is a circuit structure diagram based on fig. 24 of an ac motor speed regulating circuit according to an embodiment of the present invention. The difference from fig. 23 is that the connection lines of the first diode FD5 constituting the first freewheel module 50 and the second diode FD6 constituting the second freewheel module 60 are different, and specifically the difference is that the cathode of the first diode FD5 is connected to the cathode of the diode D1 of the second PFC module C0, and the anode of the second diode FD6 is connected to the emitter of the IGBT switching tube Q1 of the second PFC module C0. The cathode of the first diode FD5 and the anode of the second diode FD6 are connected to the output terminal of the second PFC module C0, so that the freewheeling circuit thereof is isolated by the diode D1, which requires the load to participate, and does not pass through the IGBT switching tube Q1 of the second PFC module C0, and the IPM module and the motor of the load 20 need to pass through, and the rest is the same as that in fig. 21.

Referring to fig. 26, fig. 26 is a circuit module structure diagram of an eleventh embodiment of an ac motor speed regulation circuit according to the present invention, and based on the seventh embodiment of the compressor protection circuit according to the present invention, compared with the ac motor speed regulation circuit shown in fig. 22, the difference is that connection lines of the first freewheel module 50 and the second freewheel module 60 are different, and other modules are the same as those shown in fig. 22, and therefore, description thereof is omitted.

The input end of the second flywheel module 60 is connected with the negative electrode of the output end of the first rectification module 10, and the output end of the second flywheel module 60 and one end of the motor 80 are connected to one input end of the second rectification module 30 in common; the input end of the first freewheeling module 50 is connected to the positive electrode of the output end of the second rectifying module 30, and the output end of the first freewheeling module 50 is connected to the positive electrode of the output end of the second PFC module C0.

Fig. 27 is a circuit structure diagram based on fig. 26 of an ac motor speed regulating circuit according to an embodiment of the present invention. The difference from fig. 23 is that the connection lines of the first diode FD5 constituting the first freewheel module 50 and the second diode FD6 constituting the second freewheel module 60 are different, and specifically, the difference is that the cathode of the first diode FD5 is connected to the cathode of the diode D1 of the second PFC module C0, and the anode of the second diode FD6 is connected to the cathode of the output terminal of the bridge rectifier DR 1.

When the switching transistor Q1 of the second PFC module C0 is turned on, the second PFC module C0 may also participate in forming a freewheeling loop at this time. When the current direction of the alternating current power supply starts from an L line and induced electromotive force is generated on a winding coil of the alternating current motor 80, a follow current loop of the alternating current power supply starts from the L line and returns to an N line of the alternating current power supply through a 4 th pin which is the output end of the positive pole of the rectifier bridge stack DR1, the positive pole of the direct current bus, the second PFC inductor L2, the collector and the emitter of the switching tube Q1, the negative pole of the direct current bus, the anode and the cathode of the second diode FD6 and the alternating current motor 80; when the current direction of the ac power supply is from the N-line to generate an induced electromotive force in the winding coil of the ac motor 80, since the cathode of the first diode FD5 is connected to the cathode of the diode D1 of the second PFC module C0, the freewheeling circuit cannot pass through the switching tube Q1 at this time, and needs to pass through the IPM module of the load 20, specifically, the freewheeling circuit thereof passes through the ac motor 80 from the N-line, the anode and cathode of the diode FD4, the anode and cathode of the first diode FD5, the anode of the dc bus, the IPM module and the motor of the load 20, the cathode of the dc bus, the resistor R0, the output end of the cathode of the rectifier bridge DR1, i.e., the 1 st pin, and finally the L-line returning to the ac power supply.

Similar to fig. 23, since the bleeding circuit from the ac L line directly passes through the switching tube without passing through the load when the switching tube of the PFC module is turned on, the bleeding line is shortened, and the line impedance can be reduced, which is more favorable for the rapid bleeding of the induced electromotive force when the PFC module participates in forming the bleeding circuit.

Referring to fig. 28, fig. 28 is a circuit module structure diagram provided by a twelfth embodiment of the ac motor speed regulating circuit of the present invention, and based on the first embodiment of the ac motor speed regulating circuit of the present invention, different from fig. 2 in the connection manner of the first freewheel module 50 and the second freewheel module 60, the specific connection manner of the first freewheel module 50 and the second freewheel module 60 is as follows: the output end of the second freewheel module 60, the input end of the first freewheel module 50 and one end of the motor 80 are connected to one input end of the second rectification module 30, the input end of the second freewheel module 60 is connected to the negative electrode of the output end of the first rectification module 10, and the output end of the first freewheel module 50 is connected to the positive electrode of the output end of the first rectification module 10. Since the first freewheel module 50 and the second freewheel module 60 are both connected to the input end of the second rectifier module 30, the freewheel loop does not need to be involved by the second rectifier module 30 whether the current direction of the ac power supply is from the N line or the L line.

Referring to fig. 29, fig. 29 is a circuit structure diagram of an ac motor speed regulating circuit according to an embodiment of the present invention, based on fig. 28. Different from fig. 5, the second freewheel module 60 is connected in a different manner, in which the anode of the second diode FD6 constituting the second freewheel module 60 is connected to the cathode of the output terminal of the bridge rectifier DR1, the cathode of the second diode FD6 and the anode of the first diode FD5 constituting the first freewheel module 50 and one end of the motor 80 are connected in common to one input terminal of the second rectifier module, i.e., the connection point of the anode of the diode FD4 and the cathode of the diode FD3, and the cathode of the first diode FD5 is connected to the anode of the output terminal of the bridge rectifier DR 1. The follow current loop is as follows: when the current direction of the alternating current power supply starts from the L line and generates induced electromotive force on the winding coil of the alternating current motor 80, the follow current loop of the alternating current power supply starts from the L line, passes through the output end of the positive pole of the rectifier bridge stack DR1, namely the 4 th pin, the positive pole of the direct current bus enters the direct current load 20, the negative pole of the direct current bus enters the anode and the cathode of the second diode FD6, and the alternating current motor 80 returns to the N line of the alternating current power supply, namely the participation of the second rectifier module 30 is not needed; when the current direction of the alternating current power supply starts from an N line and generates induced electromotive force on a winding coil of the alternating current motor 80, a follow current loop of the alternating current power supply starts from the N line, enters the direct current load 20 through the alternating current motor 80, the anode and the cathode of the first diode FD5 and the anode of the direct current bus, enters the negative output end, namely the 1 st pin, of the rectifier bridge stack DR1 and finally returns to an L line of the alternating current power supply, namely the second rectifier module 30 is not required to participate.

Referring to fig. 30, fig. 30 is a circuit module structure diagram of an ac motor speed regulating circuit according to a thirteenth embodiment of the present invention, and based on the twelfth embodiment of the compressor protection circuit according to the present invention, the ac motor speed regulating circuit further includes a first PFC module B0, the first PFC module B0 is connected in series between the ac input terminal and the first rectification module 10, the input terminal of the first PFC module B is connected to the ac input terminal, and the output terminal of the first PFC module B is connected to the first rectification module 10, so as to perform power factor correction on the dc voltage output by the first rectification module 10.

In this embodiment, two connection manners are specifically provided according to the difference between the connection positions of the one input end of the second rectification module 30 and the input end of the motor at the ac end with respect to the first PFC module B0, fig. 30 shows that the one input end of the second rectification module 30 and the input end of the motor are connected to the ac input end, that is, the input end side of the first PFC module B0, fig. 32 shows that the one input end of the second rectification module 30 and the input end of the motor are connected to the output end side of the first PFC module B0, and a power supply loop to the motor in fig. 32 needs to pass through the first PFC module B0. The first PFC module B0 of fig. 30 and 32 participates in a freewheeling circuit of induced electromotive force generated on the winding coil of the ac motor 80.

Fig. 31 and 33 are circuit structure diagrams based on fig. 300 and 32, respectively, of an ac motor speed regulation circuit provided in an embodiment of the present invention. Compared with the ac motor speed regulation circuit shown in fig. 5, the difference is that a PFC module B0 is added, the specific circuit of the load 20 is also different, and other modules are the same as those shown in fig. 5, and therefore, the description thereof is omitted. The first PFC module B0 mainly includes a first PFC inductor L1, which is connected in series to the ac terminal, and the PFC circuit is a passive PFC circuit, and power factor correction of the dc voltage output by the first rectifier module 10 is performed through the inductor L1.

The freewheeling circuits in the circuits shown in fig. 31 and 33 are different from those in fig. 5 in that a first PFC inductor L1 is added from the ac input terminal L to the bridge rectifier DR1, so that the freewheeling circuit thereof is added near the L-line input terminal to pass through the first PFC inductor L1, and the rest is the same as that in fig. 5. In the circuit shown in fig. 33, since the power supply loop of the ac motor needs to pass through the first PFC inductor L1 at the ac input terminal, noise generated by the switching module during high-speed switching can be effectively eliminated, and EMC performance of the circuit is improved.

Referring to fig. 34, fig. 34 is a circuit module structure diagram provided in a fourteenth embodiment of the ac motor speed regulating circuit of the present invention, and based on the twelfth embodiment of the compressor protection circuit of the present invention, the ac motor speed regulating circuit further includes a second PFC module C0, and the second PFC module C0 is connected in series between the first rectifier module 10 and the load 20 through a dc bus to perform power factor correction on the dc voltage output by the first rectifier module 10.

second freewheel modules

50 and 60 and the first rectifier module 10. Referring to fig. 35, fig. 35 is a circuit structure diagram of an ac motor speed regulating circuit according to an embodiment of the present invention, based on fig. 34. Compared with the ac motor speed regulation circuit shown in fig. 11, the difference is that the connection lines of the first freewheel module 50 and the second freewheel module 60 are different, and the rest are the same as those shown in fig. 11, and therefore, the description is omitted.

When the switching transistor Q1 of the second PFC module C0 is turned on, the second PFC module C0 may also participate in forming a freewheeling loop at this time. When the current direction of the alternating current power supply starts from an L line and induced electromotive force is generated on a winding coil of the alternating current motor 80, a follow current loop of the alternating current power supply starts from the L line and returns to an N line of the alternating current power supply through a 4 th pin which is the output end of the positive pole of the rectifier bridge stack DR1, the positive pole of a direct current bus, a second PFC inductor L2, the collector and the emitter of the switching tube Q1, the negative pole of the direct current bus, a resistor R0, the anode and the cathode of a second diode FD6 and the alternating current motor 80; when the current direction of the alternating current power supply is from the N line to generate induced electromotive force on a winding coil of the alternating current motor 80, a follow current loop of the alternating current power supply enters from the N line through the alternating current motor 80, the anode and the cathode of the first diode FD5, the positive electrode of the direct current bus into the second PFC inductor L2, the collector and the emitter of the switching tube Q1, the negative electrode of the direct current bus, the resistor R0, enters the negative output end of the rectifier bridge stack DR1, namely the 1 st pin, and finally returns to the L line of the alternating current power supply.

The second PFC module, in addition to participating in the freewheeling circuit, can also participate in the power supply of ac motor 80, and together with switching module 40, provides current for the operation of ac motor 80. IN fig. 35, IN the current circuit for supplying power to the motor, when the current of the ac power supply starts from ACN-IN, i.e. ac N line, and returns to ACL-IN, i.e. ac L line of the ac power supply through the motor 80, the diode FD4, the collector and emitter of the first switching tube Q2, and the diode FD2, the current circuit is formed, and the other branch is separated from the anode of the diode FD4 and returns to ACL-IN, i.e. ac L line of the ac power supply through the first diode FD5, the positive electrode of the dc bus, the second PFC inductor L2, the collector and emitter of the switching tube Q1, the negative electrode of the dc bus, the resistor R0, and the negative electrode of the output terminal of the rectifier bridge DR 1. The two current loops are branched from an input end of the second rectifying module 30, one current loop passes through the second rectifying module 30 and the switch module 40, the other current loop passes through the second PFC module C0, and finally returns to the AC L line, so that when a switching tube of the second PFC module C0 is switched on, the current can be shunted for the switch module 40, the current passing through the switching tube Q2 of the switch module 40 is reduced, the heat generated during the operation of the switching tube Q2 is reduced, the working reliability of the switch module is improved, meanwhile, a relatively low-power device can be adopted for the switching tube Q2 before shunting, the cost of the switch module is reduced, and the cost of the whole AC motor speed regulating circuit is reduced.

Referring to fig. 36, fig. 36 is a circuit module structure diagram provided by a fifteenth embodiment of the ac motor speed regulating circuit of the present invention, and based on the twelfth embodiment of the compressor protection circuit of the present invention, compared with the ac motor speed regulating circuit of fig. 34, the difference is that connection lines of the first freewheel module 50 and the second freewheel module 60 are different, and other modules are the same as those shown in fig. 34, and therefore, description thereof is omitted.

The input end of the second freewheel module 60 is connected to the negative electrode of the output end of the second PFC module C0, the output end of the second freewheel module 60, the input end of the first freewheel module 50 and one end of the electric machine 80 are commonly connected to one input end of the second rectification module 30, and the output end of the first freewheel module 50 is connected to the positive electrode of the output end of the second PFC module C0.

Fig. 37 is a circuit structure diagram based on fig. 36 of an ac motor speed regulating circuit according to an embodiment of the present invention. The difference from fig. 35 is that the connection lines of the first diode FD5 constituting the first freewheel module 50 and the second diode FD6 constituting the second freewheel module 60 are different, and specifically the difference is that the cathode of the first diode FD5 is connected to the cathode of the diode D1 of the second PFC module C0, and the anode of the second diode FD6 is connected to the emitter of the IGBT switching tube Q1 of the second PFC module C0. The cathode of the first diode FD5 and the anode of the second diode FD6 are connected to the output terminal of the second PFC module C0, so that the freewheeling circuit thereof is isolated by the diode D1, which requires the load to participate, and does not pass through the IGBT switching tube Q1 of the second PFC module C0, and the IPM module and the motor of the load 20 need to pass through, and the rest is the same as that in fig. 35.

Referring to fig. 38, fig. 38 is a circuit module structure diagram of an ac motor speed regulation circuit according to a sixteenth embodiment of the present invention, and based on the twelfth embodiment of the compressor protection circuit according to the present invention, compared with the ac motor speed regulation circuit shown in fig. 34, the difference is that connection lines of the first freewheel module 50 and the second freewheel module 60 are different, and other modules are the same as those shown in fig. 34, and therefore, description thereof is omitted.

The input end of the second freewheel module 60 is connected to the negative electrode of the output end of the first rectification module 10, the output end of the second freewheel module 60, the input end of the first freewheel module 50 and one end of the motor 80 are connected to one input end of the second rectification module 30, and the output end of the first freewheel module 50 is connected to the positive electrode of the output end of the second PFC module C0.

Fig. 39 is a circuit structure diagram based on fig. 38 of an ac motor speed regulating circuit according to an embodiment of the present invention. The difference from fig. 35 is that the connection lines of the first diode FD5 constituting the first freewheel module 50 and the second diode FD6 constituting the second freewheel module 60 are different, and specifically, the difference is that the cathode of the first diode FD5 is connected to the cathode of the diode D1 of the second PFC module C0, and the anode of the second diode FD6 is connected to the cathode of the output terminal of the bridge rectifier DR 1.

When the switching transistor Q1 of the second PFC module C0 is turned on, the second PFC module C0 may also participate in forming a freewheeling loop at this time. When the current direction of the alternating current power supply starts from an L line and induced electromotive force is generated on a winding coil of the alternating current motor 80, a follow current loop of the alternating current power supply starts from the L line and returns to an N line of the alternating current power supply through a 4 th pin which is the output end of the positive pole of the rectifier bridge stack DR1, the positive pole of the direct current bus, the second PFC inductor L2, the collector and the emitter of the switching tube Q1, the negative pole of the direct current bus, the anode and the cathode of the second diode FD6 and the alternating current motor 80; when the current direction of the ac power supply is from the N-line to generate an induced electromotive force in the winding coil of the ac motor 80, since the cathode of the first diode FD5 is connected to the cathode of the diode D1 of the second PFC module C0, the freewheeling circuit cannot pass through the switching tube Q1 at this time, and needs to pass through the IPM module of the load 20, specifically, the freewheeling circuit of the freewheeling circuit passes through the ac motor 80 from the N-line, the anode and cathode of the first diode FD5, the anode of the dc bus enters the IPM module and motor of the load 20, the cathode of the dc bus, the resistor R0 enters the output terminal of the cathode of the rectifier bridge DR1, i.e., the 1 st pin, and finally returns to the L-line of the ac power supply.

Similar to fig. 35, since the bleeding circuit from the ac L line directly passes through the switching tube without passing through the load when the switching tube of the PFC module is turned on, the bleeding line is shortened, and the line impedance can be reduced, which is more favorable for the rapid bleeding of the induced electromotive force when the PFC module participates in forming the bleeding circuit.

Referring to fig. 40, fig. 40 is a circuit module structure diagram provided in a seventeenth embodiment of the ac motor speed regulating circuit of the present invention, and based on the first embodiment of the ac motor speed regulating circuit of the present invention, different from fig. 2 in the connection manner of the first freewheel module 50 and the second freewheel module 60, the specific connection manner of the first freewheel module 50 and the second freewheel module 60 is as follows: the input end of the first freewheeling module 50 and one end of the motor 80 are connected to one input end of the second rectifying module 30, and the output end of the first freewheeling module 50 is connected to the positive electrode of the output end of the first rectifying module 10; the input end of the second freewheeling module 60 is connected to the negative electrode of the output end of the first rectifying module 10, and the output end of the second freewheeling module 60 is connected to the negative electrode of the output end of the second rectifying module 30. Since the first flywheel module 50 is connected to the input end of the second rectification module 30, and the second flywheel module 60 is connected to the output end of the second rectification module 30, the current direction of the alternating current power supply in the flywheel loop needs to participate in the second rectification module 30 from the L line, and the current direction of the alternating current power supply does not need to participate in the second rectification module 30 from the N line.

Referring to fig. 41, fig. 41 is a circuit structure diagram of an ac motor speed regulating circuit according to an embodiment of the present invention based on fig. 40. Different from fig. 5, the connection mode of the first freewheel module 50 is different, the anode of the second diode FD6 constituting the second freewheel module 60 is connected to the cathode of the output end of the rectifier bridge stack DR1, the cathode of the second diode FD6 is connected to the emitter of the first switch Q2 of the switch module 40, the anode of the first diode FD5 of the first freewheel module 50 and one end of the motor 80 are connected in common to the connection point of the anode of the diode FD4 and the cathode of the diode FD3, which are one input end of the second rectifier module, and the cathode of the first diode FD5 is connected to the anode of the output end of the rectifier bridge stack DR 1. The follow current loop is as follows: when the current direction of the alternating current power supply starts from the L line and generates induced electromotive force on the winding coil of the alternating current motor 80, the follow current loop of the alternating current power supply starts from the L line, passes through the output end of the positive pole of the rectifier bridge stack DR1, namely the 4 th pin, the positive pole of the direct current bus enters the direct current load 20, the negative pole of the direct current bus enters the anode and the cathode of the second diode FD6, the anode and the cathode of the diode FD3, and the alternating current motor 80 returns to the N line of the alternating current power supply, namely the participation of the second rectifier module 30 is required; when the current direction of the alternating current power supply starts from the N line and generates induced electromotive force on the winding coil of the alternating current motor 80, the follow current loop of the alternating current power supply starts from the N line, enters the direct current load 20 through the alternating current motor 80, the anode and the cathode of the first diode FD5, the anode of the direct current bus, enters the negative output end, namely the 1 st pin, of the rectifier bridge stack DR1, and finally returns to the L line of the alternating current power supply, namely the second rectifier module 30 is not needed.

Referring to fig. 42, fig. 42 is a circuit module structure diagram of an ac motor speed regulating circuit according to an eighteenth embodiment of the present invention, and based on the seventeenth embodiment of the compressor protection circuit according to the present invention, the ac motor speed regulating circuit further includes a first PFC module B0, the first PFC module B0 is connected in series between the ac input terminal and the first rectification module 10, the input terminal of the first PFC module B is connected to the ac input terminal, and the output terminal of the first PFC module B0 is connected to the first rectification module 10, so as to perform power factor correction on the dc voltage output by the first rectification module 10.

In this embodiment, two connection manners are specifically provided according to the difference between the connection positions of the one input end of the second rectification module 30 and the input end of the motor at the ac end with respect to the first PFC module B0, fig. 42 shows that the one input end of the second rectification module 30 and the input end of the motor are connected to the ac input end, that is, the input end side of the first PFC module B0, fig. 44 shows that the one input end of the second rectification module 30 and the input end of the motor are connected to the output end side of the first PFC module B0, and a power supply loop to the motor in fig. 44 needs to pass through the first PFC module B0. The first PFC module B0 of fig. 42 and 44 participates in a freewheeling circuit of induced electromotive force generated on the winding coil of the ac motor 80.

Fig. 43 and 45 are circuit structure diagrams based on fig. 42 and 44 of an ac motor speed regulating circuit provided in an embodiment of the present invention, respectively. Compared with the ac motor speed regulation circuit shown in fig. 5, the difference is that a PFC module B0 is added, the specific circuit of the load 20 is also different, and other modules are the same as those shown in fig. 5, and therefore, the description thereof is omitted. The first PFC module B0 mainly includes a first PFC inductor L1, which is connected in series to the ac terminal, and the PFC circuit is a passive PFC circuit, and power factor correction of the dc voltage output by the first rectifier module 10 is performed through the inductor L1.

The freewheeling circuits in the circuits shown in fig. 43 and 45 are different from those in fig. 5 in that a first PFC inductor L1 is added from the ac input terminal L to the bridge rectifier DR1, so that the freewheeling circuit thereof is added near the L-line input terminal to pass through the first PFC inductor L1, and the rest is the same as that in fig. 5. In the circuit shown in fig. 45, since the power supply loop of the ac motor needs to pass through the first PFC inductor L1 at the ac input terminal, noise generated by the switching module during high-speed switching can be effectively eliminated, and EMC performance of the circuit is improved.

Referring to fig. 46, fig. 46 is a circuit module structure diagram provided in a nineteenth embodiment of the ac motor speed regulating circuit according to the present invention, and based on the seventeenth embodiment of the compressor protection circuit according to the present invention, the ac motor speed regulating circuit further includes a second PFC module C0, where the second PFC module C0 is connected in series between the first rectifier module 10 and the load 20 through a dc bus, so as to perform power factor correction on the dc voltage output by the first rectifier module 10.

second freewheel modules

50 and 60 and the first rectifier module 10. Referring to fig. 47, fig. 47 is a circuit structure diagram of an ac motor speed regulating circuit according to an embodiment of the present invention based on fig. 46. Compared with the ac motor speed regulation circuit shown in fig. 11, the difference is that the connection lines of the first freewheel module 50 and the second freewheel module 60 are different, and the rest are the same as those shown in fig. 11, and therefore, the description is omitted.

When the switching transistor Q1 of the second PFC module C0 is turned on, the second PFC module C0 may also participate in forming a freewheeling loop at this time. When the current direction of the alternating current power supply is from the L line to generate induced electromotive force on the winding coil of the alternating current motor 80, the freewheeling circuit of the alternating current power supply passes from the L line through the 4 th pin which is the output end of the positive pole of the rectifier bridge stack DR1, the positive pole of the direct current bus, the second PFC inductor L2, the collector and the emitter of the switching tube Q1, the negative pole of the direct current bus, the resistor R0, the anode and the cathode of the second diode FD6, the anode and the cathode of the diode FD3, and the N line from the alternating current motor 80 back to the alternating current power supply; when the current direction of the alternating current power supply is from the N line to generate induced electromotive force on a winding coil of the alternating current motor 80, a follow current loop of the alternating current power supply enters from the N line through the alternating current motor 80, the anode and the cathode of the first diode FD5, the positive electrode of the direct current bus into the second PFC inductor L2, the collector and the emitter of the switching tube Q1, the negative electrode of the direct current bus, the resistor R0, enters the negative output end of the rectifier bridge stack DR1, namely the 1 st pin, and finally returns to the L line of the alternating current power supply.

The second PFC module, in addition to participating in the freewheeling circuit, can also participate in the power supply of ac motor 80, and together with switching module 40, provides current for the operation of ac motor 80. IN fig. 47, IN the current circuit for supplying power to the motor, when the current of the ac power supply starts from ACN-IN, i.e. ac N line, and returns to ACL-IN, i.e. ac L line of the ac power supply through the motor 80, the diode FD4, the collector and emitter of the first switching tube Q2, and the diode FD2, the current circuit is formed, and the other branch is separated from the anode of the diode FD4 and returns to ACL-IN, i.e. ac L line of the ac power supply through the first diode FD5, the positive electrode of the dc bus, the second PFC inductor L2, the collector and emitter of the switching tube Q1, the negative electrode of the dc bus, the resistor R0, and the negative electrode of the output terminal of the rectifier bridge DR 1. The two current loops are branched from an input end of the second rectifying module 30, one current loop passes through the second rectifying module 30 and the switch module 40, the other current loop passes through the second PFC module C0, and finally returns to the AC L line, so that when a switching tube of the second PFC module C0 is switched on, the current can be shunted for the switch module 40, the current passing through the switching tube Q2 of the switch module 40 is reduced, the heat generated during the operation of the switching tube Q2 is reduced, the working reliability of the switch module is improved, meanwhile, a relatively low-power device can be adopted for the switching tube Q2 before shunting, the cost of the switch module is reduced, and the cost of the whole AC motor speed regulating circuit is reduced.

Referring to fig. 48, fig. 48 is a circuit module structure diagram of an ac motor speed regulation circuit according to a twentieth embodiment of the present invention, and based on the seventeenth embodiment of the compressor protection circuit according to the present invention, compared with the ac motor speed regulation circuit shown in fig. 46, the difference is that connection lines of the first freewheel module 50 and the second freewheel module 60 are different, and other modules are the same as those shown in fig. 46, and therefore, description thereof is omitted.

The input end of the second freewheel module 60 is connected to the negative electrode of the output end of the second PFC module C0, the output end of the second freewheel module 60 is connected to the negative electrode of the output end of the second rectification module 30, the input end of the first freewheel module 50 and one end of the motor 80 are commonly connected to one input end of the second rectification module 30, and the output end of the first freewheel module 50 is connected to the positive electrode of the output end of the second PFC module C0.

Fig. 49 is a circuit structure diagram based on fig. 48 of an ac motor speed regulating circuit according to an embodiment of the present invention. The difference from fig. 47 is that the connection lines of the first diode FD5 constituting the first freewheel module 50 and the second diode FD6 constituting the second freewheel module 60 are different, and specifically the difference is that the cathode of the first diode FD5 is connected to the cathode of the diode D1 of the second PFC module C0, and the anode of the second diode FD6 is connected to the emitter of the IGBT switching tube Q1 of the second PFC module C0. The cathode of the first diode FD5 and the anode of the second diode FD6 are connected to the output terminal of the second PFC module C0, so that the freewheeling circuit thereof is isolated by the diode D1 and requires the load to participate, not via the IGBT switching tube Q1 of the second PFC module C0, but via the IPM module of the load 20 and the motor. The freewheel circuit is the same as in fig. 47.

Referring to fig. 50, fig. 50 is a circuit module structure diagram provided by a twenty-first embodiment of an ac motor speed regulation circuit according to the present invention, and based on the seventeenth embodiment of a compressor protection circuit according to the present invention, compared with the ac motor speed regulation circuit shown in fig. 44, the difference is that connection lines of the first freewheel module 50 and the second freewheel module 60 are different, and other modules are the same as those shown in fig. 46, and therefore, no further description is given.

The input end of the second freewheel module 60 is connected to the negative electrode of the output end of the first rectifier module 10, the output end of the second freewheel module 60 is connected to the negative electrode of the output end of the second rectifier module 30, the input end of the first freewheel module 50 and one end of the motor 80 are connected to one input end of the second rectifier module 30 in common, and the output end of the first freewheel module 50 is connected to the positive electrode of the output end of the second PFC module C0.

Fig. 51 is a circuit structure diagram of an ac motor speed regulating circuit according to fig. 50. The difference from fig. 47 is that the connection lines of the first diode FD5 constituting the first freewheel module 50 and the second diode FD6 constituting the second freewheel module 60 are different, and specifically the difference is that the cathode of the first diode FD5 is connected to the cathode of the diode D1 of the second PFC module C0, and the anode of the second diode FD6 is connected to the cathode of the output terminal of the bridge rectifier DR 1.

When the switching transistor Q1 of the second PFC module C0 is turned on, the second PFC module C0 may also participate in forming a freewheeling loop at this time. When the current direction of the alternating current power supply starts from an L line and induced electromotive force is generated on a winding coil of the alternating current motor 80, a follow current loop of the alternating current power supply starts from the L line and passes through a 4 th pin which is the output end of the positive pole of the rectifier bridge stack DR1, the positive pole of a direct current bus, a second PFC inductor L2, the collector and the emitter of the switching tube Q1, the negative pole of the direct current bus, the anode and the cathode of a second diode FD6, the anode and the cathode of a diode FD3 and an N line which returns to the alternating current power supply from the alternating current motor 80; when the current direction of the alternating current power supply starts from an N line and generates induced electromotive force in a winding coil of the alternating current motor 80, because the cathode of the first diode FD5 is connected with the cathode of the diode D1 of the second PFC module C0, at this time, the follow current loop cannot pass through the switching tube Q1 and needs to pass through the IPM module and the motor of the load 20, specifically, the follow current loop of the follow current loop starts from the N line and passes through the alternating current motor 80, the anode and the cathode of the first diode FD5, the anode of the direct current bus enters the IPM module and the motor of the load 20, the cathode of the direct current bus, the resistor R0 enters the output end of the cathode of the rectifier bridge stack DR1, namely the 1 st pin, and finally returns to the L.

Similar to fig. 47, since the bleeding circuit from the ac L line directly passes through the switching tube without passing through the load when the switching tube of the PFC module is turned on, the bleeding line is shortened, and the line impedance can be reduced, which is more favorable for the rapid bleeding of the induced electromotive force when the PFC module participates in forming the bleeding circuit.

The present invention further provides an air conditioner, including the above ac motor speed regulation circuit, and the specific implementation manner thereof can refer to the above embodiments, which are not described herein again.

In the description herein, references to the description of the terms "first embodiment," "second embodiment," "example," etc., mean that a particular method, apparatus, or feature described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, methods, apparatuses, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.

The above description is only a preferred embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes, which are made by using the contents of the present specification and the accompanying drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.

Claims

1. The alternating current motor speed regulation circuit is characterized by comprising an alternating current input end, a first rectification module, a load, a second rectification module, a switch module, a first follow current module, a second follow current module and an MCU (microprogrammed control Unit);

the switch module realizes switching of switch states under the control of the MCU, and when the switch module is switched on, the alternating current of the alternating current power supply flows through the alternating current motor, the second rectification module and the switch module to supply power to the alternating current motor;

2. The ac motor speed regulation circuit of claim 1, further comprising a first PFC module;

the first PFC module is connected between the alternating current input end and the first rectifying module in series to correct power factors of the direct current voltage output by the first rectifying module.

3. The ac motor speed regulation circuit of claim 1, further comprising a second PFC module;

the second PFC module is connected in series between the first rectification module and a load through the direct current bus to correct power factors of the direct current voltage output by the first rectification module.

4. An AC motor speed regulation circuit as claimed in claim 3,

the input end of the second follow current module is connected with the negative electrode of the output end of the second PFC module, and the output end of the second follow current module is connected with the negative electrode of the output end of the second rectification module;

the input end of the first follow current module is connected with the positive electrode of the output end of the second rectification module, and the output end of the first follow current module is connected with the positive electrode of the output end of the second PFC module.

5. An AC motor speed regulation circuit as claimed in claim 3,

the input end of the second follow current module is connected with the negative electrode of the output end of the first rectifying module, and the output end of the second follow current module is connected with the negative electrode of the output end of the second rectifying module;

6. The ac motor speed regulation circuit of claim 1, further comprising a filtering module;

the filtering module is connected in series between the first rectifying module and a load through the direct current bus to carry out smooth filtering on the direct current voltage output by the first rectifying module.

7. The ac motor speed regulation circuit of claim 1, wherein the first freewheel module comprises a first diode and the second freewheel module comprises a second diode;

8. The ac motor speed regulation circuit of claim 7, further comprising a first capacitor;

9. The ac motor speed regulation circuit of claim 1, wherein the switching module comprises a first switching element and a first RC absorbing element;

the first switch unit realizes the switch switching of the switch module;

the first RC absorption unit is connected in parallel to two ends of the first switch unit and used for absorbing high voltage generated at two ends of the first switch unit and two ends of a main winding of the alternating current motor when the first switch unit is switched.

10. The ac motor speed regulation circuit of claim 9, wherein the first RC absorption unit comprises a second capacitor and a second resistor;

11. The ac motor speed regulation circuit of claim 1, further comprising a second RC absorption module;

the second RC absorption module is connected in parallel to two ends of the main winding of the alternating current motor and used for absorbing high voltage generated at two ends of the main winding of the alternating current motor and two ends of the switch module when the switch of the switch module is switched.

12. An air conditioner characterized in that the air conditioner comprises an alternating current motor speed regulation circuit according to any one of claims 1 to 11.