CN107659239B - Speed regulating circuit of alternating current motor - Google Patents
Speed regulating circuit of alternating current motor Download PDFInfo
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- CN107659239B CN107659239B CN201710973659.9A CN201710973659A CN107659239B CN 107659239 B CN107659239 B CN 107659239B CN 201710973659 A CN201710973659 A CN 201710973659A CN 107659239 B CN107659239 B CN 107659239B
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P27/00—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage
- H02P27/04—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage
- H02P27/06—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage using dc to ac converters or inverters
- H02P27/08—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage using dc to ac converters or inverters with pulse width modulation
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- Control Of Ac Motors In General (AREA)
Abstract
The invention provides an alternating current motor speed regulating circuit, which comprises a motor power supply circuit consisting of a first follow current module or a second follow current module, a rectifying module and a switch module, wherein the alternating current power supply supplies power to an alternating current motor through the switch module for conducting the first follow current module or the second follow current module, so that the induced electromotive force generated on a main winding of the alternating current motor is discharged through the first follow current module or the second follow current module, and the normal operation of the alternating current motor is ensured. In addition, the first freewheel module and the second freewheel module are respectively composed of a composite tube structure formed by two triodes, and when the switch module is closed, induced electromotive force generated by the alternating current motor is discharged, due to the triode composite structure, bias current provided for maintaining the conduction of the freewheel module is very small through the switch module, so that bias power consumption provided by the switch module can be greatly reduced, the volume of the circuit is saved, and heating loss is reduced.
Description
Technical Field
The invention relates to the field of alternating current motor control, in particular to an alternating current motor speed regulating circuit.
Background
When the current speed regulating circuit of the alternating current motor realizes the speed regulation of the alternating current motor by controlling the high-speed switch of the electronic switch through the high-speed PWM (pulse width modulation) signal output by the controller, the circuit has the defects that the heating is serious due to overlarge power consumption of components and parts, and meanwhile, the cost is increased due to the fact that the large power consumption of the components and parts is needed to be adopted.
Disclosure of Invention
The invention mainly aims to provide an alternating current motor speed regulating circuit, and aims to solve the problem that the related components and parts cost is increased due to high power consumption of the related components and parts in the existing alternating current motor speed regulating circuit.
In order to achieve the above purpose, the invention provides an ac motor speed regulating circuit, which comprises a first freewheel module, a second freewheel module, a rectifying module, a switch module and an MCU;
the input end and the second output end of the first follow current module are respectively connected with the output end and the first input end of the second follow current module and two ends of a main winding of the motor in parallel, the common connection point between the second output end of the first follow current module and the first input end of the second follow current module and one end of the motor is connected with one input end of an alternating current power supply, and the first follow current module and the second follow current module comprise a composite triode circuit which is respectively composed of two triodes;
the first output end of the first follow current module is connected with the second input end of the second follow current module and one input end of the rectifying module, and the other input end of the rectifying module is connected with the other input end of the alternating current power supply;
the two output ends of the rectifying module are connected with the switch module to provide power for the operation of the switch module, and the control end of the switch module is connected with the MCU;
the switch module is controlled by the MCU to realize switch state switching, the first follow current module or the second follow current module, the rectifying module and the switch module form a power supply circuit of the motor, when the switch module is conducted, alternating current of the alternating current power supply flows through the power supply circuit of the alternating current motor to supply power to the alternating current motor, when the switch module is closed, the alternating current power supply conducts the power supply for the composite triode circuit of the first follow current module or the second follow current module through the switch module, and induced electromotive force generated on a winding coil of the alternating current motor is discharged through the composite triode circuit of the first follow current module or the second follow current module.
Preferably, the first freewheel module includes a first PNP type triode, a second PNP type triode and a first diode;
the first PNP type triode and the second PNP type triode form a composite PNP type triode circuit;
the base electrode of the first PNP type triode is a first output end of the first follow current module, the emitter electrode of the first PNP type triode is connected with the base electrode of the second PNP type triode, the collector electrode of the first PNP type triode is commonly connected with the anode of the first diode and the collector electrode of the second PNP type triode, the cathode of the first diode is a second output end of the first follow current module, and the emitter electrode of the second PNP type triode is an input end of the first follow current module.
Preferably, the first freewheel module further includes a third diode;
and the anode of the third diode is connected with the collector electrode of the second PNP type triode, and the cathode of the third diode is connected with the emitter electrode of the second PNP type triode.
Preferably, the first freewheel module further includes a first resistor;
one end of the first resistor is connected with the cathode of the first diode, and the other end of the first resistor is the second output end of the first follow current module.
Preferably, the first freewheel module further includes a first RC-absorption unit;
the first RC absorption unit is connected in parallel with two ends of the first diode so as to absorb interference pulses generated at two ends of the first diode.
Preferably, the second freewheel module includes a third NPN triode, a fourth NPN triode and a second diode;
the third NPN triode and the fourth NPN triode form a composite NPN triode circuit;
the base electrode of the third NPN triode is a second input end of the second follow current module, the emitter electrode of the third NPN triode is connected with the base electrode of the fourth NPN triode, the collector electrode of the third NPN triode is commonly connected with the cathode of the second diode and the collector electrode of the fourth NPN triode, the anode of the second diode is a first input end of the second follow current module, and the emitter electrode of the fourth NPN triode is an output end of the second follow current module.
Preferably, the second freewheel module further includes a fourth diode;
and the anode of the fourth diode is connected with the emitter of the fourth NPN triode, and the cathode of the fourth diode is connected with the collector of the fourth NPN triode.
Preferably, the second freewheel module further includes a second resistor;
one end of the second resistor is connected with the anode of the second diode, and the other end of the second resistor is the first input end of the second follow current module.
Preferably, the second freewheel module further includes a second RC-absorption unit;
the second RC absorption unit is connected in parallel with two ends of the second diode so as to absorb interference pulses generated at two ends of the second diode.
Preferably, the switch module comprises an IGBT tube and a third resistor;
the grid of IGBT pipe is the control end of switch module, the projecting pole of IGBT pipe is connected rectifier module's positive pole output, the collecting electrode of IGBT pipe is connected rectifier module's negative pole output, the third resistance is parallelly connected IGBT pipe collecting electrode and projecting pole.
Preferably, the switch module further comprises a third RC absorption unit;
and the third RC absorption unit is connected in parallel with the collector and the emitter of the IGBT tube so as to absorb interference pulses generated when the switch module performs switch switching.
Preferably, the speed regulating circuit of the alternating current motor further comprises a fourth RC absorption module;
the fourth RC absorption module is connected in parallel with two ends of the main winding of the alternating current motor so as to absorb interference pulses generated at two ends of the main winding when the alternating current motor operates.
According to the alternating current motor speed regulating circuit provided by the embodiment of the invention, the motor power supply circuit is formed by the first follow current module or the second follow current module, the rectifying module and the switching module to supply power to the alternating current motor, and when the MCU controls the switching module to be closed, the alternating current power supply supplies power to the first follow current module or the second follow current module through the switching module, so that the induced electromotive force generated on the main winding of the alternating current motor is discharged through the first follow current module or the second follow current module, and the normal operation of the alternating current motor is ensured. In addition, the first freewheel module and the second freewheel module are respectively composed of a composite tube structure formed by two triodes, and when the switch module is closed, induced electromotive force generated by the alternating current motor is discharged, due to the triode composite structure, bias current provided for maintaining the conduction of the freewheel module is very small through the switch module, so that bias power consumption provided by the switch module can be greatly reduced, the volume of the circuit is saved, and heating loss is reduced.
Drawings
FIG. 1 is a circuit diagram of a first embodiment of an AC motor governor circuit of the present invention;
FIG. 2 is a schematic diagram of a power supply circuit of a first embodiment of the speed regulating circuit of the AC motor according to the present invention;
FIG. 3 is a schematic diagram of another power supply circuit of the first embodiment of the AC motor speed regulating circuit of the present invention;
FIG. 4 is a schematic diagram of a flywheel circuit of a first embodiment of the speed regulating circuit of the AC motor according to the present invention;
FIG. 5 is a schematic diagram of another freewheel circuit according to a first embodiment of the speed regulation circuit of the AC motor of the present invention;
FIG. 6 is a circuit diagram of a second embodiment of an AC motor governor circuit according to the present invention;
fig. 7 is a circuit configuration diagram of a fourth embodiment of the speed regulating circuit of the ac motor of the present invention.
Detailed Description
Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative and intended to explain the present invention and should not be construed as limiting the invention.
Referring to fig. 1, fig. 1 is a block diagram of an ac motor speed regulating circuit according to a first embodiment of the present invention, and for convenience of explanation, only the parts related to the embodiment of the present invention are shown, and the details are as follows:
the speed regulating circuit of the alternating current motor 60 provided by the embodiment of the invention comprises a first follow current module 10, a second follow current module 20, a rectifying module 30, a switching module 40 and an MCU50;
the input terminal IN1 and the second output terminal out12 of the first freewheel module 10 are respectively connected IN parallel to the output terminal out2 and the first input terminal IN21 of the second freewheel module 20 and two ends of the main winding of the motor 60, and the common connection point between the second output terminal out12 of the first freewheel module 10 and the first input terminal IN21 of the second freewheel module 20 and one end of the motor 60 is connected to an input terminal ACN-IN of an ac power supply, as shown IN fig. 1; the first freewheel module 10 and the second freewheel module 20 include a composite triode circuit consisting of two triodes, respectively.
The first output out11 of the first freewheel module 10 is connected to the second input IN22 of the second freewheel module 20 and to one input of the rectifier module 30, the other input of the rectifier module 30 being connected to the other input of the ac power supply, such as the ac hot input ACL-IN shown IN fig. 1.
The two output ends of the rectifying module 30 are connected with the switching module 40 to provide power for the switching module 40 to work, and the control end of the switching module 40 is connected with the MCU50. The rectifier module 30 may be a separate full-bridge rectifier circuit or an integrated rectifier bridge module, and the rectifier module 30 includes two ac inputs, a dc output positive electrode and a dc output negative electrode. Specifically, as shown in fig. 1, the rectifying module 30 is a full-bridge rectifying circuit composed of four rectifying diodes FD1-FD 4.
The switch module 40 is controlled by the MCU50 to realize switch state switching, a power supply circuit of the motor 60 is formed by the first freewheel module 10 or the second freewheel module 20, the rectifying module 30 and the switch module 40, and when the switch module 40 is turned on, alternating current of the alternating current power supply flows through the power supply circuit of the alternating current motor 60 to supply power to the alternating current motor 60, and when the switch module 40 is turned off, the alternating current power supply supplies power to the first freewheel module 10 or the second freewheel module 20 through the switch module 40, and induced electromotive force generated on a winding coil of the alternating current motor 60 is discharged through the conduction of the first freewheel module 10 or the second freewheel module 20. Specifically, as shown in fig. 1, the switch module 40 includes an IGBT Q5 and a third resistor R7, the gate of the IGBT Q5 is a control end of the switch module, the emitter of the IGBT Q5 is connected to the output end of the whole rectifying module, the collector of the IGBT Q5 is connected to the output end of the negative pole of the rectifying module, and the third resistor R7 is connected in parallel to the collector and the emitter of the IGBT. The switching of the IGBT tube Q5 herein achieves the switching of the switching module 40, and when the switching module 40 is turned off, the ac power supply supplies power through the conduction of the first freewheel module 10 or the second freewheel module 20 by the third resistor R7, so as to achieve the discharging of the induced electromotive force on the winding coil of the ac motor 60, that is, the third resistor R7 provides the bias voltage for the conduction of the first freewheel module or the third freewheel module.
Specifically, the first freewheel module 10 includes a first PNP type triode Q1, a second PNP type triode Q2, and a first diode D1, where the first PNP type triode Q1 and the second PNP type triode Q2 form a composite PNP triode circuit;
the base electrode of the first PNP type triode Q1 is a first output end out11 of the first freewheel module 10, the emitter electrode of the first PNP type triode Q1 is connected with the base electrode of the second PNP type triode Q2, the collector electrode of the first PNP type triode Q1 is commonly connected with the anode of the first diode D1 and the collector electrode of the second PNP type triode Q2, the cathode of the first diode D1 is a second output end out12 of the first freewheel module 10, and the emitter electrode of the second PNP type triode Q2 is an input end in1 of the first freewheel module 10;
specifically, the second freewheel module 20 includes a third NPN type triode Q3, a fourth NPN type triode Q4, and a second diode D2, where the third NPN type triode Q3 and the fourth NPN type triode Q4 form a composite NPN type triode circuit;
the base of the third NPN triode Q3 is the second input end in22 of the second freewheel module 20, the emitter of the third NPN triode Q3 is connected to the base of the fourth NPN triode Q4, the collector of the third NPN triode Q3 is commonly connected to the cathode of the second diode D2 and the collector of the fourth NPN triode Q4, the anode of the second diode D2 is the first input end in21 of the second freewheel module 20, and the emitter of the fourth NPN triode Q4 is the output end out2 of the second freewheel module 20.
The working principle of the speed regulating circuit of the alternating current motor in the embodiment of the invention is as follows:
when the MCU50 controls the switch module 40 to be turned on, the alternating current of the alternating current power supply flows through the power supply circuit of the alternating current motor 60 to supply power to the alternating current motor 60, and since the alternating current passing through the alternating current motor 60 starts from the L line of the alternating current input end and starts from the N line of the alternating current input end, the power supply loops of the alternating current power supply circuit are different from each other according to the directions of the alternating current, as shown in fig. 2, when the alternating current starts from the N line of the alternating current power supply, the alternating current flows through the main winding of the motor 60, the emitter and the base of the second PNP transistor Q2, the emitter and the base of the first PNP transistor Q1, one input end and the positive output end of the rectifying module 30, the negative electrode and the other input end of the rectifying module 30 return to the L line of the alternating current power supply; as shown in fig. 3, when the alternating current starts from the L line of the ac power source, the alternating current flows through one input end and the positive output end of the rectifying module 30, the switching module 40, the negative electrode and the other input end of the output end of the rectifying module 30, the base and the emitter of the third NPN transistor Q3, the base and the emitter of the fourth NPN transistor Q3, and the main winding of the motor 60 back to the N line of the ac power source.
When the MCU50 outputs a high-speed switching signal (for example, the frequency is 10-30 KHz) to control the switch module 40 to switch the switch state, when the switch module 40 is turned on, the alternating current power supply supplies power to the motor 60 through the power supply loop, and when the MCU50 controls the switch module 40 to be turned off, no power is supplied to the motor 60, so that the speed regulation of the operation of the motor 60 can be realized by controlling the on time of the switch module 40, namely, the length of PWM pulse width output by the MCU50.
When the MCU50 controls the switch module 40 to be turned off, since the motor 60 is switched at a high speed when power is supplied, the main winding of the motor 60 generates an induced electromotive force at the moment of power supply turn-off, and the induced electromotive force needs to be discharged before the switch module 40 is turned on again, or the power device of the switch module 40 is damaged due to impact of high voltage generated by the induced electromotive force. When the switch module 40 is turned off, due to the electromagnetic induction characteristic of the inductance of the motor coil, the current corresponding to the induced electromotive force generated by the main winding is consistent with that before the door opening module 40 is turned off, and at this time, the ac power supply supplies power to the freewheel module in the power supply loop before the switch module 40 is turned off, so that the freewheel module can still be turned on, and the corresponding current generated by the induced electromotive force of the motor 60 is released through the freewheel module. As shown in fig. 4, when the ac motor 60 is powered by the first freewheel module 10 before the switch module 40 is turned off, a current discharge principle corresponding to an induced electromotive force of the main winding parameter of the ac motor 60 when the switch module 40 is turned off is as follows: at this time, the ac power returns to the L line of the ac power through the main winding of the ac motor 60, the emitter and the base of the second PNP type triode Q2, the emitter and the base of the first PNP type triode Q1, the diode FD4 of the rectifying module 30, the third resistor R7, and the diode FD2 of the rectifying module 30, so as to provide bias voltages to the second PNP type triode Q2 and the base of the first PNP type triode Q1, so that the two triodes can maintain a conducting state, and when the bleeder current corresponding to the induced electromotive force generated on the main winding of the ac motor 60 is discharged through the first freewheel module 10, several branches pass through the first freewheel module 10, as shown in fig. 4, the bleeder current is firstly discharged through the emitter and the collector of the second PNP type triode Q2 to the first diode D1, and then returns to the other end of the main winding of the ac motor 60, where the first diode D1 performs a shaping function on the bleeder current, and a part of the other part of the bleeder current reaches the base of the second PNP type triode Q2, such as the P1 node position of the dotted line current loop, and when the two branches are discharged through the two branches, for example, the base current is about 10/10% of the bleeder current is about the whole of the two branches, and the bleeder current is about 10% of the base current of the bleeder current is about the whole of the two branches and the collector current of the two branches and is about the current of the whole of the collector and about 10% of the collector current and the collector current, and is about the current and the current of the current and the current is about the 1; the part of the bleeder current from the base electrode of the second PNP type triode Q2 is subdivided into two branches when passing through the first PNP type triode Q1, for example, the P2 node position of the current bleeder circuit of the dotted line part in the figure, the bleeder current is subdivided into two branches at the position, namely, one branch passes through the emitter and collector of the first PNP type triode Q1 to the first diode D1, the other branch reaches the base electrode of the first PNP type triode Q1, and the other branch passes through the emitter and collector of the first PNP type triode Q1 from the base electrode to return to the input end of the ac power supply, and also, the branch current from the base electrode of the first PNP type triode Q1 is only relatively small due to the amplifying action of the first PNP type triode Q1, for example, when the amplifying factor of the triode in the figure is 10 times, the current from the base electrode of the first PNP type triode Q1 is only 10%, and the rest 90% of the current from the base electrode of the first PNP type triode Q1 passes through the branch. Specifically, let the current discharged from the main winding of the ac motor 60 be I1, the current passing through the emitter and collector of the second PNP transistor Q2 be I11, the current passing through the base of the second PNP transistor Q2 be I12, the current then enter the first PNP transistor Q1, and further layer the two branches, wherein the current passing through the emitter and collector of the branch is I121, the current coming out from the base of the branch is I122, and the working amplification factor of the two transistors is 10 times, the magnitude of the branch currents is as follows:
i1 I11+i12, and i11=i1×9/10, i12=i1×1/10;
i12 I121+i122, and i121=i12×9/10, i122=i12×1/10;
i122=i1×1/100 is obtained from the above formula;
that is, after the main winding of the motor 60 is discharged and the current passes through the first PNP type triode Q1 and the second PNP type triode Q2, most of the current is discharged through the first diode D1, and the remaining 1% of the current passes through the third resistor R7 of the switch module 40, so that the current flowing through the third resistor R7 is very small, and if the first freewheel module 10 is formed by only one triode, the current flowing out of the base electrode of the first freewheel module through the third resistor R7 is 10% of the whole discharge current, and still is relatively high, so that the power consumption of the third resistor R7 is relatively high, and the heat generation is relatively high. For example, when the main winding bleed current of the motor 60 is 300mA, if the first freewheel module 10 has only one triode, the current flowing through the third resistor R7 is 30mA, calculated by the effective value of the voltage on R7 being 220V, the power born on the third resistor R7 is 6.6W, which is very high compared with the common resistors with the specification of 1/8W or 1/4W, so that the resistor with very large volume and power consumption is selected, and the heat is high in the working process, which clearly increases the power consumption of the whole circuit, and because the resistor volume is very large, the space of the circuit board is excessively occupied to increase the area of the circuit board, while if the compound tube structure formed by two triodes in the embodiment of the invention is adopted, the current flowing through the third resistor R7 is only 3mA, the power born on the compound tube structure is only 0.66W, and therefore the power consumption of the resistor with relatively low power can be selected, so that the working power consumption of the resistor is greatly reduced, and the size of the whole circuit board is also greatly reduced.
Similarly, when the switch module 40 is turned off and the corresponding current generated by the induced electromotive force of the motor 60 is discharged through the second freewheel module 20, the current discharge circuit thereof is shown in fig. 5, and the current flowing through the third resistor R7 is very small with respect to the whole discharge current and is much smaller with respect to the discharge current constituted by one triode for the reason of the above-mentioned discharging through the first freewheel module 10.
The speed regulating circuit of the alternating current motor comprises a first freewheel module 10, a second freewheel module 20, a rectifying module 30, a switch module 40 and an MCU50, wherein when the MCU50 is conducted through controlling the switch module 40, the alternating current motor 60 is powered by a power supply circuit comprising the first freewheel module 10 or the second freewheel module 20, the rectifying module 30 and the switch module 40, and when the MCU50 is used for controlling the switch module 40 to be turned off, the alternating current power supply is used for conducting the first freewheel module 10 or the second freewheel module 20 through the switch module 40, so that the induced electromotive force generated on the main winding of the alternating current motor 60 is discharged through the first freewheel module 10 or the second freewheel module 20, and the normal operation of the alternating current motor 60 is ensured. In addition, the first freewheel module 10 and the second freewheel module 20 have a composite tube structure formed by two triodes, and when the switch module 20 is turned off, the triode composite structure is used for discharging the induced electromotive force generated by the alternating current motor 60, so that the bias current provided for maintaining the conduction of the freewheel module is very small through the switch module 20, the bias power consumption provided by the switch module can be greatly reduced, the volume of the circuit is saved, and the heating loss is reduced.
Further, 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, as shown in fig. 6, the first freewheel module 10 further includes a third diode D3; the anode of the third diode D3 is connected with the collector of the second PNP triode Q2, and the cathode of the third diode D3 is connected with the emitter of the second PNP triode Q2. In the process that the switching module 40 is switched at a high speed to supply power to the ac motor 60, since the motor winding is an inductive load, the voltage and the current loaded on the motor winding have a phase-out condition, which finally results in a high reverse voltage between the emitter and the collector of the second PNP type triode Q2, and the triode is easy to break down and damage during long-term operation, so that the voltage between the two poles can be clamped between safe voltage values by connecting a third diode D3 in parallel to the two poles, thereby playing a role of protecting the second PNP type triode Q2.
Further, the second freewheel module 20 further includes a fourth diode D4;
an anode of the fourth diode D4 is connected to an emitter of the fourth NPN transistor Q4, and a cathode of the fourth diode D4 is connected to a collector of the fourth NPN transistor Q4. Here, the fourth diode D4 functions in the same manner as the third diode D3, and also functions to protect the fourth NPN transistor Q4 from damage caused by reverse voltage breakdown.
Further, based on the first embodiment of the ac motor speed regulating circuit of the present invention, in the third embodiment of the ac motor speed regulating circuit of the present invention, as shown in fig. 6, the first freewheel module 10 further includes a first resistor R1; one end of the first resistor R1 is connected to the cathode of the first diode, and the other end of the first resistor R1 is the second output end out12 of the first freewheel module 10. The first resistor R1 is a circuit through which a bleed current corresponding to an induced electromotive force generated on the main winding of the ac motor 60 passes, and serves as a current limiting function, so as to prevent the excessive current in the bleed circuit from damaging components in the whole circuit.
Further, the second freewheel module 20 further includes a second resistor R3; one end of the second resistor R3 is connected to the anode of the second diode D2, and the other end of the second resistor R3 is the first input terminal in21 of the second freewheel module 20. Here, the second resistor R3 functions as a current limiter for the bleed current as well as the first resistor R1.
Further, based on the first embodiment of the speed regulation circuit of the ac motor of the present invention, in the fourth embodiment of the speed regulation circuit of the ac motor of the present invention, as shown in fig. 7, the first freewheel module 10 further includes a first RC absorption unit 11; the first RC absorption unit 11 is connected in parallel to two ends of the first diode D1 to absorb the interference pulses generated at the two ends of the first diode. The specific first RC absorption unit 11 includes a fourth resistor R2 and a first capacitor C1, where the fourth resistor R2 and the first capacitor C1 are connected in series and then connected in parallel to two ends of the first diode D1, and since the switch module 40 is switched at a high speed to supply power to the ac motor 60, when passing through the first diode D1, a peak interference signal is easily generated by a current corresponding to an induced electromotive force generated on the main winding of the ac motor 60, and therefore, the peak pulse is absorbed by an absorption circuit formed by the fourth resistor R2 and the first capacitor C1, so as to improve EMC (electromagnetic compatibility) performance of the whole circuit.
Further, the second freewheel module 20 further includes a second RC-absorbing unit 21; the second RC absorption unit 21 is connected in parallel to two ends of the second diode D2 to absorb the interference pulse generated at two ends of the second diode D2. The second RC absorption unit 21 specifically includes a fifth resistor R4 and a second capacitor C2, where the fifth resistor R4 and the second capacitor C2 are connected in series and then connected in parallel to two ends of the second diode D2, and the second RC absorption unit 21 has the same function as the first RC absorption unit 11.
Further, based on the first embodiment of the ac motor speed regulation circuit of the present invention, in a fifth embodiment of the ac motor speed regulation circuit of the present invention, as shown in fig. 7, the switch module 40 further includes a third RC absorption module 41; the third RC absorption unit 41 is connected in parallel to the collector and emitter of the IGBT tube Q5 to absorb the interference pulse generated when the switching module 40 performs the switching. Specifically, the third RC absorption unit 41 includes a sixth resistor R4 and a third capacitor C4, where the sixth resistor R4 and the third capacitor C4 are connected in series and then connected in parallel to the collector and the emitter of the IGBT tube Q5, and since the peak interference signals are easily generated at the two ends of the collector and the emitter of the switching module 40 during the power supply process of the ac motor 60 when the switching module is switched at a high speed, the absorption circuit formed by the sixth resistor R4 and the third capacitor C4 absorbs the peak pulse of the switching module, so as to improve the EMC (electromagnetic compatibility) performance of the whole circuit.
Further, the ac motor speed regulation circuit further includes a fourth RC absorption module 70; the fourth RC absorption module 70 is connected in parallel to two ends of the main winding of the ac motor 60 to absorb the interference pulses generated at two ends of the main winding when the ac motor 60 is operated. Specifically, the fourth RC absorption module 70 includes a seventh resistor R5 and a fourth capacitor C3, where the seventh resistor R5 and the fourth capacitor C3 are connected in series and then connected in parallel to two ends of the main winding of the ac motor 60. Since the power supply circuit of the ac motor 60 supplies power by switching the switch at a high speed and there is also a freewheeling circuit at a high speed, peak interference pulses are also present at both ends of the main winding of the ac motor 60, and the peak pulses are absorbed by the absorption circuit composed of the seventh resistor R5 and the fourth capacitor C3, so that EMC (electromagnetic compatibility) performance of the entire circuit can be improved.
In the description of the present specification, the descriptions of the terms "first embodiment," "second embodiment," "example," and the like, 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 present invention. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, methods, apparatus, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.
The foregoing description is only of the preferred embodiments of the present invention, and is not intended to limit the scope of the invention, but rather is intended to cover any equivalents of the structures or equivalent processes disclosed herein or in the alternative, which may be employed directly or indirectly in other related arts.
Claims (12)
1. The alternating current motor speed regulating circuit is characterized by comprising a first follow current module, a second follow current module, a rectifying module, a switching module and an MCU;
the input end and the second output end of the first follow current module are respectively connected with the output end and the first input end of the second follow current module and two ends of a main winding of the motor in parallel, the common connection point between the second output end of the first follow current module and the first input end of the second follow current module and one end of the motor is connected with one input end of an alternating current power supply, and the first follow current module and the second follow current module comprise a composite triode circuit which is respectively composed of two triodes;
the first output end of the first follow current module is connected with the second input end of the second follow current module and one input end of the rectifying module, and the other input end of the rectifying module is connected with the other input end of the alternating current power supply;
the two output ends of the rectifying module are connected with the switch module to provide power for the operation of the switch module, and the control end of the switch module is connected with the MCU;
the switch module is controlled by the MCU to realize switch state switching, the first follow current module or the second follow current module, the rectifying module and the switch module form a power supply circuit of the motor, when the switch module is conducted, alternating current of the alternating current power supply flows through the power supply circuit of the alternating current motor to supply power to the alternating current motor, when the switch module is closed, the alternating current power supply conducts the power supply for the composite triode circuit of the first follow current module or the second follow current module through the switch module, and induced electromotive force generated on a winding coil of the alternating current motor is discharged through the composite triode circuit of the first follow current module or the second follow current module.
2. The ac motor governor circuit of claim 1, wherein the first freewheel module includes a first PNP transistor, a second PNP transistor, and a first diode;
the first PNP type triode and the second PNP type triode form a composite PNP type triode circuit;
the base electrode of the first PNP type triode is a first output end of the first follow current module, the emitter electrode of the first PNP type triode is connected with the base electrode of the second PNP type triode, the collector electrode of the first PNP type triode is commonly connected with the anode of the first diode and the collector electrode of the second PNP type triode, the cathode of the first diode is a second output end of the first follow current module, and the emitter electrode of the second PNP type triode is an input end of the first follow current module.
3. The ac motor governor circuit of claim 2, wherein the first freewheel module further includes a third diode;
and the anode of the third diode is connected with the collector electrode of the second PNP type triode, and the cathode of the third diode is connected with the emitter electrode of the second PNP type triode.
4. The ac motor governor circuit of claim 2, wherein the first freewheel module further includes a first resistor;
one end of the first resistor is connected with the cathode of the first diode, and the other end of the first resistor is the second output end of the first follow current module.
5. The ac motor governor circuit of claim 2, wherein the first freewheel module further includes a first RC sink unit;
the first RC absorption unit is connected in parallel with two ends of the first diode so as to absorb interference pulses generated at two ends of the first diode.
6. The ac motor governor circuit of claim 1, wherein the second freewheel module includes a third NPN transistor, a fourth NPN transistor, and a second diode;
the third NPN triode and the fourth NPN triode form a composite NPN triode circuit;
the base electrode of the third NPN triode is a second input end of the second follow current module, the emitter electrode of the third NPN triode is connected with the base electrode of the fourth NPN triode, the collector electrode of the third NPN triode is commonly connected with the cathode of the second diode and the collector electrode of the fourth NPN triode, the anode of the second diode is a first input end of the second follow current module, and the emitter electrode of the fourth NPN triode is an output end of the second follow current module.
7. The ac motor governor circuit of claim 6, wherein the second freewheel module further includes a fourth diode;
and the anode of the fourth diode is connected with the emitter of the fourth NPN triode, and the cathode of the fourth diode is connected with the collector of the fourth NPN triode.
8. The ac motor governor circuit of claim 6, wherein the second freewheel module further includes a second resistor;
one end of the second resistor is connected with the anode of the second diode, and the other end of the second resistor is the first input end of the second follow current module.
9. The ac motor governor circuit of claim 6, wherein the second freewheel module further includes a second RC sink unit;
the second RC absorption unit is connected in parallel with two ends of the second diode so as to absorb interference pulses generated at two ends of the second diode.
10. The ac motor governor circuit of claim 1, wherein the switching module comprises an IGBT tube and a third resistor;
the grid of IGBT pipe is the control end of switch module, the projecting pole of IGBT pipe is connected rectifier module's positive pole output, the collecting electrode of IGBT pipe is connected rectifier module's negative pole output, the third resistance is parallelly connected IGBT pipe collecting electrode and projecting pole.
11. The ac motor governor circuit of claim 10, wherein the switch module further comprises a third RC absorption unit;
and the third RC absorption unit is connected in parallel with the collector and the emitter of the IGBT tube so as to absorb interference pulses generated when the switch module performs switch switching.
12. The ac motor speed regulation circuit of any one of claims 1 to 11, further comprising a fourth RC absorption module;
the fourth RC absorption module is connected in parallel with two ends of the main winding of the alternating current motor so as to absorb interference pulses generated at two ends of the main winding when the alternating current motor operates.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710973659.9A CN107659239B (en) | 2017-10-16 | 2017-10-16 | Speed regulating circuit of alternating current motor |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201710973659.9A CN107659239B (en) | 2017-10-16 | 2017-10-16 | Speed regulating circuit of alternating current motor |
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| CN107659239A CN107659239A (en) | 2018-02-02 |
| CN107659239B true CN107659239B (en) | 2023-11-28 |
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| CN116015164B (en) * | 2023-02-01 | 2023-07-04 | 武汉中岩科技股份有限公司 | Motor back electromotive force protection circuit |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106849830A (en) * | 2017-03-23 | 2017-06-13 | 广东美的制冷设备有限公司 | Speed-adjusting circuit of alternating and air-conditioner |
| CN106849831A (en) * | 2017-03-23 | 2017-06-13 | 广东美的制冷设备有限公司 | Speed-adjusting circuit of alternating and air-conditioner |
| CN207265918U (en) * | 2017-10-16 | 2018-04-20 | 广东美的制冷设备有限公司 | Speed-adjusting circuit of alternating |
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2017
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106849830A (en) * | 2017-03-23 | 2017-06-13 | 广东美的制冷设备有限公司 | Speed-adjusting circuit of alternating and air-conditioner |
| CN106849831A (en) * | 2017-03-23 | 2017-06-13 | 广东美的制冷设备有限公司 | Speed-adjusting circuit of alternating and air-conditioner |
| CN207265918U (en) * | 2017-10-16 | 2018-04-20 | 广东美的制冷设备有限公司 | Speed-adjusting circuit of alternating |
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