CN1877982A - Velocity feedback circuit for variable frequency control device of alternating current motor and method therefor - Google Patents
Velocity feedback circuit for variable frequency control device of alternating current motor and method therefor Download PDFInfo
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- CN1877982A CN1877982A CNA2005100752945A CN200510075294A CN1877982A CN 1877982 A CN1877982 A CN 1877982A CN A2005100752945 A CNA2005100752945 A CN A2005100752945A CN 200510075294 A CN200510075294 A CN 200510075294A CN 1877982 A CN1877982 A CN 1877982A
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Abstract
The invention discloses an AC motor speed feedback circuit with AC frequency conversion controller as single chip machine, which comprises the following parts: speed-measuring unit, receiving circuit, separating circuit, output circuit and single chip machine, wherein the speed-measuring unit generates period and speed-measuring signal in relative with AC motor rotary speed, which outputs the signal; the receiving circuit receives speed detecting signal of speed-measuring element, which transmits the signal into fitful electric parameter; the separating circuit receives the transmitted speed measuring signal from receiving circuit, which outputs electric separating signal; the output circuit receives speed-measuring signal separated by circuit separation, which transmits the measuring signal into pulse signal to output to single-chip machine output end; the single-chip machine receives speed measuring signal and accumulates the signal, which adjusts driving power frequency and voltage of AC motor.
Description
Technical field
The present invention relates to motor AC frequency conversion controller velocity feedback circuits, especially relate to the single-chip microcomputer velocity feedback circuits of the motor AC frequency conversion controller that is control device, and the speed feedback method that is used for this circuit.
Background technology
Along with the raising to domestic electric appliances energy-saving requirement and intelligent requirements, alternating frequency conversion technique has been widely used in household appliance technical field.The effect of alternating frequency conversion technique is to adjust in the AC frequency modulation mode rotating speed of motor, thereby satisfies different speed demand, plays simultaneously and avoids the motor energy to waste, and reaches the purpose of electrical energy saving.
Being extensive use of of alternating frequency conversion technique is the advantage decision by itself.This point need be illustrated from the principle of motor speed adjusting.
Motor can be divided into alternating current motor, DC motor.Ac motor structure is simple, easy to maintenance, cheap, is widely used in various occasions.Compare with direct current machine, its major defect is controlled bad.The speed regulation of alternating current machine, torque adjustment are all relatively more difficult.
Improve the control performance of alternating current machine, especially improve its speed adjusting performance, be the hot issue in Motor Control field always.Frequency control is exactly the speed regulating method of the extensive alternating current motor that adopts.
Below be the rotating speed formula of alternating current motor:
n＝60f(1-s)/p (1)
The rotating speed of n in the formula---asynchronous motor;
The frequency of f---asynchronous motor;
S---motor slip ratio;
P---motor number of pole-pairs.
By formula (1) as can be known, rotation speed n is directly proportional with frequency f, as long as change the rotating speed that frequency f can change motor, and when changing in the scope of frequency f at 0～50Hz, the non-constant width of motor speed adjustable range.Frequency control realizes speed regulation by changing the motor driven supply frequency.
Use maximum friendships one to hand over mode voltage type variable-frequency control device to form at present by rectifier, filtering system and inverter three parts always.When its work, be direct current through the bridge rectifier rectification at first with three-phase alternating current, the direct voltage of pulsation is behind smothing filtering, under the regulation and control of microprocessor, direct current another mistake is become the three-phase alternating current of voltage and frequency adjustable with inverter, it as driving power, is outputed on the motor that needs speed governing.By the principles of electric and electronic engineering as can be known, rotating speed of motor is directly proportional with supply frequency, therefore, can change motor driven power supply output frequency arbitrarily by frequency converter, thereby regulate motor speed arbitrarily, realizes level and smooth stepless speed regulation.
Fig. 1 illustrates under the prior art with the AC frequency conversion controller function block diagram of single-chip microcomputer as controlling element.
This AC converter is made up of current rectifying and wave filtering circuit, inverter circuit, inverter control circuit, power circuit, output driving frequency initialization circuit, communicating circuit.
Current rectifying and wave filtering circuit is general to adopt common bridge rectifier to add the capacitor filtering circuit bank, and main effect is that alternating current is transformed to direct current.
Inverter circuit is used for the direct current of input is converted to three-phase alternating voltage, drives the three-phase alternating current inductor motor.
Inverter control circuit is the core of whole frequency conversion plate, is made up of single-chip microcomputer, inverse changing driving circuit, communicating circuit, can also comprise the driving frequency initialization circuit.This circuit is responsible for according to command request, calculates to obtain the vector drive signal, drives inverter output three phase sine voltage, the drive motors running.
Wherein, single-chip microcomputer is used to provide and realizes that three phasor1s drive the control command signal of handling as controlling element.Single-chip microcomputer calculates and obtains described control command signal according to the demand to motor speed, torque.
Inverse changing driving circuit is the bridge that connects single-chip microcomputer and inverter circuit, its role is to accept the control command signal of single-chip microcomputer output, and exports drive pulse signal in view of the above to inverter circuit.
Communicating circuit is the circuit that carries out communication with host computer, accepts from upper instruction, and replys execution result.
The driving frequency initialization circuit is the circuit that is used for directly setting output frequency.This circuit can connect setting signal, and this setting signal can be determined output frequency according to outside incoming frequency.Can be by using different modular programs or the frequency conversion plate being set selection by the mode of communication
Power circuit is the power supply circuits of whole frequency-variable controller.
Above-mentioned frequency-variable controller can be realized rotating speed, the torque control to alternating current motor, but also has some defectives.
A major defect is that above-mentioned is the frequency-variable controller of kernel control chip with the single-chip microcomputer, can't make appropriate reaction to rapid decline of alternating current motor rotating speed even stall.
Household electrical appliance such as washing machine usually have bigger load variations in actual use.When load surpasses to a certain degree, can cause motor speed sharply to descend, even stall.Prior art be the AC frequency conversion controller of kernel control chip with the single-chip microcomputer, can not adjust motor driven supply frequency and voltage according to this kind situation.This situation causes motor slip ratio sharply to increase, and then sharply increases when causing current ratio motor by motor winding to run well, grievous injury even burn motor.
Equally, above-mentioned is the frequency-variable controller of kernel control chip with the single-chip microcomputer, can't in time adjust output according to the motor actual speed, accurately controls motor speed.
Summary of the invention
At above-mentioned defective, the technical problem that the present invention solves is: according to the characteristics of single-chip microcomputer, for above-mentioned with the single-chip microcomputer be control core the AC frequency conversion controller a kind of proper speed feedback circuit is provided, so that in time adjust driving power frequency and voltage, avoid the infringement of motor speed decline even stall to motor according to the alternating current motor change in rotational speed.Simultaneously, also provide possibility for accurately controlling described alternating current motor rotating speed.
AC motor frequency conversion controller velocity feedback circuits provided by the invention comprises detecting element, receiving circuit, buffer circuit, output circuit, single-chip microcomputer.Described detecting element is used for the generation cycle speed detection signal relevant with the alternating current motor rotating speed, and exports this signal.Described receiving circuit is used to receive the speed detection signal that described detecting element produces, and is translated into suitable electric parameter.Described buffer circuit is used to receive the speed detection signal through transforming that receiving circuit is exported, and it is carried out exporting after the electrical isolation.Described output circuit is used to receive the speed detection signal of isolating through buffer circuit, and the speed that is converted into detects pulse signal and exports to the single-chip microcomputer input.Described single-chip microcomputer, the speed that receives described output circuit output detects pulse signal, and the umber of pulse of this signal is added up, and according to the accumulation result of unit interval, calculates the rotating speed of alternating current motor; According to this rotating speed, single-chip microcomputer output corresponding instruction is to adjust the driving power frequency and the voltage of alternating current motor.
Preferably, described detecting element is a speed measuring motor.
Preferably, described detecting element also can be a Hall subassembly.
Preferably, described buffer circuit is an optical coupler.
Preferably, draw mode to single-chip microcomputer input port output speed detection signal more than the described output circuit.
Preferably, described output circuit with pull-down pattern to single-chip microcomputer input port output speed detection signal.
The method of AC motor frequency conversion controller speed feedback provided by the invention comprises:
71) periodicity to the speed detection signal of unit interval adds up;
72) read accumulation result, calculate tested alternating current motor rotating speed;
73), adjust the driving power frequency and the voltage of alternating current motor according to the rotating speed of the alternating current motor of described calculating.
Preferably, described step 71) adding up of speed detection signal carried out in the mode of interrupting.
Preferably, described step 72) further comprise and reading behind the accumulation result counter O reset.
Preferably, described step 73) further comprise rotating speed that will be calculated and the threshold values of presetting relatively, according to comparative result, whether decision adjusts the driving power frequency and the voltage of alternating current motor.
With respect to prior art, the invention has the beneficial effects as follows:
At first, the present invention provides a kind of proper speed feedback circuit for being the AC frequency conversion controller of control device with the single-chip microcomputer, has solved speed feedback problem in such cases.
Secondly, utilize the AC frequency conversion controller of speed feedback link provided by the invention, can change, suitably adjust the driving power frequency and the voltage of motor, to adapt to the excessive rotation speed change that causes of load according to motor speed.Above-mentioned adjustment can be avoided alternating current motor because the excessive electric current that causes of revolutional slip sharply increases, and makes alternating current motor avoid infringement.Especially can avoid the motor stall to burn motor.
Its three, speed feedback link provided by the invention also can be applicable to need accurately to adjust the occasion of motor speed, makes frequency-variable controller in time adjust motor power output frequency and voltage according to the actual speed of motor, obtains required rotating speed.
Description of drawings
Fig. 1 is a prior art motor AC frequency conversion controller block diagram;
Fig. 2 is the motor AC frequency conversion controller block diagram of embodiments of the invention;
Fig. 3 is the velocity feedback circuits circuit diagram of embodiments of the invention;
Fig. 4 is the speed measuring motor signal output waveform figure of embodiments of the invention;
Fig. 5 is the flow chart of the speed feedback method of the embodiment of the invention;
Fig. 6 is the operation principle flow chart of the speed counter of the embodiment of the invention.
Embodiment
With reference to the accompanying drawings, embodiments of the present invention are described.
Please refer to Fig. 2, be the structured flowchart of motor AC frequency conversion controller with speed feedback control circuit of the present invention, compared to Figure 1, this AC frequency conversion controller has the speed feedback control circuit.
Please refer to Fig. 3, be the AC motor frequency conversion controller velocity feedback circuits of the embodiment of the invention.
This velocity feedback circuits comprises: speed measuring motor CN, receiving circuit, buffer circuit, output circuit, single-chip microcomputer (figure does not show).This velocity feedback circuits is used to detect the rotating speed of motor, and feeds back to single-chip microcomputer.
Described speed measuring motor CN is one and the coaxial mounted alternating current generator of alternating current motor.This speed measuring motor CN rotation can produce ac signal.
During the alternating current motor rotation, this speed measuring motor CN is with same angular speed rotation.Along with described alternating current motor rotation, this speed measuring motor CN produces periodically variable ac signal, and this signal is speed detection signal Uv.The cycle of this speed detection signal Uv becomes the integral multiple relation with the swing circle of alternating current motor, concrete multiple is determined by speed measuring motor CN number of pole-pairs.If the number of pole-pairs of this speed measuring motor CN is 1, then tested alternating current motor whenever rotates a circle, and described speed detection signal Uv changes one-period too.Below the motor number of pole-pairs of the described speed measuring motor of hypothesis is 1.
Definite relation that the cycle of described speed detection signal Uv and the swing circle of tested alternating current motor have can be used for as tachometer signal this signal.Fig. 4 illustrates the waveform of the speed detection signal Uv of speed measuring motor CN output.The one-period of Uv changes among the figure, means that tested alternating current motor rotates a circle.
Described speed measuring motor CN is by lead-out terminal 1,2 output speed detection signal Uv.When if Uv is in positive half period, lead-out terminal 2 is that positive pole, 1 is negative pole.When Uv was in negative half-cycle, lead-out terminal 2 was a negative pole, and 1 is anodal.
The effect of described receiving circuit is to receive the speed detection signal Uv of speed measuring motor CN, is translated into suitable signal of telecommunication output.
This receiving circuit comprises resistance R 1, R2, diode D1, resistance R 3.
Described resistance R 1, R2 parallel connection, an one sys node connects the lead-out terminal 2 of described speed measuring motor CN, and another sys node connects negative electrode and the resistance R 3 of diode D1.
The anode of described diode D1 connects the lead-out terminal 1 of described speed measuring motor CN.
The other end of described resistance R 3 connects the lead-out terminal 1 of described speed measuring motor CN.
When the speed detection signal Uv of described speed measuring motor CN was in positive half period, the polarity of electrode output 2 that tests the speed was for just, and 1 polarity is for negative.At this moment, diode D1 oppositely by.Described speed detection signal Uv obtains output voltage U d through the series circuit dividing potential drop of described resistance R 1, R2 and R3 at resistance R 3 two ends, and Ud is the speed detection signal through transforming.
When the speed detection signal Uv of described speed measuring motor CN was in negative half-cycle, the polarity of electrode output 2 that tests the speed was for negative, and 1 polarity is for just.At this moment, diode D1 forward conduction.At this moment, resistance R 3 two ends are by the diode short circuit.Therefore, resistance R 3 two ends can't obtain output voltage.
Described buffer circuit is a photoelectric isolating circuit, and U1 forms by photoelectrical coupler.
The luminescent device of described optical coupler U1 is light-emitting diode D, and light receiving element is light trigger triode T.
The anode of described light-emitting diode D1 is connected with the common end points of described resistance R 3 and resistance R 1, R2, and negative electrode connects the lead-out terminal 1 of described speed measuring motor CN.
When speed measuring motor CN output voltage was in positive half period, light-emitting diode D received the voltage U d of receiving circuit output, and its conducting is also luminous.Described smooth trigger triode T is triggered saturation conduction.
When speed measuring motor CN output voltage was in negative half-cycle, receiving circuit is output voltage not, light-emitting diode D by.Described smooth trigger triode T does not receive light signal, is in by state.
Input circuit is by the light trigger triode T of described optical coupler U1, and resistance R 4, R5 form.The mode of drawing in the employing inserts single-chip microcomputer asynchronous communication port.
The collector electrode of described smooth trigger triode T connects an end of resistance R 4 and an end of resistance R 5, and emitter is connected with ground.
Described resistance R 4 other ends connect power Vcc.
The other end of resistance R 5 connects the single-chip microcomputer receiving port.
When the speed detection signal Uv of speed measuring motor CN was in positive half period, the light-emitting diode D conducting of optical coupler U1 was also luminous, triggers described smooth trigger triode T, makes its saturation conduction.At this moment, the collector potential of light emitting transistor T is an earth potential.Single-chip microcomputer UART mouth obtains a low level input signal.
When the speed detection signal Uv of speed measuring motor CN was in negative half-cycle, the light-emitting diode D of optical coupler U1 was coupled with reverse voltage and not conducting, described smooth trigger triode T by.At this moment, power source voltage Vcc is added on the single-chip microcomputer input port by resistance R 4, R5.Single-chip microcomputer UART mouth obtains the input signal of a high level.
By said process as can be known, speed measuring motor rotates a circle, and single-chip microcomputer UART mouth just obtains a pulse signal.This signal can be called speed and detect pulse signal, and each speed detects pulse signal and rotates a circle corresponding to speed measuring motor, also is that motor rotates a circle.The described speed that single-chip microcomputer obtained in the statistics set time detects pulse number, promptly can obtain motor speed information.
Fig. 5 measures the flow chart of the method for motor speed for the embodiment of the invention.This method utilizes interrupt mode that rotating speed is detected.
Step S51, initialization.Comprise zero clearing speed counter.
Step S52, whether judgement time reaches predetermined value, for example 0.5 second.In this way, enter step S53.As not, enter step S58.
Step S53, the value of reading speed speed counter.Described speed counter is to be exclusively used in the memory cell that accumulative total speed detects pulse signal.The value of this counter is by interrupt mode, described speed is detected pulse signal add up and obtain.The detailed process of interrupting is seen below and is chatted.
Step S54 calculates rotating speed.This revolution speed calculating can be with described Counter Value divided by gate time.For example use described speed counter value divided by 0.5 second scheduled time.Also can be with speed counter value itself as rotating speed.More than be the difference of rotating speed unit, control does not have substantive difference for rotating speed.
Step S55, zero clearing speed speed counter.
Step S56 according to the rotating speed that is calculated, judges whether motor speed is lower than the threshold points of setting.In this way.Then enter step S57; As not, then enter step S58.Described threshold points can be set according to the electric parameter of motor.
This threshold points can be a fixed value, and when motor speed was lower than this fixed value, it was low to illustrate that motor speed has passed through, should adjust motor driven supply frequency and voltage.
Certainly, also a plurality of threshold points can be set, motor is done interim rotating speed adjustment.
Step S57 according to measured rotating speed, adjusts motor driven supply frequency and voltage.The adjustment of this frequency and voltage specifically is that single-chip microcomputer to the instruction of inverter driving circuit output speed, by inverter driving circuit control inverter circuit, obtains the frequency and the voltage of new driving power by output port according to measured motor actual speed.The frequency of this driving power and voltage should meet with the motor actual speed, so just can avoid the excessive motor current that causes of revolutional slip too high, avoid infringement or burn motor.
Step S58 carries out other work.
The value of described step S53 medium velocity counter obtains with interrupt mode.Detailed process is referring to Fig. 6.
The rotating speed that step S61, single-chip microcomputer UART mouth receive described speed detect circuit input detects pulse signal.
Step S62 produces an interrupt signal.
Step S63 enters rotating speed and detects interrupt service routine.
Step S64 removes interrupt identification.
Step S65, the speed counter adds 1.
Step S66 finishes rotating speed and detects interrupt service routine, returns the program of originally moving.
Above circuit and method can realize that single-chip microcomputer is the speed feedback of the AC converter of control device.Under the situation that, rotating speed excessive in motor load sharply descends, in time adjust driving power output frequency and voltage, avoid the excessive motor current that causes of motor slip ratio excessive, damage even burn motor.
The foregoing description can be done some variations under the situation that does not change its basic ideas.For example:
Input circuit can adopt pull-down pattern to connect.At this moment, the emitter of the light trigger triode T of optical coupler U1 is connected with the single-chip microcomputer input port with power supply ground respectively by resistance, and collector electrode directly is connected with power Vcc.At this moment, when light trigger triode T was triggered, the single-chip microcomputer input port obtained high level; When light trigger triode T was not triggered, the single-chip microcomputer input port obtained low level.
Described speed measuring motor also can replace with Hall subassembly, and Hall subassembly is installed on the alternating current motor circumference, and the pulse signal that the generation cycle is relevant with motor speed uses this signal as speed detection signal.Other circuit is constant.
Light-emitting diode D to optical coupler U1 can take some safeguard measures, and comprising increases the protection of series aiding connection diode.
Among the described feedback method step S56, can not carry out the rotating speed adjustment yet, but, in time adjust the frequency and the voltage of alternating current motor control power supply, accurately control the alternating current motor rotating speed according to the difference of speed demand and actual speed with the method that threshold points is set.
In addition, described alternating current motor can be a single-phase AC motor, also can be three-phase alternating-current motor.
The above only is a preferred implementation of the present invention; should be pointed out that for those skilled in the art, under the prerequisite that does not break away from the principle of the invention; can also make some improvements and modifications, these improvements and modifications also should be considered as protection scope of the present invention.
Claims (10)
1. an AC motor frequency conversion controller velocity feedback circuits is characterized in that, comprises detecting element, receiving circuit, buffer circuit, output circuit, single-chip microcomputer;
Described detecting element is used for the generation cycle speed detection signal relevant with the alternating current motor rotating speed, and exports this signal;
Described receiving circuit is used to receive the speed detection signal that described detecting element produces, and is translated into suitable electric parameter;
Described buffer circuit is used to receive the speed detection signal through transforming that receiving circuit is exported, and it is carried out exporting after the electrical isolation;
Described output circuit is used to receive the speed detection signal of isolating through buffer circuit, and the speed that is converted into detects pulse signal and exports to the single-chip microcomputer input;
Described single-chip microcomputer, the speed that receives described output circuit output detects pulse signal, and the umber of pulse of this signal is added up, and according to the accumulation result of unit interval, calculates the rotating speed of alternating current motor; According to this rotating speed, single-chip microcomputer output corresponding instruction is to adjust the driving power frequency and the voltage of alternating current motor.
2, AC motor frequency conversion controller velocity feedback circuits according to claim 1 is characterized in that, described detecting element is a speed measuring motor.
3, AC motor frequency conversion controller velocity feedback circuits according to claim 1 is characterized in that, described detecting element is a Hall subassembly.
4, AC motor frequency conversion controller velocity feedback circuits according to claim 1 is characterized in that, described buffer circuit is an optical coupler.
5, AC motor frequency conversion controller velocity feedback circuits according to claim 1 is characterized in that, draws mode to single-chip microcomputer input port output speed detection signal more than the described output circuit.
6, AC motor frequency conversion controller velocity feedback circuits according to claim 1 is characterized in that, described output circuit with pull-down pattern to single-chip microcomputer input port output speed detection signal.
7, a kind of method of AC motor frequency conversion controller speed feedback is characterized in that, comprising:
71) periodicity to the speed detection signal of unit interval adds up;
72) read accumulation result, calculate tested alternating current motor rotating speed;
73), adjust the driving power frequency and the voltage of alternating current motor according to the rotating speed of the alternating current motor of described calculating.
8, the method for AC motor frequency conversion controller speed feedback according to claim 7 is characterized in that, described step 71) adding up of speed detection signal carried out in the mode of interrupting.
9, the method for AC motor frequency conversion controller speed feedback according to claim 7 is characterized in that, described step 72) further comprise and reading behind the accumulation result counter O reset.
10, the method for AC motor frequency conversion controller speed feedback according to claim 7, it is characterized in that, described step 73) further comprise rotating speed that will be calculated and the threshold values of presetting relatively, according to comparative result, whether decision adjusts the driving power frequency and the voltage of alternating current motor.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA2005100752945A CN1877982A (en) | 2005-06-10 | 2005-06-10 | Velocity feedback circuit for variable frequency control device of alternating current motor and method therefor |
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| Application Number | Priority Date | Filing Date | Title |
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| CNA2005100752945A CN1877982A (en) | 2005-06-10 | 2005-06-10 | Velocity feedback circuit for variable frequency control device of alternating current motor and method therefor |
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| CN1877982A true CN1877982A (en) | 2006-12-13 |
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| CNA2005100752945A Pending CN1877982A (en) | 2005-06-10 | 2005-06-10 | Velocity feedback circuit for variable frequency control device of alternating current motor and method therefor |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103630702A (en) * | 2013-11-05 | 2014-03-12 | 成都发动机（集团）有限公司 | Electrical-isolation accurate digital type measuring interface circuit for alternating current speed measuring motor |
| CN104009698A (en) * | 2014-06-05 | 2014-08-27 | 上海托菲机电科技有限公司 | Four-isolation single-phase motor speed regulator |
| CN104716873A (en) * | 2014-09-03 | 2015-06-17 | 佛山市顺德区美的洗涤电器制造有限公司 | Dish washing machine and motor pump rotation speed control system thereof |
| CN106655970A (en) * | 2016-12-08 | 2017-05-10 | 无锡小天鹅股份有限公司 | Washing machine and motor control system thereof |
| CN110488683A (en) * | 2019-08-01 | 2019-11-22 | 江苏斯菲尔电气股份有限公司 | A kind of active filter fan monitoring system |
| CN110912472A (en) * | 2019-11-11 | 2020-03-24 | 清华大学 | Direct current motor speed measurement and control circuit |
-
2005
- 2005-06-10 CN CNA2005100752945A patent/CN1877982A/en active Pending
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103630702A (en) * | 2013-11-05 | 2014-03-12 | 成都发动机（集团）有限公司 | Electrical-isolation accurate digital type measuring interface circuit for alternating current speed measuring motor |
| CN103630702B (en) * | 2013-11-05 | 2016-08-17 | 成都发动机（集团）有限公司 | For Electrical-isolationaccurate accurate digital type measuring interface circuit for alternating current speed measuring motor |
| CN104009698A (en) * | 2014-06-05 | 2014-08-27 | 上海托菲机电科技有限公司 | Four-isolation single-phase motor speed regulator |
| CN104009698B (en) * | 2014-06-05 | 2017-10-10 | 上海托菲机电科技有限公司 | Four isolation single-phase motor speed governors |
| CN104716873A (en) * | 2014-09-03 | 2015-06-17 | 佛山市顺德区美的洗涤电器制造有限公司 | Dish washing machine and motor pump rotation speed control system thereof |
| CN106655970A (en) * | 2016-12-08 | 2017-05-10 | 无锡小天鹅股份有限公司 | Washing machine and motor control system thereof |
| CN106655970B (en) * | 2016-12-08 | 2019-05-21 | 无锡小天鹅股份有限公司 | The electric machine control system of washing machine and washing machine |
| CN110488683A (en) * | 2019-08-01 | 2019-11-22 | 江苏斯菲尔电气股份有限公司 | A kind of active filter fan monitoring system |
| CN110912472A (en) * | 2019-11-11 | 2020-03-24 | 清华大学 | Direct current motor speed measurement and control circuit |
| CN110912472B (en) * | 2019-11-11 | 2021-07-13 | 清华大学 | Direct current motor speed measurement and control circuit |
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