CN102215027A - Cascade speed control device - Google Patents
Cascade speed control device Download PDFInfo
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- CN102215027A CN102215027A CN2010101651069A CN201010165106A CN102215027A CN 102215027 A CN102215027 A CN 102215027A CN 2010101651069 A CN2010101651069 A CN 2010101651069A CN 201010165106 A CN201010165106 A CN 201010165106A CN 102215027 A CN102215027 A CN 102215027A
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Abstract
The invention discloses a cascade speed control device based on current zero crossing point (ZCP) speed measurement. The device comprises a main circuit, a control circuit and a current ZCP detection circuit, wherein the current ZCP detection circuit comprises a rotor current sampling circuit and a ZCP generating circuit; the rotor current sampling circuit is connected between a coiling motor rotor of the main circuit and the ZCP generating circuit, and is used for detecting each phase current of the coiling motor rotor; the ZCP generating circuit is connected between the rotor current sampling circuit and the control circuit, and is used for generating pulse signals according to the detected current; and a DSP (digital signal processor) of the control circuit obtains the coiling motor speed according to the received pulse signals. The current ZCP detection circuit adopted by the cascade speed control device provided by the invention obtains coiling motor speed signals through the rotor current indirectly, thus the current ZCP detection circuit is not influenced by factors such as environment, mechanical vibration and the like, the speed control device has the characteristics of rapidness and accuracy in measurement and enhanced system stability.
Description
Technical field
The present invention relates to a kind of cascade speed regulator.
Background technology
China is the very country of shortage of an electric power resource, and is energy-conservation as an important techniques policy, and development and national economy is had far-reaching influence.The One's name is legion that blower fan and water pump are used in national economy all departments divides cloth cover extremely wide, and power consumption is huge.According to statistics, the power consumption of national blower fan and water pump accounts for more than 40% of whole industrial electric weight, and blower fan, water pump generally are in operation and all will carry out Load Regulation, and corresponding flow also will be followed the tracks of adjusting.Traditional control method is the valve opening of regulating inlet or outlet, make the 30%-40% of blower fan, water pump power consumption consume in control valve and pipe network pressure drop, this is a kind of of poor benefits, energy consumption is big, device damage is fast, maintenance capacity is big, operating cost is high backward way, not only caused the huge waste of electric energy, and sizable gap has also been arranged with the economical operation standard.If blower fan, water pump are carried out speed governing, then can obtain good energy-saving effect, increase economic efficiency.More promising high-power speed adjusting technique should be tandem control technology and high-pressure frequency-conversion technology at present, wherein tandem control technology is to realize speed governing from the rotor side, and the high-voltage frequency conversion and speed-adjusting technology is directly to come speed governing from stator side, and both are each has something to recommend him.But less demanding for those speed adjusting performances, high-power blower fan, water pump that speed adjustable range is not wide, tandem control is a kind of both economical feasible speed-regulating scheme.Yet there are shortcomings such as power factor is low, harmonic content is big in traditional cascade adjustable-speed system, and at present the chopper of the copped wave cascade adjustable-speed system that uses of industry spot adopts open loop control mostly, and its dynamic property is bad.And in taking the scheme of closed-loop control, the feedback speed signal that has adopts magnetic induction to obtain near switch, in case environment or motor shake, just occurs losing the phenomenon of pulse easily, thereby can't realize two closed-loop controls.The case that adopts indirect method to obtain rate signal is also arranged, but its amount of calculation is very big, need the operation time of a large amount of dsp controller of cost, can't satisfy the requirement of fast detecting, all these has influenced cascade speed regulator applying in blower fan, pump class even load speed governing occasion.
About the disclosed patented technology that relates to the motor speed detection in the cascade speed regulator following a few class is arranged roughly at present:
(1) open loop control type: though the main circuit of such cascade speed regulator also has the copped wave link, its deficiency is to adopt open loop control, and overcurrent protection takes place easily, and the copped wave link is not to adopt phase shifting control, and the direct current pulsation is big.As patent 02260070 disclosed self-saturation type high frequency chopping AC speed regulator.
(2) closed-loop control type: the main circuit chopper of such cascade speed regulator adopts closed-loop control, but because its speed is obtained is near switch by magnetic induction, be subjected to the influence of environment and motor oscillating easily, often lose pulse phenomenon, thereby can't realize two closed-loop controls, reduce the reliability of system.As patent 200710122573 disclosed IGBT inverter middle voltage electromotor chopped mode dual DSP digital governing systems.
(3) speed is obtained type indirectly: obtaining of motor speed is not by near switch in this types of devices, but obtain indirectly by the voltage that calculates copped wave reactor two ends, its weak point is to calculate when the different conditions according to chopper, operand is very big, is unfavorable for the rapidity of two closed-loop controls.Middle voltage electromotor slip control digital intelligent speed regulating device as patent 200820060424.7 disclosed Speedless sensors.
Summary of the invention
The technical problem to be solved in the present invention provides a kind of stability of a system cascade speed regulator preferably.
For solving the problems of the technologies described above cascade speed regulator of the present invention:
Comprise main circuit, control circuit and current zero-crossing point testing circuit;
The current zero-crossing point testing circuit comprises that rotor current sample circuit, zero crossing produce circuit;
The rotor current sample circuit, the coiling electric motor rotor and the zero crossing that are connected in main circuit produce between the circuit, are used to detect every phase current of coiling electric motor rotor;
Zero crossing produces circuit, is connected between rotor current sample circuit and the control circuit, is used for producing pulse signal according to detected electric current;
The dsp processor of control circuit draws coiling electric motor speed according to the pulse signal that receives.
Cascade speed regulator of the present invention is used for the feedback speed signal of two closed loop control algorithm outer shrouds owing to adopt current zero-crossing point testing circuit and dsp processor to obtain coiling electric motor speed, realizes normal variable speed energy saving control.The current zero-crossing point testing circuit that adopts because of the cascade speed regulator among the present invention is for to obtain the coiling electric motor rate signal indirectly by rotor current, thereby be not subjected to factor affecting such as environment, mechanical oscillation, therefore have and measure characteristics fast and accurately, increased the stability of system.
Description of drawings
The present invention is further detailed explanation below in conjunction with accompanying drawing and embodiment:
Fig. 1 is the structural representation block diagram of cascade speed regulator of the present invention;
Fig. 2 is cascade speed regulator one an instantiation circuit diagram of the present invention;
Fig. 3 is the concrete rotor current sample circuit figure among the present invention;
Fig. 4 is the detected current waveform figure of hall device in the device of the present invention;
Fig. 5 is the current waveform figure of device median filter output of the present invention;
Fig. 6 is that a concrete zero crossing produces circuit and frequency multiplier circuit in the device of the present invention;
Fig. 7 a is a zero crossing square-wave pulse signal schematic diagram of the present invention, and Fig. 7 b is the narrow wave pulse signal schematic diagram of monostable, and Fig. 7 c is the pulse signal after the frequency multiplication;
Fig. 8 is the schematic block diagram of current zero-crossing point testing circuit of the present invention.
Embodiment
Cascade speed regulator of the present invention comprises main circuit, control circuit and current zero-crossing point testing circuit three parts composition (see figure 1).(see figure 2) in a specific embodiment, main circuit can comprise coiling electric motor, rectification circuit, chopper circuit, thyristor inverter circuit, feedback transformer etc., wherein the coiling electric motor stator side directly connects 10KV or 6KV electrical network, and the rotor-side output is connected to the end of incoming cables of rectified three-phase circuit; Rectification circuit can be for by heavy-duty diode D
1To D
6The three-phase commutation bridge that constitutes, three-phase commutation bridge receives the electric current from the rotor winding; Chopper circuit is by inductance 1
2, controlled power electronic device IGBT, diode FD1 constitute; The output of chopper circuit is connected to storage capacitor C, and its both end voltage is represented with Uc; Storage capacitor C links to each other with the inverter that controllable silicon transistor SCR1 to SCR6 constitutes simultaneously, and the output of inverter is connected on end of incoming cables R, S, the T of feedback transformer Tr, and the output of feedback transformer is directly connected to electrical network.
Control circuit is made of dsp processor (digital signal processor) and PLC controller (logic controller), the dsp processor chip can adopt the TMS320LF2407 of Ti company, the PLC controller can adopt Siemens S200, can carry out exchanges data by RS485 between dsp processor and the PLC controller.Dsp processor is mainly finished the speed current double closed-loop control algolithm of (1) chopper circuit, the generation of pwm pulse; (2) overcurrent, overvoltage etc. require the error protection of rapidity; (3) speed detects the computing of pulse, obtains motor velocity signal etc.The PLC controller is mainly finished the action of the technology controlling and process and the logic of whole system, comprising the technology controlling and process of system start-up and chopper, and the technology controlling and process of inverter.In addition, the PLC controller also can carry out exchanges data by serial communication and man-machine interface, corresponding data is sent to man-machine interface shows, receives the instruction action on the man-machine interface simultaneously.
The current zero-crossing point testing circuit comprises that rotor current sample circuit, zero crossing produce the circuit (see figure 8).Wherein the rotor current sample circuit comprises hall device, is placed on the lead of every phase of winding electric machine rotor outlet side, is used to respond to the current signal of this phase conductor; Signaling conversion circuit is used for converting current signal to voltage signal; Filter is used for revising and the described voltage signal of filtering, obtains filtered current signal.A concrete rotor current sample circuit as shown in Figure 3, be specially: the hall device (not shown) is placed in respectively on every phase conductor of rotor outlet side, as the end (other end ground connection) of the hall device output current signal LM1 on the A phase conductor to the resistance string that composes in parallel by resistance R 1, R2, R7 and R8, the port of same this resistance string is connected to by resistance R 3, capacitor C 12, resistance R 4, capacitor C 11 and constitutes the second order active low-pass filter with operational amplifier chip YU1A, obtains the sine-wave current LM11 of A phase.Adopt same circuit all can obtain the sine-wave current LM33 and B sine-wave current LM22 mutually of C phase.In order to save cost, in the present embodiment, adopt following circuit to obtain B phase current LM22: will before the current signal LM11 and the LM33 that obtain constitute an adder by operational amplifier YU1D, after the voltage follower that constitutes through operational amplifier YU1C, obtain B phase current LM22 at last.In the foregoing circuit, between hall device and resistance R 1, also can connect the bi-directional voltage stabilizing pipe (wherein D30 and D31 all are that transient voltage suppresses diode) that constitutes by D30 and D31.
In the foregoing circuit, (its waveform as shown in Figure 4 for the A phase current signal LM1 of the detected coiling electric motor rotor-side of hall device, be irregular class zigzag wave), current signal LM1 changes into voltage signal after multiplying each other with the resistance string that is composed in parallel by resistance R 1, R2, R7 and R8.Acting as of the bi-directional voltage stabilizing pipe that constitutes by D30 and D31: when input voltage surpasses a scheduled voltage (as 5.8V, parameter decision by diode) time, transient voltage suppresses diode D31 and punctures conducting, when voltage less than another scheduled voltage (as-5.8V, parameter by diode determines equally) time, transient voltage suppresses diode D30 and punctures, thereby with input voltage range be controlled at preset range (as-5.8V to+5.8V) between, in order to prevent back-end chip because overtension or cross low and damage.Behind the signal process second order active low-pass filter from resistance string, realize the correction and the filtering of current waveform, output obtains A phase current LM11.The waveform of the LM11 signal that obtains is sinusoidal waveform as shown in Figure 5.In like manner can obtain C phase current LM33 and B phase current LM22.And in the present embodiment according to the electrical network three-phase current be zero principle, promptly try to achieve the electric current of B phase according to formula iA+iB+iC=0.Physical circuit is that A phase current LM11 and C phase current LM33 are constituted an adder by operational amplifier YU1D, after the voltage follower that constitutes through operational amplifier YU1C, obtain B phase current LM22.
Then for zero crossing produces circuit, be used for according to the electric current production burst signal that obtains, this circuit comprises zero crossing comparator and single-shot trigger circuit.The visible Fig. 6 of one physical circuit, operation principle is: the single current signal LM11 according to the rotor current sample circuit obtains, (see Fig. 7 a) through forming the zero crossing square-wave pulse signal behind the zero crossing comparator AU14B.Resistance AR33 effect is a current limliting among Fig. 6, and diode AD25 and AD26 constitute two-way clamp circuit, the incoming level that is input to comparator AU14B is limited within the specific limits (as ± 0.7V).Then square-wave signal enters single-shot trigger circuit, physical circuit can be: be input to the input A of monostable chip AUI7 behind the zero crossing square-wave pulse signal process sign-changing amplifier AU15B, from output Q1 and the Q2 output narrow wave pulse signal of monostable (Fig. 7 b is the waveform schematic diagram) of monostable chip AUI7.In circuit shown in Figure 6, also comprise frequency multiplier circuit, be used for the narrow wave pulse signal of monostable is carried out frequency multiplication.Be specially and the monostable narrow pulse signal outputed to or door AU19C stack two pulse signal n that differ 180 degree of output formation at last
f(seeing Fig. 7 c).
Then dsp processor is according to pulse signal n
fFollowing column operations:
According to the winding motor formula:
f
s＝s×f
r (1)
F wherein
sThe expression stator frequency, f
rThe expression rotor frequency, s represents revolutional slip.
Because f
sBe fixed as mains frequency 50Hz, calculate rotor frequency (can draw), then can obtain motor slip ratio, thereby obtain motor speed according to formula (1) from the impulse waveform of Fig. 7 c by the rotor current zero crossing.
As calculating by the pulse of A phase rotor current zero crossing, then speed is asked for formula for (to suppose that the time between adjacent two tachometer pulses is T
r), because of
Then according to formula (1), the revolutional slip formula can be expressed as
s＝2T
rf
s (2)
Again according to formula
And n=n
0(1-s), p represents a grade logarithm in the formula.
According to the coiling electric motor principle, it is as follows to get the coiling electric motor speed formula:
n＝(1-2T
rf
s)60f
s/p (3)
Consider that motor speed is when higher, the rotor-side current cycle is long, if only survey the monophase current zero crossing, can influence the rapidity that speed detects, usually have the method for two kinds of frequencys multiplication to be improved: a kind of is to take three-phase rotor current zero crossing pulse superpose the output of three circuit shown in Figure 6 (be about to superpose) for this reason, just shortened 6 times detection time like this, the speed that is to say detects and has improved 6 times; Another method is to utilize frequency multiplier circuit, and monophase current (as the A phase) is carried out 6 frequencys multiplication, equally can be shortening 6 times detection time, and speed detects response speed and improves 6 times.And after calculating coiling electric motor speed, need obtain actual coiling electric motor speed according to the frequency multiplication value with the reduction of speed numerical value.As under the situation of 6 frequencys multiplication, the numerical value that calculates is actual coiling electric motor speed divided by 6.
Resulting motor speed among the present invention is used for the feedback speed signal of two closed loop control algorithm outer shrouds, realizes normal variable speed energy saving control.Because the current zero-crossing point testing circuit that is adopted in of the present invention is for to obtain rate signal indirectly by rotor current, thereby be not subjected to factor affecting such as environment, mechanical oscillation, therefore have the characteristics fast and accurately of measuring, increased the stability of system.
Claims (3)
1. a cascade speed regulator comprises main circuit, control circuit and current zero-crossing point testing circuit, it is characterized in that:
Described current zero-crossing point testing circuit comprises that rotor current sample circuit and zero crossing produce circuit;
Described rotor current sample circuit, the coiling electric motor rotor and the described zero crossing that are connected in described main circuit produce between the circuit, are used to detect every phase current of coiling electric motor rotor;
Described zero crossing produces circuit, is connected between rotor current sample circuit and the described control circuit, is used for producing pulse signal according to detected electric current;
Described control circuit comprises dsp processor, is used for drawing coiling electric motor speed according to the pulse signal that receives.
2. according to the described cascade speed regulator of claim 1, it is characterized in that: also comprise frequency multiplier circuit, being connected in described zero crossing produces between the dsp processor of circuit and described control circuit, be used for the pulse signal that described zero crossing produces circuit output is carried out pulse signal after frequency multiplication obtains frequency multiplication, and import in the dsp processor of described control circuit.
3. according to claim 1 or 2 described cascade speed regulators, it is characterized in that:
Described rotor current sample circuit comprises hall device, is placed on the lead of every phase of described winding electric machine rotor outlet side, is used to respond to the current signal of this phase conductor; Signaling conversion circuit is used for converting described current signal to voltage signal; Filter is used for revising and the described voltage signal of filtering, obtains filtered current signal;
Described zero crossing produces circuit and comprises zero crossing comparator and single-shot trigger circuit, described zero-crossing comparator is used for producing the zero crossing square-wave pulse signal according to described filtered signal, described single-shot trigger circuit is used for exporting described dsp processor to according to behind the narrow wave pulse signal of described zero crossing square-wave pulse signal generation monostable.
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| CN2010101651069A CN102215027A (en) | 2010-04-12 | 2010-04-12 | Cascade speed control device |
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|---|---|---|---|
| CN2010101651069A CN102215027A (en) | 2010-04-12 | 2010-04-12 | Cascade speed control device |
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102647151A (en) * | 2012-04-24 | 2012-08-22 | 上海电力学院 | Cascade speed regulating device for current zero-crossing speed measurement for hardware detection |
| CN103336162A (en) * | 2013-06-17 | 2013-10-02 | 成都荣耀科技有限公司 | Signal collector for distribution transformer remote monitoring system |
| CN103368524A (en) * | 2013-06-17 | 2013-10-23 | 成都荣耀科技有限公司 | Signal conditioning circuit for remote monitoring system of distribution transformer |
| CN103368525A (en) * | 2013-06-17 | 2013-10-23 | 成都荣耀科技有限公司 | Signal conditioning module of distribution transformer remote monitoring system |
| CN107561306A (en) * | 2017-08-17 | 2018-01-09 | 湖南纬拓信息科技有限公司 | Winding motor rotating speed measurement method based on rotor current |
| CN109387660A (en) * | 2017-08-14 | 2019-02-26 | 广西万创数据科技有限责任公司 | A kind of accurately motor speed measuring method |
| CN110286554A (en) * | 2019-06-27 | 2019-09-27 | 盐城天锐先锋电子科技有限公司 | A kind of projection screen limit method and position-limit mechanism |
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| CN201174681Y (en) * | 2008-02-02 | 2008-12-31 | 上海普电节能科技有限公司 | Slip ratio controlling digital intelligent speed regulating device for motor with electric grid fast switching function |
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| CN1053332A (en) * | 1989-01-23 | 1991-07-24 | 西门子公司 | The control device of fixture for Ac-regulating |
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102647151A (en) * | 2012-04-24 | 2012-08-22 | 上海电力学院 | Cascade speed regulating device for current zero-crossing speed measurement for hardware detection |
| CN103336162A (en) * | 2013-06-17 | 2013-10-02 | 成都荣耀科技有限公司 | Signal collector for distribution transformer remote monitoring system |
| CN103368524A (en) * | 2013-06-17 | 2013-10-23 | 成都荣耀科技有限公司 | Signal conditioning circuit for remote monitoring system of distribution transformer |
| CN103368525A (en) * | 2013-06-17 | 2013-10-23 | 成都荣耀科技有限公司 | Signal conditioning module of distribution transformer remote monitoring system |
| CN109387660A (en) * | 2017-08-14 | 2019-02-26 | 广西万创数据科技有限责任公司 | A kind of accurately motor speed measuring method |
| CN107561306A (en) * | 2017-08-17 | 2018-01-09 | 湖南纬拓信息科技有限公司 | Winding motor rotating speed measurement method based on rotor current |
| CN110286554A (en) * | 2019-06-27 | 2019-09-27 | 盐城天锐先锋电子科技有限公司 | A kind of projection screen limit method and position-limit mechanism |
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Application publication date: 20111012 |