CN201146481Y - Medium-voltage motor slip-control digital intelligence speed-regulating device without speed sensor - Google Patents

Abstract

The utility model relates to a digital intelligent speed-regulating device to control the slip ratio of a speed sensor-less middle-voltage motor, which comprises a motor soft starting device, a slip ratio control speed-regulation, a slip ratio power feedback and a programmable controller and is characterized in that the slip ratio control speed-regulation comprises a rotor rectifier, a chopper and a digital signal processor DSP1 to implement the speed sensor-less speed measurement, dual loop control of the motor speed and the current and outer loop control of loading technique; the slip ratio power feedback comprises a inverter, a filter and a digital signal processor DPS2 to implement the dual loop vector control of the voltage outer loop and the current inner loop of a feedback circuit; the programmable controller implements the programming control and integration and processing of failures of the whole. An overall speed-regulation system is in a two-level management mode. The digital intelligent speed-regulating device has the advantages that the capacity of the device is less than the capacity of the motor and lower voltage component is used for controlling the middle-voltage motor, which also has the advantages of simple circuit, complete functions and convenient operation, etc.

Description

The middle voltage electromotor slip control digital intelligent speed regulating device of Speedless sensor

Technical field

The utility model discloses a kind of middle voltage electromotor slip control digital intelligent speed regulating device of Speedless sensor, be a kind of in press common winding asynchronous motor or internal feed winding asynchronous motor to use rotor slip control figure intelligent speed-regulating device, belong to (3 kilovolts of middle pressures, 6 kilovolts, 10 kilovolts) large capacity motor speed governing field.

Background technology

It is the vital task that realizes the Chinese national economy sustainable and stable development that energy-saving and emission-reduction are optimized the environment, and is social at present theme.The middle voltage electromotor variable speed energy saving of promoting the power consumption maximum is one of major action of energy-saving and emission-reducing.Along with the enhancing of whole people's awareness of saving energy, function admirable, demand safe and reliable, middle pressure ac motor speed control energy-conserving product that price is lower are increasing sharply.At present, the efficient speed regulating device of middle pressure alternating current motor mainly contain two kinds: medium voltage converter speed governing and tandem control.

The medium voltage converter speed governing is that the stator side at middle pressure alternating current motor applies the medium voltage frequency converter power supply, changes stator side voltage and frequency and regulates motor speed.The medium voltage frequency converter capacity is generally 1.2～1.3 times of alternating current motor capacity.Voltage of transformation height (6 kilovolts, 10 kilovolts) needs many power unit cascades, and mains side also needs the big capacity phase shifting transformer (capacity is 1.4～1.5 times of motor capacity) of auxiliary winding more than to give each power cell power supply.Therefore, the system configuration complexity, device volume is huge, the overall cost height.The use occasion that can not stop for on-the-spot technological requirement motor, also must increase bypass equipment, when medium voltage frequency converter breaks down, motor and medium voltage frequency converter be disconnected, again motor is directly inserted (6 kilovolts of medium voltage networks, 10 kilovolts), line-start motor is to full speed, and starting current is very big, motor quickens very fast, not only electrical network is impacted greatly, also be difficult to tackle this impact situation (as closing air door) on the production technology, cause to produce to be affected.After medium voltage frequency converter is repaired, also must earlier motor be disconnected from electrical network, in the motor docking process, connect with medium voltage frequency converter, the speed in the necessary tentative mensuration motor docking process of frequency converter provides the frequency and the voltage that adapt with this speed, if cooperate bad, can cause heavy current impact, even the high-voltage switch gear separating brake stops motor, can bring massive losses to production like this.

Tandem control is a kind of ancient mode of speed regulation, because power factor is too poor, it is big to present volume of transformer outward, and inverter circuit occurs overturning when burst has a power failure, and causes equipment fault, therefore is difficult to promote.But this mode of speed regulation is control revolutional slip speed governing in the motor rotor circuit, and rotor circuit voltage low (generally about 1000 volts) has been avoided the trouble that high pressure causes; When speed adjustable range is not high (speed adjustable range that blower fan water pump requires is all little), installed capacity has only about 60%～70% of motor capacity usually; Main circuit is simple, have only not control rectifier, smoothing reactor, thyristor inverter, present transformer outward, so cost is low; Can realize stepless speed regulation again.So exploring always, people improve this mode of speed regulation.As far back as the eighties in last century, the feedback winding motors has been cancelled outer feedback transformer in occurring, and has reduced equipment.The nineties, the copped wave tandem control has appearred again.Use copped wave (constituting chopper circuit) with thyristor, rotor commutating voltage that will be lower (its value is becoming with revolutional slip) is elevated to maximum fixedly dc inversion voltage, the power factor of thyristor inverter is improved (0.866), but the overall system power factor still is lower than the power factor of motor own when the motor high-speed cruising, along with rotating speed reduces, power factor still drops to than low value (0.4～0.5).Thyristor chopper circuit operating frequency low (600 week), complex circuit work is unreliable.Adopt thyristor inverter, current harmonics is also bigger.Existing the burst power failure equally causes inversion to overturn problem.Owing to adopt copped wave, adopted rectifier bridge voltage to be used as the method that actual speed makes up speed closed loop originally, because error can not re-use too greatly, so some product adopts the speed governing of open loop control copped wave duty ratio, speed adjusting performance is very poor naturally; Some product adopts and adds the method structure speed closed loop that simple and easy pulse is tested the speed, and trouble not only is installed, and the pulse missing that also often occurs in service causes speed problem out of control.These problems affect further applying of copped wave serial regulator device.

Summary of the invention

The technological means that the utility model adopts current advanced person's power electronic device to combine with digital control technology, solved the problem that above-mentioned cascade speed regulator exists in the prior art, a kind of middle voltage electromotor slip control digital intelligent speed regulating device of Speedless sensor are disclosed, it is that a kind of Speedless sensor tests the speed, main circuit constitute simple, digitized degree is high, safe and reliable, easy to operate, function admirable, perfect in shape and function, power factor height, man-machine interface close friend, can realize the digital intelligent speed regulating device of Long-distance Control and management.

Speedless sensor middle voltage electromotor slip control digital intelligent speed regulating device described in the utility model comprise motor M, soft start RQD equipment, rotor slip control speed governing SKT part, and slip power feedback SGH part and Programmable Logic Controller PLC form.The each several part function is distinct, perfect, and communication-cooperation is whole by the PLC unified management mutually.Wherein, rotor slip control speed governing SKT circuit comprises rotor rectifier ZR, chopper CH, digital signal processor DSP 1, the DSP1 hardware circuit adopts current Hall element testing motor rotor electric current I r, the speed that is used for calculating motor start-up course and full-speed operation, detection rotor rectified current Ic is used for the current feedback of electric current loop, adopts voltage Hall element detection dc inversion voltage U c and adds copped wave inductive drop U _LThe actual speed that is used for the calculating motor speed regulation process, this speed is used for the speed feedback of speed ring, the DSP1 also value of collection technology amount is used for the process feedback of technology ring, realize revolutional slip control and electromotor velocity adjusting by establishment DSP1 program construction technology ring, speed ring, electric current loop, to exchange slip power simultaneously and be converted to dc electric power, send into capacitor stores; Slip power feedback SGH circuit comprises inverter INV, filter LCL and digital signal processor DSP 2, and DSP2 adopts the voltage Hall element to detect dc inversion voltage U c, adopts insulate step-down transformer to detect AC supply voltage (e _a, e _b, e _c), be used to calculate electrical source voltage vector E, adopt current Hall element testing inverter INV electric current (i _a, i _b, i _c), be used to calculate inverter INV current phasor I, implement the outer voltage current inner loop dicyclo vector-controlled SVPWM of feedback circuit by establishment DSP2 program, send the pulse-width modulation PWM control impuls of inverter INV, the control inverter operation, with the energy feedback grid, the feedback electric current is sinusoidal wave; By setting the change of capacitive reactive power current value,, will effectively improve the entire system power factor as increasing the capacitive reactive power current value along with rotating speed reduces.Filter LCL elimination high-frequency harmonic makes the electric current that injects electrical network not have harmonic wave.PLC implements the program control of whole governing system, fault comprehensive and processing, and the assurance system normally moves.Native system adopts two-stage control and way to manage.Its controlled step is as follows:

1, after the control power supply send electricity, DSP1 and DSP2 self check and initialization, PLC patrols and examines whole governing system state.Before No. the 1st starting motor, need be on touch-screen input motor parameter and technological requirement parameter.Afterwards, at first differentiate whether have warning relevant with soft starting circuit and fault, if exist, PLC sends the No switching on signal and demonstrates and reports to the police and fault category on touch-screen, if alarm free and fault, PLC sends and allows the motor start-up signal; And then whether differentiation revolutional slip control speed governing SKT part exists warning and fault with slip power feedback SGH part, if exist, PLC sends on touch-screen and forbids speed-regulating signal and demonstrate reporting to the police and fault category, if alarm free and fault are sent the permission speed-regulating signal.When touching information displayed on screen, also inform distant place collective and distributive type control system DCS Central Control Room.

2, on touch-screen or in the distance the DCS Central Control Room is pressed switch knob, and PLC controls motor start-up; DSP1 detects motor operation speed, if system allows into speed governing, then changes the speed governing running over to when electromotor velocity is equal to or greater than setting speed; If system does not allow into speed governing, perhaps set on the touch-screen and directly start to full speed, then when starting to, change full-speed operation near full speed; In the motor start-up process, slip power feedback SGH regulating system is enabled, and the dicyclo vector control is devoted oneself to work, for feedback energy is got ready.

3, enter speed governing in the start-up course, or when full speed on touch-screen or in the distance the DCS Central Control Room press the speed governing button and enter speed governing, the DSP1 governing system is enabled immediately, speed electric current dicyclo governing system enters operate as normal, live through after the transient, motor is stabilized in running under the setting speed.In the governing system course of work, the slip energy of feedback is by slip power feedback system feedback grid.If desired, can change technology closed loop (pressure, flow etc.) work over to by manual change over switch.

4, PLC patrols and examines described revolutional slip control speed governing SKT system and slip power feedback SGH system, shows data such as motor operating speed, rotor rectified current, rotor commutating voltage, dc inversion voltage, inverter circuit active current, reactive current, active power, reactive power on touch-screen; During if break down, motor is switched to full speed running, and on touch-screen, show fault category and reason by soft start equipment; If when occurring reporting to the police,, remind the attendant to do reply and handle in touch-screen on display alarm information.

5, on touch-screen or in the distance the DCS Central Control Room can change setting speed according to technological requirement, perhaps, when technology closed loop (as pressure, flow etc.) is worked, changes the technique initialization value, and motor just turns round under the operating mode of new settings.

If 6 arts demand motor full-speed operations, on touch-screen or in the distance the DCS Central Control Room is pressed changes button at full speed, and motor quickens by predefined acceleration, near at full speed the time, changes full speed operation by PLC control in speed.

7, when needs stop, on touch-screen or in the distance the DCS Central Control Room all can carry out shut-down operation.After the operation, the motor free parking.In the time of need stopping in emergency, on touch-screen or the in the distance DCS Central Control Room operation of all can stopping in emergency.

The described Sensorless Speed of the middle voltage electromotor slip control digital intelligent speed regulating device of the utility model Speedless sensor is measured WSCS and control of electromotor velocity outer shroud current inner loop dicyclo and the control of load process outer shroud, comprises DSP1 hardware circuit board, software program and current/voltage acquisition system.Wherein, Sensorless Speed is measured WSCS and is united by two kinds of Sensorless Speed method of measurement and use the Sensorless Speed measurement of forming whole system.In the motor start-up process with full speed running during, use the current Hall element to gather motor rotor top-cross stream electric current I r, detect by the rotor current slip frequency, calculating motor running speed, this speed are used for speed and show with speed logic and judge; When motor speed adjusting was worked, the working voltage Hall element was gathered dc inversion voltage U c and is added copped wave inductive drop U _L, calculate speed governing course of work medium velocity value in real time, speed feedback and speed that this value is used for speed ring show.Use the current Hall element to gather current feedback and chopper current demonstration that DC chopped-wave electric current I c is used for electric current loop; The DSP1 hardware circuit is made up of digital signal processor and other integrated circuits, voltage/current translation circuit, software is realized the calculating of electric current and voltage collection value, the motor Sensorless Speed is calculated, control of speed electric current dicyclo and adjusting, control of technology ring and adjusting, output duty cycle control impuls PWM, the control revolutional slip is realized speed regulation.

The middle voltage electromotor slip control digital intelligent speed regulating device of the utility model Speedless sensor, described DSP2 implements the outer voltage current inner loop dicyclo vector-controlled SVPWM of feedback circuit, comprises DSP2 hardware circuit board, software program and electric current and voltage acquisition system.Wherein, the DSP2 hardware circuit board is made up of with other integrated circuits, voltage/current translation circuit digital signal processor, A/D, D/A, and DSP2 software is realized the digital vector control of outer voltage current inner loop dicyclo; The electric current and voltage acquisition system comprises uses insulate step-down transformer to gather supply voltage (e _a, e _b, e _c), be used to calculate supply voltage vector E, use the current Hall element to gather inverter INV ac-side current (i _a, i _b, i _c), be used to calculate active inverter current phasor I.In the course of the work, it is constant to keep dc inversion voltage U c by outer voltage, or changes by certain requirement, as when exporting capacitive reactive power, suitably improves the dc inversion magnitude of voltage, adapts to the needs that output voltage raises; In addition, change reactive current and set, as along with rotating speed descends, motor feedback winding or outside present under the prerequisite that transformer secondary coil volume allows, rising reactive current set point can improve the power factor of whole system.Because PWM adopts space vector modulation, feed-in feedback winding or the electric current of presenting transformer outward are sine-wave currents, through not having harmonic wave after the LCL filtering.That is to say that the inverter that the utility model adopts has not only been removed reactive power and harmonic wave that thyristor inverter produces, and, can also carry capacitive reactive power to system, offset the lagging reactive power that the motor stator excitation produces.If the feedback coil volume is enough, perhaps, for the scheme of outer feedback transformer, customer requirements is in speed adjustable range, and power factor is all kept high value and can be realized, this has just overcome the shortcoming of traditional string adjusting system.In service, supply voltage effective value, inverter current effective value, active current component, reactive current component, active power, reactive power all can show by being set in advance on the screen when needed.DSP2 software can also detect dc inversion overvoltage, inverter overcurrent, phase shortage, power down, fault such as overheated, carries out dependent failure and handles.

Digital signal processor adopts 2407,2812 type products or other companies product of the same type that TI company produces in the utility model.

DSP1 described in the utility model and DSP2 have by the RS232/RS485 communication interface and intercom mutually or realize the telecommunication administration subprogram with the DCS Central Control Room, also by the communicator program of forming local area network (LAN) by CAN fieldbus and DCS Central Control Room.

The middle voltage electromotor slip control digital intelligent speed regulating device of the utility model Speedless sensor when the power supply grid burst has a power failure, have electrical network and cut the function and the restart facility that has a power failure in short-term soon.Avoid burst to have a power failure in short-term generation has a strong impact on to big system as far as possible.

PLC described in the utility model implements program control, fault comprehensive and the processing of whole governing system.The application software of PLC is controlled the overall process of whole governing system.Before the motor cycling start, patrol and examine each several part, all just often provide the permission startup and can advance speed-regulating signal; If starting device demonstrates fault or warning message when undesired on screen, provide the No switching on signal simultaneously; If revolutional slip control speed governing and energy feedback partly have when reporting to the police with fault, display alarm and fault category on touch-screen provide simultaneously and forbid speed-regulating signal; As long as allow to start, during the field requirement cycling start, can first actuating motor enter full-speed operation after, be transformed into service mode, limit operation frontier inspection is repaiied.In service in system, can carry out various operations to motor at local (control cubicle) or distant place DCS.If DSP1 and DSP2 detect any fault and warning, all can deliver to PLC immediately, PLC sends halt command immediately and shows fault category for machine halt trouble; For changeing fault at full speed, do to change at full speed by soft start equipment immediately and handle, and show fault category; For a display alarm content of reporting to the police, remind the attendant to handle.The hardware of described PLC is selected the S7-200 of Siemens Company or other company's minicomputers for use.

The middle voltage electromotor slip control digital intelligent speed regulating device of the utility model Speedless sensor will bring remarkable economic efficiency and social benefit.Compare with medium voltage frequency converter, the speed regulating device price that the utility model provides has only about half of medium voltage frequency converter on various capacitance grades, and on performance, has the advantage that medium voltage frequency converter has, as start steadily, start to setting speed and just be stabilized in setting speed running, stepless speed regulation, the adjusting speed accuracy height, response is fast, the power factor height, and harmonic wave is little etc., but avoided the medium voltage frequency converter capacity greater than motor capacity, device builtin voltage height, complex circuit, bulky difficulty, control middle voltage electromotor with low-voltage device, control the motor of 100% capacity with the device of (50%～70%) motor rated capacity, main circuit is simple, and device is few, satisfy high-power blower and water pump 50% speed governing requirement equally, more valuable is convenient for maintaining.When device breaks down, can reposefully the motor raising speed be arrived at full speed by soft start equipment, then, be transformed into service mode, device keeps in repair with the motor disengagement fully, finish maintenance after, be transformed into operating condition again, press the speed governing button, turn back to former operating state reposefully.When this device has a power failure in the power supply network burst, also have electrical network and cut function soon, restore electricity fast.If interruption duration is longer, get back to starting state automatically, enter the work of speed governing state by the soft start raising speed again to setting speed during incoming call.Very little to big systematic influence.Carry out reducing energy consumption with this device, just be recoverable to installation cost in 1 year.Improvement project can be saved a large amount of electric energy, reduces production costs, and optimizes technical process.This is the major issue of benefiting the nation and the people.

Below in conjunction with accompanying drawing, the utility model is described in further detail.

Description of drawings

Fig. 1 is that interior feedback winding motors adopts electrical schematic diagram of the present utility model;

Fig. 2 is that common winding motors adopts electrical schematic diagram of the present utility model;

The utility model Sensorless Speed was calculated equivalent circuit diagram when Fig. 3 a was the IGBT conducting;

The utility model Sensorless Speed was calculated equivalent circuit diagram when Fig. 3 b was the IGBT blockade;

Fig. 4 is technology ring, speed ring, the electric current loop regulating system structure chart that the utility model adopts;

Fig. 5 is the slip power feedback electric current and voltage dicyclo vector control regulating system structure chart that the utility model adopts.

Embodiment

The utility model adopts current advanced person's the power electronic device and the digital intelligent governing system of the middle voltage electromotor revolutional slip control that digital control technology is realized Speedless sensor.

1:M is interior feedback winding asynchronous motor with reference to the accompanying drawings, and its stator winding is by 6 kilovolts or the power supply of 10 kv grids.RQD is motor soft start equipment (frequency sensitive trheostat, a water resistance etc.), motor rotor contactor control circuit and maintenance change over switch etc., and the contactor control circuit is controlled by PLC, and the state of auxiliary contact also feeds back to PLC.Usually, low capacity motor (below 1000 kilowatts) adopts frequency sensitive trheostat to start, and large capacity motor (more than 1000 kilowatts) adopts water resistance to start.Revolutional slip control speed governing SKT circuit comprises motor rotor side diode rectifier ZR, chopper CH and digital signal processor DSP 1, rotor-side electric current I r and chopper input current Ic are by the current Hall element testing, its measured value send DSP1, dc inversion voltage (capacitor C voltage) Uc is detected by the voltage Hall element, and its measured value send DSP1.Slip power feedback SGH circuit includes source inventer INV, and filter LCL and digital signal processor DSP 2, supply voltage send after by the isolating transformer step-down DSP2 to detect, and the inverter ac-side current is by the current Hall element testing, and its measured value send DSP2.

The utility model adopts technology ring that current advanced person's power electronic device and digital control technology realize comprising in the Speedless sensor middle voltage electromotor slip control digital intelligent speed regulating device, speed ring, electric current loop as shown in Figure 4.Making up these closed loops, especially how to make up the winding motors electric current loop that contains the chopper link, is controversial for many years.Key problem is how to be familiar with controlled plant.The utility model makes every effort to realize with the simplest suitable method.For this reason, at first illustrate the control principle of winding motors revolutional slip control speed governing SKT, illustrate thus how the technology ring speed ring electric current loop regulating system that the utility model adopts makes up.When illustrating principle, rotor rectification circuit ZR should be considered with chopper circuit CH, as a global analysis.With reference to the accompanying drawings 1, rotor electromotive force is direct voltage Ur after through the diode rectifier bridge rectification.Rotor rectification circuit and general rectifier circuit are distinguished to some extent, and when normal speed governing was worked, rotor electromotive force was:

Er＝S×Ur0，

In the formula, S---revolutional slip,

Ur0---motor rotor open circuit voltage;

The amplitude of rotor electromotive force and frequency all are the functions of revolutional slip, and in speed adjustable range, general highest frequency also had only for 25 weeks.In the tandem control circuit in the past, do not have chopper circuit, the commutation overlapping phenomenon is more serious in the rectification circuit, after increasing chopper circuit, commutates and overlappingly can ignore (reason sees below); Suppose that again rectifying device is desirable device, ignore tube voltage drop and leakage current, like this, in each chopping cycle, chopper current only flows in the rotor two-phase, with the resistance of rotor circuit and the DC circuit behind the leakage inductance immigration rectification circuit, with the resistance and the inductance merging of chopper circuit, the equivalent resistance after the merging is R, equivalent inductance is L, after handling like this, it is exactly the ideal rectifier voltage of rotor electromotive force that commutated direct current is pressed Ur, and this value is:

Ur＝k×S×Ur0，

In the formula, k---rectification coefficient.

Commutating voltage Ur is exactly the chopper input voltage, rectified current (being the copped wave input current) is Ic, in rotor rectification circuit and boost chopper circuit, supposes that rectified current is continuously (in 50% speed adjustable range, general always continuous), equation is arranged during copped wave pipe (IGBT or IGCT) conducting:

$L\frac{\mathrm{dIc}}{\mathrm{dt}}+\mathrm{IcR}=\mathrm{Ur},$

Equation when turn-offing, copped wave pipe (IGBT or IGCT) is arranged:

$L\frac{\mathrm{dIc}}{\mathrm{dt}}+\mathrm{IcR}=\mathrm{Ur}-\mathrm{Uc},$

Adopt the space State Average Model method, press the conducting of copped wave pipe and turn-off shared time scale, obtain the equation in one-period top two equation weightings:

$L\frac{\mathrm{dIc}}{\mathrm{dt}}+\mathrm{IcR}=\mathrm{Ur}-\mathrm{Uc}(1-D),$

In the motor speed adjusting process, rotation speed change is slower relatively, and therefore, Ur changes slower, can think constant when chopper current is discussed; Uc is a dc inversion voltage, and it is invariable being subjected to the control of slip energy feedback SGH circuit.In equation, independent variable is chopper duty ratio D, and when duty ratio D had an increment, chopper current just produced an increment.According to the increment equation, and omit and can draw chopper current Ic after the increment sign and for the transfer function of input be for output, duty ratio:

$\frac{\mathrm{Ic}}{D}=\frac{\mathrm{Uc}}{R(\mathrm{TP}+1)},$

Big inertia link in Here it is the electric current loop.As seen this link is linear.Because adopt digital quantity control, the digital sample cycle produces a time lag, this hysteresis is equal to a little inertia link.So the controlled plant of electric current loop is a big inertia link and a little inertia link.Referring to accompanying drawing 4, current regulator ACR should adopt typical pi regulator.The chopper CH duty ratio in the revolutional slip control SKT circuit is directly controlled in adjuster ACR output, the control rotor current, therefore, control electric electromechanics magnetic torque, also promptly control the revolutional slip of rotor, operate at when making the motor rotor stable state under a certain revolutional slip, when rotational speed setup changes, the control rotor slip is quickened to given rotating speed, is stabilized on the setting speed at last.

Now, illustrate the negligible reason of rotor rectification circuit commutation overlap phenomenon with chopper link.When rectified current was big, commutation overlap was serious, and this operating mode motor is that revolutional slip is very little in the high regime running, and slip frequency is very low, and the cycle is very long, and the rotor electromotive force value is also lower, and commutating voltage Ur is also lower.The moment that commutation occurs, there are two kinds of situations, a kind of is when appearing at copped wave pipe (IGBT or IGCT) conducting, the phase current of the new conducting of electromotive force official post after the commutation increases, and former conducting phase current descends, by the time copped wave pipe (IGBT or IGCT) is when turn-offing, two of commutation overlap is in parallel and flows through electric current, rectified current Ic descends fast, and the negligible resistance pressure drop has following formula:

$L\frac{\mathrm{dIc}}{\mathrm{dt}}=\mathrm{Ur}-\mathrm{Uc}.$

Because this moment, commutating voltage Ur is lower, and dc inversion voltage U c higher (800～1000 volts), very big (if equivalent inductance 1 milihenry of electric current fall off rate, speed is every millisecond 800～1000 peace) because there is electrical potential difference in the two-phase of commutation, former conducting descends faster mutually.If load is not heavy, may just be through with by a chopping cycle commutation overlap.If load is heavier, two chopping cycles finish.Another kind of situation, commutation appears at copped wave pipe (IGBT or IGCT) off state constantly, the chopper current fall off rate is big, because inductor rotor voltage is for negative, make the phase of commutation can not conducting, during copped wave pipe (IGBT or IGCT) conducting by the time, overlapping biphase current increases simultaneously, and later situation is with aforementioned situation.In a word, commutation overlap only takies 1～2 cycle, promptly 0.5～1 millisecond.If revolutional slip S=0.1,5 hertz of rotor frequencies, 200 milliseconds of cycles.Commutation overlap influences very I to ignore.

The equation of motion of motor transmission agent is:

$\frac{\mathrm{Jd\ω}}{P_n\mathrm{dt}}+T_L=T_e,$

In the formula: J---the moment of inertia (kg.m of unit ²);

P _n---the number of pole-pairs of motor;

T _L---the load resistive torque;

T _e---the electric electromechanics magnetic torque;

ω---motor angle speed.

As seen, the speed ring controlled plant is an integral element.Current closed-loop is a little inertia link in speed ring.With reference to the accompanying drawings 4, speed regulator ASR can adopt typical pi regulator.Parameter configuration is adjusted by third-order system.For blower fan and water pump load, do not allow motor speed to change fast, in the velocity setting passage, reference integrator GJ is set, the step specified rate is converted into slope rising signals slowly.Rise or fall time can be set between 30～100 seconds.

Revolutional slip control SKT governing system can under speed electric current dicyclo, work (manual mode).Speed setting value can manually provide on touch-screen (this locality), and also the DCS Central Control Room manually provides in the distance, by the conversion of this control/far control change over switch.By manual change over switch, can realize manually and the conversion mutually of automated manner ground.When automatic working method, local (on the touch-screen) or distant place DCS set the technology controlling and process value, as pressure, and flow etc., detect corresponding technology actual value in the technical process as value of feedback, process modulator AGR has two kinds of forms in the utility model: conventional PID adjuster and Fuzzy Controller.When the controlled plant model of technology ring is clear, adopt PID better; If the controlled plant more complicated, usually be accompanied by big inertia, the long-time hysteresis again, when controlled plant is difficult to describe with mathematical equation, adopt the fuzzy control adjuster better.On-the-spot process condition varies, and the user can select according to field conditions.

Speedless sensor middle voltage electromotor slip control digital intelligent speed regulating device described in the utility model, wherein, Sensorless Speed is measured WSCS and is united by two kinds of Sensorless Speed method of measurement and use the Sensorless Speed measurement of forming whole system.In the motor start-up process with full speed running during, use the current Hall element to gather motor rotor top-cross stream electric current I r, detect by zero crossing, be converted to the square wave of positive and negative each half cycle, give dsp chip, use capturing function detection rotor electric current slip frequency Sf, calculating motor running speed, this speed are used for speed and show and the speed logic judgement; When motor speed adjusting was worked, the working voltage Hall element was gathered dc inversion voltage U c and is added copped wave inductive drop U _L, calculate speed governing course of work medium velocity value in real time, speed feedback and speed that this value is used for speed ring show.

3a, 3b with reference to the accompanying drawings, the utility model is realized testing the speed in the speed regulation process according to the chopper working mechanism.In the voltage equation of rectification circuit and chopper circuit, the ratio that resistance drop accounts for is very little, can the negligible resistance pressure drop, two-phase leakage inductance in the working rotor circuit is merged the back move into circuit after the rectification, the equivalent electric circuit when ignoring the rectifying tube pressure drop simultaneously and obtaining copped wave pipe (IGBT or IGCT) conducting and turn-off.Among the figure:

The rectified value of Ur---rotor electromotive force when testing the speed calculating, can be thought definite value;

L ₁---rotor circuit two-phase leakage inductance sum;

L ₂---add the copped wave inductance.

When the conducting of copped wave pipe (IGBT or IGCT), have equation to be:

$L_1\frac{{\mathrm{dI}}_{\mathrm{on}}}{\mathrm{dt}}+L_2\frac{{\mathrm{dI}}_{\mathrm{on}}}{\mathrm{dt}}=\mathrm{Ur},$

If add inductive drop during the conducting of copped wave pipe $U_{\mathrm{on}}=L_2\frac{{\mathrm{dI}}_{\mathrm{on}}}{\mathrm{dt}},$

Then $U_{\mathrm{on}}=\frac{L_2}{L_1+L_2}\mathrm{Ur},$

When the copped wave pipe turn-offs (IGBT or IGCT), equation is:

$L_1\frac{{\mathrm{dI}}_{\mathrm{off}}}{\mathrm{dt}}+L_2\frac{{\mathrm{dI}}_{\mathrm{off}}}{\mathrm{dt}}=\mathrm{Ur}-\mathrm{Uc},$

If the copped wave pipe adds inductive drop when turn-offing $U_{\mathrm{off}}=L_2\frac{{\mathrm{dI}}_{\mathrm{off}}}{\mathrm{dt}},$

Then have: $U_{\mathrm{off}}=\frac{L_2}{L_1+L_2}(\mathrm{Ur}-\mathrm{Uc})=U_{\mathrm{on}}-\frac{L_2}{L_1+L_2}\mathrm{Uc},$

Connection is separated following formula, obtains:

$S=\frac{\mathrm{Uc}}{\mathrm{kUr}0}\frac{U_{\mathrm{on}}}{U_{\mathrm{on}}-U_{\mathrm{off}}}=C\frac{U_{\mathrm{on}}}{U_{\mathrm{on}}-U_{\mathrm{off}}},$

In the formula, C---constant.Copped wave inductive drop when detecting the conducting of copped wave pipe and turn-offing in one-period just can calculate revolutional slip S.Can obtain motor speed n by revolutional slip S.This calculating will be carried out in the cycle interruption program.

With reference to the accompanying drawings 5, illustrate the slip power feedback SGH electric current and voltage dicyclo vector control regulating system that comprises in the utility model digital intelligent speed regulating device.Power supply among the figure is meant feedback winding power supply for interior feed motivation; For common winding motors, be meant outer feedback transformer secondary winding power supply.Main circuit as shown in Figure 1, inverter is the three-phase bridge circuit that IGBT (or IGCT) forms, three-phase bridge exchanges between inlet wire and the power supply, the LCL filter is installed, the high-frequency harmonic component that contains in the elimination three-phase bridge inverter ac output voltage.The control of inverter is by the dicyclo vector control and the adjusting that encircle in the DSP2 realization inverter voltage outer shroud inverter current.As everyone knows, the dicyclo vector control must be carried out in the rotating coordinate system plane with the supply frequency rotation.Of ac in rest frame must be converted to rotating coordinate system (d, q) DC quantity in through transform vector.DC quantity is regulated through the electric current and voltage dicyclo, and Shu Chu DC quantity also must turn back in the rest frame afterwards, produces the PWM control impuls of inverter bridge.

Rotating coordinate system (d, q) in the plane, the voltage equation of inverter bridge main circuit is (establish inverter current direction for just):

U _d＝E _d+(LS+R)I _d-ωLI _q，

U _q＝E _q+(LS+R)I _q+ωLI _d，

In the formula: U _d, U _q---the d axle and the q shaft voltage component of three-phase bridge output voltage;

E _d, E _q---the d axle and the q axle electromotive force component of electrical source voltage;

I _d, I _q---the d axle and the q shaft current component of inverter current.

According to the plant equation formula, the regulating system figure that constructs the outer voltage current inner loop as shown in Figure 5.Supply voltage is the (e in the three phase static coordinate system after the isolating transformer step-down _a, e _b, e _c) give the A/D input on the DSP2 circuit board, carry out 3/2 conversion again after being converted to digital quantity, produce the potential vector relevant parameter (e in the α β two-phase rest frame _α, e _β, amplitude E and phase angle theta).Simultaneously, also can be according to phase voltage e _aZero passage detection and phase-locked processing make the phase angle theta value more accurate.Then, again with the e in the two-phase rest frame _α, e _βComponent is rotated conversion, obtains with the e in the coordinate system of supply frequency rotation _d, e _qComponent.The three-phase bridge inverter output current (i in the three phase static coordinate system _a, i _c), with the A/D input of giving after the collection of electric current Hall element on the DSP2 circuit board, be converted to digital quantity after, obtain B phase current i again _b, with i _a, i _b, i _cCarry out 3/2 conversion, obtain the i in the two-phase rest frame _α, i _βComponent is rotated conversion again, obtains the i in the supply frequency rotating coordinate system _d, i _qComponent.Dc inversion voltage U c itself is exactly a DC quantity, gives the A/D on the DSP2 circuit board input after being detected by the voltage Hall element, is converted to digital quantity, forms the Voltage Feedback amount.The voltage given value requires decision according to interior feed motivation feedback winding voltage value (for common winding motors, according to outer feedback transformer secondary winding voltage value) with reactive power compensation.Voltage regulator output is active current i _dGiven; The given i of reactive current _qTwo kinds of given ways are arranged: fixed form and calculating given way.The fixed form set-point can be set on the DSP2 man-machine interface by the user of service, but the compensation rate of reactive current must be presented in motor in the permission range of capacity of winding rated current (for common motor, presenting transformer secondary winding rated current outward).Account form is calculated by the DSP2 program and is realized, establishing feedback winding rated current is i _f, the reactive power compensation electric current that then can provide is $i_q=\sqrt{i_f^2-i_d^2},$ This mode can be used the capacity of feedback winding to greatest extent.Active current adjuster and reactive current adjuster are realized the adjusting of active current and reactive current.Active current i _dProduct and reactive current i with ω L _qDeliver to output of reactive current adjuster and the output of active current adjuster respectively with the product of ω L, synthetic with it, be for realizing the decoupling zero between d axle and the q shaft voltage equation.Active current adjuster output with the decoupling zero component synthetic after again with d axle electromotive force component e _dSynthetic, form the control component of voltage Vd on the d axle; Reactive current adjuster output with the decoupling zero component synthetic after again with q axle electromotive force component e _qSynthetic, form the control component of voltage Vq on the q axle.Control component Vd in the rotating coordinate system, Vq also must turn back to two-phase rest frame (counter-rotating conversion) again, and conversion goes out the control component V of two-phase rest frame _α, V _βAccording to control component V _α, V _β, produce the control pwm pulse of six IGBT of inverter bridge (or IGCT).

The electrical network that has in the utility model digital intelligent speed regulating device is cut function and the restart facility that has a power failure in short-term soon and is achieved in that when DSP2 detects electrical network and loses suddenly, block each device in the inverter bridge immediately, stop the inverter current circulation, simultaneously, block boost chopper, whole governing system is in blocked styate, waits for incoming call.At this moment high-voltage switch gear switched fast on electric power system was implemented, and switching is finished, and restores electricity again, and DSP2 detects electrical network electricity, immediately recovery system.If interruption duration is long, electromotor velocity descends more, might drop to lowest speed following (beyond the speed adjustable range)), for preventing this situation, governing system changes starting state automatically over to, behind the incoming call, by the soft start raising speed, change the speed governing running during to setting speed automatically over to.Reduced the influence that burst has a power failure and brings like this, to greatest extent.

Feedback winding asynchronous motor and the common winding asynchronous motor of middle pressure in pressing during the utility model is applicable to.

Embodiment 1:

With reference to the accompanying drawings 1, the concrete application example of feedback winding asynchronous motor in the utility model is used for.M is interior feedback winding asynchronous motor among the figure, by the power supply of 6 kilovolts or 10 kv grids, the rotor winding is connected to soft start equipment RQD to stator winding by high-tension switch cabinet, and motor capacity is below 1000KW, the frequency sensitive trheostats that adopt start more, and large capacity motor adopts water resistance to start.Motor start-up is controlled by PLC, during as if soft starting circuit part fault-free and warning, provides the permission enabling signal on touch-screen, if fault and warning are arranged, provides the No switching on signal; If revolutional slip control speed governing SKT part and slip power feedback SGH part fault-free and warning provide on touch-screen and allow into speed-regulating signal,, provide and forbid into speed-regulating signal if fault and warning are arranged; Starting has dual mode to select: directly advance speed governing and directly advance at full speed.If do not allow into speed governing, even select directly to advance speed governing, PLC also can guarantee directly to advance at full speed.When starting with full speed running, the electromotor velocity measurement is to calculate according to the frequency measurement of rotor current.For this reason, adopt the current Hall element to gather rotor current Ir, DSP1 detects according to zero crossing, calculates slip frequency and speed, and calculated value is used for the speed differentiation and shows.When speed governing operation, rotor rectifier bridge ZR connects through A.C. contactor and rotor winding, rotor rectifier bridge ZR and boost chopper CH constitute revolutional slip control speed governing SKT main circuit, and digital signal processor DSP 1 constitutes revolutional slip control and regulating circuit with voltage and current detection circuit.Detect chopper current Ic with the electric current Hall element, send DSP1 to be used for the current feedback of chopper current ring; Detect dc inversion condenser voltage Uc and add copped wave inductive drop U when interrupting with the interruption of cycle rate counter underflow with voltage Hall element cycle rate counter overflow in each chopping cycle _L, the instantaneous velocity of calculating motor is used for the speed feedback of speed closed loop; DSP1 is by software building chopper current ring, and speed ring and technology ring are implemented adjustment process.Be adjusted to example with speed electric current dicyclo, the process of once regulating is described.Suppose that motor turns round under a certain stable state, increment if velocity setting rises, because electromotor velocity does not also change, at the speed regulator input, just there is a velocity error, produce the given increment of chopper current in speed regulator output, motor current does not also increase, just there is a current error in the current regulator input, and current regulator produces a chopper duty ratio increment immediately, and this incremental contribution is in rectification copped wave main circuit, order about electric current of chopper and produce an increment, therefore rotor torque produces an increment, and this torque increment has destroyed original torque balance state, and motor begins raising speed, when electromotor velocity is raised near given speed, velocity error goes to zero, and current error also goes to zero, and motor is steady running under new set-point just.Vice versa.In the speed governing operation, the rotor slip power sends in streams to a place in the dc inversion capacitor by chopper and is converted to electric energy, by the slip power feedback circuit electric energy in the capacitor is delivered to electrical network again.The slip power feedback circuit is by inverter INV, filter LCL, and digital signal processor DSP 2 is formed with the electric current and voltage Acquisition Circuit.Inverter INV is connected into three phase bridge circuit by six IGBT (or IGCT); Filter LCL is connected into T shape filter circuit by filter inductance and electric capacity; Motor feedback winding voltage is passed through step-down transformer T1 with secondary voltage (e _a, e _b, e _c) deliver to DSP2, calculate electrical source voltage vector E for DSP2; Detect feedback winding phase current (i with the electric current Hall element _a, i _c) deliver to DSP2, calculate source current vector I for DSP2; Detect dc inversion voltage U c with the voltage Hall element, for the Voltage Feedback value of DSP2 calculating voltage ring; DSP2 software building outer voltage, the dicyclo regulating system of ring in the active current reactive current, adjuster output obtains voltage in the two-phase rest frame through inverse transformation, generate software by PWM again, produce the grid pulse of six IGBT (or IGCT) pipe, the control three phase bridge circuit is sent active power back to the feedback winding; Simultaneously,, increase reactive power and set (in feedback coil volume allowed band), improve the overall power factor of electric motor system along with rotating speed descends.

In all processes of system works, PLC is detecting starting device constantly always, DSP1, and the state of DSP2, the control system each several part is program run in accordance with regulations.And constantly detect the warning and the fault of each several part, and in case break down, in time the motor in the speed governing running is changeed at full speed by starting device, on man-machine interface, demonstrate fault category simultaneously; If occur reporting to the police, only on man-machine interface, demonstrate the warning classification, and notice DCS Central Control Room, remind the maintenance personal to take corresponding measure.

Embodiment 2:

With reference to the accompanying drawings 2, the utility model is used for the concrete application example of common winding asynchronous motor.M is common winding asynchronous motor among the figure, does not feed back winding.The rotor slip power will feed back to electrical network with slip power by outer feedback transformer WT, so, the former limit winding of outer feedback transformer is received the lower end of the high-tension switch cabinet that the motor stator winding connect, and presents the filter LCL leading-out terminal that transformer secondary winding is received slip power feedback circuit SGH outward.Other are identical with embodiment 1.

Claims (5)

1. the middle voltage electromotor slip control digital intelligent speed regulating device of a Speedless sensor, comprise motor soft start equipment, revolutional slip control speed governing part, slip power feedback part and Programmable Logic Controller, it is characterized in that: described revolutional slip control speed governing part comprises rotor rectifier, chopper and digital signal processor (DSP1), implement Sensorless Speed measurement, control of electromotor velocity outer shroud current inner loop dicyclo and the control of load process outer shroud, to exchange slip power simultaneously and be converted to dc electric power, send into capacitor stores; Described slip power feedback partly comprises inverter, filter and digital signal processor (DSP2), implements the outer voltage current inner loop dicyclo vector control of feedback circuit, with the slip power feedback grid; Programmable Logic Controller is implemented program control, fault comprehensive and the processing of whole governing system; Whole governing system is the two-stage control model.

2. the middle voltage electromotor slip control digital intelligent speed regulating device of Speedless sensor according to claim 1, it is characterized in that: described Sensorless Speed is measured, comprise digital signal processor (DSP1) software, hardware and current/voltage acquisition system, wherein, use the current Hall element to gather the rotor-side alternating current, detection rotor electric current slip frequency in motor start-up process and full-speed operation, computational speed are used for starting and monitoring of full-speed operation medium velocity and demonstration; The working voltage Hall element is gathered dc inversion voltage and is added the copped wave inductive drop, calculates speed regulation process medium velocity value, is used for the speed feedback of speed governing, and the dual mode combination constitutes the tachometric survey of overall process.

3. the middle voltage electromotor slip control digital intelligent speed regulating device of Speedless sensor according to claim 1, it is characterized in that: described electromotor velocity outer shroud current inner loop dicyclo control and the control of load process outer shroud, comprise digital signal processor (DSP1) software, hardware and use current Hall element collection chopper current, make up current inner loop, the working voltage Hall element is gathered dc inversion voltage and is used for speed feedback with the speed that adds copped wave inductive drop calculating generation, forms the speed current double closed-loop; When having the technology closed loop to require, the feedback of digital signal processor (DSP1) collection technology amount, implementing process ring, speed ring, current loop control; Technology ring adjuster is selected a kind of use in conventional PID adjuster and intelligent fuzzy controller.

4. the middle voltage electromotor slip control digital intelligent speed regulating device of Speedless sensor according to claim 1, it is characterized in that: described slip power feedback part outer voltage current inner loop dicyclo vector control comprises digital signal processor (DSP2) software, hardware and electric current and voltage acquisition system, wherein use insulate step-down transformer to gather supply voltage, be used to calculate the supply voltage vector; Use the current Hall element to gather the inverter ac-side current, be used to calculate current phasor, digital signal processor (DSP2) software implementation electric current and voltage vector calculates, and outer voltage current inner loop dicyclo vector control, the output pulse width modulate and control impulse, the active power and the reactive power of control feedback.

5. the middle voltage electromotor slip control digital intelligent speed regulating device of Speedless sensor according to claim 1, it is characterized in that: described Programmable Logic Controller is implemented the program control of whole governing system, and software comprises the operation of fault comprehensive and processing, motor start-up, full-speed operation, speed governing running and various state exchanges.

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