CN1114088A - Optimal power supply for electric motor - Google Patents
Optimal power supply for electric motor Download PDFInfo
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- CN1114088A CN1114088A CN 94105729 CN94105729A CN1114088A CN 1114088 A CN1114088 A CN 1114088A CN 94105729 CN94105729 CN 94105729 CN 94105729 A CN94105729 A CN 94105729A CN 1114088 A CN1114088 A CN 1114088A
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Abstract
The present invention relates to a kind of dc/ac and ac/dc/ac static prequency convertor driving ac motor and a method for providing the optimized power and a kind of device for implementing said method. The load of said method for providing optimized power for inductive load coupled to the applied object, is driven by a static frequency convertor controlled by an electronic module. Said device supplis voltage to load by utilizing weighted and/or combined one or multiple monitor parameters (MP) and through adjusting the regulation parameter supplied to the controller of the frequency convertor.
Description
The present invention relates to provides the method for best power to a kind of alternating current motor that is driven by AC/DC and ac/dc/interchange static frequency convertor, and a kind of device of implementing this method.
Is known by means of all variable alternating voltage ripple of frequency and amplitude to the principle of motor power supply.It is in such a way to the problem of direct voltage source copped wave; Promptly on the terminal of motor, obtain a kind of waveform, so that the supply power voltage of motor and its load torque are complementary with required integrating shape.Thisly be entitled as " speed change " (in the works of Speed Variation ") for what the known technology of those skilled in the art of the present technique was described in that she Wan Piersi (Yvon PEERS) shown.This device normally is made up of a kind of frequency converter of controlling with the method for pulse-width modulation (PWM) type, and this frequency converter is set between the motor of power supply and driving-application.
In order in controller-motor unit, to obtain satisfied efficient, known is based on the one or more monitoring parameters by a resume module with this control procedure, these parameters of this module analysis also draw, and are used for optimizing and/or the parameter of the element of the basic adjusted device of convergence criterion.Represent that the block diagram of each step of this method gives in Fig. 1.Physical phenomenon 11 based on this device, for example electric current, voltage or temperature, monitoring parameter 12 is measured, then to its shaping (frame 13), itself and fiducial value or optimization and/or convergence criterion (frame 14) are compared (frame 15), then its result is judged (frame 16), make then to one in the adjusting parameter 18 of device may change determine 17, and partly send it to hunting gear (frame 19) by control corresponding.
This servo-actuated control is normally by finishing as the frequency change that flows through the function of transistorized electric current, and be based on Um=H(f, p1, p2 ... Pn) law of form is that middle Um is the integrated voltage on the Terminal of motor, f is the frequency of this voltage, and P1, P2 ... Pn is a monitoring parameter.The law of this form causes the power supply of crossing of motor through regular meeting, thereby causes size of component excessive as the criterion of well known device, has improved manufacturing cost thus.Some fiducial mark is certainly restrained the danger of power supply was substantially descended, but fails to eliminate satisfactorily these shortcomings in a word.
Another major defect of such servo-actuated control is: these parameters must be with the transducer of monitoring parameter amount as much and be connected lead and measure.In addition, the optimization of having done must be considered the tolerance of element, the tolerance of capacitor, high power transistor or motor physical characteristic for example, and motor is produced the tolerance of decentralization in enormous quantities and by the tolerance of electric motor driven load.For the summation of considering these restriction amounts and do not emit the danger of upsetting control-motor-application unit work, make servo-actuated in this wise and control, promptly the actual torque that applies of motor is greater than the breakdown torque of load in the working range.Such servo-actuated control is proved to be inappropriate, because it all can not obtain optimum efficiency under all are included in possible situation in the working range.Simultaneously, such servo-actuated control usually causes drawing from electrical network the electric current of very large value when starting.This just produces the energy loss of excess enthalpy and has and does not meet about produce the not danger of the specific criteria of tolerable interference in power supply network.
Known device can not be in the requirement of satisfying the driven application of desire with when generating a disposable unit, make the balance optimization between electric installation and the drive motor, this unit has the dispersiveness that may occur in the production of the parts in electronic section-motor-application chain.
The present invention is by means of the different parts based on monitoring parameter on control section-motor-application device, need not with the law of the above-mentioned type monitoring voltage and frequency aforehand, can search for the right method of supplying power to of optimum voltage-frequency of giving motor to be supplied automatically, continuously, overcome these shortcomings.
The present invention relates to the inductive type load that is coupled with an application apparatus is provided the method for best power, this load is by being driven by the static frequency convertor of electronic module control, this method of supplying power to provides the electronic load control device, this device is by being set the parameter on the controller that is applied to frequency converter by one or more monitoring parameters (MP), provide a voltage to load at any time, this monitoring parameter is weighted and/or combines, and this setting is to carry out corresponding near the change direction the limit place of the minimum power that is absorbed by load by being recorded in one.
The invention still further relates to the device of implementing this method of supplying power to.
Therefore, the unit operating state of sample (transition state between the stable state scope, two working points, starting is around the fluctuation of a working point) whatsoever, unit is in the state corresponding to maximal efficiency consistently.
Its direct consequence is: owing to quicken to have been controlled perfectly, motor power absorbed required power in by given application is minimum, and the electric current of drawing from power supply when starting also is minimum.
This can increase the life-span of motor and keep its performance, and the life-span that increases the frequency converter high-power components, because optimized the criterion of selecting the latter.At the control electronic section, balance between motor and the application load has been optimized, and at first the method according to this invention allows the inner parameter of system to revise as the function of time and parts consume, and unit can not demoted and formed inefficient or do not meet standard.
Followingly will understand better the present invention after with reference to the description of accompanying drawing having read, and its additional advantage will be more obvious.Accompanying drawing is:
Fig. 1: described, and represented the General Principle of monitoring power supply method;
Fig. 2: expression is according to the optimization that is used for the adaptive power supply of inductive type load of the present invention;
Fig. 3 a: the expression as the monitoring parameter function by the diagram example of a load power absorbed;
Fig. 3 b: the mode table of the selection type that may be made up by parameter block is handled in expression according to the present invention;
Fig. 4 a: expression changes to the flow chart of another lower state from a lower state for the little variation of face terminals upper frequency or voltage according to the present invention;
Fig. 4 b: expression changes to the flow chart of another lower state from a lower state for the big variation of face terminals upper frequency or voltage according to the present invention;
Fig. 5: expression is according to the path that continues the transient state process in the loaded work piece zone of the present invention;
Fig. 6: expression utilizes the starting that reduces the motor that is supplied to frequency according to the present invention;
Fig. 7: expression utilizes the starting that increases the motor that is supplied to frequency according to the present invention;
Fig. 8: expression utilizes the starting that increases the motor that is supplied to frequency and corresponding optimum efficiency according to the present invention;
Fig. 9: the path that is illustrated in the lasting transient state process that has buffer status in the working range;
Figure 10: be illustrated in the path of monitoring and regulate parameter in the preferred configuration of the present invention;
Figure 11: expression is according to the envelope of the starting current as capacitor initial state of charge function of the present invention; And
Figure 12: expression can be implemented a preferable static frequency-conversion apparatus according to the inventive method.
In the following description, described in the invention is to be applied to motor, but fairly obvious, and the method according to this invention can offer any inductive load similarly, for example static transformator one is adjustable or uncontrollable, or the transformer of one or more motor is given in power supply.
In Fig. 2, express total theoretical diagram according to self-optimization of the present invention.Monitoring parameter 20 power supply 21 and/or frequency converter 22 and/or at motor 23 places measured come out, parameter box B1, B2 and B3 are corresponding with them respectively.These frames are then by a module 24 preliminary treatment, and this module is selected them, and their weightings and utilization " or " reach " with " are made up them, and then the value that will obtain and fiducial value or optimization and/or convergence criterion (frame 25) are compared.Its result is converted into and regulates parameter 26, and these regulate the controller that parameter is provided for frequency converter 22.The possibility of controller-more accurate control of motor unit is provided according to the principle of self adaptation method for searching of the present invention, it allows switching controller-motor unit between a plurality of application, because it avoids utilizing the measurement of transducer amount of carrying out on application 27.
The stationary zones of the power supply source device of frequency converter-motor-application is corresponding to a working point of this device, and corresponding to the magnitude of voltage Um that supplies with motor and corresponding to the frequency values f that supplies with motor.
As shown in Fig. 3 a, have some motor monitoring parameter (MP) that constant motor frequency involves the motor constant load and have a recessed shape or present limiting value as the voltage U m function of supplying with motor.As an example, the minimum value of absorbed power is corresponding to the maximal efficiency of motor, and the minimum value that is absorbed electric current approaches the maximal efficiency of motor, and its difference is because the apparent power factor (Cos(fi) of this motor) cause.
The invention reside in power supply, frequency converter and motor electric current and power separately is considered as monitoring parameter among frame B1, B2 and the B3, and from these electric currents and power, select and make up them according to the rule of Fig. 3 b table, be weighted or not weighting so that the voltage U m of motor is supplied with in servo-actuated control.According to Fig. 3 a, these monitoring parameters are positioned on the Y axis Y, voltage U 1 is optimum voltage to be arrived, voltage U 0 or U ' 0 are the starting voltage value of Um, and servo-actuated from Um to U1 control is to begin to make from U0 or U ' 0 value on the basis according to a monitoring parameter of this curve or a plurality of monitoring parameter change direction.The electric current that to be drawn can be used for regulating the torque that is produced by the fluctuation of load as monitoring parameter to be changed, and regulate corresponding to these torque ripples by current drawn.In fact, when near loading on a working point, fluctuating, the electric current of being drawn presents distortion, for example just reaching asymmetric between the negative half-wave, utilize these asymmetric facts of adjusting of the adjusting parameter of servo-actuated control of conversion device to accomplish motor torque and countertorque are complementary, and can limit the vibration in the unit.
Under the situation of transient area, for example: because the variation of application self character or because the variation that the device user needs carries out the transition to another stationary zones corresponding to second working point from the stationary zones corresponding to first working point, no matter which type of required or pointed disturbances of power is, preferably never will emit the danger that makes the motor stall to reduce power of electric motor.Two kinds of situations can appear according to frequency f and changing value df and voltage U m changing value dUm.The variation of these frequencies df and voltage dUm can be finished in one or more steps.
The motor that is operated in the rated condition is powered by a voltage U m, and this voltage makes its operation torque reach a working value of toppling over torque (drop-out torque) when being lower than its operating frequency.This operation torque and topple over deviation dc between the torque and cause by inner parameter that limits motor and the fine balance supplied with in stationary zones according to the present invention between the method for best power.
Use df＞0 or df＜0 and revise motor power supply wave frequency, and do not change the magnitude of voltage that offers motor, have the effect that reduces or increase deviation dc respectively.
Under df＞0 situation, guarantee that it is important that dc does not become too for a short time, it has the effect of regulating motor stability, two kinds of situations can occur:
For enough little df value, can be in one direction or with any order modification frequency f and voltage U m, can not emit the danger that reduces motor power (output).This first kind of situation is depicted among Fig. 4 a, and it represents that a stationary zones 1 f1) carries out the transition to corresponding to state 42(U2, the flow chart of another stability region 2 f2) from the voltage/frequency state 41(U1 corresponding to motor.Frequency f 1 is attended by df and changes (frame 43), till value f2 according to required fiducial value 44, that this value person of being to use needs or when application itself changes adaptive control needs.Magnitude of voltage U1 is attended by the variation of dU, and (U2, the voltage optimum value 45 of working point 2 f2) is corresponding to till value is during U2 up to state.
Corresponding bigger df value is equivalent to emit and regulates the dangerous dc value of motor stability, must award the dUm priority, so that do not emit the danger that reduces motor power (output).In fact,, and do not consider to increase dUm in advance, then can emit the danger that reduces motor power (output) if frequency is increased such value df.It is shown on Fig. 4 b that Here it is, wherein when the fiducial value that enters frame 404 need increase frequency (df＞0), at first changes voltage (frame 403), and the corresponding change of frequency then (frame 402) is so carried out till reaching desirable value U2.When the fiducial value that enters frame 404 need reduce frequency (df＜0), at first apply required variation df, voltage can correspondingly change and can not emit the danger that reduces motor power (output) in fact, because on the contrary motor the very short time by the meeting power that raises, based on the described characteristic of the present invention of Fig. 3 a, the state of system will bring back to the maximal efficiency point soon by means of basis.
An example using these flow charts is illustrated among Fig. 5.The working region 51 of motor shown in this figure, (abscissa is the linear amplitude of torque by representing the device working point for it, vertical seat value is the linear amplitude of motor speed) discrete point 52 compositions, curve C 5 expression free routings (PM), at this moment P and M continue two stationary zones points that transient area is formed at each point, a Fig. 4 a that describes according to the adaptive control of the invention described above and a differentiation that comes taking into account system in the 4b flow chart.
Have a special transient area, it is exactly the starting state of the motor of driving-application.Utilize and another inductive type load analogy mutually, the load of for example static converter type (it is adjustable or uncontrollable), or even be the transformer of powering to motor, this starting state and these loads that begin to close a floodgate are of equal value.The problem that those skilled in the art ran in starting process is exactly: have very large value the current value that is absorbed on the transient area of the electric current that is absorbed or is drawn that overcomes countertorque between a stationary zones or two stationary zones.These peak values that are absorbed electric current may pollute power supply network and/or force in the device size of component excessive.
After overcoming this starting torque, motor must increase the speed that drives application makes it arrive a certain working point.The present invention proposes the mode of two kinds of control motor acceleration.
First mode according to the present invention is to utilize the reduction frequency to realize starting, the example in order to start an asynchronous machine as shown in FIG. 6 is such, on abscissa, represent torque among the figure, the frequency of the voltage fundamental of expression supply motor or the speed of motor on ordinate.The starting technique that those skilled in the art will appreciate that this utilization reduction frequency can not be used for the motor that lacks asynchronous components.At initial moment t0 one reference frequency f1 is supplied with motor, and be accompanied by the voltage of countertorque when being suitable for overcoming starting, this frequency is higher than and the corresponding frequency in working point that will reach.Then, little by little control voltage and frequency, its frequency little by little drops to f4 from f1 via f2 and f3, reaches corresponding to the frequency values of first stationary zones or till reaching a very approaching value up to this frequency values.Curve C 6 is the speed-torque characteristics for any application of these working points, and curve C 61, C62, C63 and C64 are the speed-torque characteristics of motor.(Um, f) cumulative rule can be selected based on required acceleration law as the torque of the function of time.
Second mode according to the present invention is utilize to increase frequency to realize starting, example asynchronous motor of starting as shown in FIG. 7, and wherein abscissa is represented torque, ordinate is represented the fundamental voltage frequency on the Terminal of motor or the speed of motor.At the initial moment t0 voltage wave that to supply with frequency of motor be f1, this frequency is lower than the frequency of the working point correspondence that will reach, and is accompanied by the correspondent voltage value so that overcome countertorque when starting.Then, utilize progressively control, frequency is via f2, f3 rises to f4, up to reach with the corresponding numerical value of first stationary zones to be reached till, curve C 7 is speed-torque characteristics of an application, and curve C 71, C72, C73 and C74 are the speed-torque characteristics of motor.According to this technology, voltage all utilizes the method according to this invention coupling at any time, the accurate power of motor is supplied with guaranteeing, this makes power controlling constantly, may command absorbs in the time of if desired electric current and acceleration.
Another advantage of the present invention results from utilizes the increase frequency to realize the fact of starting.In fact, this can make motor work more quickly on the higher speed of the speed of toppling over torque than it, utilizes it is operated near near the voltage that comes servo-actuated control motor its optimum efficiency, comprises when motor is operated in acceleration mode it also being like this.So absorbed power when this servo-actuated control can reduce starting further is the electric current that draw from electrical network when just having reduced starting and the device.The optimum efficiency of the curve representation motor that with dashed lines is drawn in Fig. 8.
According to the present invention, available two kinds of different modes decide the end of starting:
According to being driven the feature that process characteristic forms and the understanding of decentralization, in a safety clearance, fix a time delay;
Or, by means of an electric current or an equivalent physical quantity, when descending, the electric current of being drawn by motor detects the end of acceleration mode.
After acceleration mode, can observe two kinds of situations:
The torque of first working point is equivalent to the torque that accelerator finishes;
Or the torque of first working point is different from the torque that accelerator finishes, for example, and priming of pump situation when beginning to close a floodgate; The situation of a refrigerant circuits when pressure reduction is established after postponing constantly with respect to starting; The situation of time-delay clutch apparatus; The situation of centrifugal pump; The situation of lathe is lathe or grinding machine for example, and they start when fastening means not, or the situation of utilizing centrifugal action that any device is devoted oneself to work.
When acceleration mode finishes, if the torque that motor provides is lower than the load countertorque that is equivalent to first working point, and when power supply not being made adjusting, motor overpower can not occur, because consider gradually changing of when above-mentioned acceleration mode time system mode, motor will emit the danger of stall.According to the present invention, there are two kinds of technology can avoid this problem.
First kind of technology is: when the parameter of first working point that is equivalent to stationary zones when being known or predictable, the voltage U m that directly will be equivalent to this working point supplies with motor when acceleration mode finishes.No matter as above-mentioned explanation ground used the starting that increases frequency or reduction frequency, this technology can be considered.
Second kind of technology according to the present invention be, when the parameter of first working point that is equivalent to stationary zones when being unknown or unpredictable, between the method for acceleration mode and control stationary zones a buffer status is set.In the working region, as shown in Figure 9, some D ' is illustrated in point to be reached in the stationary zones, and does not know the descriptive parameter to it, has selected under the situation of not knowing corresponding to a parameter of D state.It corresponding to the torque of a D torque of the maximum that may reach during required rotating speed in the stable state.On the terminal of motor, will supply with voltage U mD corresponding to the torque of D point, motor is supplied to overpower when this buffer status, but according to of the present invention be that the rapidity of method input of the control stationary zones of basic description makes it arrive the condition of power supply that is applicable to a D ' soon with Fig. 3 a, this is for application and for the real work point of motor, for it corresponding to voltage U mD '＜UmD.It is very short that motor is crossed supplying time, no matter use is raising frequency or frequency reducing.In the static transformator type more generally under the situation of inductive load, no matter it is adjustable or nonadjustable, or even to motor power supply, close a floodgate for the first time and comprise a buffer status using steady-state process former, these loads have and the corresponding applied voltage in a working point during this state, and the power of this working point is the maximum power that may reach in stable state.
In a preferred configuration of the present invention, for example shown in Figure 9, can be in the situation of two fronts regulating frequency, so that when acceleration mode finishes, frequency values as far as possible near with the corresponding frequency f mD ' of a D ', so that because the change that the variation of frequency causes can be ignored, no matter employed is raising frequency or frequency reducing.
Another preferred embodiment of the present invention is: a D is not elected as possible " target " point, but select to be more suitable for the point of required accelerating time.As the function of speed that will reach after acceleration, any point on part (B, C, D, E, F) all can be selected, because this part has represented the zone that can estimate as the breakdown torque of speed functions.Select criterion that the power supply of crossing of motor is minimized.Adopt above-mentioned method in order to reach real working point (the some D ' among Fig. 9) based on Fig. 5.
In order to implement the present invention, the waveform of supplying with Terminal of motor is to be adapted to high efficiency and its electric supply installation high efficiency of motor especially, and this waveform is an alternating voltage ripple, and its half-wave has the shape of isosceles trapezoid, its flat-top has the duration of T/6, and wherein T is the cycle of this waveform.At the rising of this half-wave and the chopping frequency on the decline slope more preferably greater than 10kHz.The advantage of this waveform is described in and is entitled as in the french patent application of " to the method for supplying power to of inductive load and implement the device of this method ", and this application is submitted on same with the application.
Be used for implementing a preferred static frequency convertor structural table of the present invention and be shown in Figure 12, this is the combination of boost an active filter and an apparent voltage step-down inverter unit from motor.This structure is described in the french patent application that is entitled as " a kind of structure of static frequency convertor ", and this application is submitted on same with the application.
This static frequency convertor is handled by monitoring parameter and 123 controls of control signal lead-out unit, and fiducial value 1216 is fed into this unit, and comprises an active filter 122 at inverter 124 terminal places, and to a load 125 power supplies.Diode bridge rectifying device 121 power supply wave shape Ue of reception also flow to rectified waveform Ur on the terminal of active filter 122.This active filter is made up of diode D1 of an inductor L1 series connection, and the two is connected with ground with a capacitor C0 and a K switch 5 of being controlled by unit 123.This active filter 122 flows to voltage E the terminal of inverter 124, inverter comprises a full-bridge at least, one of them brachium pontis comprises two capacitor C1 and C2, and another brachium pontis comprises two K switch 1 and K2, the load 125 of motor types is connected between capacitor C1 and the C2 on the one hand, is connected on the other hand between K switch 1 and the K2.Control these switches by means of unit 123 by lead 129 and 1210, and realize the method for PWM type according to the present invention, inverter 124 is transported to a voltage U m on the terminal of motor 125.This voltage U m comprises one-component UmLF, and this is the voltage of seeing from the low frequency viewpoint, and one-component UmHF, and this is the voltage of seeing from the high frequency viewpoint.Capacitor C1 and C2 have voltage V1 and V2 respectively on terminal separately.This device is to single-phase motor power supply, powers but can expand to multiphase motor.
Frame B1 to B6 is the monitoring parameter of being handled by unit 123 by lead 1212, and they are at power supply Ue place, in output place of rectifying device 121, at active filter 122 places, in inverter 124 and or the physical quantity measured of motor 125 places.These measurable physical quantitys can be voltage, electric current, power, temperature, displacement, speed, acceleration, pressure, magnetic field and/or electric field.Preferably monitoring parameter is the reflection of the amount of distortion dUmLF of voltage UmLF on the Terminal of motor.
By means of this structure, active filter 122 can be controlled in this wise, so that showing as same increasing apparatus and/or inversion unit 124, it can control in this wise, so that the magnetic flux of motor 125 has the characteristic as the inversion unit 124 that shows as dropping equipment.
In a plurality of advantages of this structure, some are arranged is particularly advantageous, for example this structure is not polluted electrical network, it can overcome the fluctuation of the power supply Ue that comes from frequency converter fully, but and also can provide the voltage fluctuation coefficient of container end portion in the inversion unit as adjusting parameter except that the above-mentioned various measure physical quantities that can arrive, this coefficient provides the reflection that a varying duty countertorque fluctuates.
These regulate the basic body of parameter can be the service time ton of the K switch 5 of active filter, so that regulate the direct voltage E on the inversion unit terminal; Reach PWM method, the apparent percentage %Um of the voltage E that sees from the motor aspect by means of servo-actuated control inversion unit switch.
Figure 10 expresses the monitoring in the present foregoing frequency changer and regulates the position of parameter.
By means of a kind of like this device, under the situation of stationary zones, the voltage on the basic adjusted Terminal of motor of electric current of drawing by motor shown in Fig. 3 a and power; Corresponding to basic adjusted direct voltage E and %Um in the change direction of selected monitoring parameter MP.Same voltage U mLF for causing on Terminal of motor almost has the selection of numerous E and %Um, because this may get more to higher voltage E copped wave.Or must lack lower voltage E copped wave.Can consider to rely on two kinds of criterions makes one's options: the scope of voltage distortion and/or make the loss of the power component of frequency converter reduce to minimum corresponding to minimum value E on Terminal of motor.
Under the situation of transient area, the structure of this frequency converter E that can irrespectively raise with the compensation of application fluctuation, so that servo-actuated control %Um and simultaneously from providing necessary flexibility to following of another working point transient area to a working point, and provide optimum voltage to motor constantly simultaneously, synchronously more slowly E is made possible optimization with the process progress, or when a new stationary zones is returned, make the optimization of E.
In addition, under the situation of motor starting, when the significant instant t=0 of motor starting, this structure can be to this begins constantly to provide and overcomes starting countertorque required voltage U mLF on the motor, utilize with power supply status and irrespectively the capacitor C1 and the C2 of inversion unit are pre-charged to required numerical value E, this or utilize the working independently of K switch 5 of increasing apparatus 122, cut-off and the K switch 1 of inversion unit 124 and K2 are remained on; Or utilize the PWM method to drive K5 and K1 and K2 work in combination in this wise, and making provides the waveform of conduction ratio 1/2 to motor, and this motor will remain on halted state, because it shows as obtaining a zero voltage UmLF.Then just much of that as long as increase %Um gradually corresponding to one of above-mentioned criterion of controlling gradually.This specific character can expand to all inductive loads similarly, promptly is used in to make it can produce necessary electric current and/or power when load regulation once closes a floodgate.
An additional advantage of the present invention is to guarantee the repeatability of starting in optimum state, because regardless of the state of power supply, the voltage of supplying with motor guarantees, and the electric current of being drawn then is minimum.
Figure 11 represents to start regional A and is the schematic diagram that reaches stationary zones B institute current drawn.When having satisfied the initial charge condition of capacitor C1 and C2 according to above-mentioned principle, the starting time is dt1, the envelope of the transient current Imrms that curve C 111 expressions are drawn.Under the situation that initial condition is not followed, root-mean-square value (rms) electric current, I 1rms, I mr ms and I2r ms rise, and become dt2 by dt1 in company with their necessary time of starting.
Another advantage of the present invention is, during starting on capacitor C1 and the C2 terminal voltage must strictly be E, to avoid the overload of inversion unit power switch.In addition, can avoid only relying on the undue increase of C1 and C2 capacity for the purpose of starting according to the present invention.In fact, if utilize the increase frequency to start, the original frequency of use may form big changing value dv on the terminal of capacitor C1 and C2.
The energy that offers capacitor C1 and C2 directly is subjected to coming from the influence of the pulsation of rectifier power source, plain mode to this effect retentive control is a switch of synchronously controlling inversion unit, so that be that high time section makes capacitor obtain ceiling capacity from power supply on the fundamental frequency of motor voltage, this is equivalent to utilize fully the effect of C1 and C2 when starting.
Second method can make C1 and C2 be operated in the state that limits voltage change dv on its terminal under the situation of utilizing the frequency reducing starting.This can diminish the changing value dv on C1 and the C2 by means of boosting and the compound action of apparent step-down reduces the E value to identical motor supply power voltage Um.
Quicken to finish with the first stationary zones point between exist under the situation of torque deviation, in a single day the present invention has the big flexibility of tracking, can not produce undesirable influence to power supply, comprises when having overcome when not knowing the required torque value of motor behind the inertia.
Also can make E have sufficiently high value and make motor work, comprise under the stringent condition that is operated in working region shown in Figure 9.In addition, when acceleration mode finishes, the %Um value can be adjusted to corresponding working region scope on the corresponding value of maximum torque choice point on.Be used to obtain the optimum voltage of stationary zones by the approximate rapidity of method servo-actuated of the present invention control %Um, it can make reduces the electronic supplying time of crossing.
The device that the method for best power is provided and implements this method according to the present invention can be used for all types of inductive loads, make the power that provided by them with by the ratio of their power absorbed when the given frequency, function as the input voltage UmLF that supplies with them reaches maximum, for example it is used for such load: asynchronous motor, synchronous motor, the asynchronous ac motor of Synchronization Control, be provided with or do not establish the parts of variable reluctance type, single-phase or heterogeneous motor, and the static frequency convertor that is similar to described motor, scalable or uncontrollable or or even to the transformer of motor power supply.
Claims (19)
1, a kind of method that inductive load with application coupling is provided best power, this load is by being driven by the static frequency convertor of electronic module control, this method of supplying power to provides the electronic load control device, this device is by being set the parameter on the controller that is applied to frequency converter by one or more monitoring parameters (MP), provide a voltage to load at any time, this monitoring parameter is weighted and/or combines, and this setting is to carry out corresponding near the change direction the limit place of the minimum power that is absorbed by load by being recorded in one.
2, according to the method for claim 1, the starting state utilization that it is characterized in that being used for reaching first stationary zones increases frequency (df) and realizes in one or more steps.
3, method according to claim 1, it is characterized in that requirement according to the user is from a working point (U1mLF, f1) change to another working point (U2mLF, f2) make like this: in frequency change value (df) when negative, utilize the value (df) that changes frequency, the value (dUmLF) that changes voltage then realizes; In frequency change value (df) is timing, utilizes the value (dUmLF) of revising voltage, and the value of frequency of amendment (df) realizes then.
4, method according to claim 1, it is characterized in that requirement according to the user is from a working point (U1mLF, f2) (U2mLF is not have order of priority ground to realize between the variation (dUmLF) of variation (df) in frequency and voltage f2) to change to another working point.
5, method according to claim 1 is characterized in that (U1mLF, (U2mLF is to utilize the correction of application itself to realize f2) f1) to change to another working point from a working point.
6, the inductive load with application coupling is provided the method for best power, this load is by being driven by the static frequency convertor of electronic module control, the starting utilization that wherein reaches first stability region reduces frequency (df) and realizes in one or more steps, then in case reach the control of stationary zones and/or from a working point (U1mLF, f1) change to another working point (U2mLF, f2) control utilizes that arbitrary method realizes in the claim 1,3 or 4.
7,, it is characterized in that the decision that starting state finishes is to make when the electric current that flows through load (ImLF) descends according to claim 2 or 5 described methods.
8, according to claim 2 or 6 described methods, the static frequency convertor type that it is characterized in that inductive load, no matter it is adjustable or non-adjustable, or or even power supply when giving the transformer of one or more motor, they are at first devoted oneself to work and are included in a preceding buffer status of stationary zones step, voltage is corresponding to a working point (D) during this state, and the power on this aspect is the maximum power of the supply load that may reach in stationary zones.
9, according to claim 2 or 6 described methods, it is characterized in that when load is a motor, starting is included in a buffer status between accelerator and the stationary zones step, voltage is corresponding to the torque of working point (D) in this state, and this torque is the breakdown torque of the supply motor that may reach during required rotating speed in stationary zones.
10, according to each described method in the aforesaid right requirement, it is characterized in that monitoring parameter (MP) is measurable physical quantity, for example voltage, electric current, power, temperature, displacement, speed, acceleration, pressure, magnetic field and/or electric field.
11, according to each described method in the aforesaid right requirement, it is characterized in that the inductive load that this method is used to is to have or do not have the asynchronous motor that can change the magnetic resistance type components, synchronous motor, the asynchronous ac motor of Synchronization Control, single-phase or multiphase motor, or a kind of static transformator, no matter be adjustable or uncontrollable.
12, according to each described method in the aforesaid right requirement, it offers a kind of waveform of face terminals (UmLF), and this waveform has isosceles-trapezium-shaped, and its platform has the duration of T/6, and T is the cycle of the comprehensive waveform in face terminals place.
13, a kind of static frequency convertor by monitoring parameter processing and control signal generating unit control, be included in the active filter at the inverter terminal place of supply load, this active filter is composed in series by an inductor and a diode, they are connected with ground with a capacitor and a switch, this switch handled by monitoring parameter and control signal generating unit is controlled, this inverter is made up of at least one full-bridge, a brachium pontis of this bridge comprises two capacitors, and another brachium pontis comprises two switches, each method of supplying power to during this device realization aforesaid right requires.
14, frequency converter according to claim 13 is characterized in that inverter only comprises a full-bridge and powers to single-phase load.
15, frequency converter according to claim 13 is characterized in that inverter comprises two full-bridges and gives the two-phase electric.
16, according to each described frequency converter in the claim 13 to 15, it is characterized in that monitoring parameter (MP) is the load power absorbed, flow through the electric current (ImLF) of load, change in voltage on capacitor terminal (dV1, the value of voltage (UmLF) distortion (dUmLF) dV2) and/or on the reflected load terminal.
17, according to each described frequency converter in the claim 13 to 16, the monitoring parameter (MP) that it is characterized in that being used to monitoring near the fluctuation working point for the voltage change on the capacitor terminal (dV1, dV2) or flow through the electric current (ImLF) of load.
18, frequency converter according to claim 13, it is characterized in that, before first time "on" position, direct voltage (E) precharge of capacitor with supply independent, this or utilize working independently of switch in the active filter, and the switch in the inversion unit keeps cut-offfing; Or utilize that in the increasing apparatus compound action of switch under PWM type mode drives reaches in the switch and inversion unit, its PWM mode offers load, and to have duty ratio be 1/2 waveform.
19, frequency converter according to claim 18 is characterized in that, inductive load is a motor, and before starting state, capacitor is with motor power supply station necessary direct voltage (E) precharge, so that the countertorque when overcoming starting.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN94105729A CN1042582C (en) | 1994-05-18 | 1994-05-18 | Optimal power supply for electric motor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN94105729A CN1042582C (en) | 1994-05-18 | 1994-05-18 | Optimal power supply for electric motor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1114088A true CN1114088A (en) | 1995-12-27 |
| CN1042582C CN1042582C (en) | 1999-03-17 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN94105729A Expired - Fee Related CN1042582C (en) | 1994-05-18 | 1994-05-18 | Optimal power supply for electric motor |
Country Status (1)
| Country | Link |
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| CN (1) | CN1042582C (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102185556A (en) * | 2011-05-10 | 2011-09-14 | 义马煤业集团股份有限公司 | Power joint control method for cage motor back-to-back frequency converter and frequency converter |
| CN104656000A (en) * | 2013-11-22 | 2015-05-27 | 法国大陆汽车公司 | Short circuit in detection switch structure |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4855652A (en) * | 1987-01-28 | 1989-08-08 | Hitachi, Ltd. | Speed control apparatus for a brushless direct current motor |
| CA2015281C (en) * | 1989-04-25 | 1995-08-29 | Minoru Maehara | Polarized electromagnetic relay |
-
1994
- 1994-05-18 CN CN94105729A patent/CN1042582C/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102185556A (en) * | 2011-05-10 | 2011-09-14 | 义马煤业集团股份有限公司 | Power joint control method for cage motor back-to-back frequency converter and frequency converter |
| CN104656000A (en) * | 2013-11-22 | 2015-05-27 | 法国大陆汽车公司 | Short circuit in detection switch structure |
| CN104656000B (en) * | 2013-11-22 | 2020-01-21 | 法国大陆汽车公司 | Device and method for detecting short circuit in switch structure |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1042582C (en) | 1999-03-17 |
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