CN1008038B - Induction motor regenerative brake control apparatus and method - Google Patents

Abstract

An AC induction motor brake control apparatus and method are provided for energizing the motor with an inverter supplied first voltage and an additional brake circuit supplied second voltage in phase with and additive to the first voltage as required to determine a desired brake torque above base speed operation.

Description

Induction motor regenerative brake control apparatus and method

The application relates to following related application, be that sequence number that (D.J.Shero) people of etc.ing D.J snow sieve submits to is 696814 and inscribes one's name and be the application of " induction motor composite control apparatus and method " (W.E.Case 50932), and the sequence number submitted to of (D.J.Shero) people of etc.ing D.J snow sieve be 696833 and autograph be the application of " arrangement for controlling induction motor and method " (W.E.Case 52232), these apply for all having transferred same assignee also in the lump as a reference here.

The present invention relates to the alternating current motor driving arrangement is provided with one and overlap closed-loop control system, wherein electric motor drive apparatus includes a three-phase alternating-current motor, this motor utilization is powered the voltage that inverter provides by the control of gate cut-off thyristor (GTO), inverter is then directly from a DC power supply.This GTO switch in inverter needs to have certain ON time between arbitrary level in every phase of motor and secondary power supply (being high pressure and low pressure), every and other two alternate correlations constitute needed AC wave shape, so that be suitable for encouraging this motor.

For a transport vehicle, the torque from one or more drive motor output should make the acceleration of vehicle or deceleration can maintain the given pace level as everyone knows.As everyone knows, because various disturbance and do not give the changing factor of material, one cover closed-loop control device need be set, determine that with it motor answers the output torque of tool and control to be added to the AC wave shape on the motor so that make the desired output torque of motor maintenance.

The output torque enough change slip-frequencies of energy of alternating current motor and/or the method for terminal voltage of motor are controlled, for the electric motor drive system that with the direct current is the input power supply, can change each parameter value of these motor with the voltage source inverter of variable voltage and variable frequency.

In prior art, known the control system that a kind of induction motor is arranged, this system includes with an inverter power supply and moves the brake torque that provides needs in the regenerative braking mode for motor, as the Ke Limendi United States Patent (USP)s that the people provided such as (Clemente) promptly is for No. 3815002.It includes whenever being in series of a different Transformer Winding and three-phase alternating-current motor and joins, and is provided with a bypass controllable silicon, is used at the motor run duration each Transformer Winding short circuit, the control brake torque by the angle modulation of silicon controlled phase.

The objective of the invention is to that the induction motor in the vehicles is provided maximum constant torque ， And provides with constant torque induction motor and brakes stably, makes the passenger obtain comfort.In prior art, only before reaching base speed, induction motor has constant torque, and torque presents nonlinear curve when base speed is above, shown in the curve 28 of Fig. 3, torque curve provided by the present invention is just like shown in the curve among Fig. 8 210, and the present invention utilizes brake apparatus shown in Figure 9 and a microprocessor synergy and achieves the above object.

Provide the inverter of a cover variable voltage and variable frequency to drive control device of electric motor and method for the induction alternating current (AC) motor drive system.Adopt the programmable microprocessor of a cover, come to determine switching on and off of motor current as required.This DC-to-AC converter is connected an additional electric electromechanics potential source, the electric electromechanics that it is attached to by the power supply of this DC-to-AC converter presses, so that provide necessary total motor voltage when the motor of a desired regenerative braking is in service to reach desired brake torque for induction motor drive system provides at needs.

To be illustrated in conjunction with following accompanying drawing for preferred embodiment of the present invention.

Fig. 1 represents the control device of the induction alternating current (AC) motor in the prior art;

Fig. 2 represents typically to orbit in the prior art and has the operation of the transport vehicle of a drive motor equipment.

Fig. 3 represents in the prior art torque of alternating current impression drive motor on the transport vehicle, the relation curve of voltage and speed;

Fig. 4 represents the block diagram of induction alternating current (AC) motor control device of the present invention;

Fig. 5 represents the function of the motor controller of induction alternating current (AC) motor control device of the present invention;

Fig. 6 represents the state of a control of induction alternating current (AC) motor control device of the present invention;

Fig. 7 represents that the braking Tx of controller for ac motor of the present invention controls accurate state;

Fig. 8 illustrates motor torque and the correlation of electromotor velocity under every kind of driving operational mode and running under braking mode among the present invention;

Fig. 9 is for providing the winding diagram of the brake apparatus of desired motor voltage for the running under braking mode in induction motor drive system of the present invention;

Figure 10 is provided by the running under braking control circuit that provided;

Figure 11 represents the inverter output voltage among the present invention and the relation of brake apparatus;

Figure 12 represents the voltage relationship of input motor;

Figure 13 represents the signal voltage relation in the running under braking control circuit shown in Figure 10;

Figure 14 is expressed as the program circuit that running under braking control circuit shown in Figure 10 provides control signal.

Controller for ac motor in the prior art has been shown among Fig. 1, comprising a DC power supply 10 is arranged, it is connected with inverter 11, in order to determine the operation of three-phase alternating-current induction motor 12, this motor 12 is connected on the load 13 of representing transport vehicle, torque sensor 14 is connected with motor 12, is used for torque is fed back to motor controller 16.Power controller 17 is accepted the input of transport vehicle weight 19 and transport wheels diameter 20 from acceleration request 18 of transport vehicle executor input the time, the requirement that power controller 17 is carried according to load 13 under the speed that acceleration request 18 is limited produces a torque force request 21, the torque of alternating current motor 12 for transport vehicle being quickened need reach represented in this request 21, and impact limiter 22 is accepted this torque force request 21 and limited it immediately and provide one and be subjected to torque force request 23 after the overbump restriction to motor controller 16.It is the start pulse 24 of the GTO of starter inverter 11 usefulness that motor controller 16 produces one, so that make torque feedback 15 and torque force request 23 couplings of impacting restriction.

Represented the transport vehicle 25 of representative load 13 in Fig. 2, it operates on the track 26.Wherein and include inverter 11, induction motor 12, motor controller 16 and be connected torque sensor 14 on the motor 12.Power supply 10 is given inverter 11 by power line 27 power supplies.

Figure 3 illustrates the torque, voltage of an induction motor in the prior art relation curve to speed.It is constant that motor driven torque shown in curve 28 is raised between fiducial value from zero in speed, when then treating speed greater than this fiducial value then driving torque descend, the value of reference speed shown in the figure is 50HZ and the travel speed of car is about 20mph.Motor voltage shown in curve 31 is linear the rising before reference speed, then remains constant then when the motor reference speed is above.

Be equivalent to car speed in orbit when operation rises to the 50HZ reference speed for motor and reach 20mph, inverter 11 drives run duration at this and provides square with all strength, shown in curve 28.During this period, the voltage that is connected on the Terminal of motor shown in the curve 31 rises according to the needs of this operation, directly before reaching this reference speed, voltage then rises according to the maximum square threshold voltage that keeps required inverter 11 outputs of constant torque, and the voltage of inverter 11 then connects on certain AC line voltage that power supply 10 attracts.After reaching reference speed, voltage 31 just is constant value, and effective torque 28 successively decreases and be approximately 80mph up to the numerical value at the 200HZ place, and effective torque 28 at this moment only is 1/16 of 50HZ place.When running under braking, inverter 11 will provide identical torque 28, and this is because still be the cause of voltage 31 on the motor.The brake motor operation will be advanced along the track and the above-mentioned rightabout of torque curve 28 because of successively decreasing of electromotor velocity.Then can increase slippage if desired to obtain big slightly torque.

Typical transport vehicle motor has 4 magnetic poles, and rotor frequency equals the RpM(revolutions per minute) mechanical frequency divided by 30.

Figure 4 illustrates the control device of electric motor that is suitable for going to control a three-phase alternating-current motor, for example be used for the drive motor of a large sightseeing bus according to the present invention.The driver proposes to quicken speed of a motor vehicle request 18 to a power controller, and power controller 17 or vehicle controller are translated into this request torque force request signal 21 and are input to signal limiter 22 so that stop irrational torque force request.It is relevant with desired impingement rate 36 that impact limiter 22 is designed to, and impacts torque-limiting request 23 so that set up one for passenger's comfort.Torque feedback determines that device 38 determines that according to system's input power of measuring torque feeds back 40, and system's input power is corresponding to rotating speed speed counter 52 that the direct voltage 43 that is provided by power supply 10 and direct current 44, inverter frequency 48 and synthesis mode 50 and the tachometer 54 that couples for the output torque of calculating motor 12 and drive motor 12 provide.Torque feedback signal 40 offer 58 1 negative inputs of adder in case with impact the positive input that torque-limiting request signal 23 offers this adder 58 and make comparisons.Should be input to motor controller 62 by 60 synthetic of torque differences signals, a control of sending from the driver allows signal 64 to ratify the drive motor operation or do not move.Motor controller 64 necessary other are input as the synthesis mode 50 of AC line voltage 43, frequency meter 52 and inverter.The output of motor controller 62 includes that the braking controllable silicon allows 68, desired drag angle 70, request inverter frequency 48 and request contravarianter voltage percentage value 74, and these all are input in inverter and the braking synthesizer 76.In addition, the braking synthesizer has an I/O state of a control 78, and determines that to motor controller 62 and torque feedback device 38 provides synthesis mode signal 50.When motor 12 is in the running under braking mode, against the auxiliary voltage that is provided by transformer braking circuit 80,78 operations of state of a control signal make synthesis mode remain on for 6 steps and stop accurate 6 step (quasi-six-step) or pulse width modulation (PWM) modes that change to.Inverter and the 76 output inverter GTO start pulses 82 of braking synthesizer are to inverter 11 and export braking GTO start pulse 86 to braking circuit 80.Inverter 11 drive motors 12 in driving and running under braking, and more than reference speed, move when needing the additional brake torque, braking circuit 80 is with motor 12 operations.

Figure 5 illustrates the function of motor controller 62, include state of a control among the figure and determine device 90, it has an I/O Current Control state 78, is used for determining next step state of a control; Its input has inverter frequency 48, car control to allow 64, it is indicated 50 operations of inverter synthesis mode, rotational frequency 52 and impacts the torque-limiting request or the torque power request of TERJ(impact restriction when inverter is allowed to) 23, be used for determining whether motor is in operational mode or the running under braking mode of driving, if TERJ23 be on the occasion of, control operation is driving condition; As TERJ23 is negative value, and then this control operation will be the running under braking mode.The effect of synthesis mode 50 is not stop in control operation to change to the operation of transformer brake apparatus when 6 go on foot.Motor controller 62 comprises a braking PI controller 102 and a slippage controller 104.State of a control setting device 90 offers 106 1 slippages of switch and allows 105, so promptly allow torque error signal 60 to be sent to slippage controller 104.This operation can for example, change the motor slippage so that can be without the transformer brake apparatus in the situation of control motor torque in expectation without transformer brake apparatus 80.In the sort of incident, switch 106 will be connected and allow torque error signal 60 to enter slippage P+I controller 104, slip-frequency 108 of an expectation of this 104 output is in limiter 110, and 110 stop bigger slippage to occur and avoid running to knee point above torque-slippage curve.Limiter 110 offers 104 1 slippage limit feedback of slippage P+I controller signal 112 and removes to limit slippage in the maximum horizontal of expectation and give and put this slippage P+I controller 104 and go the output of strangulation controller, so that make entire portion not continue to rise.The output 114 of limiter 110 also is to feed back to the slip-frequency 114 that state of a control is determined device 90, is used for controlling various state and determines.Ask the visitor in is added on the rotational frequency 52 when asking inverter frequency 48 output in adder 116 for slip-frequency 114.Function generator 120 utilizes inverter frequency 48 and slip-frequency 114 and produces the contravarianter voltage 122 of an expectation, alternating current motor 12 is in the constant air gap magnetic flux moves.The contravarianter voltage 122 of this expectation is not because the restriction of the AC line voltage that is applied is obtainable from 11 of inverters more than reference speed, so voltage limitator 124 supervision AC line voltage 43 determine whether that desired contravarianter voltage 122 can be obtained; If can not obtain this voltage 122, then voltage limitator 124 will be clamped on the output voltage that can obtain it; If can access this voltage 122, then voltage limitator 124 is promptly no longer revised voltage 122.The output of limiter 124 is request contravarianter voltages 126, and it is sent in the function generator 128 with other input direct voltage 43 and output inverter voltage percentage 74.The inverter output voltage that on behalf of maximum possible, these AC line voltage 43 multiplication by constants 0.78 promptly obtain, contravarianter voltage 126 are promptly obtained the contravarianter voltage percentage 74 of asking by the inverter output voltage that obtains divided by this maximum possible.The inverter frequency 48 of request is output from adder 116.

Brake voltage P+I controller 102 has an input switch 130.If state of a control determines device and trigger this brake monitor 102, then braking allows 129 switch 130 closed to close and permissible error signal 60 is input to braking P+I controller 102, promptly becomes complete controller and moves.The output of braking P+I controller 102 is motor voltages 132 of expectation, this 132 is imported in the adder 134 that has 6 step of other input-be called (Six-Step) contravarianter voltages 136, AC line voltage 43 is multiplied by constant K by a multiplier 138: 0.78, and the output of multiplier 138 is 6 step contravarianter voltages 136, and this 136 promptly is an inverter 11 in 6 steps maximum voltage value that can output in service.Adder 134 obtains the motor voltage 132 of this expectation and deducts this 6 step contravarianter voltage 136, Qi Wang transformer output voltage 140 consequently, this voltage is output in the function generator 142,142 also imported AC line voltage 43 with the drag angle 144 that produces expectation as its output, this angle is exactly that GTO switch in brake apparatus 80 must be done angle by required usefulness in per 180 ° of cycles, as a means of producing desired transformer output voltage 140 whereby.Function generator 142 is to utilize following relational expression to come the drag angle 144 of calculation expectation, promptly

Angle=360/ (π) * arc sin (π)/4 * (V _TX)/(V _TDC) ... (1)

In the formula: V _TXBe desired transformer output voltage 140,

V _TDCBe the instantaneous voltage of secondary side across the braking transformer, for example, transformation ratio is 0.9, when supply voltage is 600V, and then this secondary voltage is 550V.This desired drag angle 144 must be between 180 ° of 0-80 in the cycle °, and during this, the GTO switch in brake apparatus 80 will be cut off, and the brake voltage on motor 12 promptly provides by this angle.Desired drag angle 144 is input to limiter 146 and is not less than 0 ° and be not more than 80 ° as a means of the drag angle that limits this expectation, providing of 0 ° of limit is because negative time value is not suitable for ending of GTO switch, providing of 80 ° of limit is because under this angle, the GTO switch approached to end when the GTO switch had the polarity error at electric current, so that may cause and subtract each other with the motor voltage that provides and form negative voltage.An output of limiter 146 is drag angles 70 of request, and another is output as angle restriction 148, and the latter is fed and gives the braking P+I controller 102 of adjusting to remove to control the whole output of P+I controller 102.Angle restriction 148 also feeds back to state of a control setting device 90 to determine whether changing over other state of a control.For example, in case the transformer running under braking is to no-voltage situation (this may take place when drag angle reaches 80 °), then state of a control determines that device 90 can be tending towards going to the next state of a control of high slippage, this state causes and maintains this maximum drag angle, increases slippage then and obtains additional brake torque.With another example, in case the GTO switching manipulation reaches 0 ° of angle, state of a control is determined device 90 because no longer be required, so promptly break away from the transformer braking.State of a control determines that a braking of device 90 outputs controllable silicon allows 68 to remove conducting or turn off thyristor.In the state that transformer is braked, the braking controllable silicon allows 68 to keep controllable silicons to end, ought not then controllable silicon maintenance conducting in a state of transformer braking.

Inverter and braking synthesizer 76 provide a synthesis mode to determine 50.Inverter frequency 48, contravarianter voltage percentage 74 and real-time state of a control 78 all are input in the synthesizer 76, and synthesis mode output 50 will be determined the synthetic operation type that is required, for example be PWM(pulse width modulation), a kind of in accurate 6 steps or 6 steps.

Figure 6 shows that the state of a control of controller for ac motor of the present invention.The operation of this control device can be divided into three kinds of basic status, promptly turn-offs, drives or brake.

Off state can further be divided into normal and emergency shutdown state, but the both indicates this system not in operation.The normal turn-off condition is that an instruction institute that is imported by vehicle control is caused, for example from the next instruction of driver's master controller.Emergency shutdown condition system is caused by the system failure, for example resembles due to the fortuitous events such as overcurrent or line brownout take place.

Driving condition is divided into and is below or above two intervals of reference speed.Be divided into the interval and be because when being lower than reference speed, motor is that to operate in every hertz voltage be under the condition of constant basically, and at this moment the magnetic density in the air gap remains on desired numerical value; Yet in being higher than the reference speed scope, invertor operation is in 6 step modes, so that make electronic function provide maximum getable output torque, and the magnetic density in the gap reduces because of the increase of speed.

On-position comprises two basic divide identical with driving condition, promptly is lower than and is higher than two intervals of reference speed.Inverter itself also is same as the situation in the driving in the interval that is lower than reference speed, because can provide required torque; Be higher than the reference speed interval,, and must adopting regenerative braking circuit 80, so problem is complicated more because inverter can not satisfy the requirement that produces needed torque alone.The braking that is higher than the reference speed district is divided into three sections again:

A) be higher than reference speed and braking when being lower than rated slip;

B) be higher than reference speed and at the rated slip place, have regenerative circuit but not at the maximum capacity place;

C) be higher than the braking of reference speed, have the maximum capacity place of regenerative circuit and be higher than the rated value place at slippage.

For the state that can allow according in real time state of a control and condition, adopted the special conversion program that defines these possible state of a controls to finish conversion between these state of a controls, so that can realize being transformed into the on-position of the above-mentioned A that is higher than reference speed and is lower than rated slip from the driving condition that is higher than reference speed, but, be not to be transformed into the on-position that two other is higher than the condition B or the C of reference speed.

Basic control principle is a slippage control, promptly utilizes the change inverter operating frequency to regulate the slippage of motor to reach desired output torque.When being lower than the reference speed section operation, it is to move under the condition of constant voltage that motor remains on every hertz, and at this moment the air gap magnetic flux density is a rated value; Yet be higher than the reference speed interval, inverter is in " 6 step " and is in maximum voltage output place, and under this operational mode, contravarianter voltage can not be controlled to and produce specified air gap magnetic flux density.

If motor is to move in the on-position more than reference speed, and expectation can obtain bigger than regulate the getable brake torque of slippage under maximum voltage output, it is unpractiaca then not increasing certain motor voltage and seek out desired braking ratio, here the transformer circuit of having used a special use provides needed auxiliary voltage to motor, when the motor of braking more than reference speed, the slippage of control motor makes the torque that reaches desired, when if slippage arrives rated value and also can not get desired torque, then slippage is remained on herein, and the opening of transformer voltage controller increased voltage on the motor to be increased in the needed torque output of braking aspect, drag angle up to maximum reaches about 80 °, then the transformer controller is latched in this position, and with the slippage controller opens, allow slippage to rise, reaches till the absolute maximum slippage that satisfies torque-demand more than the rated value at it always.In realizing this measure, should make the electric current that remains in the GTO switch give the 350A(root-mean-square value of adjusting) the limit below, to avoid when providing when satisfying desired torque owing to the former of overcurrent thereby circuit being cut-off.

This control operation is initialized to the state of a control of urgent disconnection, so starting or driving operation all are to be in the operation of urgent disconnection, except urgent disconnection, unique other next state is normal disconnection, and the vehicle controller of driver control can carry out this conversion.In being in normal disconnection, vehicle controller is promptly asked operation, and one jump and arrive or the recovery routine state, promptly drives open loop situations, or is lower than " 6 step " state-driven.When in urgent off-state, check and look at this recovery time whether device is stopping that this time device is in order to keep the urgent state of a control one that disconnects to give the fixed time interval.Then, state of a control changes to normal disconnection, just changes to after again or drives being lower than " 6 step ", drives open loop, or recovers according to service conditions.As soon as invertor operation, should determine the mode program promptly carries out to check whether must change to other state, for example, if this control is at the driving condition that was lower than for 6 steps, and receive a braking request, so just change to the on-position that was lower than for 6 steps possibly, and this operation will soon change braking into from driving.The most of paths that are shown among Fig. 6 are determined in definite mode program, this program is at the patent application S.N.696833(W.E.Case 52282 of aforementioned coherent reference) in open, but do not mention in 6 steps and be lower than change between 6 steps, this synthetic conversion is disclosed in patent application S.N.696814(W.E.Case 50932 in the aforesaid coherent reference) in.Determine also to have in the mode program other path at this, for example, if state of a control is to be lower than 6 step driving conditions in real time, should determine that mode program will check that this conditioned disjunction is to drive open loop or carry out braking being lower than for 6 steps, and these all are " unique selection are effective ", and this synthetic conversion is carried out the condition that 6 steps drove with inspection.

Fig. 7 has represented the accurate state of braking TX, and it is the state of a control at as shown in Figure 6 braking TX.In the 10 kinds of different state of a controls that have shown in Fig. 6, and include 6 kinds of accurate states at the braking TX shown in Fig. 7.Whenever carry out once determining whether the operational cycle of mode program has the requirement of carrying out a different state of a control or controlling accurate state once with regard to visual inspection, this determines that the mode program checkout gives fixed standard, checks the requirement of the other state of a control that whether changes.

The speed of induction alternating current (AC) motor 12 and torque are subjected to the control of contravarianter voltage percentage 74 of being asked and the inverter frequency 48 of being asked, if the frequency 48 of being asked is led in the actual machine frequency that drives motor 12 in service, then motor is in positive torque raising speed in service; And if the frequency 48 of request lags in the actual machine frequency of motor 12, then motor runs on mode of braking and deceleration.Motor 12 is made every effort to ultimately near the inverter frequency 48 of being asked.The operation that moves ahead and reverse of motor control is realized on extremely to two of inverter by the start pulse of switching GTO.

Inverter 11 can be included as each identical a top GTO switch and a bottom GTO switch, power supply 10 is 600V in this embodiment, top GTO switch to every phase is to be connected on the 600V line voltage of power supply 10, and the bottom GTO switch of every phase is to be connected on the earth connection of power supply 10.According to conducting is which GTO switch decides which phase line that is connected on the motor should be connected to high pressure or be connected to ground.Utilize the conducting of the relevant GTO switch of modulation and the operation that ends to make desired voltage be input to mutually every in the motor 12.In this measure, inverter 11 produces the desired motor voltage 31 on the alternating current motor winding as shown in Figure 3.

In Fig. 8, the needed brake torque of curve 210 expression, this is in order to provide the desired braking ratio institute must be satisfied.Per second 3 ^MphThe required power of rate of acceleration provide according to driving torque curve 212, and driving torque curve 212 begins more than 214 to descend in reference speed, this is because the cause that inverter output voltage 216 just no longer increases more than 214 in reference speed.Desired per second 3 in running under braking ^MphThe brake torque that needs of deceleration be shown on the curve 210 50 ^MphAbove part is about 125 herein ^HZ, brake torque is 80 then ^MphThe place reduces and makes deceleration be lower than per second 2.5 ^Mph, this place is equivalent to about 200 ^HZThis brake torque is being lower than 125 ^HZThe place is about 800 ^Ft-1b, shown in curve 210, and driving torque is 50 ^HZBelow be about 800 ^Ft-1b, 800 ^MphLocate about 50 ^Ft-1bTorque provide in driving by motor, the brake torque of expectation is 800 ^MphThe place requires to have an appointment 650 ^Ft-1b, the brake torque of this expectation is moved about 125 at car ^HZShi Ze rises to 800 ^Ft-1b, the voltage that need add percentage value to motor for this running under braking is providing a desired slippage, and inverter 11 itself can not provide to reaching the needed voltage of this purpose.The characteristic of motor is, slippage can increase till the torque in driving no longer increases always, and in braking, negative slippage can only be increased to torque and reach the motor voltage of only being supplied with by inverter 11 and cause till the brake torque, and can not reach desired brake torque.

The drag angle signal 70 that is shown in the request among Fig. 4 is an output of motor controller 62, and this signal 70 enters in inverter and the braking synthesizer 76, has wherein carried out the drag angle multiplication and has calculated.

Patent application serial number NO.696814(W.E.Case 50932 at aforementioned coherent reference) in, inverter wherein and braking synthesizer include one 6 step square frame, and desired drag angle signal 70 is input in this square frame.Be provided with inverter GTO start pulse 82 and braking GTO start pulse 86 beyond 6 step square frames, they lump together computing.

In the computing of the interrupt routine the patent application serial number 696833(W.E.Case 52282 at aforementioned coherent reference), no matter when have a pulse one of to deliver in the inverter generated time device, then microprocessor just is interrupted.

Synthetic in service in 6 steps, be disclosed in the patent application serial number S.N.696814(W.E.50932 of aforementioned coherent reference) in, a new inverter generated time is calculated, and during the interrupt routine of microprocessor, output in the suitable generated time device, during the similarly disconnected hereinto program, to one mutually two braking times of the braking GTO switch of usefulness carry out beginning to calculate from request drag angle 70, and result of calculation outputed to when if the drag angle 70 of request is not equal to 0 ° into that mutually in two braking generated time devices of usefulness; If it equals 0 °, output time not then, this is because do not need the cause of transformer braking.These two braking times are calculated in 6 step calculation procedures, and when jointly determine in brake apparatus 80 by the braking GTO of that phase with by how long.Braking time device circuit utilizes one that this two times produce in this braking GTO start pulse 86 to be input in the brake apparatus 80, and two time devices remove to control each the braking GTO switch in the other two-phase in an identical manner.

Figure 9 illustrates a phase connection of brake apparatus 80, wherein the torque of motor can be represented with following relation approx:

T＝K×V ² _M×S×1/F ²…（2）

In the formula: V _MBe motor voltage, unit: the V(root-mean-square value)

S is the slip-frequency between stator and rotor, unit: HZ

F is the inverter frequency that is added on the stator, unit: HZ

K is the proportionality constant that is decided by the concrete parameter of system.

When inverter 11 the reference speed shown in 8 more than 214 when 6 steps worked under the synthesis modes and all AC line voltage has been added on the motor, V so ² _MReach the peak value V shown in curve among Fig. 8 216 _Max, as known slippage S, then torque equation can be write as:

T＝K×V ² _max×S×1/F ²…（3）

Wherein, first three items is essentially constant, so following formula becomes:

T _A＝Kx1/F ²…（4）

So effective torque T _AUnder a given slip-frequency with square being inversely proportional to of inverter frequency.

According to the relation of aforesaid equation (4), be higher than T in order under the condition that is higher than reference speed, frequency, to obtain _ATorque, then must increase the voltage that is added on the motor.Because the inverter 11 of drive motor 12 is connected on the effective DC power supply 10.Not further equipment such as the preposition chopper between direct current track and inverter, so inverter 11 can not provide the voltage of required increase, do not expect simultaneously the preposition chopper of an additional cover yet, must deal with total power more than reference speed because consider it, and it must work in the chopper that falls as same step and rank for a real system.

The brake apparatus that is shown in Fig. 9 is effective to increasing motor voltage, provide an independent transformer 220 power supplies mutually for the every of motor, this transformer is connected between motor 12 and the inverter 11, and per 1,2 carry out modulation operations with 3 in mutually, and this transformer utilizes a GTO switch 222 to offer 12 1 auxiliary voltages of motor to increase its effective torque.For the purpose of illustrating, for motor 12 the 3rd mutually the transformer of usefulness schematically be shown in Fig. 9, have back-to-back reverse-blocking tetrode thyristor 224 and 226, be used for during the running under braking that drives operation or appropriateness transformer 220 short circuits, this is meant by the relation of aforementioned formula (4) determines to compare T _AWhen less torque and inverter 11 can satisfy alone and needs, rectifier bridge 228 is used for converting the alternating current that motor 12 produces to DC power supply 10 desired waveforms.GTO switch 222 is as the arcing time factor of modulation to the transformer of motor circuit power supply, and diode 230 and power supply 10 coupled in series cause power supply 10 short circuits to prevent gate cut-off thyristor switch 222.

From Fig. 9 as seen, this brake apparatus 80 is connected in series with inverter 11, the output voltage at point 4,5 and 6 places that inverter 11 is derived offers on transformer secondary winding 234,235 and 236, so changed the input voltage of the motor reality on phase 3,2 and 1 respectively.Problem is to control the voltage of this transformer, make the voltages of deriving from winding 236,235 and 234 respectively with inverter output voltage 4,5 and 6 same-phases so that make motor each mutually 1,2 and 3 input voltage is than higher at point 4,5 and 6 voltages that produced by inverter 11.

Referring to motor 3 braking circuit mutually, when the complete continuously conducting of controllable silicon 224 and 226, Transformer Winding 234 is by short circuit, and when they were not conducting continuously, controllable silicon will be because of added AC wave shape final coutoff; When controllable silicon 224 and 226 during not with transformer 220 short circuits, then motor current promptly flows through transformer secondary winding 234.For convenience of explanation, suppose that now motor current direction shown in arrow among Fig. 9 280 flows, then the direction that the electric current of induction is arrow 282 in winding 232 flows.In order to make the current direction in the winding 232 is the direction of arrow 282, electric current must flow through diode 284 and 286, in case and electric current flow through diode 284, then electric current must flow through diode 230.The anode voltage of diode 230 must be more higher than the voltage of its negative electrode, because this negative electrode is connected on the power line 288, so its voltage is 600V, because diode drop is about 1V, so the anode voltage of diode 230 will should be 601V, the anode of diode 284 must be 602V, therefore the terminal voltage of the Transformer Winding 232 that links to each other with the anode of diode 284 should be 602V, the other end of transformer 232 is to be connected on the negative electrode of diode 286, and it is switched on the earth lead 290 by the diode 286 of conducting.Offer the promptly about 600V of voltage at winding 232 two ends of transformer 220 like this.If there is 600V voltage to be added in winding 232 two ends one time, this just means has an appointment 550V voltage on secondary 234, because transformer voltage ratio is 0.9, this 550V across the voltage on the winding 234 be in braking circuit GTO222 for by the time provide, the polarity of this 550V voltage is such, be 550V at the instantaneous voltage of point on 3 promptly, it is lower than some the instantaneous voltage on 6.When current direction reverses, flow also reverse at the electric current of one time 232 winding, and two diode current flows in addition in the bridge circuit 228.In this case, the polarity that is connected across the 550V voltage on the transformer secondary winding 234 is also reverse, so that is that 550V is higher than some the instantaneous voltage on 6 at the instantaneous voltage of point on 3.

The voltage waveform 282 that inverter 11 outputs to a little on 6 is shown among Figure 11, and this is a typical synthetic inverter output waveform of 6 steps.Suppose that power supply is 600V, then end from symbol 281 places of 280 to 180 ° of 0 ° of symbols on the waveform 282 that output point 6 is 600V, from all the other parts of 281 to 360 ° of 180 ° symbols, the voltage of point 6 is 0V.Waveform 287 is illustrated in the voltage of the line of the reality that alternating current motor 12 sees to neutral point among Figure 11, supposes that at this moment brake apparatus 80 does not have work.As seen, this line to the electric electromechanics corrugating 287 of neutral point be directly with the output point 6 that is shown in inverter 11 among Fig. 9 on voltage waveform 282 same-phases.Equally, because brake apparatus does not have work, so the voltage on output point 6 and the point 3 equates.If alternating current motor 12 is being braked, then current waveform 286 will lag behind voltage waveform 282 and 287 about 135 °, so the mistake 0: 280 of voltage waveform 282 is to the interest for delinquency that has 135 ° between the mistake 0: 284 of electric current 286.If brake apparatus 80 is devoted oneself to work, voltage on the transformer secondary winding 234 promptly causes flowing through the electric current of winding 234, voltage on the winding 234 also promptly equals a little voltage on 3 and subtracts voltage on the output point 6, it is identical with voltage waveform 288, this is at controllable silicon 224 and 226 voltage that provides under situation of conducting and GTO222 not, as shown in figure 11, transformer secondary voltage 288 and output voltage 282 out-phase, and therefore when adding together, output voltage 282 adds that 288 resultant voltages that cause of transformer secondary voltage have phase shift to voltage 282 on phase 3, this phase shift will cause the electric current in motor with the waveform that is shown in 286 phase shift to be arranged, this current phase is moved and will be caused the bigger phase shift of transformer secondary voltage 288, and other etc.After having considered all phase shift, voltage synthetic on motor phase 3 only is higher than inverter output voltage 282 a little, so be unfavorable.GTO222 makes the secondary voltage of transformer realize controlled, if GTO 222 conductings, then the voltage on the transformer one time 232 is reduced to 0V, also make simultaneously the voltage on the transformer secondary 234 be reduced to 0V, by control GTO222, transformer secondary voltage can be controlled to forever and inverter output voltage 282 homophases, can obtain maximum possible transformer secondary voltage and with inverter output voltage 282 homophases, shown in waveform 289.Electric current takes place in transition 297 crosses 0: 284 place, and the mid point 293 of transformer voltage waveform 289 is the mid points between transition 295 and 297, and the mid point 292 of inverter output voltage waveform 282 is the centres in transition 280 and 281.If mid point 292 and 293 takes place simultaneously, then transformer secondary voltage 289 just with inverter output voltage 282 homophases.When these two voltages are same phase time, their direct additions are promptly producing a higher motor input voltage on 3 mutually.Equally, because these two voltage homophases, so motor current 286 no additive phases move, transition 295 be by GTO222 end cause, 297 of transition are caused by the GTO222 conducting, and transition 298 is to end institute by GTO222 to cause, and transition 299 then is by due to the GTO222 conducting.Because in fact motor current 286 is not a pure sine wave, and because electric current is crossed 0: 284 also not just in time 135 ° of displacements, for the purpose of practicality, the secondary transformer voltage is restricted to waveform 290, the Dui Ying GTO222 limited angular breadth of time of ending is from 283 to 285 herein, and this represents that promptly maximum angular width is 80 ° in 360 ° of cycles.Mid point 294 is the mid points between transition 283 and 285, and it and occur simultaneously at the mid point 292 of inverter output voltage 282.When transformer voltage 290 is followed inverter output voltage 282 when producing, mutually on 3 synthetic motor input voltage promptly shown in waveform 296, the voltage gain that 296 dash area has represented to utilize this brake apparatus 80 to be obtained.

Representative shown in Figure 12 is input to motor 1 and 2 voltage waveform 231 and 233 mutually, voltage 237 is the voltage of the line of motor to neutral point, be to have utilized the transformer secondary voltage 290 of the maximum of brake apparatus 80 generations to synthesize, the magnitude of voltage that is provided separately by inverter 11 in voltage 237 is shown in the waveform 287.

If the line voltage to neutral 237 of motor is less than as shown in figure 12 desired value.Then the time width of GTO222 remain off reduces under the prerequisite of not mobile mid point 294, this width be decided by transition 283 to the time between the transition 285 as shown in figure 11.

Figure 10 illustrates the wiring of running under braking control circuit, show the brake apparatus circuit 268 of motor one phase in more detail, address date and control line 260 are connected with MOtorola 68000 microprocessor in inverter and braking synthesizer 76, comprising a delivery outlet 262 is arranged, this is a common 74LS373 chip, it has 8 outputs, has used wherein 4 bit lines.First bit line 264 is used for determining the conducting of triode 266, controls the controllable silicon start-up plate with this, and this plate control controllable silicon 224 and 226 causes short circuit or not short circuit transformer secondary winding 234(to see Fig. 9).Other two-phase of motor every there are two same thyristors mutually.This controllable silicon start-up plate is that this technical field is well-known, and is to send gate pulse or the gate pulse of not bothering to see me out to these controllable silicons continuously, is " 1 " value if export 264, and then this start-up plate produces continuous gate pulse; If have 0 value and export 264, then controllable silicon will can not get continuous start pulse.Three GTO gate control circuits 268,270 and 272 are arranged, be respectively applied for each phase of motor.In gate control circuit 268, two time devices 274 and 276 are arranged, they are 8254 common time devices.The 3rd mouth of each time device is used to each control circuit 268,270 and 272.Time device 274 is delay time devices, and time device 276 is the timing device.A controlled GTO switch (for example 222 shown in Fig. 9) is all arranged in the braking circuit of the every utmost point transformer of motor.

Use Fourier analysis and known braking circuit arcing time factor and this line voltage and contravarianter voltage position, how wide the width that then can determine the expectation voltage on the motor and from then on can draw the braking circuit pulse 291 that is shown among Figure 11 should be.Motor controller 62 is determined desired motor voltage and is determined voltage 282, can utilize line voltage associated voltage except that inverter 11 and known.The amount of the voltage 290 that is provided by transformer brake apparatus 80 is decided by the arcing time factor of waveform 290, so produce between the great voltage 290 at the arcing time factor of back and transformer brake apparatus 80 mathematical relationship is arranged.The voltage 290 of brake apparatus is added that contravarianter voltage 282 has promptly reached desired voltage, reach maximum when drag angle is 80 °, the numerical value that provides can satisfy the requirement of braking.

The output in the centre of controller 62 is desired total motor voltage, the many high voltages that provide according to the inverter of determining 11, the voltage that is differed from promptly need be provided by transformer brake apparatus 80 confirming can not to surpass under the condition of electric current 286 for 0 mistake 0: 284, the drag angle of GTO is provided according to this voltage difference that is provided by transformer brake apparatus 80, this drag angle is less than 80 °, and determines the deadline of GTO222.The patent application S.N.696814(W.E.Case 50932 of coherent reference as described above) disclosed this synthetic operation is known, the head end 280 of this contravarianter voltage 282 and terminal 281, calculate head end 280 and the time between the time 283 at contravarianter voltage 282 then, this time is the time that GTO is cut off; And calculate from the time of time 283 to 285, this is the time that GTO is switched on.We expect contravarianter voltage 282 fully with brake apparatus voltage 290 homophases, the center 292 and 294 no matter when voltage waveform 282 and 290 all appear in hope is aligned on the line and is complete homophase.This synthetic operation is determined time 280 and time 281.

The brake control circuit that is shown among Figure 10 includes time device 274, and this 274 is delay time devices, and it provides the time of delay between time 280 and time 283 when GTO is cut off, and this time is calculated the back and is passed in this time device 274.When signal 300 continues about 1 microsecond to a high position, what provide is low levels by 302, then NOR gate 304 will produce the grid 306 that pulse that a low level continues 1 microsecond enters time device 274, and the rising edge of the pulse of this low level 1 microsecond will be opened time device 274 and pick up counting.Output 308 will be low level in certain time interval, and this time equals to go on foot transition times 280 and GTO synthetic 6 and begins desired time between deadline 283.In case low level output 308 jumps to a high position, this also is to finish time of delay, time device 276 picks up counting, 310 will become low level in time device 276 output that picks up counting, and it is parked in low level a period of time at interval, equal time interval of expecting that GTO222 is cut off during this period of time, this real time is less than or equal to 80 ° equivalent time at interval.

When another input 312 was low level, NOR gate 314 had had two low level inputs, so it provides a high-order output 316 to OR-gate 318.When line 330 was low level, OR-gate 318 output high signal 320 were to top triode 322, so 322 conductings.This high signal 320 of inverter 324 wraparounds becomes low level signal 326 and bottom triode 328 is ended.When triode 322 conductings and triode 328 by the time, sense of current is opposite with the required direction of starting GTO222, so GTO222 can not start and end, triode 322 promptly is cut off signal 310 once uprising then, and triode 328 is conducting, thereby starting GTO is provided the electric current of 222 directions.When be input to NOR gate 314 312 when being 0 value, its allows time device 276 by GTO.If this input 312 is 1 values, then force GTO 222 eternal conductings.Input 312 is not one and allows signal, but it really pick-off signal make the time device by and make the GTO conducting.Be input to 330 of OR-gate 318 and passed through inverter inverter 332, when signal 330 is that 0 value is when being added in the input of OR-gate 318, this will allow the time device to enter into controllable state, yet one 1 value has been added in that this just forces GTO to end in the input of OR-gate 318, and this is because top triode 322 is conducting and bottom triode 328 is causes of cut-off state forever.When the signal 302 in being shown in Figure 10 was 0 value, then the GTO switch of brake control circuit in just can operating transformer brake apparatus 80 was to ending, and supply line 331 is 1 value, and line 312 is 0 value.

Figure 13 illustrates signal relation chart in the brake control circuit of Figure 10, curve 340 expressions are added to the control signal 300 of an input on the NOR gate 304, waveform 340 corresponding to control signal 300 is normal low level signals, this signal has the high digit pulse of one 1 microsecond time, occurs once in the inverter output voltage 282 each transition shown in its transition 280 and 281 in Figure 11.Control signal 300 is actually by the inverter synthetic control circuit and is produced, and this circuit promptly refers to the patent application serial number NO.696814(W.E.50932 of aforementioned coherent reference) in the circuit described.The waveform 344 that is shown among Figure 13 is the output 306 of NOR gate 304, and waveform 346 is the output 308 of delay time device 274, and waveform 348 is the output 310 of time device 276, when waveform 348 during in a high position, and the GTO conducting; When waveform 348 during at low level, GTO ends, and the voltage waveform that causes transformer secondary is 290.

Calculate delay time device 274 for produce waveform 346 required times and calculate in the flow process that is shown on Figure 14 for the necessity that produces waveform 348 required times by timing device 276.

In Figure 14, to the time the mid point 292, the 6 variable times in step were represented in waveform 282 from the time the transition 280 to 281 from the transition point 280 of contravarianter voltage output waveform 282 in the calculating of time 90 representative in the square frame 217.In square frame 219, braking GTO deadline is the time that outputs to timing device 276, and is the time that expectation GTO 222 is cut off, and being calculated as of this time be multiply by for 6 times in step with the drag angle 70 of request and removed by 180 °.In other words, braking GTO is the time with the drag angle equivalence of request deadline.In square frame 221, braking GTO positioning time is the time that outputs to delay time device 274, and it is calculated as, with braking GTO deadline by 2 results that remove and from the time 90, subtract the back gained.

Claims (8)

1, a kind of method of induction motor regenerative braking control, this motor is connected on the power supply and responds a torque request signal, includes following step:

Provide first voltage signal to encourage this motor with an inverter that is connected on the power supply,

With being connected on the power supply and providing second voltage signal to encourage this motor with a braking auxiliary circuit that above-mentioned inverter joins,

The very first time width of first voltage signal of a response torque request signal is provided,

Second time width of second voltage signal of a response torque request signal is provided, and

The pass of controlling this first voltage signal and second voltage signal is a homophase so that encourage this motor.

2, control method as claimed in claim 1 comprises step:

The time width of second voltage signal of control response torque request signal is so that encourage this motor to provide one to meet the desired output torque of torque request signal.

3, control method as claimed in claim 1 adopts second voltage signal is added first voltage signal to increase with respect to the excitation to this motor with the first voltage signal excited electric motor.

4, control method as claimed in claim 1, employing has the motor and the employing of reference speed and sets up this motor output torque request signal of an expectation, and adopt second voltage signal, operate in said reference speed is provided increase when above by motor output torque with box lunch.

5, control method as claimed in claim 1 adopts first voltage signal to encourage this motor so that an alternating current with zero crossing to be provided, and adopts the time width of second voltage signal to be limited by described zero crossing.

6, control method as claimed in claim 1, for a motor with reference speed:

Adopt first voltage signal, it is that of inverter output gives fixed voltage when described reference voltage is above, and

Adopt second time width of second voltage signal to give fixed maximum time width less than one.

7, control method as claimed in claim 1 for the control with induction motor of slippage and reference speed, comprises step:

The slippage of control motor more than reference speed remains rated slip,

Adopt first voltage signal, it is the maximum voltage of inverter output when described reference speed is above.And

Adopt second voltage signal, it is that to respond described torque request signal when described reference speed is above determined and determined the output torque of this motor by it.

8, control method as claimed in claim 1 reaches one with second voltage signal and maintains this maximum when giving fixed maximum, and

In the described torque request signal of response, improve slippage to more than the described rated slip according to reaching described peaked second voltage signal.

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