CN1024878C

CN1024878C - Brushless step-governor d.c. motor

Info

Publication number: CN1024878C
Application number: CN 92100072
Authority: CN
Inventors: 韦文德
Original assignee: Institute of Electrical Engineering of CAS
Current assignee: Institute of Electrical Engineering of CAS
Priority date: 1992-01-14
Filing date: 1992-01-14
Publication date: 1994-06-01
Anticipated expiration: 2007-01-14
Also published as: CN1061876A

Abstract

The present invention relates to a brushless DC motor with step-governor speed regulation. A plurality of sets of independent three-phase star armature windings with centralization even space or single-phase armature windings with central taps are respectively connected to corresponding electronic commutation switching circuits which are orderly powered off in a decreasing way, and step-governor speed regulation is implemented. The brushless DC motor with step-governor speed regulation of the present invention has the advantages of no commutation sparks, no mechanical contact, and favorable performance of speed regulation; mixed speed regulation can be implemented.

Description

Brushless step-governor d.c. motor

The invention belongs to motor.

At mechanical commutation DC motor category, recently a kind of variable brush step occurs and adjusted DC motor, (see figure 2), though this variable brush step speed regulation dc motor is more energy-conservation, life-span is longer, commutation spark is little, but also has Mechanical Contact and commutation spark after all, sees Chinese patent 911104009.9.

The purpose of this invention is to provide the contact of a kind of nothing machinery, the DC motor of the novel electron reversing switch step-governor d of non-commutation spark.

Another object of the present invention provides a kind of mixing speed regulating method, i.e. the constant portion T of motor load.Regulated by the electronic commutation switching circuit, pulsation part ± δ T is regulated by conventional pulse-width modulation circuit.

Important feature of the present invention is that whole determinative star connects armature winding or the single-phase armature winding of centre cap is connected on respectively on the corresponding electronic commutation switching circuit in many covers three-phase set independent of each other, the outage of successively decreasing successively of said electronic commutation switch, enforcement step-governor d.

Non-commutation spark of the present invention does not have the machinery contact, good speed adjustment features, and can implement to mix speed governing, reduced the cost and the volume of motor.

Fig. 1 is one group of DC motor mechanical property family that had not only become the mechanical property slope but also become no-load speed.

Fig. 2 be the two pairs of utmost points become that the brush double stars connect three phase windings brush mechanical commutation dc electromotor principle figure arranged.

Fig. 3 connects the bridge type electric commutation power switch circuit brushless motor schematic diagram of three phase winding all-waves operation for many cover stars.

Fig. 4 connects the electronic commutation power switch circuit brushless motor schematic diagram of three phase winding half-waves operation for many cover stars.

Fig. 5 is brushless governing speed and steady speed controlled dc electromotor principle figure.

Know by Fig. 1, and sharp DC motor, particularly permanent magnet direct current motor, can obtain constant no-load speed when constant and armature circuit resistance changes when the armature winding number of turn and only become one group of mechanical property family of mechanical property slope.If the load of a permanent torque of this driven by motor then has many intersection points with mechanical property family, this shows that motor can have a plurality of steady operation rotating speeds.Hold P ₂The motor of characteristic is operated in n ₂Rotating speed, and hold P ₁Characteristic then be operated in n ₁Rotating speed.Connect armature winding if motor has the three-phase star of the different winding parameters of many covers, then when supply power voltage was constant, the empty load of motor rotating speed during umber of turn that cover electronic commutation circuit working how certainly will reduce and locked-rotor torque increases.As the n among Fig. 1.From and can obtain one group of new variable slope mechanical property family.Hold P ₄The working speed of characteristic is n ₄, hold P ₃The working speed of characteristic is n ₃

The brshless DC motor of Fig. 3, there are two cover electronic commutation power switchs at the two poles of the earth, and each power switch was only switched on for 1/3 cycle, and be 1/6 cycle the overlapping conduction time of power positive end switch and power supply negative terminal switch in the different circuit.From Fig. 3 as seen, any power switch quits work, and just arranged in the week 1/3 cycle time, and armature winding does not produce torque.When two power switchs of end of the same name quit work, just arranged 2/3 cycle time in the week, armature winding does not produce torque.The rest may be inferred by analogy.Obviously, the electronic commutation brushless electric machine also have with the mechanical commutation brush motor similar outside, motor is normal to be started and work in order to make, reserving the complete electronic commutation power switch circuit of a cover, not participate in speed governing operation be necessary.Special working procedure situation exception for example starts earlier at full speed.Thereafter rotating speed is turned down.

Motor among Fig. 3, wherein one overlaps when commutating the power switch circuit operation during the lunar New Year identical of the every phase winding parameter of every cover, and its torque is T=T _N, P for example _A, P _B, P _CAnd n _A, n _B, n _COperate as normal.

During the full operate as normal of two cover commutation power switch circuits, the locked-rotor torque of motor is

T _2P＝2T _N

Thereafter commutation power switch of the same name successively decreases successively and deactivates, for example with n _XThe switch outage, then locked-rotor torque reduces to become

T ₅＝（1+2/3）T _N＝5/3T _N

At n _XAnd n _YWhen disconnection was deactivated, locked-rotor torque continued to be reduced to

T ₄＝（1+1/3）T _N＝4/3T _N

At n _xAnd n _y, n _zWhen all deactivating, locked-rotor torque becomes

T ₃＝T _N

Concrete operating state is as follows, and the path of three electricity is arranged in every cover electronic commutation switching circuit.There are two each interval sixth cycles just can lead to the electronic commutation switch in 1/3rd electricity cycles in every circuit.At this two switch indirect, one phase armature winding, each organizes reversing switch of the same name three/one-period of conducting successively in turn.Turn-off three/two cycles, in the brushless electric machine principle tie lines as shown in Figure 3, positive switch P _A1/3 cycling in, in preceding 1/6 cycle, the negative switch n in it and the B circuit _BEnergising together, in 1/6 cycle of back, the negative switch n in it and the C circuit _CEnergising together; And the negative switch n in the same A circuit _AWait until P _ACut off the power supply and can start working after 1/6 cycle, totally 1/3 cycle, at this moment, and in preceding 1/6 cycle, it and B circuit anode switch P _BEnergising together, in 1/6 cycle of back, the positive switch P in it and the C circuit _CEnergising together, the working condition of other switches, the rest may be inferred.

Fig. 4 is an another embodiment of the present invention.Many covers electronic commutation power switch circuit brushless motor embodiment of half-wave operation.Unlimited many group three-phase stars connect armature winding, add unlimited many cover electronic commutation power switch circuits.Have 3(n-1)+the adjustable same a plurality of rotating speeds of mechanical property of 1 Different Slope.Be 3(n-1)+1 grade of rotating speed.

The mixing speed regulating method of brushless electric machine, the advantageous condition of brushless electric machine is directly to utilize the performer of electronic commutation power switch circuit as alignment circuit, come part to reduce speed regulator cost and volume, perhaps control the brushless electric machine of larger capacity at the switch that utilizes lower-wattage, its unfavorable factor is that brushless electric machine is excitatory with high-performance permanent magnet, can not utilize magnetic field to regulate the method for rotating speed, therefore increase the power and the cost of speed adjusting gear again.One of the object of the invention, it is exactly resultant mixing speed regulating method.Example T ₁Motor load can be divided into two ones, T wherein ₀Part is by P ₃Mechanical property satisfies, and sees Fig. 1, promptly solves with the sub-reversing switch circuit of power transformation, and remaining pulsation part ± δ T promptly adopts conventional pulse-width modulation (PWM) circuit to solve.Like this, both can reduce the cost and the volume of speed regulator, can improve the efficient of buncher again.

Fig. 5 is an embodiment who mixes speed regulating method.Brushless governing speed and steady speed controlled DC motor, total 2P=8 magnetic pole N1, N2, N3, N4 and S1, S2, S3, S4; And have two to overlap centre tapped single-phase winding A, B and X, Y.Each single-phase umber of turn W _bAnd W _yDirectly be arbitrarily with line.Electric phase difference P θ between each single-phase winding also is arbitrarily, they and corresponding secondary electron commutation power switch group P separately _A, P _BAnd P _x, P _yCircuit links, whole commutating circuit can be with a commutation position transducer, remaining available self back-emf feedback commutation is with the commutation of the position of substitution transducer, and the commutation cycle is 180 ° of half electricity cycles, utilizes that magnetic is asymmetric on the stator core locatees to avoid starting the dead band.When motor operation speed ratio is big, can select for use different umber of turns recently to satisfy the demand.The stable control of machine operation speed then reaches the input F of phase frequency detector in the PWM system by the power adjustment pipe T that the phase-locked speed-stabilizing circuit of pulse-width modulation (PWM) goes to control in the main circuit _RBe reference signal frequency, F _VBe the tachometer signal frequency.In the PWM system, the most stable pulse duty cycle when the most reliable of working is about about 1: 1.This is to be difficult to accomplish among the drive unit of the constant supply voltage of the conventional brushless electric machine of how fast speed stabilizing that changes of 100: 5000 per minutes at a large speed ratio.But after utilizing design of the present invention, problem has just solved easily.During high-speed cruising with few that of umber of turn cover electronic commutation power circuit, during low cruise then with that many cover electronic commutation power circuit of umber of turn.And in governing speed and steady speed controlled system with the stationary component T in the load torque.Divide the processing of coming with wave component δ T.Be its stationary component T.Come balance by step-governor d torque of the present invention.The fluctuation part is then compensated by the phase-locked speed regulator of PWM.So, the power of the phase-locked speed regulator of PWM is dwindled greatly, speed regulation quality is improved greatly.

Claims

1, the brushless step-governor d DC motor is characterized by in many covers three-phase set independent of each other that whole determinative star connects armature winding or the single-phase armature winding of centre cap is connected on respectively on the corresponding electronic commutation switching circuit, said electronic commutation switch, step-governor d is implemented in the outage of successively decreasing successively.

2, it is characterized by by the described brushless step-governor d DC motor of claim 1 and overlap respectively in the three-phase set independently that whole determinative star connects the parameter of armature winding and the of the same name alternate phase place in each cover can be identical, also can be different, and the motor number of pole-pairs be also unrestricted.

3, the mixing speed regulating method of brushless step-governor d DC motor is characterized in that connecing on the electronic commutation switching circuit conventional pulse-width modulation circuit and forms the mixing speed governing, the constant portion that said mixing speed governing is a motor load carries out speed governing by the electronic commutation switching circuit, and its pulsation part is carried out speed governing by conventional pulse-width modulation circuit.