CN107707093A - A kind of pouring-in vernier reluctance motor of current harmonics and system - Google Patents

Abstract

The invention discloses a current harmonic injection type vernier reluctance motor and system. The vernier reluctance motor body part includes a stator, a rotor and a winding. Both the stator and the rotor have a salient pole structure, and the winding is a single-layer concentrated winding. Two sinusoidal alternating currents with different frequencies are injected into each phase winding. On the basis of ensuring that the current in the winding is a three-phase symmetrical current, two different The sinusoidal AC current component of the frequency produces an armature magnetomotive force with the same number of pole pairs but different rotation speeds. One of the magnetomotive forces is modulated by the air gap permeance to produce the same armature magnetomotive force with the same number of pole pairs and the same rotation speed. A spatial magnetic field with a certain included angle. This magnetic field interacts with the magnetomotive force of another armature, thereby generating torque and realizing electromechanical energy conversion. Compared with the prior art, its current utilization rate is 11% higher than that of the DC injection type vernier reluctance motor; in addition, the complexity of the controller part of the motor system is significantly reduced, and the cost is also greatly reduced.

Description

A current harmonic injection vernier reluctance motor and system

technical field

The invention belongs to the technical field of reluctance motors, and more specifically relates to a current harmonic injection type vernier reluctance motor and a system.

Background technique

Permanent magnet motors have the advantages of high power density and high efficiency, but the permanent magnets are expensive, the overall cost is high, and the permanent magnets have the risk of demagnetization and difficulty in demagnetization under fault conditions. High requirements for cost control and high reliability are required. , or it is difficult to apply in harsh environments. Compared with permanent magnet motors, electric excitation motors have no risk of demagnetization, higher reliability and lower cost. Such as synchronous reluctance motors, switched reluctance motors, asynchronous motors, etc., have a wide range of applications.

The synchronous reluctance motor control system is simple, but the stator windings are generally overlapping windings with long ends and complex windings; and the general rotor structure is complex, difficult to process, and high in cost.

The stator and rotor of the switched reluctance motor have a doubly salient pole structure, and a single-tooth concentrated winding is used. The structure is simple and the current density is relatively high. However, due to its specific power supply mode, the drive system is more complicated and the cost of the drive system is higher.

The stator windings of asynchronous motors are generally overlapping windings with long ends and complex windings; there are windings (or squirrel cages) on the rotor, and the heat dissipation of the rotor needs to be considered.

The stator winding of the DC current injection vernier reluctance motor is a single-tooth winding with fractional slots and non-overlapping concentrated windings. The motor drive circuit adopts an open-winding inverter structure. The current expression in the winding is:

i _a =I _dc +I _ac sin(ω _c t+α)

However, since the vernier reluctance motor is fed with DC current, the drive circuit adopts an open-winding structure, the wiring is complicated with multiple controllers, and the cost of the control system is high; the utilization rate of DC current is lower than that of sinusoidal current.

Contents of the invention

Aiming at the above defects or improvement needs of the prior art, the present invention provides a current harmonic injection type vernier reluctance motor and system, the purpose of which is to solve the problem of complex wiring structure controller of the existing DC current injection type vernier reluctance motor technical problem.

In order to achieve the above object, according to one aspect of the present invention, a current harmonic injection type vernier reluctance motor is provided, including a stator, a rotor and three-phase windings, each phase winding has only one port connected to an external circuit; each phase winding The current passed in is formed by the superposition of two sinusoidal current components with different frequencies; among them, the rotating magnetic potential generated by one sinusoidal current component interacts with the air gap permeance to generate a modulated magnetic field, and then combines with the rotating magnetic potential generated by the other sinusoidal current component. interact to generate torque.

Preferably, the number of winding pole pairs satisfies or

Among them, P _a is the number of winding pole pairs, N _r is the number of rotor slots, and N _s is the number of stator slots.

Preferably, when the phase sequence of two sinusoidal currents injected into three phases A, B, and C is the same, the angular frequency of the two sinusoidal currents satisfies the formula |ω ₁ +ω ₂ |=ω _r , when injected into A, B, and C When the phase sequence of the two sinusoidal currents in the three phases is different, the angular frequencies of the two sinusoidal currents satisfy |ω ₁ -ω ₂ |=ω _r ;

In the formula, ω ₁ is the angular frequency of the first sinusoidal current, ω ₂ is the angular frequency of the second sinusoidal current, and ω _r is the angular frequency of the rotor.

Preferably, when the effective values of the two sinusoidal currents in the same phase winding are equal and the phase angles differ by 90°, the torque of the vernier reluctance motor is maximum.

Preferably, the windings are connected in a star-shaped and delta-shaped manner, and when the rotor adopts an unequal pitch structure, the torque ripple can be weakened.

Preferably, the number of windings connected in a star connection is the same as the number of windings connected in a delta connection, and the attenuation effect is the best at this time.

Preferably, the rotor adopts a multi-segment structure, and two adjacent segments are staggered by 180°, which can further weaken the torque ripple.

According to another aspect of the present invention, a vernier reluctance motor system is provided, including a vernier reluctance motor and a drive circuit, the drive circuit includes three bridge arms, a capacitor and a DC power supply, and one end of each bridge arm is connected to the positive pole of the DC power supply , the other end of each bridge arm is connected to the negative pole of the DC power supply, one end of the capacitor is connected to the positive pole of the DC power supply, the other end of the capacitor is connected to the negative pole of the DC power supply, one end of the i-th phase winding of the vernier reluctance motor is connected to the neutral point of the j-th bridge arm connect;

Wherein, i is the phase number, j is the bridge arm number, i=a, b, c, 1≤j≤3.

Generally speaking, compared with the prior art, the above technical solutions conceived by the present invention can achieve the following beneficial effects:

1. The present invention provides a vernier reluctance motor. The reluctance motor adopts a single-layer concentrated winding, and the winding is connected to two sinusoidal alternating currents of different frequencies, and the two currents of different frequencies in the winding are used to generate two pole pairs with the same number but different rotational speeds. One of the magnetic potentials generates a magnetic field with the same rotational speed and a certain angle as the other magnetic potential through permeance modulation, thereby generating torque.

2. Compared with the existing technology, only one end of the winding is connected to the external circuit, and the driving circuit is only half of the original, which greatly simplifies the driving circuit; in addition, the current in the winding is a sinusoidal current, and the utilization rate of the sinusoidal current is higher than that of the DC current. 11%, improving the current utilization.

Description of drawings

Fig. 1 is the structural diagram of the current harmonic injection type vernier reluctance motor embodiment provided by the present invention;

Fig. 2 is the winding connection method in the current harmonic injection type vernier reluctance motor provided by the present invention;

Fig. 3 is a schematic diagram of laminations with unequal tooth pitch structure of the rotor in the current harmonic injection type vernier reluctance motor provided by the present invention;

Fig. 4 is a schematic diagram of the vernier reluctance motor system provided by the present invention.

detailed description

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not constitute a conflict with each other.

The current harmonic injection vernier reluctance motor provided by the present invention includes a stator 1, a rotor 2 and a winding 3, the stator 1 and the rotor 2 are arranged as coaxial sleeves, and the structure of the stator and rotor can be an outer rotor inner stator structure, or an outer stator Inner rotor structure, only one port of each phase winding is connected to the external circuit, and the current passed into each phase winding is formed by the superposition of two sinusoidal current components with different frequencies. Among them, the rotating magnetic potential generated by a sinusoidal current component interacts with the air gap permeance to generate a modulated magnetic field, and then interacts with the rotating magnetic potential generated by another sinusoidal current component to generate torque.

Both the stator 1 and the rotor 2 have a salient pole structure, and the salient pole structure of the rotor plays the role of modulating the excitation magnetic potential, and its modulation effect can be expressed as:

Λ(θ _s ,t)≈Λ _r0 -Λ _r1 cos[Z _r (θ _S -w _r t)]

Among them, Z _r is the number of rotor slots; θ _s is the spatial position; t is time; w _r is the angular frequency of the rotor.

When the number of winding pole pairs satisfies formula (1):

Among them, P _a is the number of winding pole pairs, and N _r is the number of rotor slots.

When the phase sequence of the two sinusoidal currents in the three phases A, B, and C is the same, that is, the current in the three phases A, B, and C is:

Among them, I _ac1 is the amplitude of the first sinusoidal current, ω ₁ is the angular frequency of the first sinusoidal current, α ₁ is the phase angle of the first sinusoidal current, I _ac2 is the amplitude of the second sinusoidal current, ω ₂ is the angular frequency of the second sinusoidal current, and α ₂ is the phase angle of the second sinusoidal current.

The angular frequency ω ₁ of the first sinusoidal current and the angular frequency ω ₂ of the second sinusoidal current satisfy the following formula:

|ω ₁ +ω ₂ |＝ω _r (3)

When the number of pole pairs of the winding satisfies the formula (1) and the phase sequence of the two sinusoidal currents in the three phases A, B, and C is the same, the magnetic potential generated by a sinusoidal current in the winding is modulated by the rotor 2, so that the sinusoidal The magnetic potential generated by the current forms a magnetic field with the same number of pole pairs and the same rotation speed as the magnetic potential generated by another sinusoidal current with a certain included angle, which satisfies the formula (3), and then generates torque.

When the phase sequence of the two sinusoidal currents in the three phases A, B, and C is opposite, that is, the currents in the three phases A, B, and C are:

The angular frequency ω ₁ of the first sinusoidal current and the angular frequency ω ₂ of the second sinusoidal current satisfy the following formula:

|ω ₁ -ω ₂ |＝ω _r (5)

When the number of winding pole pairs satisfies the formula (1) and the phase sequence of the two sinusoidal currents in the three phases A, B, and C is opposite, the magnetic potential generated by a sinusoidal current in the winding is modulated by the rotor 2, so that the sinusoidal The magnetic potential generated by the current forms a magnetic field with the same number of pole pairs as the magnetic potential generated by another sinusoidal current, the same rotational speed and a certain angle, that is, the formula (5) is satisfied, and then torque is generated.

The number of winding pole pairs can also satisfy formula (6):

Among them, P _a is the number of winding pole pairs, N _r is the number of rotor slots, and N _s is the number of stator slots.

At this time, the phase sequence of the two sinusoidal currents flowing into the three phases A, B, and C can be the same or opposite.

When the phase sequence of the two sinusoidal currents in the three phases A, B, and C is the same, the angular frequency ω ₁ of the first sinusoidal current and ω ₂ of the second sinusoidal current satisfy the formula (3).

When the number of pole pairs of the winding satisfies the formula (6) and the phase sequence of the two sinusoidal currents in the three phases A, B, and C is the same, the magnetic potential generated by a sinusoidal current in the winding is modulated by the stator 1 and the rotor 2, Make the magnetic potential generated by the sinusoidal current form a magnetic field with the same number of pole pairs and the same rotation speed and a certain angle as the magnetic potential generated by another sinusoidal current, that is, satisfy the formula (3), and then generate torque.

When the phase sequence of the two sinusoidal currents in the three phases A, B, and C is opposite, the angular frequency ω ₁ of the first sinusoidal current and the angular frequency ω ₂ of the second sinusoidal current satisfy the formula (5).

When the number of pole pairs of the winding satisfies the formula (6) and the phase sequence of the two sinusoidal currents in the three phases A, B, and C is opposite, the magnetic potential generated by a sinusoidal current in the winding is modulated by the stator 1 and the rotor 2, Make the magnetic potential generated by the sinusoidal current form a magnetic field with the same number of pole pairs and the same rotation speed and a certain angle as the magnetic potential generated by another sinusoidal current, that is, satisfy the formula (5), and then generate torque.

In the existing motors that use DC current and AC current to generate magnetic potential, in the square wave magnetic potential established by DC, the effective value of the fundamental wave is equal to the effective value of the square wave. times. The vernier reluctance motor provided by the invention, compared with the existing motors that use DC current and AC current to generate magnetic potential, the effective value of the current is improved

In the vernier reluctance motor provided by the present invention, when the effective values of the two sinusoidal currents in the same phase winding are equal and the phase angles differ by 90°, the vernier reluctance motor has the maximum torque.

Fig. 1 is a structural diagram of an embodiment of a current harmonic injection vernier reluctance motor provided by the present invention, the stator has 12 slots, the rotor has 10 slots, and the windings are 5 pairs of poles. Two currents of different frequencies generate two magnetic potentials with 5 pairs of poles but different rotational speeds. One of the 5 pairs of magnetic potentials generates a 5 pairs of poles magnetic field through the modulation of the 10 pairs of poles of the rotor teeth. The magnetic field and another 5 pairs of magnetic potentials have the same number of pole pairs, the same rotation speed and a certain angle, and interact to generate torque.

Fig. 2 is the winding connection method in the current harmonic injection type vernier reluctance motor provided by the present invention, one group of windings A1, B1, C1 adopts the delta connection method, and the other group of windings A2, B2, C2 adopts the star connection method, Fig. 3 is a schematic diagram of the unequal pitch laminations of the rotor in the current harmonic injection vernier reluctance motor provided by the present invention. The rotor adopts an unequal tooth pitch structure to form a phase-difference rotor permeance corresponding to two sets of phase-differenced three-phase windings. The two sets of phase-differenced three-phase windings are delta-connected three-phase windings and star Type-connected three-phase windings, thereby generating multiple torques with phase differences, the peak of a torque corresponds to the trough of another torque, superimposed to eliminate torque ripple. When the number of windings in star connection is the same as that in delta connection, the effect of weakening the torque ripple is the best.

In order to eliminate the torque ripple in the vernier reluctance motor, the rotor structure adopts a multi-stage structure, and the angle of two adjacent rotors is staggered by 180 degrees. Multiple torques with phase differences are generated inside the motor, and torques with multiple phase differences are generated inside the motor. Superposition realizes elimination of torque ripple.

Through the above measures, the torque ripple of the vernier reluctance motor is greatly reduced, which can be reduced from 200% to about 35%, which further increases the use value.

Fig. 4 is a schematic diagram of a VRM system provided by the present invention, the VRM includes a VRM and a driving circuit, and the driving circuit includes three bridge arms, a capacitor and a DC power supply.

The first bridge arm is composed of the first triode S1 and the second triode S2 in series, the second bridge arm is composed of the third triode S3 and the fourth triode S4 in series, and the third bridge arm It is composed of the fifth three-stage tube S5 and the sixth three-stage tube S6 connected in series. One end of each bridge arm is connected to the positive pole of the DC power supply, the other end of each bridge arm is connected to the negative pole of the DC power supply, and one end of the capacitor is connected to the positive pole of the DC power supply. The other end of the capacitor is connected to the negative pole of the DC power supply. One end of the A-phase winding of the vernier reluctance motor is connected to the neutral point of the first bridge arm, one end of the B-phase winding of the vernier reluctance motor is connected to the neutral point of the second bridge arm, and one end of the C-phase winding of the vernier reluctance motor is connected to the neutral point of the first bridge arm. Three-leg neutral connection. The other end of the A-phase winding, the other end of the B-phase winding, and the other end of the C-phase winding are connected to each other.

By controlling the conduction period of the first triode S1 to the sixth triode S6, two sinusoidal currents with different frequencies are injected into phase A, phase B and phase C, and the two sinusoidal currents with different frequencies generate two pole pairs The same number of magnetic potentials but different rotational speeds, one of the magnetic potentials generates a magnetic field with the same rotational speed and a certain included angle as the other magnetic potential through permeance modulation, thereby generating torque.

In the vernier reluctance motor system provided by the present invention, the drive circuit is only half of the original one, which greatly simplifies the drive circuit; in addition, the current in the winding is a sinusoidal current, and the utilization rate of the sinusoidal current is 11% higher than that of the direct current, which improves the current utilization Rate.

Those skilled in the art can easily understand that the above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention, All should be included within the protection scope of the present invention.

Claims (8)

1. a kind of pouring-in vernier reluctance motor of current harmonics, it is characterised in that including stator, rotor and three-phase windings, often Phase winding only has a port and is connected with external circuit, and the electric current being passed through in every phase winding is by two frequencies different sinusoidal current point Amount is formed by stacking；Wherein, rotating magnetic potential caused by a sinusoidal current component and air-gap permeance effect produces modulation magnetic field, then with separately Rotating magnetic potential caused by one sinusoidal current component interacts, and produces torque.

2. vernier reluctance motor as claimed in claim 1, it is characterised in that winding number of pole-pairs meetsOr

Wherein, P_aFor winding number of pole-pairs, N_rFor rotor slot number, N_sFor number of stator slots.

3. vernier reluctance motor as claimed in claim 1 or 2, it is characterised in that sinusoidal electric when injecting two in A, B, C three-phase When flow component phase sequence is identical, the angular frequency of two sinusoidal currents meets formula | ω₁+ω₂|=ω_r, when injecting in A, B, C three-phase Two sinusoidal current component phase sequence differences when, the angular frequency of two sinusoidal currents meets | ω₁-ω₂|=ω_r；

In formula, ω₁For the angular frequency of first sinusoidal current, ω₂For the angular frequency of second sinusoidal current, ω_rFor rotor angular frequency Rate.

4. the vernier reluctance motor as described in any one of claims 1 to 3, it is characterised in that when two in the same phase winding The virtual value of individual sinusoidal current component is equal and during 90 ° of carrier phase shift, the torque of vernier reluctance motor is maximum.

5. the vernier reluctance motor as described in any one of Claims 1-4, it is characterised in that winding uses star and triangle Hybrid connections mode, and rotor uses unequal blade spacing structure.

6. vernier reluctance motor as claimed in claim 5, it is characterised in that the winding quantity using Y-connection is with adopting The winding quantity connected with triangle is identical.

7. the vernier reluctance motor as described in any one of claim 1 to 6, it is characterised in that the rotor uses multisection type knot Structure, and adjacent two sections are staggered 180 °.

A kind of 8. electric system of the vernier reluctance motor based on described in any one of claim 1 to 7, it is characterised in that including Vernier reluctance motor and drive circuit, drive circuit include three bridge arms, electric capacity and dc source, each bridge arm one end with DC power anode connects, and the negative pole connection of each the bridge arm other end and dc source, electric capacity one end connects with DC power anode Connect, the electric capacity other end is connected with DC power cathode, i-th phase winding one end and j-th of the bridge arm neutral point of vernier reluctance motor Connection；

Wherein, i is phase sequence number, and j is bridge arm sequence number, i=a, b, c, 1≤j≤3.