A brushless doubly-fed motor with multi-phase symmetrical double sets of independent rotor windings

Abstract

The present invention provides a brushless doubly-fed motor with multi-phase symmetrical dual-set independent rotor windings. The brushless doubly-fed motor comprises: a stator structure and a rotor structure, the stator structure comprises a stator core and a stator winding, the rotor structure comprises a rotor core and a rotor winding; the rotor winding comprises two sets of independent windings, namely a rotor power winding and a rotor control winding, which are connected in series in the same phase sequence or in series in the opposite phase sequence; and are both arranged in the same slot in the same rotor core; the number of pole pairs of the rotor power winding is p p and the number of rotor control winding pole pairs p c are not equal, the rotor power winding and the rotor control winding generate p p and p c Two pole pair numbers of magnetomotive force. It solves the problems of abundant harmonics, vibration noise, and low motor efficiency in the existing brushless doubly-fed motor structure, and eliminates the rotor magnetomotive force harmonics of the brushless doubly-fed motor through two sets of independent windings, reduces motor leakage reactance, improves vibration noise, and improves motor operating efficiency.

Description

Technical Field

[0001] The present invention belongs to the technical field of AC motors, and more specifically, relates to a brushless double-fed motor using multi-phase symmetrical double sets of independent rotor windings. Background Art

[0002] Improving energy efficiency and developing and utilizing new clean energy are key ways to achieve the national "dual carbon" strategic goal. While eliminating the brushes and slip rings of the traditional brushless doubly-fed motor, the brushless doubly-fed motor also inherits the advantages of the brushless doubly-fed motor, such as small inverter capacity and flexible control characteristics. It has the characteristics of solid structure, reliable operation and low maintenance cost. It is very suitable for applications in variable speed constant frequency power generation and variable frequency speed regulation drive. It has unique advantages in explosion-proof, petrochemical, offshore and other application environments, and has attracted extensive attention from many experts and scholars.

[0003] In order to meet the requirements of dual main wave magnetic field, the brushless doubly-fed motor needs to generate two magnetic fields with different pole pairs at the same time. In the process of modulating and generating magnetic fields with different pole pairs, the change of magnetomotive force or magnetic resistance will cause harmonic magnetic fields with other pole pairs. Existing brushless doubly-fed motors mostly use the method of adjusting the pitch and number of turns of a single set of rotor windings to improve harmonics, but they cannot completely eliminate harmonics. There are still problems such as rich magnetic field harmonics, vibration and noise, and low motor operation efficiency. At the same time, the method of adjusting the pitch and number of turns of a single set of rotor windings leads to unequal turns and unequal pitch rotor winding structures. The current design methods and processing and manufacturing processes of such motors are relatively complex, which is not conducive to their large-scale promotion and application. Summary of the invention

[0004] In view of the defects of the prior art and the need for improvement, the present invention proposes a brushless doubly-fed motor with a multi-phase symmetrical dual-set independent rotor winding, aiming to solve the problem of adjusting the pitch and number of turns of a single set of rotor windings to improve harmonics. However, the harmonics cannot be completely eliminated, and it leads to an unequal turns and unequal pitch rotor winding structure, which causes vibration noise and low operating efficiency of the motor itself.

[0005] To achieve the above object, the present invention provides a brushless doubly-fed motor using multi-phase symmetrical dual sets of independent rotor windings, comprising: a stator structure and a rotor structure, wherein the stator structure comprises a stator core and a stator winding, and the rotor structure comprises a rotor core and a rotor winding;

[0006] The rotor winding includes two sets of independent windings, namely, a rotor power winding and a rotor control winding, which are connected in series in the same phase sequence or in the opposite phase sequence; and are both arranged in the same slot in the same rotor core;

[0007] Pole pairs of rotor power winding p p and the number of rotor control winding pole pairs p care not equal, the rotor power winding and the rotor control winding generate p p and p c Magnetomotive force for two pole pairs.

[0008] Optionally, the rotor power winding pole pair number p p The number of pole pairs of the rotor control winding p c The difference is an even number.

[0009] Optionally, when the rotor power winding and the rotor control winding are connected in series in the same phase sequence, the brushless doubly-fed motor is in a "differential modulation" mode, and the equivalent pole pair number of the brushless doubly-fed motor is p c With p p The absolute value of the difference.

[0010] Optionally, when the rotor power winding and the rotor control winding are connected in series in reverse phase sequence, the brushless doubly-fed motor is in "sum modulation" mode, and the equivalent pole pair number of the brushless doubly-fed motor is p c With p p The sum.

[0011] Optionally, the number of phases of the rotor power winding and the rotor control winding is the same and is greater than or equal to 2.

[0012] Optionally, the rotor power winding and the rotor control winding are symmetrical windings with the same electrical angle difference in space.

[0013] Optionally, the stator winding adopts a double winding or a single winding structure.

[0014] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects:

[0015] (1) The brushless doubly-fed motor with two sets of multi-phase symmetrical independent rotor windings provided by the present invention can give full play to the excellent electrical performance of the two sets of independent windings, eliminate the rotor magnetomotive force harmonics of the brushless doubly-fed motor as much as possible, thereby reducing the motor leakage reactance, improving vibration noise, and improving the operating efficiency of the motor.

[0016] (2) The present invention provides a brushless doubly-fed motor with two sets of multi-phase symmetrical independent rotor windings. The two sets of rotor windings can be conveniently connected in series in the opposite phase sequence or in the same phase sequence of the corresponding phases to form the "sum modulation" and "difference modulation" of the brushless doubly-fed motor, which effectively makes up for the defect that the traditional brushless doubly-fed motor structure is difficult to form the "difference modulation" mode, and expands the variable speed operation range of the brushless doubly-fed motor.

[0017] (3) The brushless doubly-fed motor provided by the present invention has two sets of multi-phase symmetrical independent rotor windings, and the number of phases of the rotor winding can be flexibly selected to be two-phase, three-phase, four-phase, five-phase or other multi-phases (that is, the number of phases can be flexibly designed to be an integer ≥2). There is no restriction on the number of pole pairs of the brushless doubly-fed motor, which is beneficial to improving the utilization rate of the rotor winding.

[0018] (4) The brushless doubly-fed motor provided by the present invention has two sets of multi-phase symmetrical independent rotor windings. The rotor design method can refer to the traditional regular multi-phase symmetrical windings, and has the advantages of simple design method, standardized design process, and simple rotor winding manufacturing and processing technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A schematic diagram of the connection of two sets of independent rotor windings in a brushless doubly-fed motor provided in the first embodiment of the present invention;

[0020] Figure 2 A slot number phase diagram of a rotor power winding of a brushless double-fed motor provided by an embodiment of the present invention;

[0021] Figure 3 A slot number phase diagram of a rotor control winding of a brushless double-fed motor provided by an embodiment of the present invention;

[0022] Figure 4 A schematic diagram of the connection of two sets of independent rotor windings in another brushless doubly-fed motor provided in the second embodiment of the present invention. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended 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 conflict with each other.

[0024] Embodiment 1

[0025] Figure 1 A schematic diagram of the connection of two sets of independent rotor windings in a brushless doubly-fed motor provided in Embodiment 1 of the present invention.

[0026] like Figure 1 As shown, a brushless doubly-fed motor using multi-phase symmetrical dual sets of independent rotor windings includes: a stator structure and a rotor structure, wherein the stator structure includes a stator core and a stator winding, and the rotor structure includes a rotor core and a rotor winding.

[0027] The rotor winding includes two sets of independent windings, namely the rotor power winding and the rotor control winding, both of which are arranged in the same slot in the same rotor core, and the rotor power winding and the rotor control winding are connected in series in the same phase sequence; Figure 1 As shown, rotor winding 1 is the rotor power winding, and rotor winding 2 is the rotor control winding; the multi-phase windings at one end of the rotor power winding and the rotor control winding are connected in series, and the A phase A in the rotor power winding rp Connect phase A in the rotor control winding rc , phase B in the rotor power winding rp Connect phase B in the rotor control winding rc , C phase C in the rotor power winding rp Connect the C phase of the rotor control winding to rc The other end multi-phase windings of the rotor power winding and the rotor control winding are connected in parallel to form a common terminal, so that the rotor power winding and the rotor control winding form a complete self-closed loop. p and the number of rotor control winding pole pairs p c Not equal, such as Figure 1 As shown, p is generated in the circuit respectively. p and p c The circular rotating magnetomotive force with two pole pair numbers has the same spatial direction.

[0028] Optional, rotor power winding pole pair number p p The number of pole pairs of the rotor control winding p c The difference is an even number.

[0029] Optionally, the number of phases of the rotor power winding and the rotor control winding is the same and is greater than or equal to 2.

[0030] Optionally, the rotor power winding and the rotor control winding are symmetrical windings with the same electrical angle difference in space.

[0031] For example, in this embodiment, the number of rotor power winding pole pairs p is selected p =1, rotor control winding pole pair number p c =3, rotor winding phase number m=3, rotor slot number Z=18 slots rotor winding scheme. This embodiment provides a brushless double-fed motor with a three-phase symmetrical double-set independent winding. The three windings of the rotor winding in this embodiment are spaced 120° apart. The rotor winding connection method is as follows Figure 1 As shown, since the two sets of rotor windings are connected in series corresponding to the same phase sequence and then connected in parallel, the "differential modulation" mode of the brushless doubly fed motor is satisfied. The equivalent pole pair number of the brushless doubly fed motor is p c With p p The absolute value of the difference, that is, the number of equivalent pole pairs of the motor is 2.

[0032] Among them, for the pole pair number p p =1, the slot number phase diagram of the rotor power winding is as follows Figure 2 As shown. The A phase coil is 1, 2, 3, -10, -11, -12; the B phase coil is 7, 8, 9, -16, -17, -18; the C phase coil is 13, 14, 15, -4, -5, -6; the pitch is selected as 5 / 6 of the pole pitch, that is, the pitch y is selected. p =7 double-layer winding can effectively eliminate the 5th and 7th harmonics.

[0033] For the pole pair number p c =3 rotor control winding, its slot number phase diagram is as follows Figure 3 As shown. The A phase coil is 1, 7, 13, -4, -10, -16; the B phase coil is 3, 9, 15, -6, -12, -18; the C phase coil is 5, 11, 17, -2, -8, -14; the pitch is 5 / 6 of the pole pitch, that is, the pitch y is selected. c =2 double-layer winding can effectively eliminate the 5th and 7th harmonics.

[0034] After setting the phase diagram of each phase coil corresponding to the slot number of the rotor power winding and the rotor control winding, p can be generated at the same time p With p c The two pole pairs have different magnetomotive forces and retain the excellent characteristics of low harmonic content of the two sets of windings, which fully meet the requirements of the brushless doubly-fed motor for the rotor structure. The two sets of independent windings use standard regular AC windings, which do not contain harmonics themselves, so they do not contain harmonics after being connected in the prescribed manner. It effectively makes up for the defect that the traditional brushless doubly-fed motor structure is difficult to form a "differential modulation" mode, and expands the variable speed operation range of the brushless doubly-fed motor.

[0035] Furthermore, according to the design requirements of the brushless doubly-fed motor, the stator winding can be selected to adopt a double winding structure or a single winding structure.

[0036] The existing related technology improves harmonics by adjusting the pitch and number of turns of a single set of rotor windings. The rotor windings are usually unequal turns and unequal pitches, and the processing and manufacturing are very complicated, with poor regularity, and it is difficult to produce them using automated processes. The brushless doubly-fed motor with multi-phase symmetrical dual sets of independent rotor windings proposed in this embodiment has a structure with equal turns and equal pitches, and can be automatically generated using standard winding processing and manufacturing processes, which has the advantages of simple design methods, standardized design processes, and simple rotor winding manufacturing processes.

[0037] The technical solution of the embodiment of the present invention adopts a multi-phase symmetrical double-set independent rotor winding design for a brushless doubly-fed motor, wherein the rotor winding includes two sets of independent multi-phase symmetrical windings, namely a rotor power winding and a rotor control winding, which are connected in series in the same phase sequence or in series in the opposite phase sequence; and are both arranged in the same slot in the same rotor core; the number of pole pairs of the rotor power winding is p p and the number of rotor control winding pole pairs p c are not equal, and produce p p and p c Two pole pair numbers of magnetomotive force. It solves the technical problem that the harmonics can be improved by adjusting the pitch and number of turns of a single set of rotor windings, but the harmonics cannot be completely eliminated, and it leads to unequal turns and unequal pitch rotor winding structures, which causes vibration noise and low motor operating efficiency. It achieves the beneficial effect of eliminating the rotor magnetomotive force harmonics of the brushless doubly fed motor through the excellent electrical performance of two sets of independent windings, thereby reducing the motor leakage reactance, improving vibration noise, and improving the motor's operating efficiency.

[0038] Embodiment 2

[0039] Figure 4 A schematic diagram of the connection of two sets of independent rotor windings in another brushless doubly-fed motor provided in the second embodiment of the present invention.

[0040] On the basis of the above embodiments, a new rotor winding is formed by adopting a different connection method.

[0041] like Figure 4 As shown, a brushless doubly-fed motor using multi-phase symmetrical dual sets of independent rotor windings includes: a stator structure and a rotor structure, the stator structure includes a stator core and a stator winding, and the rotor structure includes a rotor core and a rotor winding.

[0042] The rotor winding includes two sets of independent windings, namely the rotor power winding and the rotor control winding. Both are arranged in the same slot in the same rotor core. The rotor power winding and the rotor control winding are symmetrical windings with the same electrical angle difference in space. The rotor power winding and the rotor control winding are connected in series in reverse phase sequence. The multi-phase windings at one end of the two sets of rotor windings are connected in series, such as Figure 4 As shown, rotor winding 1 is the rotor power winding, and rotor winding 2 is the rotor control winding; the A phase in the rotor power winding is rp Connect phase A in the rotor control winding rc , phase B in the rotor power winding rp Connect the C phase of the rotor control winding to rc , C phase C in the rotor power winding rp Connect phase B in the rotor control winding rcThe other end multi-phase windings of the rotor power winding and the rotor control winding are connected in parallel to form a common terminal, so that the two sets of rotor windings form a complete self-closed loop. p and the number of rotor control winding pole pairs p c are not equal, and p is generated in the circuit respectively p and p c The circular rotating magnetomotive force with two pole pair numbers has opposite spatial directions of the rotating magnetomotive force.

[0043] Pole pairs of rotor power winding p p The number of pole pairs of the rotor control winding p c Any positive integer can be selected, and the difference between the two pole pairs is an even number. For example, in this embodiment, the rotor winding adopts a double winding structure, and the rotor power winding pole pair number p is selected. p =1, rotor control winding pole pair number p c =3, rotor winding phase number m=3, rotor slot number Z=18 slots rotor winding scheme. This embodiment provides a brushless double-fed motor with a three-phase symmetrical double-set independent winding rotor. The rotor winding connection method is as follows Figure 4 As shown, since the two sets of rotor windings are connected in series in reverse phase sequence and then in parallel, the "sum modulation" mode of the brushless doubly fed motor is satisfied. The equivalent pole pair number of the brushless doubly fed motor is p c With p p The sum of the equivalent pole pairs of the motor is 4.

[0044] Among them, for the pole pair number p p =1, the slot number phase diagram of the rotor power winding is as follows Figure 2 As shown. The A phase coil is 1, 2, 3, -10, -11, -12; the B phase coil is 7, 8, 9, -16, -17, -18; the C phase coil is 13, 14, 15, -4, -5, -6; the pitch is selected as 5 / 6 of the pole pitch, that is, the pitch y is selected. p =7 double-layer winding can effectively eliminate the 5th and 7th harmonics.

[0045] For the pole pair number p c =3 rotor control winding, its slot number phase diagram is as follows Figure 3 As shown. The A phase coil is 1, 7, 13, -4, -10, -16; the B phase coil is 3, 9, 15, -6, -12, -18; the C phase coil is 5, 11, 17, -2, -8, -14; the pitch is 5 / 6 of the pole pitch, that is, the pitch y is selected. c =2 double-layer winding can effectively eliminate the 5th and 7th harmonics.

[0046] After setting the phase diagram of each phase coil corresponding to the slot number of the rotor power winding and the rotor control winding, p can be generated at the same time pWith p c The two pole pairs have different magnetomotive forces and retain the excellent characteristics of low harmonic content of the two sets of windings, which fully meet the requirements of the brushless double-fed motor for the rotor structure. The two sets of independent windings use standard regular AC windings, which do not contain harmonics themselves, so they do not contain harmonics after being connected in the prescribed way.

[0047] Furthermore, according to the design requirements of the brushless doubly-fed motor, the stator winding can be selected to adopt a double winding structure or a single winding structure.

[0048] Furthermore, the rotor design method can draw on the traditional regular multi-phase symmetrical winding, which has the advantages of simple design method, standardized design process, and simple rotor winding manufacturing and processing technology.

[0049] Embodiment 3

[0050] Based on the above embodiments, optionally, the number of phases of the rotor winding can be flexibly selected to be two-phase, three-phase, four-phase, five-phase or other multi-phases, the number of phases is an integer greater than or equal to 2, and the number of phases of the rotor power winding and the rotor control winding is the same.

[0051] The multi-phase setting can meet the different needs of the brushless doubly-fed motor, breaking through the limitation of the number of phases of the traditional brushless doubly-fed motor on the combination of pole pairs, which is beneficial to improving the utilization rate of the rotor winding.

[0052] Furthermore, the two sets of rotor windings can be independently designed and manufactured, and the effective turns of the two sets of windings and the effective turns ratio between the two sets of windings can be flexibly designed and matched according to the motor operation and control performance.

[0053] By designing and adjusting the ratio of the effective number of turns of the rotor, the inductance and resistance parameters of the motor are changed, thereby affecting the motor's efficiency, power factor, response time and other motor operation and control performance, thereby achieving optimization of the brushless doubly-fed motor.

[0054] The brushless doubly-fed motor provided in this embodiment adopts a multi-phase symmetrical double-set independent rotor winding, and has two sets of independent rotor windings. Both independent windings can refer to the design method of traditional standard windings, and the two connection methods of the two sets of windings (in-phase sequence and reverse-phase sequence) meet the special requirements of the brushless doubly-fed motor, realize the "differential modulation" and "sum modulation" of the brushless doubly-fed motor, expand the variable speed operation range of the brushless doubly-fed motor, and simplify the manufacturing and design process of the rotor winding.

[0055] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A brushless doubly-fed motor with multi-phase symmetrical dual sets of independent rotor windings, characterized in that: include: A stator structure and a rotor structure, wherein the stator structure comprises a stator core and a stator winding, and the rotor structure comprises a rotor core and a rotor winding; The rotor winding includes two sets of independent windings, namely, the rotor power winding and the rotor control winding, which are connected in series in the same phase sequence or in the opposite phase sequence; the rotor power winding and the rotor control winding have the same number of phases, which is greater than or equal to 2; the rotor power winding and the rotor control winding are symmetrical windings with the same electrical angle difference in space; the two sets of windings are arranged in the same slot in the same rotor core; The rotor power winding and the rotor control winding generate p p and p c The magnetomotive force of the two pole pairs, the rotor power winding pole pair number p p The number of pole pairs of the rotor control winding p c The difference is an even number.

2. The brushless doubly-fed motor according to claim 1, characterized in that: When the rotor power winding and the rotor control winding are connected in series in the same phase sequence, the brushless double-fed motor is in a "differential modulation" mode, and the equivalent pole pair number of the brushless double-fed motor is p c With p p The absolute value of the difference.

3. The brushless doubly-fed motor according to claim 1, characterized in that: When the rotor power winding and the rotor control winding are connected in series in reverse phase sequence, the brushless doubly-fed motor is in "sum modulation" mode, and the equivalent pole pair number of the brushless doubly-fed motor is p c With p p The sum.

4. The brushless doubly-fed motor according to claim 1, characterized in that: The stator winding adopts a double winding or a single winding structure.

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