A windingless end motor and motor system

Abstract

This invention discloses a winding-free end motor, composed of one or more unit motors. The stator coils of the unit motors adopt a Robert transposed strip coil structure, with one turn of conductor in each stator core slot. Within a unit, all turns of conductor or any end of the strip coil are short-circuited and welded together as a whole as the neutral point, and the other end serves as the output terminal. The invention also discloses a winding-free end motor system, in which a multi-phase bridge inverter circuit is connected to the motor output terminal, and multiple capacitors are connected in series at the motor voltage input terminal. The number of capacitors is the same as that of the unit motor, and each capacitor is connected in parallel on both sides of the corresponding unit motor. This invention eliminates the need for cross-pole connections in the coils, thus avoiding the winding ends of conventional motors. With only one conductor in the slot, there is no need to distinguish between upper and lower coil layers, eliminating inter-turn insulation and improving slot utilization. Furthermore, the strip coil is a straight line, enabling flat wire hard winding in any slot type.

Description

Technical Field

[0001] This invention belongs to the field of motor technology, and particularly relates to a windingless end motor and a windingless end motor system. Background Technology

[0002] Currently, all electric motors have armature windings with ends. The function of these ends is to connect coils in different slots in series according to a set pattern. To achieve this series connection, the winding ends need to extend axially beyond the core. To prevent crossover, the winding ends are bent at a certain angle along the circumference and are generally double-layered. The current in the conductors at the winding ends does not generate effective torque with the main magnetic field turns; it merely serves as a circuit connection lead.

[0003] The winding ends increase the axial length of the motor in terms of volume, increase ineffective copper losses in terms of efficiency, and are far from the core, making heat dissipation difficult. They are often the hottest points and weakest points in the insulation of the motor. When winding shaped coils with ends are wound, they must be embedded radially into the core slots (for conventional radial flux motors), which restricts the core slot type to open slots or semi-open slots.

[0004] To reduce the length of the winding ends, concentric windings and saddle-shaped windings were developed. Although these reduced the length of the winding ends to some extent, they are only suitable for three-phase motors and cannot completely eliminate the winding ends.

[0005] For a concentrated fractional slot motor, the series connection of adjacent slot conductors is realized, and the winding end is only one slot pitch. There is no interference problem with the ends of other coils. It can be considered that the adverse effects of the winding end have been basically eliminated. However, due to the large number of poles, high rotor loss and high vibration, the concentrated fractional slot motor is only suitable for low-speed applications. Summary of the Invention

[0006] In view of the adverse effects of existing motor winding ends, one of the objectives of this invention is to propose a high-speed, low-voltage, high-torque-density winding-endless motor powered by a frequency converter.

[0007] The technical solution adopted by the present invention to solve its technical problem is: a winding-free end motor, which is composed of one or more unit motors. The stator coil of the unit motor adopts the Robert transposed bar coil structure. Each stator core slot has one turn of conductor. In a unit, all turns of conductor or any one end of the bar coil are short-circuited and welded into a whole as a neutral point end, and the other end is used as the output end.

[0008] The aforementioned windingless end motor has a strip coil that is a straight line that is radially embedded from the slot or inserted from one end of the stator core.

[0009] The windingless end motor described above typically uses multiple flat wires wound together as its turns, and employs Robert transposition to reduce AC losses.

[0010] The stator core of the aforementioned windingless end motor adopts open slots, semi-open slots, semi-closed slots, or closed slots.

[0011] One of the objectives of this invention is to provide a windingless end motor system, including a windingless end motor and a multi-phase bridge inverter circuit connected to the motor output terminal, i.e., the output terminal is powered by the multi-phase bridge inverter circuit. It also includes multiple capacitors connected in series at the motor voltage input terminal, the number of which is the same as that of the unit motor. Each capacitor is connected in parallel on both sides of the corresponding unit motor, thereby indirectly realizing the series connection between multiple unit motors.

[0012] The beneficial effects of this invention are:

[0013] This invention treats each conductor in a slot as an independent phase, and the number of slots in each symmetrical motor unit is the number of phases of the motor. One end of all phases is welded together as a neutral point, and the other end is connected to the multi-phase bridge inverter circuit as an input terminal, thus truly eliminating the ends of the windings.

[0014] The coil of this invention no longer requires cross-pole connection, so there is no winding end of conventional motor. There is only one conductor in the slot, and there is no need to distinguish between upper and lower coil layers. There is no inter-turn insulation, which improves the slot utilization rate. Moreover, the strip coil is a straight line, and flat wire hard winding can be realized under any slot shape.

[0015] Since this invention eliminates the winding ends, the heat dissipation and insulation problems at the winding ends are also eliminated, reducing ineffective copper losses and improving efficiency. The coil no longer requires cross-pole connections, and with only one conductor in the slot, there is no need to distinguish between upper and lower coil layers. There is no inter-turn insulation, improving slot utilization. Furthermore, the strip coil is a straight line, which can be inserted into the core slot through the end, enabling flat wire hard windings in any slot type, further improving motor efficiency and vibration / noise performance.

[0016] The present invention is applied to high-speed low-voltage motors. Due to the low voltage and high linear speed, the number of turns in series per phase is very small. The present invention specifically refers to the case where only half a turn is needed, or the voltage of each unit is reduced by series connection to match half a turn. Attached Figure Description

[0017] Figure 1 This is the wiring diagram for the 12-phase integer slots of the present invention, where one pair of poles constitutes one unit;

[0018] Figure 2 This is the 12-phase phase diagram of the integer slots of the present invention, with 1 pair of poles constituting 1 unit;

[0019] Figure 3This is the wiring diagram for a 6-phase integer slot of the present invention, where 1 pair of poles constitutes 1 unit;

[0020] Figure 4 This is the 6-phase phase diagram of the integer slots of the present invention, with 1 pair of poles constituting 1 unit;

[0021] Figure 5 A schematic diagram of a windingless end motor system consisting of multiple unit motors connected in series. Detailed Implementation

[0022] The specific embodiments of the present invention will now be described in conjunction with the accompanying drawings and examples to enable those skilled in the art to better understand the present invention. Example 1

[0023] This invention discloses a winding-free end motor, composed of one or more unit motors. The motors have multiple symmetrical cycles, thus forming multiple completely equivalent units. These units can be connected in parallel to accommodate low-voltage, high-current applications or in series to accommodate high-voltage, low-current applications. For an integer-slot motor, each unit motor has one pole pair; for a fractional-slot motor, it is a symmetrical unit. The stator coil of the unit motor adopts a Robert transposed strip coil structure. Each stator core slot contains only one turn of conductor. Within a unit, all turns of conductor or any end of the strip coil are short-circuited and welded together as a single unit, serving as the neutral point. The other end serves as the output terminal. The strip coil is a straight line inserted radially from the slot opening or inserted from one end of the stator core. The turns of conductor are generally composed of multiple flat wires wound together, and Robert transposition is used to reduce AC losses. The stator core uses various slot types, such as open slots, semi-open slots, semi-closed slots, or closed slots.

[0024] For the case where there are 12 slots under each pair of poles in an integer slot, 12 phases will be formed in one cell, namely A1+, A2+, A3+, A4+, B1+, B2+, B3+, B4+, C1+, C2+, C3+, and C4+, with each phase differing by 30° electrical angle. For the case where there are 6 slots under each pair of poles in an integer slot, 6 phases will be formed in one cell, namely A1+, A2+, B1+, B2+, C1+, and C2+, with each phase differing by 60° electrical angle.

[0025] Figure 1 and Figure 2The diagram shows the wiring and phase diagram of the 12-phase, integer-slot, unwinding end-mounted motor of the present invention. The symmetrical period of the 12-phase, integer-slot motor is one pair of poles. Within one pair of poles, the stator corresponds to 12 slots. Each slot contains one conductor (this conductor uses multiple flat wires wound in parallel and transposed by Roberts). Each conductor in a slot corresponds to a phase: A1+, A2+, A3+, A4+, B1+, B2+, B3+, B4+, C1+, C2+, C3+, and C4+. Each phase differs by 30° electrical angle. The neutral point can connect all the conductors in all slots via a shorting busbar. The cross-sectional area of ​​the shorting busbar should accommodate the maximum current between the 12 phases. The other end is powered by a 12-phase bridge inverter circuit, providing the corresponding phase current to each conductor in each slot according to the phase relationship.

[0026] To reduce the number of wiring connections between the inverter and the motor, the inverter should be integrated into the motor terminal. When the motor has p pole pairs, it has p equivalent 12-phase units. Figure 1 In a series configuration of p equivalent 12-phase units, the DC input voltage is divided into p voltage segments through a series capacitor. Each voltage segment is connected to a 12-phase bridge inverter circuit to power one 12-phase unit of the motor, thus meeting high voltage requirements. Alternatively, the p equivalent 12-phase units can be powered by p independent 12-phase bridge inverters. Or, all p equivalent 12-phase units can be connected in parallel, forming a single 12-phase unit for the entire motor. Example 2

[0027] Figure 3 , Figure 4 The diagram shows the wiring and phase diagram of the windingless end motor based on an integer slot 6-phase motor of the present invention. The symmetrical period of the integer slot 6-phase motor is one pair of poles. Within one pair of poles, the stator corresponds to 6 slots. Each slot contains one conductor (the conductor is made of multiple flat wires wound in parallel and transposed by Robert). Each conductor in the slot corresponds to one phase, namely A1+, A2+, B1+, B2+, C1+, and C2+, with each phase differing by 60° electrical degrees. Other features are the same as in Embodiment 1. Example 3

[0028] Reference Figure 5 As shown, the present invention discloses a windingless end motor system, including a windingless end motor and a multi-phase bridge inverter circuit connected to the motor output terminal, i.e., the output terminal is powered by the multi-phase bridge inverter circuit. It also includes multiple capacitors connected in series at the motor voltage input terminal, the number of which is the same as that of the unit motor. Each capacitor is connected in parallel on both sides of the corresponding unit motor. When p equivalent units need to be connected in series, the DC input voltage should be divided into p voltage segments through the series connection of capacitors. Each voltage segment is connected to a multi-phase bridge inverter circuit to power one unit motor, thereby indirectly realizing the series connection between multiple unit motors.

[0029] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several modifications and improvements without departing from the inventive concept of the present invention, and these all fall within the protection scope of the present invention.

Claims

1. A windingless end motor, characterized in that: It consists of one or more unit motors. The stator coil of the unit motor adopts the Robert transposed bar coil structure. Each stator core slot has one turn of conductor. Either end of the turn of conductor or the bar coil is short-circuited as the neutral point terminal, and the other end is used as the output terminal to connect to the multiphase bridge inverter circuit.

2. The windingless end motor according to claim 1, characterized in that, The strip coil is a straight line that is radially embedded from the slot or inserted from one end of the stator core.

3. A windingless end motor according to claim 1, characterized in that, The aforementioned turn conductor is made of multiple flat wires wound together and employs Robert transposition.

4. A windingless end motor according to claim 1, 2, or 3, characterized in that, The stator core is described as having an open slot, a semi-open slot, a semi-closed slot, or a closed slot.

5. A windingless end motor system, characterized in that, The device includes the windingless end motor as described in claim 1 and a multi-phase bridge inverter circuit connected to the motor output terminal, and also includes multiple capacitors connected in series at the motor voltage input terminal. The number of capacitors is the same as that of the unit motor, and each capacitor is connected in parallel on the input side of the corresponding unit motor inverter circuit to realize the series connection between multiple unit motors.

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