A multiphase brushless motor

Abstract

This invention relates to a multiphase brushless motor, comprising a stator and a permanent magnet rotor rotating relative to the stator. The stator has stator slots for coil insertion, and the coils comprise several groups, each group of coils being wound in an interleaved manner. A single magnetic pole of the rotor corresponds to all groups of coils simultaneously, and the winding direction of a single group of coils is consistent with the direction of the rotor's magnetic pole. The brushless motor also includes a power drive circuit for outputting corresponding drive signals based on the magnetic pole position. In this structure, each group of coils is independent, enabling all coils to participate in operation. This results in high coil utilization and high utilization of the permanent magnet magnetic field, increasing the motor's torque without changing its size or volume, achieving greater torque at the same power, and greater energy savings under the same load.

Description

Technical Field

[0001] This invention relates to the field of motors, and in particular to a multiphase brushless motor. Background Technology

[0002] Currently, most mobile power equipment, new energy vehicles, drones, and electric manned aircraft use three-phase brushless motors, and the only solution to extend their range is to increase battery capacity. In some cases where weight is a constraint, increasing battery capacity means increasing size and weight, thus directly impacting their development.

[0003] A multiphase brushless motor mainly consists of a stator, a permanent magnet rotor, and coils. The rotor is located at the center of the motor, with permanent magnets either on the surface or embedded within it. The stator is a ring-shaped iron core surrounding the rotor, with multiple slots evenly distributed on the inner side of the core. All phase coils are embedded in these stator slots. The coils are wound in phase groups, with each phase consisting of several turns of coil. The coils of different phases are staggered at a fixed angle on the circumference of the stator. The number of phases in a multiphase brushless motor is determined by the number of coils. The number of coil groups is the number of phases divided by 2 (e.g., four-phase motors have two coil groups, six-phase motors have three coil groups, eight-phase motors have four coil groups, and so on). All coil groups in the phase count are wound in an interlaced manner, and the interlacing coil groups must correspond to the same pair of N and S poles of the permanent magnet (e.g., ...). Figure 7 Commutation is controlled by Hall effect sensors. The number of Hall effect sensors for each phase can be halved, and the corresponding phase control signal can be obtained by converting high and low levels. The commutation angle is 360 / number of phases (e.g., the commutation angle for a four-phase phase is 360 / 4=90 degrees, and the commutation angle for a six-phase phase is 360 / 6=60 degrees, etc.).

[0004] Existing multiphase brushless motors commonly use star (Y) and delta connections for their multiphase windings. The star connection is characterized by each phase winding having two ends, a start end and a tail end. All tail ends of all phases are connected together to form a common neutral point; the start end of each phase is led out separately and connected to the multiphase driver output. The delta connection is characterized by the tail end of one phase being connected to the start end of the next phase, with the start and tail ends connected in series to form a closed loop, without a common neutral point.

[0005] However, in existing technologies, only a portion of the coils are utilized at any given time point. The unused coils generate back electromotive force (EMF), which forms a loop and creates a counterforce, reducing conversion efficiency. Furthermore, the unused coils and magnetic field contribute to the overall reduced utilization rate. For example, in a three-phase motor with U, V, and W terminals, if current flows into U at a given time point while current flows out into V and W, back EMF will be generated at the V and W terminals, forming a loop and creating a counterforce that reduces efficiency. Summary of the Invention

[0006] Therefore, it is necessary to provide a multiphase brushless motor to address the above problems.

[0007] A multiphase brushless motor includes: a stator and a permanent magnet rotor that rotates relative to the stator; the stator is provided with stator slots for coil insertion, the coils include several groups, and each group of coils adopts an intersecting winding method, a single magnetic pole of the rotor corresponds to all groups of coils at the same time, and the winding direction of a single group of coils is consistent with the direction of the magnetic pole of the rotor.

[0008] The brushless motor also includes a power drive circuit for outputting a corresponding drive signal based on the magnetic pole position.

[0009] In one embodiment, the coil is wound across a predetermined number of stator slots to form a loop, and adjacent loops of the same coil share a stator slot, and the winding direction within the shared stator slot is the same.

[0010] In one embodiment, the coil is wound across a predetermined number of stator slots to form a loop, and the adjacent loops of the same coil are respectively inserted into the two sides of a common stator slot core, and the winding directions on both sides of the common stator slot core are the same.

[0011] In one embodiment, the coil is wound across at least two preset numbers of stator slots to form a circumference, each preset number corresponding to a winding method;

[0012] The winding method includes: adjacent rings of the same coil share a stator slot, and the winding direction in the shared stator slot is the same; one side of adjacent rings of the same coil is inserted into both sides of the shared stator slot core, and the winding direction on both sides of the shared stator slot core is the same.

[0013] In one embodiment, the magnetic pole position is obtained by a sensor or algorithm. The sensor includes at least one of a Hall element, a photoelectric encoder, and a rotary transformer, and the algorithm includes at least one of the back electromotive force method and the high-frequency signal injection method.

[0014] In one embodiment, the power drive circuit includes a plurality of switching transistors connected in series in pairs, with the two ends of each coil connected to the connection point of the corresponding series-connected switching transistor.

[0015] In one embodiment, when the magnetic pole position is obtained by Hall elements, the number of Hall elements is the same as the number of phases of the multiphase brushless motor, and the electrical angle between Hall elements is 360° divided by the number of Hall elements; two axisymmetric Hall elements are used simultaneously to control the conduction and cutoff of the switching transistors connected to the two ends of the corresponding coils.

[0016] In one embodiment, the number of Hall elements is half the number of phases of the multiphase brushless motor, and the electrical angle between the Hall elements is 180° divided by the number of Hall elements; each Hall element is used to simultaneously control the on and off of the switching transistor connected to the two ends of the corresponding coil.

[0017] In one embodiment, the output terminal of each Hall element is connected to the base of the corresponding transistor, and the base and collector of the transistor are connected to the control terminal of the switching transistor connected to the two ends of the corresponding coil.

[0018] The aforementioned multiphase brushless motor includes: a stator and a permanent magnet rotor rotating relative to the stator; the stator is provided with stator slots for coil insertion, the coils include several groups, and each group of coils adopts an interleaved winding method, a single magnetic pole of the rotor corresponds to all groups of coils at the same time, and the winding direction of a single group of coils is consistent with the direction of the rotor's magnetic pole; the brushless motor also includes a power drive circuit for outputting corresponding drive signals according to the magnetic pole position. In this structure, each group of coils is independent of each other, and all coils can participate in the work, resulting in high coil utilization; because all coils participate in the work, there is no reaction force generated by back electromotive force, and when all coils are working, all corresponding iron cores generate magnetic fields, so it can be considered as having no magnetic reluctance. Therefore, this invention can improve the coil utilization and permanent magnet magnetic field utilization, increase the motor torque without changing the motor size and volume, achieve greater torque at the same power, and be more energy-efficient under the same load. Attached Figure Description

[0019] Figure 1 This is a structural diagram of a four-phase brushless motor in one embodiment;

[0020] Figure 2 This is a schematic diagram of the simulated current entering the moving position in one embodiment. Figure 1 ;

[0021] Figure 3 This is a schematic diagram of the simulated current entering the moving position in one embodiment. Figure 2 ;

[0022] Figure 4 This is a schematic diagram of the simulated current entering the moving position in one embodiment. Figure 3 ;

[0023] Figure 5 This is a schematic diagram of a six-phase four-pole external rotor brushless motor in one embodiment;

[0024] Figure 6 This is a schematic diagram showing the corresponding magnetic pole positions of the slot winding method for the same slot magnetic pole pair of a four-phase brushless motor in one embodiment.

[0025] Figure 7 This is a schematic diagram showing the corresponding magnetic pole positions of the slot winding method for the same slot magnetic pole pair of a six-phase brushless motor in one embodiment.

[0026] Figure 8 This is a schematic diagram of a single-coil winding with poles opposite each other in the same slot of a four-phase brushless motor in one embodiment.

[0027] Figure 9This is a schematic diagram of the winding of a single coil pole pair of adjacent slots in a four-phase brushless motor in one embodiment;

[0028] Figure 10 This is a schematic diagram of a four-phase brushless motor with twelve slots and ten poles, single-group coil with staggered magnetic poles, in one embodiment.

[0029] Figure 11 This is a schematic diagram of the winding of a six-phase brushless motor with twelve slots and eight poles in one embodiment.

[0030] Figure 12 This is a circuit control diagram of a four-phase brushless motor with four Hall elements in one embodiment;

[0031] Figure 13 Figure 12 The state of the four-phase brushless motor shown Figure 1 ;

[0032] Figure 14 Figure 12 The state of the four-phase brushless motor shown Figure 2 ;

[0033] Figure 15 Figure 12 The state of the four-phase brushless motor shown Figure 3 ;

[0034] Figure 16 Figure 12 The state of the four-phase brushless motor shown Figure 4 ;

[0035] Figure 17 Figure 12 The state of the four-phase brushless motor shown Figure 5 ;

[0036] Figure 18 This is a circuit control diagram of a four-phase brushless motor with two Hall elements in one embodiment;

[0037] Figure 19 This is a circuit control diagram for a six-phase brushless motor in one embodiment;

[0038] Figure 20 This is a circuit control diagram for an eight-phase brushless motor in one embodiment;

[0039] Figure 21 This is a circuit control diagram for a ten-phase brushless motor in one embodiment;

[0040] Figure 22 In one embodiment, the coil is wound around a single iron core magnetic field line of the stator. Figure 1 ;

[0041] Figure 23 In one embodiment, the coil is wound around a single iron core magnetic field line of the stator. Figure 2 ;

[0042] Figure 24 A schematic diagram of the magnetic flux lines of a single iron core wound around a prior art coil in one embodiment;

[0043] Figure 25 This is a schematic diagram of a Hall element detecting the offset angle of the N and S poles in one embodiment of magnetic pole movement;

[0044] Figure 26 This is a schematic diagram of a three-phase brushless motor with an existing delta connection.

[0045] Figure 27 for Figure 26 The diagram shows a three-phase brushless motor receiving external current.

[0046] Reference numerals: 1. Stator; 2. Rotor; 3-1. First coil group; 3-2. Second coil group; 3-3. Third coil group; 4. First stator slot; 5. Second stator slot; 6. Third stator slot; 7. Fourth stator slot; 8. Drive circuit; 9. Signal conversion unit; 10-1. First Hall element; 10-2. Second Hall element; 10-3. Third Hall element; 10-4. Fourth Hall element; 10-5. Fifth Hall element; A. Port 1 of the first coil group; B. Port 2 of the first coil group; C. Port 1 of the second coil group; D. Port 2 of the second coil group; E. Distance between individual iron cores; F. Distance between coil combinations; G. Magnetic lines of force; R. Offset angle. Detailed Implementation

[0047] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0048] One embodiment of this application provides a multiphase brushless motor, including a stator and a permanent magnet rotor rotating relative to the stator. The rotor can be an outer rotor, an inner rotor, or a disc type, and the magnetic poles can be multi-pole. The stator is provided with stator slots for coil insertion, and the coils include several groups, with each group of coils using an intersecting winding method.

[0049] For example Figure 1Taking a four-phase brushless motor as an example, the diagram includes a stator and a rotor. The stator includes a first stator slot, a second stator slot, a third stator slot, and a fourth stator slot. A first coil group and a second coil group are embedded in the four slots of the stator core. The first coil group includes a first coil group port one and a first coil group port two, and the second coil group includes a second coil group port one and a second coil group port two. The first coil group and the second coil group are interleaved and embedded in the stator slots.

[0050] In this embodiment, the brushless motor further includes a Hall element for detecting the position of the magnetic poles and a power drive circuit for outputting different drive signals according to the Hall element. For example... Figures 1 to 4 This represents the current flow direction of a four-phase brushless motor under different drive signals. Figure 1 In the first coil group, the current flows in from port one and out from port two, and the current flows in from port one and out from port two in the second coil group. Figure 2 In the first coil group, the current flows in from port two and out from port one, while the current in the second coil group flows in from port one and out from port two. Figure 3 In the first coil group, the current flows in from port two and out from port one, and the current flows in from port two and out from port one in the second coil group. Figure 4 In the first coil group, the current flows in from port one and out from port two, while the current in the second coil group flows in from port two and out from port one.

[0051] like Figure 5 The diagram shown is a structural schematic of a six-phase four-pole external rotor brushless motor, which shows the intersecting winding structure of each group of coils.

[0052] In this embodiment, a single magnetic pole of the rotor corresponds to all groups of coils simultaneously. For example... Figure 6 As shown, the correspondence between coils and magnetic poles in a four-phase three-pole brushless motor at a certain moment is demonstrated by unfolding the stator and rotor, which have a circular ring structure. The four-phase brushless motor has two coil groups. Figure 6 The left-hand N pole corresponds to two stator slots, in which the first coil group and the second coil group are inserted respectively. Similarly, the S pole and the right-hand N pole also correspond to the first coil group and the second coil group. For example... Figure 7 The figure shows the correspondence between the coils and magnetic poles in a six-phase three-pole brushless motor at a certain moment. The motor has three coil groups. The left N pole corresponds to three stator slots, and the first coil group, the second coil group, and the third coil group are inserted into the three stator slots respectively. The S pole and the right N pole also correspond to the first coil group, the second coil group, and the third coil group.

[0053] In this embodiment, the winding direction of a single coil is consistent with the direction of the rotor's magnetic poles. For example... Figure 7 As shown, the coil is wound downwards to correspond to all the N poles and upwards to correspond to all the S poles.

[0054] In one embodiment, the coil winding method includes two types: pole-to-slot winding and pole-to-opposite-slot winding. Pole-to-slot winding is further divided into pole-to-same-slot winding and pole-to-adjacent-slot winding, while pole-to-opposite-slot winding is a combination of same-slot winding and adjacent-slot winding.

[0055] Among them, the same-slot winding method involves winding two adjacent loops with one side on the same slot, and the winding direction in the same slot must be the same, such as... Figure 8 As shown, adjacent stator slots shared by all rings include slots 3, 5, and 7 from the left (subsequent stator slot numbers are based on the leftward position). The number of slots varies depending on the number of phases, specifically the number of coil groups. For example... Figure 6 The two sets of coils are separated by two slots and wound around slots 1 and 3. Figure 7 The three sets of coils are wound in slots 1 and 4, with more phases (more sets of coils) following the same pattern.

[0056] The adjacent slot winding method involves winding two adjacent loops with one side on either side of the same stator slot cam (the fourth stator slot cam), and the winding directions on both sides are the same. The number of slots varies depending on the number of phases, and is determined by the number of coil groups. For example... Figure 9 The four-phase winding is made by winding around slots 1 and 4, then around slots 3 and 6, and so on until all slots are filled. The six-phase winding is made by winding around slots 1 and 5, then around slots 4 and 8, and so on. For example... Figure 11 The diagram shows a single-phase, octagonal coil. The six-phase combination with adjacent slots is wound in the following order: slots 1 and 3 are wound, then slots 4 and 6, then slots 7 and 9, up to slots 10 and 12, and so on. More phases follow the same pattern.

[0057] The staggered-slot winding method involves winding the coil in multiple slots. The number of slots between slots varies depending on the actual number of stator slots, and is a combination of the same-slot winding method and the adjacent-slot winding method. For example... Figure 10 The diagram shows an example of a four-phase ten-pole single-group coil with staggered slot winding. In the diagram, slots 1 and 5 form the first loop, slots 2 and 6 form the second loop, slots 3 and 7 form the third loop, slots 7 and 11 form the fourth loop, slots 8 and 12 form the fifth loop, and slots 9 and 13 form the sixth loop. The first, second, and third loops are adjacent slot windings, the fourth, fifth, and sixth loops are adjacent slot windings, and the third and fourth loops are same slot windings.

[0058] from Figure 10As can be seen, in the adjacent slot winding method, the right side of the first loop is to the right of the fourth stator slot cam from the left, and the left side of the second loop is to the left of the second stator slot cam from the left, with both sides winding upwards. Therefore, the adjacent slot winding method can also be used where one side of the two loops is wound on both sides of the same set of stator slot cams, and the number of stator slot cams in the same set of stator slot cams depends on the number of coil groups.

[0059] In one embodiment, the rotor magnetic poles are determined according to the winding direction of the coil. Each adjacent winding has a downward direction as an N pole and an upward direction as an S pole, thereby setting the number of rotor circumferential magnetic poles.

[0060] In one embodiment, such as Figure 12 The diagram shows the drive circuit, Hall effect elements, and coil group connection structure of a four-phase two-pole brushless motor. The drive circuit is an H-bridge structure, including power transistors Q1, Q2, Q3, Q4, Q5, Q6, Q7, and Q8. Q1 and Q2 are connected in series and their connection point is connected to port one of the second coil group; Q3 and Q4 are connected in series and their connection point is connected to port two of the second coil group; Q5 and Q6 are connected in series and their connection point is connected to port two of the first coil group; and Q7 and Q8 are connected in series and their connection point is connected to port one of the first coil group. The number of Hall effect elements is the same as the number of phases, namely the first Hall effect element, the second Hall effect element, the third Hall effect element, and the fourth Hall effect element. The electrical angle between the Hall effect elements is 90°. The axially symmetrical first and second Hall effect elements correspond to the series-connected power transistors at the two ports (C and D) of the second coil group. Specifically, the first Hall effect element is connected to the control terminals of Q2 and Q3, and the second Hall effect element is connected to the control terminals of Q1 and Q4. Similarly, the axisymmetric third and fourth Hall elements correspond to the series-connected power transistors at the two ports (A and B) of the first coil group. Specifically, the third Hall element is connected to the control terminals Q5 and Q8, and the fourth Hall element is connected to the control terminals Q7 and Q6. Each Hall element is used to generate an on-time signal to turn on the power transistor when the N pole of the permanent magnet is sensed.

[0061] Rotor in Figure 12 In this state, E1 and E3 sense the rotor's N pole and generate a signal to activate Q2, Q3, Q5, and Q8. The current in the first coil group flows from the positive terminal through Q5 to coil B, then flows from slot 2 into slot 1, out to end A, and through Q8 to the negative terminal. The current in the second coil group flows from the positive terminal through Q3 to coil D, then flows from slot 3 into slot 4, out to end C, and through Q2 to the negative terminal. Assuming that the current flowing into a sub-slot generates an electromagnetic N pole and the current flowing out generates an electromagnetic S pole, slots 2 and 3 generate electromagnetic N poles, and slots 1 and 4 generate electromagnetic S poles. The permanent magnet rotor rotates under the influence of like poles pushing each other and unlike poles attracting each other.

[0062] When the permanent magnet moves from Figure 12 Rotate to Figure 13At the moment of commutation, E3 is off and E4 is on. E3 disengages from the permanent magnet's N pole, closing Q5 and Q8. E1 remains on, while Q2 and Q3 remain open. The current in the first coil group flows from the positive terminal through Q5 to coil B, then flows from slot 2 into slot 1, out to end A, and through Q8 to the negative terminal. Slot 3 generates an electromagnetic N pole, and slot 4 generates an electromagnetic S pole. The permanent magnet continues to rotate.

[0063] When the permanent magnet moves from Figure 13 Rotate to Figure 14 When the position is reached, the permanent magnet commutation is completed. E3 is closed, E4 is open, and Q6 and Q7 are open. E1 remains open, and Q2 and Q3 are open. The current in the first coil group flows from the positive terminal through Q7 to coil A, then flows from slot 1 into slot 2, out to terminal B, and through Q6 to the negative terminal. The current in the second coil group flows from the positive terminal through Q3 to coil D, then flows from slot 3 into slot 4, out to terminal C, and through Q2 to the negative terminal. Slots 1 and 3 generate the electromagnetic N pole, and slots 2 and 4 generate the electromagnetic S pole. Figure 3 As shown, the permanent magnet continues to rotate.

[0064] When the permanent magnet moves from Figure 14 Rotate to Figure 15 In position, E1 is closed, E2 is open, and Q1 and Q4 are open. E4 remains open, and Q6 and Q7 are open. The current in coil group 1 flows from the positive terminal through Q7 to end A of the coil, flows into slot 1, exits through slot 2, reaches end B, and flows through Q6 to the negative terminal. The current in coil group 2 flows from the positive terminal through Q1 to end C of the coil, flows into slot 4, exits through slot 3, reaches end D, and flows through Q4 to the negative terminal. Slot 1 and slot 4 generate the electromagnetic N pole, and slots 2 and 3 generate the electromagnetic S pole. The permanent magnet continues to rotate.

[0065] When the permanent magnet moves from Figure 15 Rotate to Figure 16 When in position, E4 is off, E3 is on, and Q5 and Q8 are on. E2 remains on, and Q1 and Q4 are on. The current in the first coil group flows from the positive terminal through Q5 to coil B, then flows from slot 2 into slot 1, out to end A, and through Q8 to the negative terminal. The current in the second coil group flows from the positive terminal through Q1 to coil C, then flows from slot 4 into slot 3, out to end D, and through Q4 to the negative terminal. Slots 2 and 4 generate electromagnetic N poles, and slots 1 and 3 generate electromagnetic S poles. The permanent magnet continues to rotate.

[0066] When the permanent magnet moves from Figure 16 Rotate to Figure 17 When in position, E2 is off and E1 is on, Q2 and Q3 are on, E3 remains on, and Q5 and Q8 are on. The current in the first coil group flows from the positive terminal through Q5 to coil B, then flows from slot 2 into slot 1, out to terminal A, and through Q8 to the negative terminal. The current in the second coil group flows from the positive terminal through Q3 to coil D, then flows from slot 3 into slot 4, out to terminal C, and through Q2 to the negative terminal. Slots 2 and 3 generate electromagnetic N poles, and slots 1 and 4 generate electromagnetic S poles. The permanent magnet completes one electrical cycle and continues to rotate.

[0067] In this embodiment, the motor coils are connected in parallel before control, and each group of coils is independent after control. The linkage is achieved by the rotor position signal, and the power output mode is cyclic power output.

[0068] In one embodiment, the number of Hall elements is half the number of phases, and in this case, the control of the multi-phase coil is achieved through a signal conversion unit. For example... Figure 18 The diagram shows the connection of Hall elements, drive circuit, signal conversion unit, and coils in a four-phase brushless motor. There are two Hall elements, designated as the first and second Hall elements, installed with a 90° electrical offset between them. The signal conversion unit includes transistors V1 and V2, whose bases are connected to the outputs of the first and second Hall elements, respectively. Their collectors are connected to the power supply VCC via a current-limiting resistor R, and their emitters are grounded. The base of V1 is connected to Q5 and Q8, and its collector to Q6 and Q7. The base of V1 is connected to Q1 and Q4, and its collector to Q2 and Q3. When the rotor rotates to the point where the second Hall element outputs a low level, the base of transistor V1 is pulled low, transistor V2 is cut off, and VCC outputs a high-level position signal. When the rotor rotates to the point where the internal switch of the second Hall element is turned off, the output pin becomes a floating high-impedance pin, the base of transistor V1 is saturated by the resistor, and the collector is pulled to GND, outputting a low level. Therefore, the Hall element calculates the rotor position through the phase signal, outputs a drive signal to drive the electric commutation, and thus continuously drives the motor to rotate.

[0069] The more phases, the more Hall elements, and consequently, the more transistors. For example... Figure 19 The diagram shown illustrates the connection of the Hall elements, drive circuit, signal conversion unit, and coils of a six-phase brushless motor, including a first Hall element, a second Hall element, and a third Hall element. Figure 20 The diagram shown illustrates the connection of Hall elements, drive circuit, signal conversion unit, and coils in an eight-phase brushless motor, including a first Hall element, a second Hall element, a third Hall element, and a fourth Hall element. Figure 21 The diagram shows the connection of Hall elements, drive circuit, signal conversion unit and coil of a ten-phase brushless motor, which includes a first Hall element, a second Hall element, a third Hall element, a fourth Hall element and a fifth Hall element.

[0070] like Figure 22 and Figure 23 The image shown is a schematic diagram of the magnetic field lines of a single iron core wound around a coil. Figure 24 A schematic diagram of the magnetic flux lines of a single iron core wound around a stator in existing technology. Based on... Figure 22 and Figure 23 In stator slot design, after determining the winding method, the width of a single coil winding in the slot should be greater than the width of the iron core, that is, the coil combination distance should be greater than the distance of a single iron core.

[0071] like Figure 25 As shown, the rotor magnetic poles should be compensated during manufacturing to reduce the commutation error caused by the magnetic field line identification offset of the rotor position identification element.

[0072] like Figure 26 As shown, this is a traditional delta connection. At a given time point, current enters from terminal U and exits from terminals V and W. Assuming no back electromotive force (EMF) is generated between terminals V and W, the voltages at terminals V and W are equal (assuming equal resistances for all coils). Therefore, no current flows through terminals V and W in the absence of back EMF. When the rotor rotates, each coil cuts the magnetic lines of force, generating back EMF. Since back EMF suppression circuits are now well-established, the back EMF only produces a reverse voltage and no reverse current flow from the coils, or the current flowing is very small. Therefore, it can be determined that the back EMF generated by each coil does no work and does not produce a reaction force. Thus, the back EMF generated by each coil itself does not directly affect the motor.

[0073] When the rotor is rotating at this point in time, back electromotive forces Wa and Va will be generated at terminals W and V. Assuming the back electromotive force voltage is Wa > Va, then there will be a voltage difference between terminals W and V. The input voltage at terminal W is equal to that at terminal V (…). Figure 1 According to the superposition theorem, the voltage from the W terminal to the V terminal of the coil is the back electromotive force (EMF) voltage. Since the back EMF suppression circuit at these two terminals generates no reverse current or the generated current is negligible, the external input current of the motor will become a reverse current I3 flowing from the W terminal to the V terminal due to the voltage difference between the W and V terminals. Furthermore, there is no back EMF itself generating a superposition current (e.g., ...). Figure 27 Therefore, the back electromotive force voltage Wa, together with Va and the external input reverse current I3, will generate a reverse force between the coil at the W end and the V end, reducing the conversion efficiency of the motor.

[0074] Public data shows that the back electromotive force voltage is close to the input voltage, from Figure 27 It can be seen that the coils from W to V are connected in parallel. According to the parallel current division formula, the reverse current I3 is equal to half of the current I2 flowing through the coil from U to W. The reverse current I3, together with the back electromotive force Wa and Va, will do work and generate a reaction force. This reaction force will then cancel out the positive force equal to itself. Therefore, the reverse current I3 x 2 is the amount of work done in vain. Thus, it can be concluded that the motor does 2 / 3 of the useful work, while 1 / 3 is wasted work that cancels out its own power. Therefore, the traditional delta connection method has a maximum conversion efficiency of 66.66%.

[0075] Traditional Y-connected motors do not exhibit the adverse effect of back electromotive force combining with external input current to generate a reaction force. Under the same power supply voltage, the power output of a delta-connected motor is three times that of a Y-connected motor. Current technology primarily uses delta-connected motors to maximize power; therefore, the Y-connected motor will not be discussed further here.

[0076] In summary, in the existing technology, there are always two ends where the current flows in the same direction, which will lead to the following three disadvantages:

[0077] 1. The coil between these two ends does not participate in the operation, resulting in low coil utilization;

[0078] 2. The back electromotive force generated because the coils at both ends do not participate in the operation will create a reaction force, reducing the conversion efficiency;

[0079] 3. Since the coils at both ends do not participate in the work, the corresponding coil core in the iron-core permanent magnet motor will attract the magnetic field of the permanent magnet due to the lack of magnetic field generation, thus generating magnetic resistance and further reducing the working efficiency.

[0080] To address the aforementioned issues, the internal circuit of the motor of this invention does not contain a coil path that generates a reaction force. Therefore, 100% of the coils perform useful work. In contrast, one-third of the coils in the existing delta-connected technology are wasted due to performing useless work and offsetting their own positive force. Thus, this invention improves the conversion efficiency by 33.33% with the same number of coils performing useful work (i.e., the same power). Similarly, one-third of the coils in the existing technology do not perform useful work, so the proportion of useful work performed by this invention is increased by 33.33%. Correspondingly, the utilization rate of the permanent magnet magnetic field performing useful work is also increased by 33.33%. Therefore, compared with existing technologies, the motors of this invention can achieve a maximum working efficiency increase of 100% at the same power (same number of coils performing useful work). Furthermore, with the same number of coils, the power is one-third higher (in a three-phase motor with three sets of coils in a delta connection, only two sets of coils perform useful work; the six-phase motor of this invention also has three sets of coils, but only three sets perform useful work; the three-phase motor's delta connection is in parallel, while in this invention, each set of coils is in parallel; therefore, the power of this invention is one-third greater than that of existing motors with the same number of coils). It conforms to the law of conservation of energy and the superposition theorem of circuits.

[0081] Therefore, the technical working principle of this invention is to change the internal circuit of the motor rather than the external circuit, that is, to change it from the root and completely eliminate the defects of the prior art. Compared with the delta connection of a three-phase motor, it improves the coil efficiency for doing useful work and the utilization rate of the permanent magnet magnetic field. Moreover, the more phases there are, the greater the power of the motor will be.

[0082] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0083] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

[0084] In the description of this application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0085] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0086] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

Claims

1. A multiphase brushless motor, characterized in that, include: A stator and a permanent magnet rotor rotating relative to the stator; the stator is provided with stator slots for inserting coils, the coils include several groups, and each group of coils is wound in an intersecting manner, a single magnetic pole of the rotor corresponds to all groups of coils at the same time, and the winding direction of a single group of coils is consistent with the magnetic pole direction of the rotor; The brushless motor also includes a power drive circuit for outputting a corresponding drive signal based on the magnetic pole position.

2. The multiphase brushless motor according to claim 1, characterized in that: The coil is wound across a predetermined number of stator slots to form a loop. Adjacent loops of the same coil share a stator slot, and the winding direction within the shared stator slot is the same.

3. A multiphase brushless motor according to claim 1, characterized in that: The coil is wound across a predetermined number of stator slots to form a circumference. One side of an adjacent circumference of the same coil is inserted into both sides of a common stator slot core, and the winding directions on both sides of the common stator slot core are the same.

4. A multiphase brushless motor according to claim 1, characterized in that: The coil is wound across at least two preset numbers of the stator slots to form a loop, and each preset number corresponds to a winding method; The winding method includes: adjacent rings of the same coil share a stator slot, and the winding direction in the shared stator slot is the same; one side of adjacent rings of the same coil is respectively inserted into the two sides of the shared stator slot core, and the winding direction on both sides of the shared stator slot core is the same.

5. A multiphase brushless motor according to claim 1, characterized in that: The magnetic pole position is obtained by a sensor or algorithm. The sensor includes at least one of a Hall element, a photoelectric encoder, and a rotary transformer. The algorithm includes at least one of the back electromotive force method and the high-frequency signal injection method.

6. A multiphase brushless motor according to claim 1, characterized in that: The power drive circuit includes several switching transistors connected in series in pairs, and the two ends of each coil are respectively connected to the connection point of the corresponding series switching transistor.

7. A multiphase brushless motor according to claim 6, characterized in that: When the magnetic pole position is obtained by the Hall element, the number of Hall elements is the same as the number of phases of the multiphase brushless motor, and the electrical angle between the Hall elements is 360° divided by the number of Hall elements; the two axially symmetrical Hall elements are used simultaneously to control the conduction and cutoff of the switching transistors connected to the two ends of the corresponding coil.

8. A multiphase brushless motor according to claim 7, characterized in that: The number of Hall elements is half the number of phases of the multiphase brushless motor, and the electrical angle between the Hall elements is 180° divided by the number of Hall elements; each Hall element is used to simultaneously control the on and off of the switching transistor connected to the two ends of the corresponding coil.

9. A multiphase brushless motor according to claim 8, characterized in that: The output terminal of each Hall element is connected to the base of the corresponding transistor, and the base and collector of the transistor are connected to the control terminal of the switching transistor connected to the two ends of the corresponding coil.

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