A winding switching control device and method for permanent magnet synchronous motor
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHEARIHI (ANHUI) TECH CO LTD
- Filing Date
- 2026-04-15
- Publication Date
- 2026-07-14
AI Technical Summary
Existing methods for switching the windings of permanent magnet synchronous motors suffer from problems such as contact arcing, ablation, motor phase sequence disorder, and limited hardware solutions, making them difficult to adapt to different cost and space requirements.
By employing a drive module, a Y-Δ winding switching module, a control module, and a current and voltage detection module, combined with three relay configurations (single-pole double-throw, single-pole single-throw, and multi-contact relay), and optimizing the wiring method through soft-start energy dissipation and zero-voltage switching, flexible winding switching control is achieved.
It improves relay life, protects IPM devices, ensures constant motor direction, enhances system adaptability and reliability, is suitable for various motor types, has strong adaptability, and is highly practical for industrial applications.
Smart Images
Figure CN122394467A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of permanent magnet synchronous motor drive control technology, specifically to a permanent magnet synchronous motor winding switching control device and method. Background Technology
[0002] Permanent magnet synchronous motors (PMSMs) are widely used in equipment such as compressors, pumps, and fans due to their advantages such as high efficiency, high torque density, and fast response. To meet the requirements of both low-speed high torque and high-speed wide speed range operation, a Y-Δ winding switching method is usually adopted: a Y-connection is used at low speeds to improve voltage utilization and obtain high torque; a Δ connection is used at high speeds to reduce winding phase voltage and expand the speed range.
[0003] In existing technologies, the switching of Y-Δ windings in permanent magnet synchronous motors often adopts the method of switching relays after direct shutdown, which has many technical problems: First, after the motor stops, the winding inductance stores energy, and the back electromotive force generated by the rotor rotation will cause residual voltage in the winding. Directly switching the relay can easily cause contact arcing and burning, reduce the relay life, and even cause contact adhesion, resulting in single-phase operation of the motor. Second, if the drive module bridge arm is not completely turned off or the energy is not discharged in time, the residual voltage will form a follow current through the bridge arm, damaging the IPM power devices. Third, if the connection method of the start and end of the delta connection of the winding is not properly designed, it will cause the motor phase sequence to be disordered, and the motor will reverse after switching.
[0004] Furthermore, existing switching device hardware solutions are relatively simple, often employing three single-pole double-throw relays. While these offer good synchronization, they lack flexibility in situations where cost is extremely sensitive or installation space is limited. For example, in some scenarios, using multiple low-cost single-pole single-throw relays may be more cost-effective; while in other scenarios with high reliability requirements, using highly integrated multi-contact relays may be superior.
[0005] To address the aforementioned issues, there is an urgent need for a permanent magnet synchronous motor winding switching control device and method to solve the problems existing in traditional methods. Summary of the Invention
[0006] The purpose of this invention is to provide a permanent magnet synchronous motor winding switching control device and method. The hardware scheme is flexible and diverse, and can be adapted to different cost and space requirements. It adopts the lower bridge arm soft opening energy discharge to avoid current surge and protect IPM devices. Zero voltage switching completely eliminates contact arcing and extends relay life. Optimized wiring ensures constant motor direction. It has strong adaptability, high industrial applicability, and significantly improves the operating energy efficiency and reliability of the motor across the entire speed range.
[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A permanent magnet synchronous motor winding switching control device includes: a drive module, a Y-Δ winding switching module, a control module, and a current and voltage detection module. The current and voltage detection module is connected to the drive module and the control module. The control module is connected to the drive module and the Y-Δ winding switching module. The drive module is connected to the first end of the permanent magnet synchronous motor winding, and the Y-Δ winding switching module is connected to the first and last ends of the permanent magnet synchronous motor winding. The drive module is used to output frequency- and voltage-adjustable three-phase AC power to the permanent magnet synchronous motor; The control module is used to output control signals to realize the switching action of the drive module and the relay action of the Y-Δ winding switching module; The current and voltage detection module is used to detect the phase current, line current and winding terminal voltage of the permanent magnet synchronous motor. The Y-Δ winding switching module is used to switch between Y-shaped and Δ-shaped wiring states of the motor windings, and the Y-Δ winding switching module adopts any one of the following three topologies: It consists of three single-pole double-throw power relays; It consists of six single-pole single-throw power relays; It consists of two multi-contact power relays.
[0008] Furthermore, the IPM module of the drive module includes a three-phase upper bridge arm switch, a three-phase lower bridge arm switch, and a drive circuit.
[0009] Furthermore, when the Y-Δ winding switching module uses three single-pole double-throw power relays, the three-phase windings of the permanent magnet synchronous motor are set as U-U', V-V', and W-W'. The common terminal of the three single-pole double-throw relays is connected to the U' terminal, V' terminal, and W' terminal respectively. The normally closed terminals of the three single-pole double-throw relays are connected together to form a Y-shaped neutral point. The normally open terminals of the three single-pole double-throw relays are connected to the V terminal, W terminal, and U terminal respectively to form a Δ-shaped closed-loop connection.
[0010] Furthermore, when the Y-Δ winding switching module uses six single-pole single-throw power relays, the three-phase windings of the permanent magnet synchronous motor are set as U-U', V-V', and W-W'. The six single-pole single-throw relays are divided into two groups: a first group of single-pole single-throw relays and a second group of single-pole single-throw relays. One end of the first group of single-pole single-throw relays is connected to the U', V', and W' ends of the motor windings, respectively. The other ends of the first group of single-pole single-throw relays are connected together to form a Y-shaped neutral point. The second group of single-pole single-throw relays are connected in series between the U' and V ends, the V' and W ends, and the W' and U ends of the motor windings, respectively, to achieve a Δ-shaped closed-loop connection.
[0011] Furthermore, when the Y-Δ winding switching module uses two multi-contact power relays, the three-phase windings of the permanent magnet synchronous motor are set as U-U', V-V', and W-W'. The two multi-contact power relays are a first multi-contact power relay and a second multi-contact power relay, respectively. Each multi-contact power relay includes at least three sets of independent normally open or normally closed contacts, namely three first contacts and a second contact corresponding to the first contacts. The three first contacts of the first multi-contact power relay are respectively connected to the U', V', and W' ends of the motor windings. The three second contacts of the first multi-contact power relay are connected together to form a Y-shaped neutral point. The three sets of contacts of the second multi-contact power relay are respectively connected across the U' end and the V end, the V' end and the W end, and the W' end and the U end to form a Δ-shaped closed-loop connection.
[0012] Furthermore, the rated current of the contacts of the single-pole double-throw power relay, the single-pole single-throw power relay, and the multi-contact power relay is greater than or equal to twice the peak value of the maximum phase current of the permanent magnet synchronous motor winding, and the withstand voltage of the contacts is greater than or equal to 1.5 times the rated operating voltage of the drive module. The coils of the single-pole double-throw power relay, the single-pole single-throw power relay, and the multi-contact power relay are driven by DC 5V-DC 24V and connected in reverse parallel with freewheeling diodes.
[0013] The present invention also provides a method for controlling the switching of permanent magnet synchronous motor windings, applied to the aforementioned permanent magnet synchronous motor winding switching control device, comprising: Step 1: The control module determines whether the permanent magnet synchronous motor needs winding switching. If so, it sends a stop command to the drive module. The drive module stops outputting PWM signals and turns off the three-phase upper bridge arm switch and the three-phase lower bridge arm switch. Step 2: The control module delays for a first preset time to decelerate the motor rotor until it comes to a stop. The current and voltage detection module confirms that the motor speed is approaching 0 and the winding terminal voltage is decreasing. Step 3: The control module controls the IPM module of the drive module to keep the three-phase upper bridge arm switch transistors off, and the three-phase lower bridge arm switch transistors are soft-turned on by gradually increasing the duty cycle of the PWM method, so as to realize the soft discharge of the energy stored in the motor winding inductance. During the discharge process, the current detection module limits the maximum current of the lower bridge arm. Step 4: After the discharge is completed, the control module turns off all bridge arm switches of the drive module, and after a preset delay, sends a wiring switching command to the Y-Δ winding switching module to achieve zero-voltage switching of Y / Δ wiring state; Step 5: After the winding switching is completed, delay for a second preset time to avoid the mechanical vibration process that may occur when the drive module switches; Step 6: The control module controls the drive module to re-output the PWM signal, driving the permanent magnet synchronous motor to operate in the switched wiring state.
[0014] Furthermore, in step 2, the first preset time is 500-5000ms.
[0015] Furthermore, in step 3, the PWM method of gradually increasing the duty cycle is specifically as follows: The PWM duty cycle starts from 0 and gradually increases to 100% with a slope of 1%-5% / 100-1000μs, and is maintained for 10-100ms before being turned off.
[0016] Furthermore, in step 4, a wiring switching command is sent to the Y-Δ winding switching module to achieve zero-voltage switching between the Y-connection and Δ-connection states, specifically as follows: When using six single-pole single-throw power relays, first disconnect the three single-pole single-throw power relays corresponding to the current operating state, and after confirming the disconnection feedback signal, close the three relays corresponding to the target state. When two multi-contact power relays are used, the coils of the two multi-contact power relays are driven synchronously. By utilizing the internal mechanical linkage characteristics of the multi-contact power relays, the synchronous action of opening the Y-shaped neutral point and closing the Δ-shaped circuit is achieved.
[0017] In summary, the present invention has at least one of the following beneficial technical effects: 1. Flexible and diverse hardware solutions: Three relay configuration options are provided. Option 1 uses three single-pole double-throw relays, offering good synchronization and simple control. Option 2 uses six single-pole single-throw relays, with low-cost and readily available components, suitable for cost-sensitive applications. Option 3 uses two multi-contact relays, featuring small size and high integration, suitable for applications with limited installation space. Users can flexibly choose the optimal solution according to their actual needs, significantly improving the system's adaptability and market competitiveness.
[0018] 2. Safe and reliable residual pressure relief: The energy relief method adopts the soft opening of the lower bridge arm after the rotor decelerates and stops, which avoids the current impact of instantaneous short circuit. It can not only realize the complete release of the energy stored in the winding inductance, but also effectively protect the power devices of the drive module IPM, which greatly improves the safety of the switching process and the life of the devices.
[0019] 3. Zero-voltage switching improves contact life: By delaying the turn-off of the bridge arm after the discharge is completed, the residual voltage of the winding is fully released, realizing zero-voltage switching of the relay contacts. This completely avoids contact arcing and burning problems, significantly extends the service life of the relay, and ensures the long-term reliability of the system.
[0020] 4. Ensure constant motor rotation direction: By optimizing the connection method of the start and end of the delta connection, the phase sequence of the motor remains unchanged after the winding is switched, which fundamentally avoids the problem of motor reversal caused by wiring errors and improves the stability and safety of the system.
[0021] 5. Strong adaptability and wide industrial applicability: This invention is applicable to permanent magnet synchronous motors for compressors driven by drive modules of various rated voltage levels, and parameters such as discharge time can be adaptively adjusted according to different motor inertia and operating conditions without the need for complex hardware modifications. It has good industrial applicability and promotion value. Attached Figure Description
[0022] Figure 1 This is a structural block diagram of the device of the present invention; Figure 2 The present invention is illustrated in the block diagram of the device structure when three single-pole double-throw power relays are used. Figure 3 This is a block diagram of the device structure of the present invention when using two multi-contact power relays; Figure 4 This is a block diagram of the device structure of the present invention when using two multi-contact power relays; Figure 5 This is a flowchart of the method steps of the present invention; Figure 6 A schematic diagram of a PWM method that gradually increases the duty cycle; Figure 7 This is a schematic diagram of the IPM module structure. Detailed Implementation
[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.
[0024] like Figure 1 As shown, the present invention provides a permanent magnet synchronous motor winding switching control device, including: a drive module, a Y-Δ winding switching module, a control module and a current and voltage detection module. The current and voltage detection module is connected to the drive module and the control module. The control module is connected to the drive module and the Y-Δ winding switching module. The drive module is connected to the first end of the permanent magnet synchronous motor winding, and the Y-Δ winding switching module is connected to the first and last ends of the permanent magnet synchronous motor winding. The drive module is used to output frequency- and voltage-adjustable three-phase AC power to the permanent magnet synchronous motor; The control module is used to output control signals to realize the switching action of the drive module and the relay action of the Y-Δ winding switching module; The current and voltage detection module is used to detect the phase current, line current and winding terminal voltage of the permanent magnet synchronous motor. The Y-Δ winding switching module is used to switch between Y-shaped and Δ-shaped wiring states of the motor windings, and the Y-Δ winding switching module adopts any one of the following three topologies: It consists of three single-pole double-throw (SPDT) power relays; It consists of six single-pole single-throw (SPST) power relays; It consists of two multi-contact power relays.
[0025] like Figure 7 As shown, the IPM module of the drive module includes a three-phase upper bridge arm switch, a three-phase lower bridge arm switch, an upper bridge arm drive circuit, and a lower bridge arm drive circuit. The upper bridge arm drive circuit is connected to the three-phase upper bridge arm switch, and the lower bridge arm drive circuit is connected to the three-phase lower bridge arm switch.
[0026] like Figure 2 As shown, when the Y-Δ winding switching module uses three single-pole double-throw power relays, the three-phase windings of the permanent magnet synchronous motor are set as U-U', V-V', and W-W'. The common terminal of the three single-pole double-throw relays is connected to the U' terminal, V' terminal, and W' terminal respectively. The normally closed terminals of the three single-pole double-throw relays are connected together to form a Y-shaped neutral point. The normally open terminals of the three single-pole double-throw relays are connected to the V terminal, W terminal, and U terminal respectively to form a Δ-shaped closed-loop connection, ensuring that the motor rotation direction remains unchanged after the winding is switched. This invention provides an embodiment in which all three single-pole double-throw power relays are JQX-30F-1ZDC24V, which in... Figure 2 The three signals are K1, K2, and K3, respectively. The control module outputs three synchronous signals to drive the coil of the single-pole double-throw power relay. Due to its single-pole double-throw structure, it mechanically ensures that the Y-shaped disconnection is followed by the Δ-shaped closure (or vice versa). There is no need for complex software interlocking. It is only necessary to ensure that it operates at zero voltage. It is suitable for occasions with high requirements for switching synchronization and simplified control programs.
[0027] like Figure 3 As shown, when the Y-Δ winding switching module uses six single-pole single-throw power relays, the three-phase windings of the permanent magnet synchronous motor are set as U-U', V-V', and W-W'. The six single-pole single-throw relays are divided into two groups, namely the first group of single-pole single-throw relays (…). Figure 3 K_Y1, K_Y2, K_Y3) and the second group of single-pole single-throw relays ( Figure 3In the first group of single-pole single-throw relays (K_Δ1, K_Δ2, K_Δ3), one end is connected to the U', V', and W' terminals of the motor winding, respectively. The other ends of the first group of single-pole single-throw relays are connected together to form a Y-shaped neutral point. The second group of single-pole single-throw relays are connected in series between the U' and V terminals, the V' and W terminals, and the W' and U terminals of the motor winding, respectively. Figure 3 As shown, K_Δ1 is connected in series between the U' end and the V end, K_Δ2 is connected in series between the V' end and the W end, and K_Δ3 is connected in series between the W' end and the U end, which is used to realize the Δ-shaped closed loop connection; When implementing the Y-to-Δ conversion, the control module first disconnects K_Y1-K_Y3, delays for 5-10ms to confirm the physical disconnection (which can be confirmed by auxiliary contacts or voltage detection), and then closes K_Δ1-K_Δ3. When implementing the Δ to Y conversion, first disconnect K_Δ1-K_Δ3, delay for confirmation, and then close K_Y1-K_Y3; The control module controls the first group of single-pole single-throw relays and the second group of single-pole single-throw relays to interlock, ensuring that at most one group of relays is closed at any time. It is absolutely forbidden for the Y group and Δ group of relays to close at the same time, otherwise it will cause a power short circuit. Figure 3 The solution shown is suitable for cost-sensitive applications, where there is an ample stock of single-pole single-throw relays, and where PCB layout space allows.
[0028] like Figure 4 As shown, when the Y-Δ winding switching module uses two multi-contact power relays, the three-phase windings of the permanent magnet synchronous motor are set as U-U', V-V', and W-W'. The two multi-contact power relays are the first multi-contact power relay k1 and the second multi-contact power relay k2. Each multi-contact power relay includes at least three sets of independent normally open or normally closed contacts, namely three first contacts and corresponding second contacts. The three first contacts of the first multi-contact power relay are respectively connected to the U', V', and W' ends of the motor windings. The three second contacts of the first multi-contact power relay are connected together to form a Y-shaped neutral point. The three sets of contacts of the second multi-contact power relay are respectively connected across the U' end and V end, V' end and W end, and W' end and U end to form a Δ-shaped closed-loop connection. Alternatively, a single multi-channel relay with more than 6 sets of contacts can be used to simultaneously switch between Y-shaped neutral point short-circuiting and Δ-shaped end-to-end interconnection through internal contact logic allocation; The control module outputs two control signals. If two independent multi-contact relays are used, the logic is the same. Figure 3 The technical solution shown (break first, then combine); If a specially customized multi-channel relay (mechanical interlock type) is used, it can be like... Figure 2 The recorded technical solution achieves near-synchronous switching, further simplifying control; Figure 4 The technical solution shown is suitable for applications with limited installation space where it is desirable to reduce the number of relays while maintaining a high degree of integration.
[0029] The rated contact current of the single-pole double-throw power relay, single-pole single-throw power relay, and multi-contact power relay is greater than or equal to twice the peak value of the maximum phase current of the permanent magnet synchronous motor winding, and the contact withstand voltage is greater than or equal to 1.5 times the rated operating voltage of the drive module. The coils of the single-pole double-throw power relay, single-pole single-throw power relay, and multi-contact power relay are driven by DC 5V-DC 24V and connected in reverse parallel with freewheeling diodes.
[0030] This invention also provides a permanent magnet synchronous motor winding switching control method, applied to the aforementioned permanent magnet synchronous motor winding switching control device. The flowchart of the method is shown below. Figure 5 As shown, it includes: Step 1: The control module determines whether the permanent magnet synchronous motor needs winding switching. If so, it sends a stop command to the drive module. The drive module stops outputting PWM signals and turns off the three-phase upper bridge arm switch and the three-phase lower bridge arm switch. Step 2: The control module delays for a first preset time to decelerate the motor rotor until it comes to a stop. The current and voltage detection module confirms that the motor speed is approaching 0 and the winding terminal voltage is decreasing. Step 3: The control module controls the IPM module of the drive module to keep the three-phase upper bridge arm switch transistors off, and the three-phase lower bridge arm switch transistors are soft-turned on by gradually increasing the duty cycle of the PWM method, so as to realize the soft discharge of the energy stored in the motor winding inductance. During the discharge process, the current detection module limits the maximum current of the lower bridge arm. Step 4: After the discharge is completed, the control module turns off all bridge arm switches of the drive module, and after a preset delay, sends a wiring switching command to the Y-Δ winding switching module to achieve zero-voltage switching of Y / Δ wiring state; Step 5: After the winding switching is completed, delay for a second preset time to avoid the mechanical vibration process that may occur when the drive module switches; Step 6: The control module controls the drive module to re-output the PWM signal, driving the permanent magnet synchronous motor to operate in the switched wiring state.
[0031] In step 2, the first preset time is 500-5000ms.
[0032] In step 3, the PWM method of gradually increasing the duty cycle is as follows: like Figure 6As shown, the duty cycle of the PWM starts from 0 and gradually increases to 100% with a slope of 1%-5% / 100-1000μs, and is turned off after being held for 10-100ms.
[0033] In step 4, a wiring switching command is sent to the Y-Δ winding switching module to achieve zero-voltage switching between Y-connection and Δ-connection states, specifically as follows: When using six single-pole single-throw power relays, first disconnect the three single-pole single-throw power relays corresponding to the current operating state, and after confirming the disconnection feedback signal, close the three relays corresponding to the target state. When two multi-contact power relays are used, the coils of the two multi-contact power relays are driven synchronously. By utilizing the internal mechanical linkage characteristics of the multi-contact power relays, the synchronous action of opening the Y-shaped neutral point and closing the Δ-shaped circuit is achieved.
[0034] In step 5, the second preset time is 20-200ms.
[0035] The above method is applicable to permanent magnet synchronous motors for compressors driven by drive modules with a rated voltage of AC 220V, and supports switching between operating conditions with a maximum line current peak of 30A for Y-connection and a maximum line current peak of 60A for Δ-connection.
[0036] Embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.
[0037] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.
[0038] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.
[0039] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.
[0040] Contents not described in detail in this specification are prior art known to those skilled in the art. It is hereby indicated that the above description is intended to help those skilled in the art understand this invention, but does not limit the scope of protection of this invention. Any equivalent substitutions, modifications, improvements, or simplifications of the above descriptions that do not depart from the essential content of this invention fall within the scope of protection of this invention.
Claims
1. A permanent magnet synchronous motor winding switching control device, characterized in that, include: The system includes a drive module, a Y-Δ winding switching module, a control module, and a current and voltage detection module. The current and voltage detection module is connected to the drive module and the control module. The control module is connected to the drive module and the Y-Δ winding switching module. The drive module is connected to the first end of the permanent magnet synchronous motor winding, and the Y-Δ winding switching module is connected to the first and last ends of the permanent magnet synchronous motor winding. The drive module is used to output frequency- and voltage-adjustable three-phase AC power to the permanent magnet synchronous motor; The control module is used to output control signals to realize the switching action of the drive module and the relay action of the Y-Δ winding switching module; The current and voltage detection module is used to detect the phase current, line current and winding terminal voltage of the permanent magnet synchronous motor. The Y-Δ winding switching module is used to switch between Y-shaped and Δ-shaped wiring states of the motor windings, and the Y-Δ winding switching module adopts any one of the following three topologies: It consists of three single-pole double-throw power relays; It consists of six single-pole single-throw power relays; It consists of two multi-contact power relays.
2. The permanent magnet synchronous motor winding switching control device according to claim 1, characterized in that, The IPM module of the drive module includes three-phase upper bridge arm switching transistors, three-phase lower bridge arm switching transistors, and drive circuitry.
3. The permanent magnet synchronous motor winding switching control device according to claim 1, characterized in that, When the Y-Δ winding switching module uses three single-pole double-throw power relays, the three-phase windings of the permanent magnet synchronous motor are set as U-U', V-V', and W-W'. The common terminal of the three single-pole double-throw relays is connected to the U', V', and W' terminals respectively. The normally closed terminals of the three single-pole double-throw relays are connected together to form a Y-shaped neutral point. The normally open terminals of the three single-pole double-throw relays are connected to the V, W, and U terminals respectively to form a Δ-shaped closed-loop connection.
4. The permanent magnet synchronous motor winding switching control device according to claim 1, characterized in that, When the Y-Δ winding switching module uses six single-pole single-throw power relays, the three-phase windings of the permanent magnet synchronous motor are set as U-U', V-V', and W-W'. The six single-pole single-throw relays are divided into two groups: a first group and a second group. One end of the first group of single-pole single-throw relays is connected to the U', V', and W' ends of the motor windings, respectively. The other ends of the first group of single-pole single-throw relays are connected together to form a Y-shaped neutral point. The second group of single-pole single-throw relays are connected in series between the U' and V ends, the V' and W ends, and the W' and U ends of the motor windings, respectively, to achieve a Δ-shaped closed-loop connection.
5. The permanent magnet synchronous motor winding switching control device according to claim 1, characterized in that, When the Y-Δ winding switching module uses two multi-contact power relays, the three-phase windings of the permanent magnet synchronous motor are set as U-U', V-V', and W-W'. The two multi-contact power relays are a first multi-contact power relay and a second multi-contact power relay. Each multi-contact power relay includes at least three sets of independent normally open or normally closed contacts, namely three first contacts and a second contact corresponding to the first contacts. The three first contacts of the first multi-contact power relay are respectively connected to the U', V', and W' ends of the motor windings. The three second contacts of the first multi-contact power relay are connected together to form a Y-shaped neutral point. The three sets of contacts of the second multi-contact power relay are respectively connected between the U' end and the V end, the V' end and the W end, and the W' end and the U end to form a Δ-shaped closed-loop connection.
6. The permanent magnet synchronous motor winding switching control device according to claim 1, characterized in that, The rated contact current of the single-pole double-throw power relay, single-pole single-throw power relay, and multi-contact power relay is greater than or equal to twice the peak value of the maximum phase current of the permanent magnet synchronous motor winding, and the contact withstand voltage is greater than or equal to 1.5 times the rated operating voltage of the drive module. The coils of the single-pole double-throw power relay, single-pole single-throw power relay, and multi-contact power relay are driven by DC 5V-DC 24V and connected in reverse parallel with freewheeling diodes.
7. A method for controlling the switching of windings in a permanent magnet synchronous motor, applied to the permanent magnet synchronous motor winding switching control device described in claims 1-6, characterized in that, include: Step 1: The control module determines whether the permanent magnet synchronous motor needs winding switching. If so, it sends a stop command to the drive module. The drive module stops outputting PWM signals and turns off the three-phase upper bridge arm switch and the three-phase lower bridge arm switch. Step 2: The control module delays for a first preset time to decelerate the motor rotor until it comes to a stop. The current and voltage detection module confirms that the motor speed is approaching 0 and the winding terminal voltage is decreasing. Step 3: The control module controls the IPM module of the drive module to keep the three-phase upper bridge arm switch transistors off, and the three-phase lower bridge arm switch transistors are soft-turned on by gradually increasing the duty cycle of the PWM method, so as to realize the soft discharge of the energy stored in the motor winding inductance. During the discharge process, the current detection module limits the maximum current of the lower bridge arm. Step 4: After the discharge is completed, the control module turns off all bridge arm switches of the drive module, and after a preset delay, sends a wiring switching command to the Y-Δ winding switching module to achieve zero-voltage switching of Y / Δ wiring state; Step 5: After the winding switching is completed, delay for a second preset time to avoid the mechanical vibration process that may occur when the drive module switches; Step 6: The control module controls the drive module to re-output the PWM signal, driving the permanent magnet synchronous motor to operate in the switched wiring state.
8. The method for switching control of permanent magnet synchronous motor windings according to claim 7, characterized in that, In step 2, the first preset time is 500-5000ms.
9. The method for switching control of permanent magnet synchronous motor windings according to claim 7, characterized in that, In step 3, the PWM method of gradually increasing the duty cycle is as follows: The PWM duty cycle starts from 0 and gradually increases to 100% with a slope of 1%-5% / 100-1000μs, and is maintained for 10-100ms before being turned off.
10. The method for switching control of permanent magnet synchronous motor windings according to claim 7, characterized in that, In step 4, a wiring switching command is sent to the Y-Δ winding switching module to achieve zero-voltage switching between Y-connection and Δ-connection states, specifically as follows: When using six single-pole single-throw power relays, first disconnect the three single-pole single-throw power relays corresponding to the current operating state, and after confirming the disconnection feedback signal, close the three relays corresponding to the target state. When two multi-contact power relays are used, the coils of the two multi-contact power relays are driven synchronously. By utilizing the internal mechanical linkage characteristics of the multi-contact power relays, the synchronous action of opening the Y-shaped neutral point and closing the Δ-shaped circuit is achieved.