Series winding motor winding phase sequence switching topology system, modulation method and inverter

Abstract

The invention belongs to but is not limited to the technical field of alternating current motors and driving control, and discloses a series winding motor winding phase sequence switching topological system, a modulation method and an inverter, the series winding motor winding phase sequence switching topological system comprises a first bridge arm L1, a second bridge arm L2, a third bridge arm L3, a fourth bridge arm L4 and bipolar diodes TR1, TR2, TR3 and TR4, the four bipolar diodes are turned on or turned off, and the series winding motor winding phase sequence switching topological system is formed. And the phase sequence of the series winding motor can be changed. And then, a corresponding modulation strategy is switched to realize that the three-phase series winding motor uses a torque output topological structure at low speed and heavy load and uses a rotating speed output topological structure at high speed and light load. By means of switching of the topological structure of the series winding motor, the working interval and efficiency of the series winding motor can be optimized so as to adapt to different operation conditions, and the torque-rotating speed operation domain of the three-phase series winding motor is effectively expanded.

Description

Technical Field

[0001] The present invention belongs to but is not limited to the field of AC motor and drive control technology, and in particular relates to a series winding motor winding phase sequence switching topology system, a modulation method and an inverter. Background Art

[0002] The motor drive topology widely used in industry at present is the three-phase star connection topology, which has the advantages of high stability and low loss. However, this topology can only output 57.7% bus voltage utilization in the linear modulation area, which seriously limits the motor speed operating range. In addition, the star connection topology has only two current degrees of freedom and its fault tolerance is poor. The series winding motor topology can achieve 100% bus voltage utilization by connecting the beginning and end of each phase winding sequence in series, effectively expanding the motor speed operating range. In addition, this topology can provide three current control degrees of freedom and has higher fault tolerance.

[0003] However, when using this topology drive, due to the middle bridge arm of the inverter L 2 , L 3 The greater current stress will limit the overall torque output capacity of the drive system. In order to reduce the bridge arm stress and increase the torque output, the B Phase winding sequence, B Phase winding input terminal connected to bridge arm L 3 , B Phase winding output terminal connected to bridge arm L 2 , at this time the middle bridge arm L 2 and L 3 The current stress of the motor will decrease and be equal to the current stress of the bridge arms on both sides, so its torque output capacity can be improved. However, this topology reduces the motor bus voltage utilization rate and limits its high speed application.

[0004] In summary, a single output mode cannot maximize the use of the working range of the series-wound motor. In addition, the existing technology does not propose a suitable modulation strategy to adapt to different output modes of the series-wound motor. Summary of the invention

[0005] In view of the problems existing in the prior art, the present invention provides a series-winding motor winding phase sequence switching topology system, a modulation method and an inverter.

[0006] The present invention is implemented as follows: a series winding motor winding phase sequence switching topology system is composed of four bridge arms, namely bridge arm L 1 ,L 2 , L 3 , L 4 , and four bipolar diodes: TR 1 , TR 2 , TR 3 , TR 4 ; Each bridge arm is composed of an upper and a lower power switch device; the DC bus voltage source is connected to the upper node of each upper power switch device, and the power ground is connected to the lower node of the lower power switch device; Three-phase series winding motor A , B , C three-phase stator winding. A The input end of the phase winding is connected to the bridge arm L 1 , A The output end of the phase winding is connected to the bridge arm L 2 ; B The input end of the phase winding is connected to the bridge arm L 2 , B The output end of the phase winding is connected to the bridge arm L 3 ; Bipolar diode TR 1 , TR 3 connect B Phase winding input terminal, TR 2 , TR 4 connect B Phase winding output terminal; C The input end of the phase winding is connected to the bridge arm L 3 , C The output end of the phase winding is connected to the bridge arm L 4 .

[0007] Another object of the present invention is to provide a modulation method for winding phase sequence switching of a series winding motor winding phase sequence switching topology system, which realizes free switching of speed or torque mode by controlling the conduction or disconnection of four bipolar diodes under working conditions; (1) When the bipolar diode TR 1 and bipolar diodes TR 4 Conductive, bipolar diode TR2 and bipolar diodes TR 3 When shutting down, B The phase winding is connected in positive direction, which can provide high DC voltage utilization but cannot provide large current. It is suitable for the motor to run under high speed and light load conditions, which is the speed mode; (2) When the bipolar diode TR 2 and TR 3 Conductivity, TR 1 and TR 4 When shutting down, B The phase winding is reversed, which can provide large current but cannot provide high DC voltage utilization. It is suitable for the motor to operate under low speed and high torque conditions, which is the torque mode.

[0008] further, TR 1 and TR 4 Should have the same conduction action; TR 2 and TR 3 Have the same conduction action to achieve smooth switching between the two topologies; TR 1 and TR 2 It should have opposite conduction action to ensure that the motor winding is not short-circuited when the bipolar diode is turned on.

[0009] Furthermore, in the speed mode, the drive control is performed through the following steps: In speed mode, the control algorithm is adjusted to speed drive mode; Collect current motor speed n , and set the reference motor speed n* ; The speed loop PI controller is used to calculate the speed deviation control and project the result to dq plane, get the reference current i q * ; set up dq Reference current of the axis i d *、i 0 * is zero; Collect the current of each phase i A , i B , iC , after Clark transformation, the result is projected to α-β-0 Plane, get i α , i β and i 0 ; Will i α , i β After Park transformation, the result is projected to dq-0 plane, get the current dq Plane current i d , i q and i 0 ; The reference current i q * , i d * and i 0 * and current dq-0 Flat i d , i q 、i 0 Get the reference voltage through the PI controller u q * , u d *、u 0 * ; Will u q * , u d *、u 0 * Through Anti-Park, switch to α-β-0 In the plane ， get α-β-0 Reference voltage of the plane u α * , u β *、u 0 * ; Will uα * , u β *、u 0 * Input into the inverter and u α * , u β *、u 0 * Convert to abc In the coordinate system, we get abc Reference voltage in coordinate system u A * , u B * , u C * .

[0010] Bridge arm L 1 The duty cycle is: (1); Bridge arm L 2 The duty cycle is: (2); in, V dc is the DC bus voltage.

[0011] Bridge arm L 3 The duty cycle is: (3); Bridge arm L 4 The duty cycle is: (4); The common mode voltage is injected into the duty cycle of the four bridge arms respectively: (5); The duty cycles of the four bridge arms are: (6); The duty ratios of the four bridge arms are outputted respectively to drive the three-phase series winding motor to operate in the speed mode.

[0012] Further, in torque mode, adjustments are made through the following steps: In torque mode, the control algorithm is adjusted to torque drive mode; Collect current motor speed n , and set the reference motor speed n* ; The speed loop PI controller is used to calculate the speed deviation control and project the result to dq plane, get the reference current i q * ; Setting the reference current i d *、i 0 * is zero; Collect the current of each phase i A , i B , i C , after Clark transformation, the result is projected to α-β-0 Plane, get i α , i β and i 0 ; Will i α , i β After Park transformation, the result is projected to dq-0 plane, get the current dq Plane current i d , i q and i 0 ; Through the reference current i q * , i d * and i 0 * and current dq-0 Flat i d , i q 、i 0 Get the reference voltage through the PI controller u q * , u d *、u0 * ; Will u q * , u d *、u 0 * Obtained by Anti-Park transformation u α * , u β *、u 0 * ; Will u α * , u β *、u 0 * Input into the inverter and u α * , u β *、u 0 * Convert to abc In the coordinate system, we get u A * , u B * , u C * Reference value; Bridge arm L 1 The duty cycle is: (7);

[0013] Bridge arm L 2 The duty cycle is: (8); The bridge arm L 3 The duty cycle is: (9); The bridge arm L 4 The duty cycle is: (10); The zero-sequence voltage is injected into the duty cycle of the four bridge arms respectively: (11); The duty cycles of the four bridge arms are: (12); The duty ratios of the four bridge arms are outputted separately to drive the three-phase series winding motor to operate in torque mode.

[0014] Another object of the present invention is to provide an inverter, comprising the series winding motor winding phase sequence switching topology system.

[0015] In combination with the above technical solutions and the technical problems solved, the advantages and positive effects of the technical solutions to be protected by the present invention are as follows: First, the present invention provides a modulation strategy for switching the phase sequence of the windings of a series-wound motor. After the online topology reconstruction of the series-wound motor is performed, two online switching topologies of the torque output mode and the speed output mode are obtained. Then the present invention provides different modulation strategies suitable for these two topologies, thereby ensuring that the motor stably operates in the torque output mode at low speed and heavy load, and stably operates in the speed output mode at high speed and light load, effectively expanding the torque-speed operating domain of the three-phase series-wound motor, so that the motor can meet the performance requirements under different operating conditions; the proposed corresponding switching modulation algorithm is simple and easy to implement, and can achieve smooth control of different series-wound motor operating modes.

[0016] (1) The technical solution of the present invention fills the technical gap in the industry at home and abroad: Among the various motor drive topologies, the series winding motor topology has shown unique advantages. Compared with the existing star-connected winding motor, the series winding motor has significant advantages such as high DC bus voltage utilization and strong fault tolerance.

[0017] You should know that in application scenarios such as electric vehicles and ships, there are often certain restrictions on the DC bus voltage. For example, in electric vehicles, in order to expand the speed range of the vehicle, the 800V silicon carbide platform has been widely used. These methods increase the charging speed on the one hand and expand the speed operating range on the other hand by increasing the DC bus voltage level. Then, these platforms are all based on star-connected winding motors, and this topology can only utilize 57.7% of the bus voltage utilization rate. The above-mentioned advantages of the series-wound motor just make it highly consistent with the needs of these occasions, can better meet the various requirements in practical applications, and have broad application prospects. However, when using the series winding topology to drive, due to the intermediate bridge arm of the inverter L 2 , L 3The greater current stress will limit the overall torque output capacity of the drive system. In order to reduce the bridge arm stress and increase the torque output, the B Phase winding sequence, B Phase winding input terminal connected to bridge arm L 3 , B Phase winding output terminal connected to bridge arm L 2 , at this time the middle bridge arm L 2 and L 3 The current stress of the motor will decrease and be equal to the current stress of the bridge arms on both sides, so its torque output capacity can be improved. However, this topology reduces the motor bus voltage utilization rate and limits its high speed application.

[0018] The existing scheme does not propose a method that can simultaneously meet the wide speed range and heavy-load application mode. In addition, the existing technology does not provide a high-performance modulation switching algorithm for two different drive modes. The present invention discloses a three-phase series winding motor winding phase sequence switching topology, which divides the three-phase series winding motor into two drive modes: speed mode and torque mode. In speed mode, the series winding motor can achieve 100% bus voltage utilization. In torque mode, the winding can be suitable for heavy load conditions. These two topologies can meet the needs of industrial scenarios for wide speed and heavy load applications. By using four bipolar diodes, it is possible to switch directly between these two drive modes. However, considering that the prior art does not provide a simple, intuitive and effective drive algorithm for these two drive topologies, the present invention provides a modulation algorithm for the two drive topologies. The modulation algorithm is based on a carrier comparison method and has the advantages of being simple, intuitive and easy to implement. The technical solution of the present invention can provide a feasible solution for realizing the commercial application of series winding motors.

[0019] Second, the technical problems solved by the technical solution of the present invention in industrial applications.

[0020] 1) Limitations of speed and torque mode switching in existing technologies In traditional three-phase motor control, the motor usually operates with a fixed winding configuration and cannot flexibly switch between speed mode and torque mode.

[0021] Conventional topology structures cannot take into account both high-speed light-load and low-speed high-torque operating conditions at the same time, resulting in the inability to fully optimize system performance, especially poor performance under variable load environments.

[0022] 2) Insufficient flexibility in winding configuration The phase sequence of traditional motor windings is usually fixed, and switching operating modes requires relying on complex external hardware switching devices or multiple inverters, which increases system complexity and cost.

[0023] Hardware switching of windings can easily lead to transient shocks during the switching process, which may damage the life of the motor and increase maintenance costs.

[0024] 3) It is difficult to balance current utilization and energy efficiency When running at high speed, the existing technology cannot fully utilize the DC bus voltage, resulting in energy waste.

[0025] When running at low speeds, the output current is insufficient to meet high torque requirements, limiting the applicability of the equipment under heavy load conditions.

[0026] Significant technical advancements of the present invention: 1) Innovative topology structure to achieve dynamic switching of winding phase sequence The present invention realizes dynamic switching between forward connection and reverse connection of the winding by designing a topological structure including four bridge arms and four bipolar diodes.

[0027] This topology can flexibly adjust the winding configuration of the motor without the need for additional switching devices, thereby achieving free switching between speed mode (high voltage utilization) and torque mode (high current output) in a single system.

[0028] The coordinated turn-on and turn-off of the diodes ensures smooth switching, avoids winding short circuits and transient shocks, and improves system reliability.

[0029] 2) Efficient use of DC bus voltage In speed mode, the utilization rate of the DC bus voltage is significantly improved by connecting the winding in the positive direction, thereby improving the energy efficiency of high-speed operation.

[0030] In torque mode, large current output is provided by reversing the winding to meet the needs of low-speed and heavy-load conditions, expanding the application scenarios of the motor.

[0031] 3) Flexibility of dual-mode operation Combining the control algorithm and topology, the system can dynamically adjust the working mode according to load demand and achieve smooth switching between speed and torque modes.

[0032] This flexibility is particularly suitable for industrial equipment with variable working conditions, such as cranes, conveyors and wind turbines, significantly improving the adaptability of the equipment.

[0033] 4) Optimize motor performance and life The present invention dynamically adjusts the conduction time of the bipolar diode and the bridge arm switch by optimizing the modulation strategy, thereby ensuring that the motor winding will not be subjected to voltage or current shock during switching.

[0034] In both modes, it can provide stable output characteristics, extending the service life of the motor and related electronic components.

[0035] 5) Reduce hardware costs and system complexity This technical solution integrates multiple functions in a single topology structure, reduces the need for external switching devices, and reduces hardware costs.

[0036] A single inverter is used to complete winding phase sequence switching and control, which simplifies system design and reduces development and maintenance costs.

[0037] 6) Enhance industry competitiveness The present invention significantly improves the operating efficiency and flexibility of the motor, solves the bottleneck problem of traditional technology, and meets the requirements of modern industrial equipment for high performance, high efficiency and multi-function.

[0038] The scalability of the technical solution makes it suitable for multiple fields such as industrial automation, transportation equipment, electric vehicles and smart homes, providing strong technical support for industrial applications.

[0039] The present invention solves the problems of low speed and torque mode switching efficiency, insufficient winding flexibility, and motor performance limitations in traditional technologies through innovative winding phase sequence switching topology and modulation strategy. Its significant technical progress is reflected in topological flexibility, improved energy utilization efficiency, hardware simplification, and enhanced system reliability, providing an efficient and reliable solution for multiple scenarios in industrial applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 is a winding sequence switching topology diagram of a series winding motor provided by an embodiment of the present invention; Figure 2 is a topology diagram of a series winding motor in a speed mode provided by an embodiment of the present invention; Figure 3 is a topology diagram of a series winding motor in a torque mode provided by an embodiment of the present invention; Figure 4 It is a control block diagram of a winding sequence topology switching of a series-wound motor provided by an embodiment of the present invention; Figure 5 is a flow chart of an online control method for series winding motor topology switching provided by an embodiment of the present invention; Figure 6 It is a duty cycle simulation waveform diagram of the series winding motor switching from torque mode to speed mode; Figure 7 It is the simulation waveform of bridge arm current stress when the series winding motor switches from torque mode to speed mode; Figure 8 It is the experimental waveform diagram of the torque mode of the series winding motor; Fig. 9It is the experimental waveform diagram of the speed mode of the series winding motor. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0042] The present invention uses four bridge arms ( L 1 , L 2 , L 3 , L 4 ) and four bipolar diodes ( TR 1 , TR 2 , TR 3 , TR 4 ) to build a series winding motor winding phase sequence switching topology system. Each bridge arm consists of two upper and lower power switches. The DC bus voltage source is connected to the upper node of the upper switch device of the bridge arm, and the power ground is connected to the lower node of the lower switch device of the bridge arm. The windings of the three-phase motor are connected in series through the bridge arm: A Phase winding connection bridge arm L 1 and L 2 , B Phase winding connection bridge arm L 2 and L 3 , C Phase winding connection bridge arm L 3 and L 4 . Bipolar diodes (such as TR 1 , TR 4 ) is used to control the phase sequence switching of the winding. Turning on or off the bipolar diode can switch the forward or reverse connection of the winding to achieve dynamic adjustment of the speed mode and torque mode.

[0043] In the speed mode, by turning on the bipolar diode TR 1 and TR 4 (Shutdown TR 2 and TR 3 ),make BThe phase winding is connected in a positive direction. At this time, the motor can obtain high DC voltage utilization, but because the current is limited, it is suitable for high-speed and light-load conditions. The control algorithm adjusts the motor operation to the speed drive mode, collects the current motor speed, compares it with the reference speed, calculates the speed deviation through the speed loop PI controller, and generates dq Then, the reference voltage is generated by the current loop controller and then transformed to abc The reference voltage of the coordinate system. These reference voltages are used to adjust the duty cycle of each bridge arm and drive the motor to achieve speed mode operation.

[0044] In torque mode, by turning on the bipolar diode TR 2 and TR 3 (Shutdown TR 1 and TR 4 ),make B The phase winding is reversed. At this time, the motor can output a large current, but the DC voltage utilization rate is low, which is suitable for low-speed and high-torque conditions. The control algorithm is adjusted to the torque drive mode, the motor speed is collected, the speed deviation is calculated with the reference speed, and the reference current is generated. Similar to the speed mode, after dq The current control and voltage calculation of the plane generate a three-phase reference voltage for driving the motor. When the current is large, the algorithm dynamically adjusts the conduction time of the bipolar diode to ensure smooth switching and avoid winding short circuit.

[0045] The on and off of the bipolar diode needs to be coordinated with the action of the bridge arm power switch device. Specifically, TR 1 and TR 4 They must be turned on or off at the same time to achieve the speed mode; TR 2 and TR 3 must be turned on or off at the same time to achieve torque mode. TR 1 and TR 2 , TR 3 and TR 4 They cannot be turned on at the same time at any time to avoid short circuit of the motor winding. In addition, by dynamically adjusting the conduction state of the diode, the system can achieve seamless switching between the two modes, ensuring stable operation of the motor in speed and torque mode.

[0046] Regardless of speed mode or torque mode, the system converts the three-phase current intoα-β-0 plane, and then get it through Park transformation dq-0 The current loop PI controller generates a corresponding reference voltage in combination with the reference current. The reference voltage adjusts the bridge arm duty cycle through the inverse Park transformation and the inverter to achieve precise control of the three-phase motor winding current and voltage.

[0047] When switching between the two modes, the controller dynamically adjusts the conduction state of the bipolar diode and the duty cycle of the bridge arm by detecting the current speed and load status to ensure a smooth transition during the switching process. Common-mode voltage is introduced in the duty cycle adjustment to optimize the waveform quality and reduce high-frequency interference. At the same time, the switching frequency and conduction time of the bridge arm power switch are accurately calculated to avoid sudden changes in the motor winding current and voltage, further improving the stability and efficiency of the system.

[0048] like Figure 1 As shown, the present invention provides a series winding motor speed-torque winding sequence switching topology system, including a bridge arm L 1 , Bridge Arm L 2 , Bridge Arm L 3 , Bridge Arm L 4 And bipolar diodes TR 1 , TR 2 , TR 3 , TR 4 .

[0049] A The input end of the phase winding is connected to the bridge arm L 1 , A The output end of the phase winding is connected to the bridge arm L 2 ; B The input end of the phase winding is connected to the bridge arm L 2 , TR 1 and TR 3 , B The output end of the phase winding is connected to the bridge arm L 3 , TR 2 and TR 4 ; C The input end of the phase winding is connected to the bridge arm L 3 , CThe output end of the phase winding is connected to the bridge arm L 4 ; like Figure 5 As shown, the present invention provides a modulation method for switching the topology of a series winding motor, which realizes free switching of the speed / torque mode by controlling the on / off of four bipolar diodes.

[0050] In order to achieve smooth switching between the two topologies, TR 1 and TR 4 Should have the same conduction action; TR 2 and TR 3 In addition, to ensure that the motor winding is not short-circuited when the bipolar diode is turned on, TR 1 and TR 2 Should have opposite conduction action.

[0051] When the bipolar diode TR 1 and bipolar diodes TR 4 Conductive, bipolar diode TR 2 and bipolar diodes TR 3 When shutting down, B The phase winding is connected in a positive direction, which can provide high DC voltage utilization but cannot provide large current. Therefore, it is suitable for the motor to run under high speed and light load conditions, which is the speed mode. At this time, the motor winding connection method is as follows Figure 2 As shown; When the bipolar diode TR 2 and bipolar diodes TR 3 Conductive, bipolar diode TR 1 and bipolar diodes TR 4 When shutting down, B The reverse connection of the phase winding can provide large current but cannot provide high DC voltage utilization. Therefore, it is suitable for the motor to operate under low speed and high torque conditions, which is the torque mode. At this time, the motor winding connection sequence is as follows Figure 3 shown.

[0052] The present invention also proposes a CBPWM modulation strategy for the above winding sequence switching, the purpose of which is to achieve a smooth output of the motor performance before and after the topology switching, and the output mode of the motor can be adjusted accordingly as expected after the switching. The modulation strategy includes: When the operating condition is high speed and light load, Figure 4 The modulation controller shown is switched to speed mode; Collect current motor speed n , and set the reference motor speed n* ; The speed loop PI controller is used to calculate the speed deviation control and project the result to dq plane, get the reference current i q * ; Setting the reference current i d *、i 0 * is zero; Collect the current of each phase i A , i B , i C , after Clark transformation, the result is projected to α-β-0 Plane, get i α , i β and i 0 ; Will i α , i β After Park transformation, the result is projected to dq-0 plane, get the current dq Plane current i d , i q and i 0 ; Through the reference current i q * , i d * and i 0 * and current dq-0 Flat i d , i q 、i 0 Get the reference voltage through the PI controller u q* , u d *、u 0 * ; Will u q * , u d *、u 0 * Obtained by Anti-Park transformation u α * , u β *、u 0 * ; Will u α * , u β *、u 0 * Input into the inverter and u α * , u β *、u 0 * Convert to abc In the coordinate system, we get u A * , u B * , u C * Reference value.

[0053] Bridge arm L 1 The duty cycle is: (1); The bridge arm L 2 The duty cycle is: (2); Bridge arm L 3 The duty cycle is: (3); Bridge arm L 4 The duty cycle is: (4); The zero-sequence voltage is injected into the duty cycle of the four bridge arms respectively: (5); The duty cycles of the four bridge arms are: (6); The duty ratios of the four bridge arms are outputted respectively to drive the three-phase series winding motor to operate in the speed mode.

[0054] When the operating condition is low speed and heavy load, Figure 4 The modulation controller shown switches to torque mode; Collect current motor speed n , and set the reference motor speed n* ; The speed loop PI controller is used to calculate the speed deviation control and project the result to dq plane, get the reference current i q * ; Setting the reference current i d *、i 0 * is zero; Collect the current of each phase i A , i B , i C , after Clark transformation, the result is projected to α-β-0 Plane, get i α , i β and i 0 ; Will i α , i β After Park transformation, the result is projected to dq-0 plane, get the current dq Plane current i d , i q and i 0 ; Through the reference current i q * , i d* and i 0 * and current dq-0 Flat i d , i q 、i 0 Get the reference voltage through the PI controller u q * , u d *、u 0 * ; Will u q * , u d *、u 0 * Obtained by Anti-Park transformation u α * , u β *、u 0 * ; Will u α * , u β *、u 0 * Input into the inverter and u α * , u β *、u 0 * Convert to abc In the coordinate system, we get u A * , u B * , u C * Reference value, bridge arm L 1 The duty cycle is: (7); The bridge arm L 2 The duty cycle is: (8); Bridge arm L 3 The duty cycle is: (9); Bridge arm L 4 The duty cycle is: (10); The zero-sequence voltage is injected into the duty cycle of the four bridge arms respectively: (11); The duty cycles of the four bridge arms are: (12); The duty ratios of the four bridge arms are outputted separately to drive the three-phase series winding motor to operate in torque mode.

[0055] In the simulation environment, the duty cycle waveform obtained when the torque mode switches to the speed mode is as follows: Figure 6 As shown, the bridge arm current waveform is as follows Figure 7 As shown. It can be seen from the figure that when the series-wound motor operates in the torque mode, the duty cycle amplitude is higher, indicating that its bus voltage utilization rate is lower; but the currents in each bridge arm are equal and the amplitudes are smaller, indicating that its torque output capacity is stronger. When the series-wound motor operates in the speed mode, the duty cycle amplitude is lower, indicating that its bus voltage utilization rate is higher; but the current stress in the middle bridge arm is higher and the amplitude is larger, indicating that its torque output capacity is weaker. The series-wound motor winding sequence switching topology and its modulation strategy disclosed by the present invention can effectively expand its speed-torque operating domain, and the proposed modulation strategy can smoothly control the motor before and after the topology switching.

[0056] In order to verify the technical solution of the present invention, the solution was verified in detail in the laboratory. A set of 1kW three-phase four-bridge arm series winding motor drag test bench was built in the laboratory. The parameters of the series winding motor are: the number of pole pairs is 4; the resistance is 1.52Ω; d The shaft inductance is 3.77mH; q The shaft inductance is 3.77mH; the zero-sequence inductance is 1.55mH; the rotor flux is 0.129Wb; the third rotor flux harmonic is 0.0059Wb; the rated speed is 2500rpm; the rated torque is 4N·m; and the sampling frequency is 10kHz. The effectiveness of the modulation algorithm proposed in the present invention is verified by the motor dragging experiment. The relevant experimental results are also reflected in the technical solution of the present invention.

[0057] The experimental platform tested the operating performance of the present invention in steady state and dynamic state. The speed was set to 200 rpm and the load was 2 N·m in steady state. The speed obtained wasi dq0 Current, three-phase current, iαβ The experimental waveforms of current, duty cycle and bridge arm current are as follows: Figure 8 and 9 shown.

[0058] The experimental waveform of the speed mode is as follows: Figure 8 As shown. It can be seen that the motor runs at 200rpm, 4N·m, and the DC bus voltage is 50V. It can be seen that in the torque mode, the current values ​​of the four bridge arms are close, and the peak-to-peak value is about 4.3A. The duty cycle is about 0.9pu. The experimental waveform of the speed mode is as follows Fig. 9 As shown, in the speed mode, the duty cycle is relatively small, about 0.6pu, and the peak-to-peak current flowing through the middle bridge arm is about 7.8A, which is greater than the current of the bridge arms on both sides.

[0059] As can be seen from the figure, under a load of 4N·m, in the speed mode, the current flowing through the two middle bridge arms of the inverter is large, and it cannot operate under heavy load conditions. However, its duty cycle is small, which means that this mode can also operate at a higher speed. In the torque mode, the current flowing through the middle bridge arm and the current of the bridge arms on both sides are equal and small in amplitude, which means that this mode can also drag a larger load. However, its duty cycle is large, which means that this mode is difficult to operate at high speeds.

[0060] It should be noted that the embodiments of the present invention can be implemented by hardware, software, or a combination of software and hardware. The hardware part can be implemented using dedicated logic; the software part can be stored in a memory and executed by an appropriate instruction execution system, such as a microprocessor or a dedicated design software. A person of ordinary skill in the art will appreciate that the above-mentioned devices and methods can be implemented using computer executable instructions and / or contained in a processor control code, such as a carrier medium such as a disk, CD or DVD-ROM, a programmable memory such as a read-only memory (firmware), or a data carrier such as an optical or electronic signal carrier. Such code is provided on the carrier medium. The device and its modules of the present invention can be implemented by hardware circuits such as very large-scale integrated circuits or gate arrays, semiconductors such as logic chips, transistors, etc., or programmable hardware devices such as field programmable gate arrays, programmable logic devices, etc., can also be implemented by software executed by various types of processors, and can also be implemented by a combination of the above-mentioned hardware circuits and software, such as firmware.

[0061] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any modifications, equivalent substitutions and improvements made by any technician familiar with the technical field within the technical scope disclosed by the present invention and within the spirit and principle of the present invention should be covered by the protection scope of the present invention.

Claims

1. A series winding motor winding phase sequence switching topology system, characterized in that: It consists of four bridge arms, namely L 1. L 2. L 3. L 4, and four bipolar diodes: TR 1. TR 2. TR 3. TR 4; Each bridge arm is composed of an upper and a lower power switch device; the DC bus voltage source is connected to the upper node of each upper power switch device, and the power ground is connected to the lower node of the lower power switch device; A The input end of the phase winding is connected to the bridge arm L 1, A The output end of the phase winding is connected to the bridge arm L 2; B The input end of the phase winding is connected to the bridge arm L 2, B The output end of the phase winding is connected to the bridge arm L 3. Bipolar diode TR 1. TR 3. Connect B Phase winding input terminal, TR 2. TR 4Connect B Phase winding output terminal; C The input end of the phase winding is connected to the bridge arm L 3. C The output end of the phase winding is connected to the bridge arm L 4.

2. The modulation method for phase sequence switching of series winding motor windings of the series winding motor phase sequence switching topology system according to claim 1 is characterized in that: In working condition, the free switching of speed or torque mode is realized by controlling the conduction or cut-off of four bipolar diodes; (1) When the bipolar diode TR 1 and bipolar diode TR 4 conduction, bipolar diode TR 2 and bipolar diodes TR 3 When shutting down, B The phase winding is connected in positive direction, which can provide high DC voltage utilization but cannot provide large current. It is suitable for the motor to run under high speed and light load conditions, which is the speed mode; (2) When the bipolar diode TR 2 and TR 3 conduction, TR 1 and TR 4 When shutting down, B The phase winding is reversed, which can provide large current but cannot provide high DC voltage utilization. It is suitable for the motor to operate under low speed and high torque conditions, which is the torque mode.

3. The modulation method for switching the phase sequence of windings of a series-wound motor according to claim 2, characterized in that: TR 1 and TR 4 should have the same conduction action; TR 2 and TR 3. Have the same conduction action to achieve smooth switching between the two topologies; TR 1 and TR 2 should have opposite conduction action to ensure that the motor winding is not short-circuited when the bipolar diode is turned on.

4. The modulation method for switching the phase sequence of windings of a series-wound motor according to claim 2, characterized in that: In speed mode, drive control is performed through the following steps: In the speed mode, the controller is adjusted to the speed drive mode; Collect current motor speed n , and set the reference motor speed n* ; The speed loop PI controller is used to calculate the speed deviation control and project the result to dq plane, get the reference current i q * ; Setting the reference current i d *、i 0 * is zero; Collect the current of each phase i A , i B , i C , after Clark transformation, the result is projected to α-β-0 Plane, get i α , i β and i 0 ; Will i α , i β After Park transformation, the result is projected to dq-0 plane, get the current dq Plane current i d , i q and i 0 ; Through the reference current i q * , i d * and i 0 * and current dq-0 Flat i d , i q 、i 0 Get the reference voltage through the PI controller u q * , u d *、u 0 * ; Will u q * , u d *、u 0 * Obtained by Anti-Park transformation u α * , u β *、u 0 * ; Will u α * , u β *、u 0 * Input into the inverter and u α * , u β *、u 0 * Convert to abc In the coordinate system, we get u A * , u B * , u C * Reference value, bridge arm L The duty cycle of 1 is: ； The bridge arm L The duty cycle of 2 is: ； Bridge arm L The duty cycle of 3 is: ； Bridge arm L The duty cycle of 4 is: ； The zero-sequence voltage is injected into the duty cycle of the four bridge arms respectively: ； The duty cycles of the four bridge arms are: ； The duty ratios of the four bridge arms are outputted respectively to drive the three-phase series winding motor to operate in the speed mode.

5. The modulation method for phase sequence switching of series winding motor windings as claimed in claim 2, characterized in that: In torque mode, adjust by following the steps below: In the torque mode, the controller is adjusted to the torque drive mode; Collect current motor speed n , and set the reference motor speed n* ; The speed loop PI controller is used to calculate the speed deviation control and project the result to dq plane, get the reference current i q * ; Setting the reference current i d *、i 0 * is zero; Collect the current of each phase i A , i B , i C , after Clark transformation, the result is projected to α-β-0 Plane, get i α , i β and i 0 ; Will i α , i β After Park transformation, the result is projected to dq-0 plane, get the current dq Plane current i d , i q and i 0 ; Through the reference current i q * , i d * and i 0 * and current dq-0 Flat i d , i q 、i 0 Get the reference voltage through the PI controller u q * , u d *、u 0 * ; Will u q * , u d *、u 0 * Obtained by Anti-Park transformation u α * , u β *、u 0 * ; Will u α * , u β *、u 0 * Input into the inverter and u α * , u β *、u 0 * Convert to abc In the coordinate system, we get u A * , u B * , u C * Reference value, bridge arm L The duty cycle of 1 is: ； The bridge arm L The duty cycle of 2 is: ； The bridge arm L The duty cycle of 3 is: ； The bridge arm L The duty cycle of 4 is: ； The zero-sequence voltage is injected into the duty cycle of the four bridge arms respectively: ； The duty cycles of the four bridge arms are: ； The duty ratios of the four bridge arms are outputted separately to drive the three-phase series winding motor to operate in torque mode.

6. An inverter, characterized in that: It comprises the series winding motor winding phase sequence switching topology system as claimed in claim 1.

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