Variable topology motor driver and flexible variable topology switching control method thereof

Abstract

The application belongs to the field of AC motor driving, and particularly discloses a variable topology motor driver and a flexible variable topology switching control method thereof, which comprises power switch bridge arms L1, L2, L3 and L4, and single-pole double-throw switching switches K1, K2 and K3; the single-pole double-throw switching switches comprise a movable end and a fixed end X and Y; the left node of an A-phase winding is connected to the output node of L1, and the right node is connected to the movable end of K1; the left node of a B-phase winding is connected to the output node of L2 and the fixed end X of K1, and the right node is connected to the fixed end Y of K1 and the movable end of K2; the left node of a C-phase winding is connected to the output node of L3 and the fixed end X of K2, and the right node is connected to the fixed end Y of K2 and the fixed end X of K3; the movable end of K3 is connected to L4, and the fixed end Y is connected to L1. The circuit structure of the application maximally utilizes the capacity of the bridge arms, reduces the number of switches, and avoids the short circuit of the bridge arms caused by the simultaneous conduction of the switches.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of AC motor drive, more particularly, to a variable topology motor drive and a flexible variable topology switching control method thereof. BACKGROUND

[0002] Currently, the complex changing environment of emerging application scenarios such as new energy vehicles, industrial robots and numerical control machine tools requires motor drive systems to have a wide efficient operation range. However, due to the performance limitations of the three-phase half-bridge topology structure, the traditional motor drive system cannot adapt to a wide range of speed and torque changes. To solve this problem, patent CN110707989A discloses an inverter with a three-phase half-bridge-series winding topology switching and a switching method thereof. The switching circuit structure designed by the patent can realize the switching of three modes of inverter topology and the expansion of the motor operating range. The patent utilizes the current zero-crossing turn-off characteristics of bidirectional transistors to achieve flexible transition of the topology structure. However, the switching circuit and method used in the patent have three problems: first, during the switching process to the high-speed topology, the DC voltage utilization rate may decrease, which may cause topology switching failure; second, in the low-speed topology, one bridge arm is idle and not used, which does not fully utilize the power device capacity; third, the scheme requires four bidirectional transistors, and the constant on-state voltage drop of semiconductors is large, which may reduce the efficiency of the drive system during normal operation.

[0003] Therefore, patent CN112532144A discloses a multi-modal flexible switching motor drive and topology switching control method, which can realize the switching of four topologies, expand the motor operating range, and improve the control freedom and fault tolerance of the drive. The patent solves the first problem of patent CN110707989A, ensuring that the DC voltage utilization rate does not decrease during the switching process, but problems two and three still exist.

[0004] Patent CN115102458A discloses a star-delta flexible switching motor drive, drive system and control method, which can realize flexible switching of star and delta topology structures and expand the motor operating range. The patent solves the second problem of patent CN110707989A, but problems one and three still exist due to insufficient control freedom and the need for six switching switches. In addition, the delta topology has the problem of uncontrollable zero sequence circulating current, which increases the operating loss, torque ripple and demagnetization risk at high speed.

[0005] It can be seen that the current topology switching circuit still has some defects, and cannot maximize the use of power device capacity and improve the operation efficiency while ensuring the switching effect. Therefore, in view of the defects of the existing switching technology, a new variable topology motor driver and a flexible variable topology switching strategy are needed, which can improve the above three problems. SUMMARY

[0006] In view of the above defects or improvement needs of the prior art, the present application provides a variable topology motor driver and a flexible variable topology switching control method, which aims to maximize the use of power device capacity and improve the operation efficiency while ensuring the switching effect.

[0007] To achieve the above-mentioned purpose, according to the first aspect of the present application, a variable topology motor driver is provided, which comprises four power switch bridge arms L1, L2, L3 and L4, and three single-pole double-throw switching switches K1, K2 and K3; each single-pole double-throw switching switch comprises a moving terminal M and two fixed terminals X and Y.

[0008] The left node of the motor A-phase winding is connected to the output node of the bridge arm L1, and the right node of the A-phase winding is connected to the moving terminal of the switching switch K1.

[0009] The left node of the motor B-phase winding is connected to the output node of the bridge arm L2 and the fixed terminal X of the switching switch K1, and the right node of the B-phase winding is connected to the fixed terminal Y of the switching switch K1 and the moving terminal of the switching switch K2.

[0010] The left node of the motor C-phase winding is connected to the output node of the bridge arm L3 and the fixed terminal X of the switching switch K2, and the right node of the C-phase winding is connected to the fixed terminal Y of the switching switch K2 and the fixed terminal X of the switching switch K3.

[0011] The moving terminal of the switching switch K3 is connected to the bridge arm L4, and the fixed terminal Y is connected to the bridge arm L1.

[0012] As a further preferred, the output node of the bridge arm is specifically: each bridge arm comprises an upper bridge arm power switch device and a lower bridge arm power switch device, wherein the upper node of the upper bridge arm power switch device is connected to the DC bus voltage, the lower node of the lower bridge arm power switch device is connected to the power supply ground, and the lower node of the upper bridge arm power switch device and the upper node of the lower bridge arm power switch device are connected as the output node of the bridge arm.

[0013] As a further preferred, the power switch device in the bridge arm is a current fully controlled switch.

[0014] As a further preferred, the power switch device in the bridge arm is a MOSFET or an IGBT with a reverse-parallel diode.

[0015] As a further preferred, the single-pole double-throw switch is a mechanical switch or a power switch composed of semiconductor devices.

[0016] According to a second aspect of the present application, there is provided a variable topology motor driver, comprising four power switch bridge arms L1, L2, L3, L4, and two single-pole double-throw switching switches K1, K2; each single-pole double-throw switching switch comprises one moving terminal M and two stationary terminals X, Y;

[0017] The left node of the motor A-phase winding is connected to the output node of the bridge arm L1, and the right node of the motor A-phase winding is connected to the moving terminal M of the switching switch K1;

[0018] The left node of the motor B-phase winding is connected to the output node of the bridge arm L2 and the stationary terminal X of the switching switch K1, and the right node of the motor B-phase winding is connected to the stationary terminal Y of the switching switch K1 and the moving terminal M of the switching switch K2;

[0019] The left node of the motor C-phase winding is connected to the output node of the bridge arm L3 and the stationary terminal X of the switching switch K2, and the right node of the motor C-phase winding is connected to the stationary terminal Y of the switching switch K2 and the output node of the bridge arm L4.

[0020] According to a third aspect of the present application, there is provided a flexible variable topology switching control method, which is implemented based on the above-mentioned variable topology motor driver, and the variable topology motor driver has four topology structures: a three-phase half-bridge topology structure, referred to as A topology; a three-phase four-bridge-arm topology structure, referred to as B topology; a half-six-phase four-bridge-arm topology structure, referred to as C topology; and a three-phase series winding topology structure, referred to as D topology.

[0021] Switching from the A topology to the B topology comprises the steps of: closing the L4 drive signal; switching K3 to a high-resistance state, and changing the voltage modulation algorithm from the A topology to the B topology; switching K3 to an X conduction state, and opening the L4 drive signal, so as to switch to the B topology;

[0022] Switching from the B topology to the C topology comprises the steps of: controlling the motor zero-axis current to be 0.5 times the C-phase current, so as to reduce the current in K2 to zero; generating a zero-axis voltage lookup table, and implementing zero-axis current open-loop operation based on feedforward zero-axis voltage injection; switching K2 to a high-resistance state, and changing the voltage modulation algorithm from the B topology to the C topology; switching K2 to an X conduction state; closing the feedforward zero-axis voltage injection, and opening the zero-axis current closed-loop control, so as to control the motor zero-axis current to be zero, and thus switch to the C topology;

[0023] Switching from C topology to D topology, comprising the steps of: controlling the motor zero-axis current to be negative A-phase current, so that the current in K1 is reduced to zero; generating a zero-axis voltage lookup table, and realizing zero-axis current open-loop operation based on feedforward zero-axis voltage injection; switching K1 to high resistance state, and changing the voltage modulation algorithm from C topology to D topology; switching K1 to X conduction state; turning off the feedforward zero-axis voltage injection, and turning on the zero-axis current closed-loop control to control the motor zero-axis current to be zero, so as to switch to D topology.

[0024] According to a fourth aspect of the present application, a flexible variable topology switching control system is provided, comprising a computer readable storage medium and a processor, the computer readable storage medium is used to store executable instructions; the processor is used to read the executable instructions stored in the computer readable storage medium, and execute the above flexible variable topology switching control method.

[0025] Overall, compared with the prior art, the above technical solutions conceived by the present application mainly have the following technical advantages:

[0026] 1. The novel driver circuit structure proposed by the present application maximizes the capacity of the power switch bridge arm, reduces the number of switching switches, and thus reduces the overall cost and volume of the driving system. At the same time, based on the design of the structure and the single-pole double-throw switch, the bridge arm short circuit fault caused by the simultaneous conduction of the switching switch is avoided, and the reliability of the motor driver is ensured.

[0027] 2. The novel motor driver circuit structure of the switchable topology proposed by the present application can adopt the corresponding suitable topology structure under different motor operating conditions, realize the expansion of the motor working interval, and improve the control freedom and fault tolerance capability.

[0028] 3. The present application also designs a simplified version of the motor driver circuit structure, which saves the use of one switching switch, and at the same time, by controlling the L4 driving signal to open / close, it also has four switchable topology structures.

[0029] 4. The flexible switching method proposed by the present application makes the topology switching process not affect the mechanical motion such as motor angle, speed and torque, and also avoids the voltage and current impact on the switching switch during switching transient, so that the topology switching operation can be quickly and repeatedly performed while ensuring the reliability of the switching switch and the stability of the load mechanical motion, meeting the demand of complex and rapidly changing operating conditions. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 The figure is a variable topology motor driver circuit structure diagram of the embodiment of the present application.

[0031] Figure 2Fig. 1 is a structural diagram of a variable topology motor driver in four topological modes according to an embodiment of the present application, wherein (a) is a structural diagram of the motor driver in a three-phase half-bridge topology (A topology), (b) is a structural diagram of the motor driver in a three-phase four-leg topology (B topology), (c) is a structural diagram of the motor driver in a half six-phase four-leg topology (C topology), and (d) is a structural diagram of the motor driver in a three-phase series winding topology (D topology);

[0032] Figure 3 Fig. 2 is a mode switching flowchart of a flexible variable topology switching control method according to an embodiment of the present application, wherein (a) is a flowchart of A topology to B topology switching, (b) is a flowchart of B topology to C topology switching, and (c) is a flowchart of C topology to D topology switching;

[0033] Figure 4 Fig. 3 is a motor speed, torque, voltage and current test waveforms when the variable topology motor driver switches topologies according to an embodiment of the present application;

[0034] Figure 5 Fig. 4 is a structural diagram of a simplified version of a variable topology motor driver circuit according to another embodiment of the present application. DETAILED DESCRIPTION

[0035] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application 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 only used to explain the present application and should not be used to limit the present application. In addition, the technical features involved in the various embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0036] An embodiment of the present application provides a variable topology motor driver, as shown in Figure 1 which includes four power switch legs for composing a topology of the motor driver: a first leg L1, a second leg L2, a third leg L3, and a fourth leg L4, and three single-pole double-throw switching switches for composing a switching circuit: a first switching switch K1, a second switching switch K2, and a third switching switch K3.

[0037] Each leg contains an upper leg power switch device and a lower leg power switch device, the upper node of the upper leg power switch device of each leg is connected to a DC bus voltage, the lower node of the lower leg power switch device is connected to a power supply ground, the lower node of the upper leg power switch device is connected to the upper node of the lower leg power switch device, serving as an output node of the leg.

[0038] The three single-pole double-throw switches that make up the switching circuit are used to switch the topology of the motor driver. Each single-pole double-throw switch contains a moving terminal M and two stationary terminals X and Y. The moving terminal M has three output states: X on state, Y on state, and high impedance state.

[0039] Specifically, the power switching devices are current-controlled switches, such as MOSFETs or IGBTs with anti-parallel diodes; single-pole double-throw switches can be mechanical switches such as relays or contactors, or power switches composed of semiconductor devices.

[0040] The specific connection method between the three-phase windings of the motor and the motor driver circuit structure is as follows:

[0041] The left node of phase A winding is connected to the output node of bridge arm L1, and the right node of phase A winding is connected to the moving end of switch K1.

[0042] The left node of the B-phase winding is connected to the output node of bridge arm L2 and the stationary terminal X of switch K1, and the right node of the B-phase winding is connected to the stationary terminal Y of switch K1 and the moving terminal of switch K2.

[0043] The left node of the C-phase winding is connected to the output node of bridge arm L3 and the stationary terminal X of switch K2, and the right node of the C-phase winding is connected to the stationary terminal Y of switch K2 and the stationary terminal X of switch K3.

[0044] The moving end of the switch K3 is connected to bridge arm L4, and the stationary end Y is connected to bridge arm L1.

[0045] like Figure 2 As shown in (a), when K1, K2, and K3 are all in the Y-conducting state, the motor driver is in a three-phase half-bridge topology, called the A-topology. At this time, the DC voltage utilization rate of the system during normal operation is 58%, and it does not have zero-axis current control capability. Bridge arms L2 and L3 bear the phase current, and L1 and L4 output nodes are connected in parallel to jointly bear the phase current.

[0046] like Figure 2 As shown in (b), when K1 and K2 are in the Y-conducting state and K3 is in the X-conducting state, the motor driver is in a three-phase four-arm bridge topology, called the B topology. At this time, the DC voltage utilization rate of the system is 58% during normal operation, and it has zero-axis current control capability. The bridge arms L1, L2 and L3 bear the phase current, while L4 does not bear the current.

[0047] like Figure 2 As shown in (c), when K1 is in the Y-conducting state and K2 and K3 are in the X-conducting state, the motor driver is in a half-six-phase four-bridge-arm topology, called the C-topology. At this time, the DC voltage utilization rate of the system is 58% during normal operation, and it has zero-axis current control capability. Bridge arms L1, L2 and L4 bear the phase current, and L3 bears twice the phase current.

[0048] As Figure 2 As shown in Fig. 1 (d), when K1, K2, K3 are all in X-on state, the motor driver is in three-phase series winding topology, which is called D topology. At this time, the utilization rate of the direct current voltage for normal operation of the system is 100%, and the bridge arms L2 and L3 bear the line current, and L1 and L4 bear the phase current.

[0049] It can be seen that by changing the state of only one switching switch each time, the four topologies A, B, C and D can be converted into each other in turn, and this feature provides the basis for online switching of the driver structure during motor operation. Through online switching of the topology, the motor driver can meet the different operating condition requirements of the motor, thereby adaptively expanding the motor operating interval, improving the operating efficiency, and providing the ability of fault-tolerant operation.

[0050] Based on the above variable topology motor driver, the present application proposes a flexible variable topology switching method, and the purpose of the switching method is to realize the online mutual switching of the four topologies of the driver. The following describes the flexible variable topology switching method by taking the forward order switching of the topologies as an example. For reverse order switching of the topologies, only the steps need to be operated in reverse.

[0051] As Figure 3 As shown in Fig. 1 (a), for switching from A topology to B topology, the following steps are included: ① closing the L4 drive signal; ② switching K3 to high resistance state, and changing the voltage modulation algorithm from A topology to B topology; ③ switching K3 to X-on state, and opening the L4 drive signal, thereby switching to B topology.

[0052] As Figure 3 As shown in Fig. 1 (b), for switching from B topology to C topology, the following steps are included: ① controlling the motor zero-axis current to be 0.5 times the C-phase current, so that the current in K2 is reduced to zero; ② generating a zero-axis voltage lookup table, and realizing open-loop operation of the zero-axis current based on the feedforward zero-axis voltage injection; ③ switching K2 to high resistance state, and changing the voltage modulation algorithm from B topology to C topology; ④ switching K2 to X-on state; ⑤ closing the feedforward zero-axis voltage injection, and opening the zero-axis current closed-loop control, and controlling the motor zero-axis current to be zero, thereby switching to C topology.

[0053] As Figure 3 As shown in Fig. 1 (c), for switching from C topology to D topology, the following steps are included: ① controlling the motor zero-axis current to be negative A-phase current, so that the current in K1 is reduced to zero; ② generating a zero-axis voltage lookup table, and realizing open-loop operation of the zero-axis current based on the feedforward zero-axis voltage injection; ③ switching K1 to high resistance state, and changing the voltage modulation algorithm from C topology to D topology; ④ switching K1 to X-on state; ⑤ closing the feedforward zero-axis voltage injection, and opening the zero-axis current closed-loop control, and controlling the motor zero-axis current to be zero, thereby switching to D topology.

[0054] As Figure 4 shown, based on the flexible variable topology switching method, the topology switching process does not affect the mechanical motion such as motor rotation angle, rotation speed and torque, and avoids the voltage and current impact of switching transient on the switching switch, thereby ensuring the flexibility and reliability of system operation.

[0055] Another embodiment of the present application provides a simplified variable topology motor driver, as Figure 5 shown, which includes four power switch bridge arms for composing the topology of the motor driver: a first bridge arm L1, a second bridge arm L2, a third bridge arm L3, a fourth bridge arm L4, and two single-pole double-throw switching switches for composing the switching circuit: a first switching switch K1, a second switching switch K2; the connection mode is as follows:

[0056] The left node of the A-phase winding is connected to the output node of the bridge arm L1, and the right node of the A-phase winding is connected to the movable terminal of the switching switch K1;

[0057] The left node of the B-phase winding is connected to the output node of the bridge arm L2 and the stationary terminal X of the switching switch K1, and the right node of the B-phase winding is connected to the stationary terminal Y of the switching switch K1 and the movable terminal of the switching switch K2;

[0058] The left node of the C-phase winding is connected to the output node of the bridge arm L3 and the stationary terminal X of the switching switch K2, and the right node of the C-phase winding is connected to the stationary terminal Y of the switching switch K2 and the output node of the bridge arm L4.

[0059] In the case of the L4 drive signal being turned on, the connection mode of the simplified circuit structure is equivalent to fixing the movable terminal of the K3 switching switch of the aforementioned variable topology motor driver circuit structure to the X on state; and in the case of the L4 drive signal being turned off, it is equivalent to fixing the movable terminal of the K3 switching switch to the Y on state, at which time the driver circuit is in A topology structure; other topology structures are similar to the aforementioned embodiment, and will not be described here.

[0060] The simplified variable topology motor driver can save the use of one switching switch; compared with the simplified version, the aforementioned embodiment has the switching switch K3, and the bridge arm L1 and the bridge arm L4 can be combined, thereby enhancing the current output capability and improving the torque output capability.

[0061] Those skilled in the art will readily understand that the above description is only the preferred embodiment of the present application, and is not intended to limit the present application, and any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A variable topology motor driver, characterized in that, It includes four power switch bridge arms L1, L2, L3, and L4, and three single-pole double-throw (SPDT) switches K1, K2, and K3; each SPDT switch includes one moving terminal M and two stationary terminals X and Y. The left node of the motor's A-phase winding is connected to the output node of bridge arm L1, and the right node of the A-phase winding is connected to the moving end of the switching switch K1. The left node of the B-phase winding of the motor is connected to the output node of the bridge arm L2 and the stationary terminal X of the switch K1, and the right node of the B-phase winding is connected to the stationary terminal Y of the switch K1 and the moving terminal of the switch K2. The left node of the C-phase winding of the motor is connected to the output node of the bridge arm L3 and the stationary terminal X of the switch K2, and the right node of the C-phase winding is connected to the stationary terminal Y of the switch K2 and the stationary terminal X of the switch K3. The moving end of the switch K3 is connected to bridge arm L4, and the stationary end Y is connected to bridge arm L1.

2. The variable topology motor driver as described in claim 1, characterized in that, The output node of the bridge arm is specifically as follows: each bridge arm includes an upper bridge arm power switch device and a lower bridge arm power switch device. The upper node of the upper bridge arm power switch device is connected to the DC bus voltage, and the lower node of the lower bridge arm power switch device is connected to the power supply ground. The lower node of the upper bridge arm power switch device is connected to the upper node of the lower bridge arm power switch device, which serves as the output node of the bridge arm.

3. The variable topology motor driver as described in claim 2, characterized in that, The power switching devices in the bridge arm are current-controlled switches.

4. The variable topology motor driver as described in claim 3, characterized in that, The power switching devices in the bridge arm are MOSFETs or IGBTs with anti-parallel diodes.

5. The variable topology motor driver as described in any one of claims 1-4, characterized in that, A single-pole double-throw switch is either a mechanical switch or a power switch composed of semiconductor devices.

6. A variable topology motor driver, characterized in that, It includes four power switch bridge arms L1, L2, L3, and L4, and two single-pole double-throw (SPDT) switches K1 and K2; each SPDT switch includes one moving terminal M and two stationary terminals X and Y. The left node of the motor's A-phase winding is connected to the output node of bridge arm L1, and the right node of the A-phase winding is connected to the moving end of the switching switch K1. The left node of the B-phase winding of the motor is connected to the output node of the bridge arm L2 and the stationary terminal X of the switch K1, and the right node of the B-phase winding is connected to the stationary terminal Y of the switch K1 and the moving terminal of the switch K2. The left node of the C-phase winding of the motor is connected to the output node of bridge arm L3 and the stationary terminal X of switch K2, and the right node of the C-phase winding is connected to the stationary terminal Y of switch K2 and the output node of bridge arm L4.

7. A flexible topology switching control method, characterized in that, Based on the variable topology motor driver as described in any one of claims 1-5, the variable topology motor driver has four topologies: a three-phase half-bridge topology, referred to as topology A; a three-phase four-arm topology, referred to as topology B; a half-six-phase four-arm topology, referred to as topology C; and a three-phase series winding topology, referred to as topology D. Switching from topology A to topology B involves the following steps: turning off the L4 drive signal; switching K3 to a high-impedance state to change the voltage modulation algorithm from topology A to topology B; and switching K3 to the X-on state to turn on the L4 drive signal, thereby switching to topology B. Switching from topology B to topology C includes the following steps: controlling the zero-axis current of the motor to be 0.5 times the C-phase current, so that the current in K2 drops to zero; Generate a zero-axis voltage lookup table and implement open-loop operation of zero-axis current based on feedforward zero-axis voltage injection; switch K2 to high-impedance state and change the voltage modulation algorithm from B topology to C topology; switch K2 to X conduction state; Turn off feedforward zero-axis voltage injection, turn on zero-axis current closed-loop control, control the motor zero-axis current to zero, and thus switch to C topology; Switching from topology C to topology D includes the following steps: controlling the zero-axis current of the motor to be a negative A-phase current, so that the current in K1 drops to zero; Generate a zero-axis voltage lookup table and implement open-loop operation of zero-axis current based on feedforward zero-axis voltage injection; Switch K1 to high impedance state and change the voltage modulation algorithm from C topology to D topology; Switch K1 to the X-conducting state; Turn off feedforward zero-axis voltage injection, enable zero-axis current closed-loop control, control the motor zero-axis current to zero, and thus switch to D topology.

8. A flexible variable topology switching control system, characterized in that, The device includes a computer-readable storage medium and a processor, wherein the computer-readable storage medium is used to store executable instructions; and the processor is used to read the executable instructions stored in the computer-readable storage medium and execute the flexible topology switching control method as described in claim 7.

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