CN110061678B - An integrated system for driving and charging of electric excitation doubly salient motor - Google Patents

Abstract

The invention discloses an integrated system for driving and charging an electric excitation double salient motor and a method thereof. The system comprises a battery, first to sixth switch tubes, a first switch, a double salient motor, a DC filter capacitor, and a three-phase bridge. inverter, EMI filter and second switch. The invention utilizes the integration of the split excitation winding of the doubly salient motor and the inductance of the DC/DC converter, and combines the excitation control circuit and the system booster circuit of the electric excitation doubly salient motor to reduce the volume and weight of the system and make it The structure is more compact and the loss is reduced. Combined with the driving and charging control methods, it has the characteristics of high grid-side power factor in charging mode and small motor output torque ripple in driving mode, giving full play to the high reliability of the electric excitation doubly salient motor system. , The advantages of wide speed range, high efficiency and high fault tolerance.

Description

An integrated system for driving and charging of electric excitation doubly salient motor

technical field

The invention relates to the field of motor systems and control, in particular to an integrated system for driving and charging an electric excitation doubly salient motor.

Background technique

With the increasingly serious problems of environmental pollution and energy depletion, the search for new energy sources to replace fossil fuels has become a hot topic of research around the world. Because of the characteristics of energy saving and environmental protection of new energy vehicles, related technologies and industries are developing rapidly. Compared with hybrid vehicles, pure electric vehicles use a single electric energy source, and the internal structure is greatly simplified because there is no mechanical transmission system, and the mechanical loss and noise of the vehicle are also reduced, which is the main development direction of today's new energy vehicles. .

At present, the motors used in electric vehicles include induction motors, permanent magnet synchronous motors and switched reluctance motors, which have their own characteristics and their own applicable occasions. The induction motor has a compact structure, small size, light weight, low torque ripple, low price, and easy maintenance. Even if the inverter is damaged and short-circuited, there will be no back electromotive force, so there is no possibility of sudden braking, but the power The disadvantages of low factor and poor speed regulation performance are the main factors that limit its development. Currently, it is mainly suitable for high-speed and high-power occasions. Some companies represented by Tesla electric vehicles in the United States have adopted new high-efficiency AC asynchronous motor.

In China, permanent magnet synchronous motor is generally used as the main drive motor for electric vehicles. It has a large power factor and high efficiency. Due to the elimination of components such as excitation windings, the structure is greatly simplified and maintenance is convenient. In this case, its magnetic permeability will decline or even demagnetize, so its control is more complicated, and with the increasing demand of rare earth materials, the price of rare earth materials is also rising, and the cost problem will become more and more obvious.

Switched reluctance motor is the latest generation of stepless speed regulation system after frequency conversion speed regulation system and brushless DC motor speed regulation system. It runs, but it has the problem of large output torque fluctuation and noise.

Doubly salient motor is a new type of motor proposed by T.A.Lipo, a famous American motor expert in the 1990s, on the basis of traditional reluctance motors. It can be widely used in the driving and charging integrated system of electric vehicles. Because the motor adds a set of excitation device to the stator (or rotor) of the switched reluctance motor, it has the characteristics of strong anti-interference ability of brushless DC motor, few electrical components, simple structure, low cost and high power factor. However, there is a mutual relationship between the excitation current and the armature current, and the magnitude of the excitation current cannot be directly controlled.

At present, there are usually two ways to charge power batteries on the market, one is an independent charging system, and the other is an on-board charging system. The independent charging system uses the ground DC charging pile to charge the battery, but it takes up a lot of vehicle space and needs to be configured

The ground fast charging device requires a large investment. Although on-board charging is more convenient, fast and flexible, it is slow and takes a long time to charge, and will increase the weight of the car itself. The electric excitation doubly salient motor drive and charging integrated system with split field windings can use the motor's drive system for on-board charging, which reduces the loss of the device and the system. Therefore, a high-power drive and charging integrated system is studied. of great value.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to provide an integrated system for driving and charging of an electric excitation doubly salient motor, aiming at the defects involved in the background technology.

The present invention adopts the following technical solutions for solving the above-mentioned technical problems:

An integrated system for driving and charging an electric excitation doubly salient motor, comprising a battery, first to sixth switch tubes, a first switch, a doubly salient motor, a DC filter capacitor, a three-phase bridge converter, an EMI filter and the second switch;

The excitation winding of the doubly salient motor is cut and divided into two sections of equal length, namely the first excitation winding section and the second excitation winding section, and the three-phase armature winding of the doubly salient motor is an open structure;

The second switch is a three-phase single-pole double-throw switch, one side of which is connected to the external power grid through an EMI filter, and the other side is correspondingly connected to one end of the three-phase armature winding of the doubly salient motor; The other ends of the three-phase armature windings of the pole motor are respectively connected with the midpoints of the three bridge arms of the three-phase bridge converter;

The first to sixth switch tubes, the first switch, the first excitation winding segment, and the second excitation winding segment form a charge-discharge DC/DC converter, wherein the first to third switch tubes are connected in series to form a charge-discharge converter. The input bridge arm of the discharge DC/DC converter, and the fourth to sixth switch tubes are connected in series to form the output bridge arm of the charge and discharge DC/DC converter; one end of the first excitation winding section and the first switch tube, The midpoint of the second switch tube is connected to the midpoint of the second switch tube, and the other end is connected to the midpoint of the fourth switch tube and the fifth switch tube; one end of the second excitation winding section is connected to the second switch tube and the third switch tube. The midpoint is connected, and the other end is connected to the midpoint of the fifth switch tube and the sixth switch tube; the emitter of the third switch tube is connected to the emitter of the sixth switch tube through the first switch;

The first to sixth switch tubes are all anti-parallel diodes;

The two ends of the input bridge arm of the charge and discharge DC/DC converter are connected to the two ends of the battery, and the two ends of the output bridge arm of the charge and discharge DC/DC converter pass through the DC filter capacitor and the three-phase The bridge converters are cascaded.

The invention also provides a control method when the electric excitation doubly salient motor driving and charging integrated system is in a driving mode:

The second switch is closed to short-circuit the ends of the three-phase armature windings of the electric excitation doubly salient motor to form a star connection mode, the EMI filter does not work, and the connection with the power grid is disconnected;

The first switch is closed, the charge-discharge DC/DC converter is switched to Boost converter, and it works in boost mode, the first and second switches are turned on, the third and fourth switches are turned off, and the fifth and sixth switches are turned off. The tube works in PWM chopper mode, and the first excitation winding section and the second excitation winding section are equivalently connected in parallel. At this time, the charging and discharging DC/DC converter increases the voltage of the battery, and drives the motor to run through the latter-stage three-phase bridge converter. .

The invention also provides a control method when the electric excitation doubly salient motor driving and charging integrated system is in the charging mode:

The second switch is turned on, and the ends of the three-phase armature windings of the electric excitation doubly salient motor are connected to the EMI filter, which is equivalent to a three-phase filter inductance;

When the system is in the charging mode, the first switch is turned on, the charging and discharging DC/DC converter is switched to the Buck converter, the fourth switch works in the PWM chopper mode, the sixth switch is turned on, the first, second, The third and fifth switch tubes are turned off, and the first excitation winding section and the second excitation winding section are equivalently connected in reverse series to realize the degaussing function of the electric excitation doubly salient motor. The three-phase bridge converter works in the PWM rectifier mode. The three-phase alternating current is converted into direct current, which is then stepped down by the Buck converter to charge the battery.

Compared with the prior art, the present invention adopts the above technical scheme, and has the following technical effects:

The invention integrates the split excitation winding of the doubly salient motor with the inductance of the DC/DC converter, and combines the excitation control circuit and the system boosting circuit of the electric excitation doubly salient motor together, so that the structure of the vehicle-mounted equipment is more simplified and the reduction of energy consumption is reduced. The cost of ground charging is lighter than that of on-board charging, and the split excitation winding of the doubly salient motor is integrated with the DC/DC converter inductance, which saves energy and reduces costs. At the same time, the doubly salient motor has a high power density. , the advantage of high output torque; the two modes of driving and charging are reliably and effectively switched through the charging and discharging switch K2, which successfully realizes the networking of the electric vehicle and the grid, and realizes the two-way flow of energy between the vehicle and the grid through the grid dispatching.

In the driving mode, the present invention combines the excitation control circuit of the electric excitation doubly salient motor with the system booster circuit, eliminating the need for an additional excitation power source for excitation of the traditional electric excitation doubly salient motor in the driving mode, and solves the problem of solving the problem. Compared with the permanent magnet motor, there is the problem of excitation loss, which reduces the components and the overall loss of the system, and improves the operation efficiency.

In the charging mode, the switching tube arrangement of the DC/DC converter designed by the present invention enables two-section split excitation windings to be connected in reverse series without additional switching switches on the DC/DC converter side, and the armature windings are biconvex after being energized. The positive and negative torque generated by the pole motor can be offset, thereby suppressing the motor torque output and reducing additional losses.

Description of drawings

Figure 1 is a schematic diagram of the structure of an integrated driving and charging system for the multiplexing of the excitation windings of the electric excitation doubly salient motor;

Figure 2 is a schematic diagram of the connection mode of the excitation winding for a 12/10-pole electric excitation doubly salient motor;

Fig. 3 is a schematic diagram of two-segment excitation windings connected in series with 4-segment excitation windings of an electrically-excited doubly salient motor;

FIG. 4 is a schematic diagram of the parallel connection of four sections of excitation windings of an electrically excited doubly salient motor into two sections of excitation windings;

Figure 5 is the current simulation waveform of the split-type excitation winding F1 of the motor during the starting process of the motor in the drive mode;

Fig. 6 is the simulation waveform of the output side voltage of the DC/DC converter during the starting process of the motor in the drive mode;

Fig. 7 is the simulation waveform of the motor speed during the starting process of the motor in the drive mode;

Figure 8 is the simulation waveform of the motor armature current in the charging mode;

Figure 9 shows the simulation waveform of battery charging current in charging mode.

Detailed ways

Below in conjunction with accompanying drawing, the technical scheme of the present invention is described in further detail:

The present invention may be embodied in many different forms and should not be considered limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the drawings, components are exaggerated for clarity.

In order to reduce the volume and weight of the integrated driving and charging system, make the structure more compact and reduce the loss, it has a high power factor on the grid side in the charging mode, and the motor output torque ripple is small in the driving mode, giving full play to the double convexity of the electric excitation. The pole motor system has the advantages of high reliability, wide speed range, high efficiency, and high fault tolerance. 1, this embodiment is an electric excitation doubly salient motor drive and charging integrated system with split field windings, the system mainly includes a battery, a charge and discharge DC/DC converter, a doubly salient pole with split field windings Motors, three-phase bridge converters, EMI filters, and charge-discharge switches.

The electric excitation doubly salient motor adopts a 12/10-pole structure. The arrangement of the armature winding and the field winding is shown in Figure 2. The field winding of the doubly salient motor can also be cut into several sections. When the doubly salient motor is cut to form When the number of segments of the excitation winding is more than two, two segments of the excitation winding can be formed in series or in parallel. As shown in Figure 3, the schematic diagram of four segments of excitation windings connected in series is shown in Figure 4. As shown in Figure 4, the four segments of excitation windings are connected in parallel A schematic diagram of two sections.

The battery is connected to the input end of the charging and discharging DC/DC converter, the split excitation winding of the doubly salient motor is reused for the charging and discharging DC/DC converter, and the output of the DC/DC converter passes through the DC side filter capacitor and the three-phase bridge conversion The electric excitation double salient pole motor has an open structure, and the armature winding is connected to the three-phase single-pole double-throw switch charge and discharge switch K2.

The system realizes the switching between driving and charging states through the charging and discharging switch K2. When the system is in the drive mode, the charge and discharge switch K2 is in the closed state, short-circuiting the ends of the three-phase armature windings of the electric excitation doubly salient motor to form a star connection mode, the EMI filter does not work, and disconnects the power grid. Connection; when the system is in charging mode, the charging and discharging switch K2 is automatically turned on by the power grid, and the end of the three-phase armature winding of the electric excitation doubly salient motor is connected to the EMI filter, which is equivalent to a three-phase filter inductor.

The charge-discharge DC/DC converter is composed of 6 switch tubes S1-S6, a switch K1, the split excitation windings F1 and F2 of the electric excitation doubly salient motor and the filter capacitor C1, and three switch tubes S1, S2 and S3. A bridge arm is formed in series in sequence. The midpoints of S1 and S2 and the midpoints of S2 and S3 are respectively connected to one end of the two-section excitation windings of the electric excitation doubly salient motor. Switch tubes S4, S5, and S6 are connected in series to form another bridge arm. , the midpoints of S4 and S5 and the midpoints of S5 and S6 are respectively connected to the other ends of the two-stage excitation windings of the electric excitation doubly salient motor, the switch tube K1 is located in the middle of the two bridge arms, and the filter capacitor C1 is located in the charging and discharging DC/DC the output of the converter.

The charging and discharging DC/DC converter adopts the voltage and current double closed-loop control mode, collects the voltage of the battery and the capacitor respectively, controls the capacitor voltage in a closed-loop during the discharge process, and controls the battery voltage in a closed-loop during the charging process. And output it to the current loop as a given current. Compared with the actual current fed back, the PWM control signal is generated by the current regulator to selectively control S4, S5, and S6, so as to realize the control of the excitation current and the output voltage of the charging and discharging DC/DC converter. adjust.

In the drive mode, the switch K1 is closed, and the charge _- discharge DC/DC converter is switched to the boost converter, which works in the boost mode to increase the voltage of the battery, and drives the motor to run through the rear-stage three-phase bridge converter.

Switch tubes S1 and S2 are turned on to control the output voltage, S3 and S4 tubes are turned off, S5 and S6 tubes work in PWM chopper mode, and the split excitation windings F1 and F2 are equivalently connected in parallel. Under certain circumstances, by adjusting the duty ratios of S5 and S6, the excitation current control of the two-stage excitation windings can be realized.

The duty cycle of each switch tube can be adjusted through the PI regulator, so as to adjust the excitation current and the bus voltage at the output side of the DC/DC converter when the drive is running. The parameters of the PI regulator affect the dynamic response process of the system. The power feedforward adjustment can be added to the controller, so as to quickly realize the dynamic response process and increase the stability of the system, so that the duty cycle of each switch, the size of the excitation current and the bus voltage on the output side of the DC/DC converter meet the requirements. The requirements for the range of the input DC voltage for a given three-phase bridge converter.

In the drive mode, the position signal of the doubly salient motor needs to be collected, and the inverter switch tubes S7-S12 of the three-phase bridge converter are turned on and off according to the switch conduction logic of the traditional drive electric excitation doubly salient motor. The current sensor detects the three-phase armature winding current for closed-loop control, and then the motor is controlled by the command to output the electromagnetic torque.

In the charging mode, the switch K ₁ is turned on, the charging and discharging DC/DC converter is switched to the Buck converter, and the three-phase bridge converter works in the PWM rectifier mode, which converts the three-phase alternating current into direct current, and then reduces the voltage through the Buck converter. Charge the battery.

S4 tube works in PWM chopper mode, S6 tube is turned on, S1, S2, S3, S5 tubes are turned off, and the split excitation windings F1 and F2 are equivalently connected in reverse series to realize the degaussing function of the electric excitation doubly salient motor.

The main control circuit controls the switches S1-S6 by adjusting the duty cycle D. From the relationship between the input voltage and the output voltage Vo=DVi, we only need to control the duty cycle D of the switch tube (defined as the ratio of the on-time of the pulse waveform of the control power tube to its period, and its value is always less than 1 ), the effect of reducing blood pressure can be achieved. When the battery charging current is too large, reduce the duty cycle; when the charging current is too small, increase the duty cycle.

Test example one:

Control the electric excitation doubly salient motor driving and charging integrated system with split excitation windings according to the specific implementation mode, and simulate the motor driving process. /10-pole electric excitation double salient motor, the self-inductance of the motor armature winding is a constant value of 10mH, the mutual inductance between the armature windings is a constant value of 4.6mH, the self-inductance of the split excitation winding is a constant value of 210mH, and the mutual inductance between the excitation windings is 0mH , the resistance of the armature winding is 0.23Ω, and the resistance of the excitation winding is 6.2Ω; the given speed of the motor is 600rpm, the given current of each field winding is 25A, the motor has a constant torque load, the moment of inertia of the motor is 20kg·m ² , and the capacitance in the circuit The value size is 1.5mF. The current simulation waveform of the split excitation winding F1 in the motor driving process is shown in Figure 5, the voltage simulation waveform at the output side of the DC/DC converter is shown in Figure 6, and the motor speed simulation waveform is shown in Figure 7. Among them, 0.4s before the simulation waveform is the transient process when the motor starts and accelerates, and after 0.4s is the situation after the motor excitation current, the output voltage of the DC/DC converter and the motor speed all reach a steady state.

As shown in Figure 5, there is a ripple in the current during the driving process, which is caused by the current commutation of the armature winding and the mutual inductance between the armature winding and the excitation winding. It also exists in the traditional system that controls the excitation current in a separate excitation manner. . As shown in Figure 6, when the motor is in the acceleration state, the output voltage of the DC/DC converter will have a certain amount of overshoot, but then due to the voltage closed-loop control, the output voltage will stabilize around the given voltage. As shown in Figure 7, in the test example, the motor can achieve a relatively stable acceleration process, and finally stabilizes to a given speed near a given speed.

This test example verifies that the system described in the present invention can realize the control of the motor excitation current and the motor drive voltage under the condition that the split excitation winding is integrated with the DC/DC converter inductance, so that the motor can be driven normally.

Test example two:

According to the specific embodiment, the electric excitation double salient motor driving and charging integrated system with split excitation winding is controlled. After connecting the three-phase power grid, the simulation of high-power charging is carried out. The simulation parameters are given: the motor adopts a 12/10-pole electric excitation double Salient pole motor, the self-inductance of the motor armature winding is a constant value of 10mH, the mutual inductance between the armature windings is a constant value of 4.6mH, the self-inductance of the split excitation winding is a constant value of 210mH, the mutual inductance between the excitation windings is 0mH, and the armature winding resistance is 0.23Ω, the resistance of the excitation winding is 6.2Ω; given a charging current of 3A, the capacitor voltage of the DC/DC converter is 135V, and the capacitance value of the capacitor is 0.15mF.

The simulation waveform of the motor armature current in the charging mode is shown in Figure 8. In the figure, the three-phase armature current can be sinusoidally controlled by SPWM. Since it is not filtered by the EMI filter, there are high-order harmonics in the current.

The simulation waveform of the battery charging current in the charging mode is shown in Figure 9. It can be seen that the current will eventually stabilize at about 3A.

This test example verifies that the system described in the present invention can realize high-speed and high-power charging of the battery through the three-phase power grid.

It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It should also be understood that terms such as those defined in the general dictionary should be understood to have meanings consistent with their meanings in the context of the prior art and, unless defined as herein, are not to be taken in an idealized or overly formal sense. explain.

The specific embodiments described above further describe the purpose, technical solutions and beneficial effects of the present invention in further detail. It should be understood that the above descriptions are only specific embodiments of the present invention, and are not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims (3)

1. An electro-magnetic doubly salient motor driving and charging integrated system is characterized by comprising a storage battery, first to sixth switching tubes, a first change-over switch, an electro-magnetic doubly salient motor, a direct-current filter capacitor, a three-phase bridge converter, an EMI filter and a second change-over switch;

the excitation winding of the electric excitation doubly salient motor is cut off and divided into two sections with equal length, namely a first excitation winding section and a second excitation winding section, and the three-phase armature winding of the electric excitation doubly salient motor is of an open structure;

the second change-over switch is a three-phase single-pole double-throw switch, one side of the second change-over switch is connected with an external power grid through an EMI filter, and the other side of the second change-over switch is correspondingly connected with one end of a three-phase armature winding of the electro-magnetic doubly salient motor; the other end of the three-phase armature winding of the electro-magnetic doubly salient motor is correspondingly connected with the middle points of three bridge arms of the three-phase bridge type converter respectively;

the first to sixth switching tubes, the first change-over switch, the first excitation winding section and the second excitation winding section form a charging and discharging DC/DC converter, wherein the first to third switching tubes are sequentially connected in series to form an input bridge arm of the charging and discharging DC/DC converter, and the fourth to sixth switching tubes are sequentially connected in series to form an output bridge arm of the charging and discharging DC/DC converter; one end of the first excitation winding section is connected with the middle points of the first switching tube and the second switching tube, and the other end of the first excitation winding section is connected with the middle points of the fourth switching tube and the fifth switching tube; one end of the second excitation winding section is connected with the middle points of the second switching tube and the third switching tube, and the other end of the second excitation winding section is connected with the middle points of the fifth switching tube and the sixth switching tube; the emitter of the third switching tube is connected with the emitter of the sixth switching tube through a first change-over switch;

the first to sixth switching tubes are all anti-parallel diodes;

two ends of an input bridge arm of the charging and discharging DC/DC converter are connected with two ends of the storage battery, and two ends of an output bridge arm of the charging and discharging DC/DC converter are cascaded with the three-phase bridge converter through the direct current filter capacitor.

2. The control method of the integrated system of driving and charging an electro-magnetic double-salient motor according to claim 1, wherein the control method when the integrated system of driving and charging an electro-magnetic double-salient motor is in a driving mode is as follows:

the second change-over switch is closed, the tail end of a three-phase armature winding of the electric excitation double-salient motor is short-circuited to form a star connection mode, the EMI filter does not work, and the connection with a power grid is disconnected;

the first change-over switch is closed, the charging and discharging DC/DC converter is switched to a Boost converter, the charging and discharging DC/DC converter works in a Boost mode, the first switch tube and the second switch tube are switched on, the third switch tube and the fourth switch tube are switched off, the fifth switch tube and the sixth switch tube work in a PWM chopping mode, the first excitation winding section and the second excitation winding section are connected in parallel in an equivalent mode, at the moment, the charging and discharging DC/DC converter promotes the voltage of a storage battery, and the motor is driven to run by the rear-stage three-phase bridge converter.

3. The control method of the integrated system of driving and charging an electro-magnetic double-salient motor according to claim 1, wherein the control method when the integrated system of driving and charging an electro-magnetic double-salient motor is in a charging mode is as follows:

the second change-over switch is opened, and the tail end of a three-phase armature winding of the electric excitation doubly salient motor is connected with an EMI filter and is equivalent to a three-phase filter inductor;

when the system is in a charging mode, the first switch is turned on, the charging and discharging DC/DC converter is switched to a Buck converter, the fourth switch tube works in a PWM chopping mode, the sixth switch tube is turned on, the first, second, third and fifth switch tubes are turned off, the first excitation winding section and the second excitation winding section are equivalently and reversely connected in series, the demagnetization function of the electro-excitation double-salient motor is realized, the three-phase bridge converter works in the PWM rectifier mode, three-phase alternating current is converted into direct current, and the direct current is reduced by the Buck converter to charge the storage battery.

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