JP5063274B2 - Electric vehicle control device - Google Patents

Description

The present invention relates to an electric vehicle control device for a railway vehicle, and more particularly to idling control.

As a propulsion control device for a railway vehicle, a method of driving a multiphase AC motor with an inverter device of variable voltage and variable frequency is becoming common. In railway vehicles, regardless of the propulsion system, there are cases where the so-called tangential force decreases, causing idling or gliding and temporarily preventing propulsion or braking. Generally, a propulsion control device for a railway vehicle is configured by a torque control system. When the tangential force is reduced and the vehicle is idling, the rotational speed of the wheels and the rotational speed of the electric motor as a drive source are rapidly increased. The tangential force is a propulsive force acting between the driving wheel and the rail, and in a normal adhesion state, the peripheral speed of the driving wheel and the vehicle speed substantially coincide with each other. However, if raindrops, snow, etc. intervene on the contact surface between the rail and the wheel, and the adhesive state cannot be maintained, the torque of the motor of the drive source is not transmitted to the rail, only the driving wheel peripheral speed increases, and the vehicle speed and the driving wheel peripheral This is a so-called idling state in which a large differential speed (sliding speed) occurs in the speed.

In the case of sliding, only the driving wheel peripheral speed decreases with respect to the vehicle speed, but in the following description, only the idle side is described for the sake of simplicity.
In conventional AC motor drive systems, it is common to detect idling immediately after the start of idling based on the rate of change in the rotational speed of the motor, etc., and quickly reduce the command torque to prevent the rotational speed of the motor and wheels from diverging. It is.
FIG. 2 is a block diagram showing an example of an electric vehicle control device to which a conventional adhesion control system is applied. The rotation speeds of the motors 21 and 22 are detected by the speed detectors 31 and 32, converted into control information by the speed calculation unit 107, and the idling detection unit 121 performs time differentiation to obtain a change rate signal, and the idling detection level. The set value is compared, and an idling detection signal is output when the rate of change of the motor rotation speed exceeds the detection level. The idling detection signal is a logic signal, and the adhesion control unit 120 outputs a command torque reduction coefficient signal in a predetermined time series when receiving the idling detection signal. In the command torque reduction method of this example, the command value is manipulated by multiplying the original command value 100 by the coefficient multiplier 110 with the reduction coefficient signal. FIG. 3 is an example of a reduction coefficient signal with time on the horizontal axis and the reduction coefficient on the vertical axis.

Conventionally, it has been considered that the relationship between the sliding speed and the tangential force that can be transmitted to the rail is as shown in FIG. That is, the tangential force is maximized in a region where the sliding speed is very small, and the tangential force is unilaterally reduced when the sliding speed is increased. Therefore, in the conventional adhesion control, a control algorithm for reducing the sliding speed as much as possible is applied, and when the idling is detected, the command torque is quickly reduced.
JP-A-6-335106

The command torque of the motor is originally set to drive the vehicle at a predetermined acceleration, but the predetermined acceleration cannot be obtained at the time of idling by the above-mentioned adhesion control algorithm that lowers the command torque by detecting the idling. become.

According to the first aspect of the present invention, there is provided an electric vehicle control device for driving an AC electric motor , wherein the difference between the vehicle speed corresponding to the sliding speed of the wheel and the rail and the rotational speed of the electric motor is detected, and the tangential force has a maximum value. Of the two differential speeds shown, while the differential speed is less than or equal to the larger differential speed (S0), normal torque control is performed without changing the torque command, and the larger differential speed (S0) is set. When exceeding, a torque reduction characteristic corresponding to the increase amount of the differential speed is added.

According to the present invention, the electric vehicle control device according to claim 1 for driving an AC motor, wherein the predetermined target speed is set as a slip ratio that is a ratio of the differential speed and the vehicle speed. It is characterized by that.

According to the present invention, the electric vehicle control device according to claim 1, which drives an AC motor,
The motor rotation speed is an average value of induction motors driven in parallel.

According to the present invention, the electric vehicle control device according to claim 1, which drives an AC motor,
The motor speed is obtained by calculating from the motor current and the terminal voltage command or terminal voltage detection value.

According to the present invention, the electric vehicle control device according to claim 1, which drives an AC motor,
The vehicle speed is obtained from a T-axis speed or an ATC device.

According to a seventh aspect of the present invention, in the electric vehicle control device according to the first aspect of the present invention, the alternating current motor is driven, and the limited target value is set when the limited target value is set at the predetermined differential speed and at the predetermined slip ratio. The torque control is performed by switching the case of setting in the vehicle speed region.

That is, the difference speed between the vehicle speed corresponding to the sliding speed of the wheel and the rail and the motor rotation speed is detected, and normal torque control is performed while this value is less than or equal to a predetermined value. Adhesion control algorithm to which torque reduction characteristics are added according to the deviation of the differential speed from the target limit value is applied.

The present invention provides an electric vehicle control device that makes it possible to obtain a predetermined vehicle acceleration even in an idling state. Conventional adhesion control assumes the tangential force peak on the left side of FIG.
The slip speed was controlled to be as small as possible. The present invention makes it possible to use the tangential force on the right side of FIG.

FIG. 1 is a block diagram showing an electric vehicle control apparatus to which the adhesion control system of the present invention is applied.

FIG. 1 shows an example of a system in which the electric vehicle control device 1 drives the AC motors 21 and 22. The inverter control unit 103 independently controls the torque component current deviation and the excitation component current deviation of the AC motor to be minimized. Each deviation is obtained by calculating a deviation between each command value and the actual current by the deviation calculation units 105 and 106, respectively. The torque component current command and the excitation component current command are outputs of the current command generator 102, and are calculated from the command inputs of the torque command 100 and the magnetic flux command 101. The torque command 100 passes through the coefficient multiplier 110 before being input to the current command generator 102. The coefficient multiplying unit 110 has conventionally been a part for reducing the torque for quick re-adhesion control. However, in FIG. 1, the coefficient multiplying unit 110 is a torque command operating unit for preventing the divergence of the slip speed during idling.
The current calculation unit 104 obtains phase information of the output voltage from the inverter control unit 103, and outputs each current component obtained by vector decomposition from the inverter output current into an actual torque component current and an actual excitation component current. A sliding speed calculation unit 109 calculates a differential speed between the vehicle speed 4 and the driving wheel peripheral speed. In addition to the torque component current deviation and the excitation component current deviation information, the inverter control unit 103 needs input information obtained by converting the rotation speed of the motor into the inverter output frequency.
The speed detectors 31 and 32 detect the motor rotation speed, and the speed calculation unit 107 converts the detected amount such as the number of pulses per unit time of the output signals of the speed detectors 31 and 32 into the inverter output frequency. The unit of motor rotation speed is usually expressed in [rad / sec], but the unit when converted to the inverter output frequency is [Hz], and will be described below as [km / h] when converted to the peripheral speed of the driving wheel. . Although the output of the speed calculation unit 107 is used in various ways, they are all in a proportional relationship, and are used by multiplying the respective proportional coefficients by each reference unit. The slip speed signal is the difference between the moving wheel peripheral speed obtained from the motor rotation speed signal 108 and the vehicle speed 4.
The present invention is based on the result of investigation in which the relationship between the sliding speed and the tangential force is as shown in FIG. The difference from the conventional method is that a logic signal for detecting slipping is not created.
The idling prevention unit 111 sets the output reduction coefficient value to 1.0 so that the command torque is not reduced while the sliding speed signal is small. When the slip speed increases and reaches a region where a larger tangential force cannot be expected, the idling prevention unit 111 reduces the output reduction coefficient value to 1.0 or less according to the slip speed, and the tangential force and the motor output torque. The balance state is obtained, and the divergence of the sliding speed is prevented.
The reduction coefficient value corresponding to the sliding speed is represented by a straight line passing through two points (S0, 1.0) (S1, 0.0) as shown in FIG. 6, for example, according to the coordinate mark (sliding speed, reduction coefficient value). Such reduction characteristics are sufficient.

In FIG. 1, the speed detection unit 107 shows a configuration for detecting the speeds of the electric motors 21 and 22. In the conventional device that required a logic signal for detecting idling, the selected axis was switched based on the minimum value during power running, the maximum value during braking, or power running and braking and the traveling direction (such as going up and down). When using a state where the sliding speed is high, it is easier to secure the propulsive force by using the average speed value.
That is, when one of the parallel drive shafts idles and the rotational speed increases, the average value also increases, and the inverter output frequency is increased. Since the increase rate of the average value is smaller than the increase rate of the idle shaft, the torque of the idle shaft decreases, but the torque of the non-idle shaft increases as the inverter output frequency increases. The transient state of the contradictory torque between the idle shaft and the non-idle shaft is also convenient for maintaining the propulsive force of the vehicle because the total torque hardly changes before and after the idle rotation of one shaft. In this state, it is possible to prevent the acceleration performance of the vehicle from being deteriorated due to momentary rotational speed unevenness when passing through the rail joint or one-axis minute idling.
When all the shafts are idle, the acceleration performance of the vehicle can be maintained because the vehicle is driven at a sliding speed in accordance with the tangential force characteristics shown in FIG.

FIG. 7 is a block diagram of an electric vehicle control apparatus that does not use a speed sensor. The speed detectors 31 and 32 in FIG. 1 are omitted, and the input of the speed calculator 107 is an inverter output current signal and an inverter output voltage signal. The rotation speed of the motor can be calculated using the voltage / current and the motor constant, and when the motors are driven in parallel, the calculation result of the speed is naturally an average value of each motor. Therefore, it is easy to realize this adhesion control method in an electric vehicle control device that does not use a speed sensor.

The difference between the average value of the rotational speeds of the motors driven in parallel and the vehicle speed is the sliding speed. The vehicle speed can be obtained by various methods. As one method of using the control information of the vehicle system in the train, there is a method of outputting the speed information of the ATC device to the outside and taking it into the electric vehicle control device according to the present invention. The simplest and most reliable system can be easily configured. FIG. 8 shows the configuration of the ATC speed detector, the ATC device, and the control signal transmission line. The positional relationship with the T-axis speed detector is also shown in FIG.
Usually, as a method of detecting the vehicle speed other than the electric vehicle control device, a speed sensor is attached to the end of the axle. In some cases, the selected axle is a T-axis (trailer axle) for the purpose of eliminating the effect of idling, and the brake force is also reduced from other axes for the purpose of eliminating the effect of sliding. As a specific means for using the speed information of the ATC device, a dedicated equipment line for the signal may be provided, or the speed information may be added to an existing vehicle control information transmission line in the train. Since the change in the order of several tens of mS is originally minute, the addition of a signal to the transmission line is sufficient to ensure the performance.

When the independence of the control device is required without relying on signals from other devices, the vehicle speed is estimated from the rotational speed of the electric motor.
As described above, the method of calculating the rotation speed of the motor using the voltage, current, and motor constant can shorten the data update cycle compared to the method of counting the output frequency of the conventional speed detection device. This increases the detection accuracy of the speed change rate of the motor, accelerates the vehicle by transmitting the motor output torque to the wheels and the inertia of the drive system (known in design) and the rail. It is possible to separate the component into tangential force. FIG. 9 shows an embodiment of the vehicle speed estimation method.
In general, the vehicle control apparatus is called jerk control for both starting from a stopped state and turning on torque control from a coasting state, and gradually increases a torque command from a small value. Therefore, it can be considered that the rotational speed of the electric motor and the vehicle speed coincide with each other immediately after being turned on. Then, the mass of the vehicle is estimated from the motor torque and the speed change rate within a period in which the torque is small in the jerk control. The vehicle mass estimated here includes the boarding rate and the gradient condition.
Acceleration a = tangential force f / estimated mass m 2 The vehicle speed v is obtained by integrating the acceleration a.
In principle, it is possible to estimate the vehicle speed during idling for each control unit from the estimated value of the vehicle mass and the tangential force when the rotation speed of the motor suddenly increases, but the adhesion coefficient decreases extremely. In consideration of the worst condition that the idling has increased over the entire knitting, it is desirable that the vehicle mass is the entire knitting, and that the tangential force is handled by the sum of all the control devices in the knitting because the error is reduced.
An example of a method for obtaining the sum of the tangential forces of the control devices in the knitting is to output the tangential force information of each control device to the vehicle control information line, and the information central device determines the sum and transmits it to each device. do it.
As another realization means, for example, when there are two control devices in the knitting, a dedicated line for information exchange between the control devices may be provided, and the sum of the other tangential force and its own tangential force may be calculated. . In any case, FIG. 10 shows an example of a method for estimating the vehicle speed in the case where the tangential force and the vehicle mass are handled as the sum of the knitting.

The difference speed between the vehicle speed and the peripheral speed of the driving wheel is referred to as a slip speed, and a ratio obtained by dividing the slip speed by the vehicle speed is referred to as a slip ratio. As shown in FIG. 5, the sliding speed at which the tangential force exhibits a peak tends to increase as the speed increases. Taking this tendency into account, in order to use the tangential force more effectively, the values of S0 and S1 of the torque reduction characteristics for preventing the divergence of the slip speed can be moved to the higher speed as the vehicle speed increases. That's fine. That is, by adding a torque reduction characteristic according to the slip rate in addition to the torque reduction characteristic according to the slip speed, an electric vehicle control device that can ensure acceleration characteristics in a high speed range can be realized.

In the above-described embodiment, the torque reduction characteristic in the high speed range is described as a method corresponding to the slip rate. Therefore, referring to the vehicle speed, the two control methods can be combined by selecting the reduction characteristic calculation block based on the slip speed if the speed is lower than the predetermined speed and the reduction characteristic calculation block based on the slip ratio if the speed is higher than the predetermined speed. An example of the above configuration is shown in FIG.

The electric vehicle control device for driving the AC motor of the present application has conventionally kept the sliding state of the rail and the wheel in a minute range, but it becomes impossible to secure a predetermined tangential force in the minute sliding state due to adhesion of raindrops or the like. However, the tangential force can be obtained by expanding the sliding range, and can be applied to induction motor systems that assume parallel drive as well as to synchronous motor systems that require individual control. .

Block diagram of an embodiment of the present invention Block diagram of conventional control method Cohesive pattern for re-adhesion control Example of relationship between sliding speed and tangential force Example of relationship between sliding speed and tangential force Example of torque reduction characteristics Block diagram of speed sensorless control system Example of capturing vehicle speed Examples of vehicle speed calculation Slip rate control Control example with switching function of reduction characteristic calculation block

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electric vehicle control apparatus 21 AC motor 22 AC motor 31 Speed detector 32 Speed detector 4 Vehicle speed signal 100 Torque command 101 Magnetic flux command 102 Current command generation part 103 Inverter control part 104 Current calculation part 105 Torque component current deviation calculation part 106 Magnetic flux component current deviation calculation unit 107 Speed calculation unit 108 Electric motor actual rotation speed signal 109 Sliding speed calculation unit 110 Coefficient multiplication unit 111 Idling divergence prevention unit 120 Adhesion control unit 121 Idling detection unit 122 Signal selector 123 Switching signal 124 Slip rate correction unit 125 Slip Rate Control Signal 126 Speed Area Discriminating Unit 130 Speed Sensorless Motor Rotational Speed Calculation Unit

Claims (1)

An electric vehicle control device for driving an AC motor, which detects a difference between a vehicle speed corresponding to a sliding speed of a wheel and a rail and a motor rotation speed, and the tangential force exhibits a maximum value, It said difference speed, between the differential velocity (S0) below the larger torque command performs normal torque control as is, when more than the differential velocity of the larger (S0) is increasing the differential velocity An electric vehicle controller characterized by adding torque reduction characteristics corresponding to a large amount.

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