JP6092020B2 - Electric vehicle control device - Google Patents

Description

  Embodiments described herein relate generally to an electric vehicle control device that controls an electric vehicle.

  In general, when speed sensorless vector control for controlling the torque of the main motor without detecting the rotation speed of the main motor is applied, the rotation speed, that is, the rotor angular frequency is estimated based on the induced voltage of the main motor.

  However, since the induced voltage of the main motor becomes an extremely small value while the electric vehicle is stopped or rotating at a very low speed range, an error occurs in the estimation of the rotor angular frequency due to the error of the detector, etc. The torque may not be output, resulting in acceleration failure.

  For this reason, it is necessary to perform speed estimation by another method in the extremely low speed range. For example, it is known to perform speed estimation by setting a disturbance torque due to a gradient.

Japanese Patent Laid-Open No. 9-149667

  However, when performing control near zero speed (for example, when starting an electric vehicle on an ascending slope), there is no known electric vehicle control that reliably eliminates torque shortage.

  For example, when speed estimation is performed by setting a disturbance torque due to a gradient in advance, if there is a difference between the gradient assumed for setting the disturbance torque and the actual gradient, torque reduction may occur. .

  Accordingly, an object of the embodiment of the present invention is to provide an electric vehicle control device that has improved torque characteristics in control near zero speed.

  An electric vehicle control device according to an embodiment of the present invention includes an inverter that outputs AC power to an induction motor that is a power source of an electric vehicle, and AC current detection means that detects an AC current output from the inverter. A disturbance torque estimating means for estimating a disturbance torque of the induction motor based on the alternating current detected by the alternating current detecting means; a current command value for the alternating current output from the inverter; and the disturbance torque estimating means. Based on the estimated disturbance torque, the rotor angular frequency estimating means for estimating the rotor angular frequency of the induction motor, and on the basis of the rotor angular frequency and the current command value estimated by the rotor angular frequency estimating means, Inverter control means for controlling the inverter.

The block diagram which shows the structure of the electric vehicle control apparatus which concerns on embodiment of this invention. The graph which shows the correlation of the generated torque in the 30 ‰ uphill gradient of a conventional type electric vehicle control apparatus, and a generated torque command value. The graph which shows the correlation with the generated torque and generated torque command value in the 30 ‰ up slope of the electric vehicle control apparatus which concerns on this embodiment. The graph which shows the correlation with the generated torque and generated torque command value in the 10 ‰ upslope of the conventional electric vehicle control apparatus. The graph which shows the correlation with the generated torque and generated torque command value in 10 ‰ up-slope of the electric vehicle control apparatus which concerns on this embodiment.

  Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment)
FIG. 1 is a configuration diagram showing a configuration of an electric vehicle control device 20 according to an embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the same part in subsequent figures, the detailed description is abbreviate | omitted, and a different part is mainly described.

  The electric vehicle control device 20 is a control device that drives and controls an induction motor (main motor) 1 that is a power source of the electric vehicle. The electric vehicle control device 20 does not require a speed sensor and performs variable speed control of the induction motor 1 by vector control. The electric vehicle control device 20 performs any one of forward control performed when the electric vehicle moves forward, reverse control performed when the electric vehicle moves backward, and mechanical simulator control performed when the electric vehicle is near zero speed. Here, the electric vehicle control device 20 in the case of performing the machine simulator control will be mainly described, and description of other controls will be omitted.

  The electric vehicle control device 20 includes an inverter 2, two coordinate converters 3 and 4, an integrator 5, a current controller 6, a voltage regulator 7, a simulator 8, a disturbance torque calculation unit 9, a slip angular frequency command calculation unit 10, An excitation current calculation unit 11, a torque current calculation unit 12, an adder 13, two subtracters 14 and 15, and three current detectors 16 are provided.

A secondary magnetic flux command value Φ2 * for the induction motor 1 is input to the excitation current calculation unit 11. The exciting current calculation unit 11 uses the secondary magnetic flux command value Φ2 * according to the following equation to obtain a magnetic flux current command that is a command value for the magnetic flux current (d-axis current in the dq-axis rotation coordinate system) I1d output from the inverter 2. The value (d-axis current command value) I1d * is calculated. The exciting current calculation unit 11 outputs the calculated magnetic flux current command value I1d * to the voltage regulator 7, the simulator 8, the slip angular frequency command calculation unit 10, and the subtractor 15.

  Here, Mm is a mutual inductance.

The torque current calculator 12 receives the secondary magnetic flux command value Φ2 * and the torque command value Torq * for the induction motor 1. The torque current calculation unit 12 uses the secondary magnetic flux command value Φ2 * and the torque command value Torq * according to the following equation to command the torque current (q-axis current in the dq-axis rotational coordinate system) I1q output from the inverter 2. A torque current command value (q-axis current command value) I1q * which is a value is calculated. The torque current I1q is a current orthogonal to the magnetic flux current I1d. The vector sum of the magnetic flux current I1d and the torque current I1q is the primary current. The torque current calculation unit 12 outputs the calculated torque current command value I1q * to the voltage regulator 7, the simulator 8, the slip angular frequency command calculation unit 10, and the subtractor 14.

  Here, L2 is a secondary self-inductance, and Mm is a mutual inductance.

  The three current detectors 16 are installed on the output side of the inverter 2. The three current detectors 16 detect AC currents Iu, Iv, and Iw of each phase that flow from the inverter 2 to the induction motor 1. The current detector 16 outputs the detected phase currents Iu, Iv, and Iw to the coordinate converter 4.

  The coordinate converter 4 uses the phase θ1 calculated by the integrator 5 to convert the three-phase AC currents Iu, Iv, Iw detected by the three current detectors 16 into the dq-axis current I1d, Convert to I1q. The coordinate converter 4 outputs the d-axis current (magnetic flux current) I1d to the subtractor 15 and the q-axis current (torque current) I1q to the subtractor 14.

  The subtractor 15 outputs a difference value obtained by subtracting the d-axis current I1d calculated by the coordinate converter 4 from the d-axis current command value I1d * calculated by the excitation current calculation unit 11 to the current controller 6.

  The current controller 6 calculates the d-axis voltage command value Vd * so that the difference between the d-axis current command value I1d * calculated by the subtracter 15 and the d-axis current I1d becomes zero. That is, the current controller 6 feeds back the detected d-axis current I1d and controls the d-axis current I1d to coincide with the d-axis current command value I1d *. The current controller 6 outputs the calculated d-axis voltage command value Vd * to the coordinate converter 3.

The voltage regulator 7 uses the d-axis current command value I1d * calculated by the excitation current calculation unit 11 and the q-axis current command value I1q * calculated by the torque current calculation unit 12 to Command value Vq * is calculated. The voltage regulator 7 outputs the calculated q-axis voltage command value Vq * to the coordinate converter 3.

  Here, σ = 1−Mm ^ 2 / (L1 · L2). R1 is a primary winding resistance, L1 is a primary self-inductance, L2 is a secondary self-inductance, and Mm is a mutual inductance.

  The coordinate converter 3 uses the phase θ1 calculated by the integrator 5 to convert the dq axis voltage command values Vd * and Vq * calculated by the current controller 6 and the voltage regulator 7 into the three-phase voltage command value Vu *. , Vv *, Vw *. The coordinate converter 3 outputs the converted three-phase voltage command values Vu *, Vv *, Vw * to the inverter 2.

  The inverter 2 is a voltage source inverter. The inverter 2 is a three-phase alternating current based on a gate command generated by triangular wave comparison PWM (pulse width modulation) control or the like based on the three-phase voltage command values Vu *, Vv *, Vw * input from the coordinate converter 3. Generate power. Thereby, the induction motor 1 is driven and controlled.

The slip angular frequency command calculation unit 10 uses the d-axis current command value I1d * calculated by the excitation current calculation unit 11 and the q-axis current command value I1q * calculated by the torque current calculation unit 12 by the following equation: The slip angular frequency command value ωs * is calculated. The slip angular frequency command calculation unit 10 outputs the calculated slip angular frequency command value ωs * to the adder 13.

  Here, R2 is a secondary winding resistance, and L2 is a secondary self-inductance.

  The subtractor 14 calculates a difference obtained by subtracting the q-axis current command value I1q * calculated by the torque current calculation unit 12 from the q-axis current I1q calculated by the coordinate converter 4. The subtractor 14 outputs the difference between the calculated q-axis current I1q and the q-axis current command value I1q * to the disturbance torque calculation unit 9.

  The adder 13 receives the slip angular frequency command value ωs * calculated by the slip angular frequency command calculation unit 10 and the rotor angular frequency estimated value (rotor angular acceleration estimated value) ωrest calculated by the simulator 8. The adder 13 adds the slip angular frequency command value ωs * and the rotor angular frequency estimated value ωrest to calculate the inverter output frequency (primary angular frequency) ω1. The adder 13 outputs the calculated inverter output frequency ω1 to the integrator 5, the voltage regulator 7, and the disturbance torque calculator 9.

  The disturbance torque calculation unit 9 includes a disturbance torque set value TLset that is set in advance, a difference between the q-axis current I1q calculated by the subtractor 14 and the q-axis current command value I1q *, and an adder 13 that calculates the difference. The inverter output frequency ω1 is input. The disturbance torque set value TLset is determined on the assumption of a situation such as an upward gradient of 30 ‰ when the vehicle is full such as a commuter train. Here, a possible range (for example, 0 ‰ to 30 ‰) of the gradient is determined in advance. Therefore, the gradient assumed for determining the disturbance torque set value TLset may be the maximum value (for example, 30 ‰) of the possible range. The disturbance torque set value TLset is obtained using the assumed gradient and the equivalent inertia mass set value.

The disturbance torque calculation unit 9 determines whether or not to perform machine simulator control based on the inverter output frequency ω1. For example, when the inverter output frequency ω1 is within a range of ± 1 Hz, the disturbance torque calculation unit 9 determines to perform the machine simulator control. When the disturbance torque calculation unit 9 determines to perform the machine simulator control, the disturbance torque set value TLset and the difference between the q-axis current I1q and the q-axis current command value I1q * are used to calculate a proportional-integral calculation formula shown in the following equation: Thus, the disturbance torque estimated value TLest is calculated. The disturbance torque calculation unit 9 outputs the calculated disturbance torque estimated value TBest to the simulator 8. When determining that the machine simulator control is not performed, the disturbance torque calculation unit 9 outputs the disturbance torque set value TLset as the disturbance torque estimated value TLest.

  Here, KTP is a proportional gain of the disturbance torque calculator, and KTI is an integral gain of the disturbance torque calculator.

The simulator 8 includes a d-axis current command value I1d * calculated by the excitation current calculation unit 11, a q-axis current command value I1q * calculated by the torque current calculation unit 12, and a disturbance calculated by the disturbance torque calculation unit 9. The estimated torque value TLest is input. The simulator 8 uses the d-axis current command value I1d *, the q-axis current command value I1q *, and the disturbance torque estimated value TLest to calculate the rotor angular frequency estimated value ωreest according to the simulator equation model shown below. The simulator 8 outputs the calculated rotor angular frequency estimated value ωreest to the adder 13.

  Here, P is the number of pole pairs, Jset is rotational inertia, Mm is mutual inductance, and L2 is secondary inductance. Rotational inertia is a parameter determined by the mass and size of gears and wheels.

  This simulator mathematical model is a mathematical model in which the inertial force of the rotor balances with the force obtained by subtracting the disturbance torque from the generated torque. Moreover, since the disturbance torque estimated value TLest always changes according to the equation (5), this mathematical model is sequentially calculated in real time.

  With these configurations, a torque control system based on speed sensorless vector control is formed.

  Next, the operation of the machine simulator control by the electric vehicle control device 20 will be described. The machine simulator control is executed, for example, at the time of starting from an ascending zero speed. At the time of start-up from the zero speed of the ascending slope, the electric vehicle moves backward a little and then gradually decelerates. After reaching the zero speed, the electric vehicle starts moving forward and gradually accelerates. At this time, the electric vehicle control device 20 is executed in the order of reverse control, mechanical simulator control, and forward control.

  If an error occurs in the estimated rotor angular frequency value ωrest during the machine simulator control and the slip angular frequency varies from the slip angular frequency command value ωs *, the q-axis current I1q varies from the q-axis current command value I1q *. Therefore, by compensating the deviation between the q-axis current I1q and the q-axis current command value I1q * to the disturbance torque estimated value TLest, the error of the rotor angular frequency estimated value ωreest is reduced. As a result, the estimated rotor angular frequency value ωreest is in accordance with the actual disturbance torque, so that torque according to the torque command value Torq * is output regardless of the gradient.

  Next, effects of the electric vehicle control device 20 will be described with reference to FIGS. 2 to 5 are graphs showing the correlation between the generated torque Te and the generated torque command value Te * by numerical simulation. 2 and 4 show conventional electric vehicle control, and FIGS. 3 and 5 show electric vehicle control according to the present embodiment. Here, the conventional electric vehicle control is configured such that a fixed disturbance torque set value TLset is always input to the simulator 8. The disturbance torque set value TLset is set assuming a 30 ‰ uphill when the commuter train is full.

  FIGS. 2 and 3 are simulation results assuming an activated state with a 30 ‰ up slope when the commuter train is full.

  In the conventional control, as shown in FIG. 2, the generated torque Te follows the generated torque command value Te * in the first direction, but shifts with time. As a result, the rotor angular frequency estimated value ωrest deviates with time.

  In the control of this embodiment, as shown in FIG. 3, the generated torque Te follows the generated torque command value Te * from the beginning to the end. Therefore, it can be said that appropriate acceleration was performed. Accordingly, it can be said that the present embodiment is superior to the conventional type in torque control even under the conditions assumed by the disturbance torque set value TLset.

  FIG. 4 and FIG. 5 show simulation results assuming an activated state with a 10% up slope when the commuter train is full.

  In the conventional control, as shown in FIG. 4, the engine can be started from zero speed, but the generated torque Te is lower than the generated torque command value Te *, and it is understood that the torque is reduced. This is because the rotor angular frequency estimation value ωreest is obtained from the disturbance torque setting value TLset set to be equivalent to a gradient 30 ‰ by the machine simulator rotation speed estimation formula.

  In the control of the present embodiment, as shown in FIG. 5, the generated torque Te follows the generated torque command value Te * even when the gradient is 10 ‰. Therefore, even in the case of a gradient of 10 ‰, the engine starts without a torque drop from zero speed. Therefore, it is clear that the present embodiment is superior to the conventional type in torque control under conditions not assumed by the disturbance torque set value TLset.

  According to this embodiment, based on the deviation between the detected q-axis current I1q and the q-axis current command value I1q *, the disturbance torque estimated value TLest is calculated, and the calculated disturbance torque estimated value TLest is used. The rotor angular frequency is estimated by the simulator 8. As a result, the electric vehicle control device 20 follows the torque command value Torq * even if the disturbance torque applied to the induction motor 1 fluctuates due to an external factor such as a gradient, as long as the gradient is assumed in advance. Can output the torque of the induction motor 1. Therefore, the torque characteristics of the induction motor 1 in the control near the zero speed can be improved.

  In addition, although some embodiment of this invention was described, these embodiment is shown as an example and is not intending limiting the range of invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 1 ... Induction motor, 2 ... Inverter, 3, 4 ... Coordinate converter, 5 ... Integrator, 6 ... Current controller, 7 ... Voltage regulator, 8 ... Simulator, 9 ... Disturbance torque calculation part, 10 ... Slip angular frequency Command calculating unit, 11 ... excitation current calculating unit, 12 ... torque current calculating unit, 13 ... adder, 14,15 ... subtractor, 16 ... current detector, 20 ... electric vehicle control device.

Claims (4)

An inverter that outputs AC power to an induction motor that is a power source of the electric vehicle;
AC current detection means for detecting AC current output from the inverter;
Disturbance torque estimating means for estimating the disturbance torque of the induction motor based on the alternating current detected by the alternating current detecting means;
Rotor angular frequency estimating means for estimating a rotor angular frequency of the induction motor based on a current command value for the alternating current output from the inverter and the disturbance torque estimated by the disturbance torque estimating means;
An electric vehicle control device comprising: inverter control means for controlling the inverter based on the rotor angular frequency estimated by the rotor angular frequency estimation means and the current command value. The disturbance torque estimating means estimates the disturbance torque by performing a proportional integral calculation based on a deviation between a torque component of the alternating current detected by the alternating current detecting means and a torque component of the current command value. The electric vehicle control device according to claim 1. The rotor angular frequency estimation means uses the disturbance torque estimated by the disturbance torque estimation means as a mathematical model that balances the inertial force of the rotor with the force obtained by subtracting the disturbance torque from the generated torque. The electric vehicle control device according to claim 1, wherein the electric vehicle control device estimates the electric vehicle. Detects AC current output from an inverter that outputs AC power to the induction motor that is the power source of the electric vehicle,
Based on the detected alternating current, estimate the disturbance torque of the induction motor,
Based on the current command value for the alternating current output from the inverter and the estimated disturbance torque, the rotor angular frequency of the induction motor is estimated,
An electric vehicle control method comprising controlling the inverter based on the estimated rotor angular frequency and the current command value.

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