KR100894380B1 - Electric car control device - Google Patents

Abstract

An object of the present invention is to obtain an electric vehicle control device capable of detecting a state in which only one phase of one induction motor is disconnected in a system in which a plurality of induction motors are connected and driven in parallel by one vector controlled inverter device.

The electric vehicle control device according to the present invention is based on the q-axis current I1q, the d-axis current I1d, the q-axis voltage command E1qr, the d-axis voltage command E1dr, and the inverter angular frequency ωinv, which are obtained from the vector control unit 2, and the torque of the induction motor. Torque calculation unit 5 for calculating the; A torque fluctuation range calculating section 6 for calculating a torque fluctuation range from the maximum value and the minimum value of the torque calculation result in a preset time width based on the torque calculation result; The comparator 7 which outputs a disconnection detection signal when the said torque fluctuation range exceeded the torque fluctuation range reference value is provided.

Description

Electric vehicle control device {ELECTRIC CAR CONTROL DEVICE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric vehicle control device, and more particularly, to an electric vehicle control device having a function of detecting disconnection of a motor line that supplies AC power from an inverter device to an induction motor.

In the phase detection method of the conventional electric vehicle control apparatus, the average value Iu, Iv, and Iw of each phase current of the three-phase alternating current output from the inverter device is taken, and the average value of each phase current is again obtained. The average value Io = (Iu + Iv + Iw) / 3 is obtained, and the difference between the average value of each phase current and the averaged value again | Iu-Io |, | Iv-Io |, | Iw-Io | When is over the reference value, it is detected as an open phase.

Patent Document 1: Japanese Patent Laid-Open No. 6-245301

In the conventional electric vehicle control apparatus as described above, in the case of a system in which a plurality of, for example, four induction motors are connected and driven in parallel by one inverter device controlled by vector, one of four induction motors is induced. There was a problem that only one phase of the electric motor could not detect a disconnected state. Since the current of the induction motor is controlled at high speed by the vector control, the average current of each phase for four induction motors does not change even if one phase of one induction motor is disconnected. Because of this, | Iu-Io |, | Iv-Io |, | Iw -Io | Does not exceed the reference value.

SUMMARY OF THE INVENTION The present invention has been made to solve this problem, and in the system for driving a plurality of induction motors connected in parallel with one vector controlled inverter device, the electric vehicle control capable of detecting only one phase of one induction motor is disconnected. The purpose is to obtain a device.

The present invention is an electric vehicle control device for vector-controlling an induction motor with an inverter device, which calculates q-axis current I1q, d-axis current I1d, q-axis voltage command E1qr, d-axis voltage command E1dr and inverter angular frequency ωinv of the induction motor. A vector control unit; A torque calculating unit that calculates a torque of the induction motor based on the q-axis current I1q, the d-axis current I1d, the q-axis voltage command E1qr, the d-axis voltage command E1dr, and the inverter angular frequency? Inv; A torque fluctuation calculator for calculating a torque fluctuation range from a maximum value and a minimum value of the torque calculation result in a preset time width based on the torque calculation result calculated by the torque calculator; And a comparator for comparing the torque fluctuation range calculated by the torque fluctuation range calculating unit with a preset torque fluctuation range reference value and outputting a disconnection detection signal when the torque fluctuation range exceeds the torque fluctuation range reference value.

BRIEF DESCRIPTION OF THE DRAWINGS It is a block diagram of the electric vehicle control apparatus of Embodiment 1 of this invention.

2 is an explanatory diagram showing waveforms of respective phase currents and torque calculation results in the normal state in the electric vehicle control device according to the first embodiment of the present invention.

Fig. 3 shows waveforms of the phase current and torque calculation results for each phase current in a state where the W phases of one induction motor are disconnected in the electric vehicle control device of Embodiment 1 of the present invention.

It is explanatory drawing which shows the state which W phase of one induction motor disconnected in the electric vehicle control apparatus of Embodiment 1 of this invention.

Embodiment 1.

1 shows an electric vehicle control device according to the first embodiment of the present invention. As shown in FIG. 1, four induction motors 3a, 3b, 3c and 3d are connected to the inverter device 1. These four induction motors 3a, 3b, 3c and 3d are connected in parallel and vector controlled by one inverter device 1. The vector control unit 2 is connected to the inverter device 1, and the inverter device 1 is a switching element (not shown) provided inside the inverter device 1 by a gate signal output from the vector control unit 2. The power is supplied to four induction motors 3a, 3b, 3c and 3d connected in parallel to the inverter device 1 by switching. The phase currents Iu, Iv, and Iw output from the inverter device 1 are detected by the phase current detection CTs 4a, 4b, and 4c, and are input to the vector control unit 2. The q-axis current I1q, the d-axis current I1d, the q-axis voltage command E1qr, the d-axis voltage command E1dr and the inverter angular frequency ωinv of the induction motor obtained in the process of the vector control operation performed by the vector control unit 2 are the vector control unit 2. Is input to the torque calculating section 5 from. In the torque calculating section 5, the torque calculation result Tqcal is calculated based on this input value. The corresponding torque calculation result Tqcal calculated by the torque calculating section 5 is input to the torque fluctuation range calculating section 6. The torque fluctuation range ΔTqcal calculated by the torque fluctuation range calculating unit 6 is input to the comparator 7. The comparator 7 compares the preset torque fluctuation reference value? Tqref with the torque fluctuation range? Tqcal and outputs a disconnection detection signal to the vector control unit 2 based on the comparison result.

Next, the operation will be described. In the torque calculating section 5, based on the q-axis current I1q, the d-axis current I1d, the q-axis voltage command E1qr, the d-axis voltage command E1dr, and the inverter angular frequency ωinv, input from the vector control unit 2, the following equation (1) ) Tqcal is obtained by performing the calculation of (Equation 5).

Calculation of d- and q-axis primary fluxes Φ1d and Φ1q of induction motors

Φ1d = (E1qr-R1 · I1q-sΦ1q) / ωinv (Equation 1)

Φ1q = (-E1dr + R1 · I1d + sΦ1d) / ωinv (Equation 2)

Calculation of d- and q-axis secondary currents I2d and I2q of induction motors

I2d = (Φ1d-L1 · I1d) / M (Equation 3)

I2q = (Φ1q-L1I1q) / M (Equation 4)

Calculation of Torque Tqcal of Induction Motor

Tqcal = pM (I1qI2d-I1dI2q) (Equation 5)

Where R1 is the primary resistance of the induction motor, s is the differential operator, L1 is the primary self inductance of the induction motor, M is the mutual inductance of the induction motor, and p is the maximum number of induction motors. In addition, since the torque is calculated by the following equations (1) to (5), the accurate torque can be calculated in a short time.

In Fig. 2, each phase current Iu, Iv, Iw and torque calculation result Tqcal in a normal state without disconnection in each phase wiring between the induction motors 3a, 3b, 3c, 3d connected in parallel in the inverter device 1. An example waveform is shown. The torque fluctuation calculating section 6 calculates the torque fluctuation range? Tqcal within the time width Tw by obtaining the maximum value and the minimum value of the Tqcal result of the torque calculation in the set time width Tw (corresponding to Tw1, Tw2 and Tw3 in Fig. 2). For example, when the maximum value of the torque calculation result in Tw1 of FIG. 2 is Tqmax and the minimum value of the torque calculation result in Tw1 is Tqmin, the torque fluctuation range in Tw1 is calculated as (DELTA) Tqcal = Tqmax-Tqmin.

The torque fluctuation range? Tqcal calculated by the torque fluctuation range calculating section 6 is compared with the torque fluctuation range reference value? Tqref by the comparator 7 and outputs a disconnection detection signal in accordance with the logical table as follows.

TABLE 1

Logical Disconnection detection signal

△Tqref| △ Tqcal |

△ Tqref 0 (no disconnection) | △ Tqcal | > △ Tqref 1 (with open circuit)

In the state shown in Fig. 2, the torque fluctuation range ΔTqcal is smaller than the torque fluctuation reference value ΔTqref, and as shown in the above logic table, the disconnection detection signal is “0”, so that the vector control result from the vector control unit 2 to the inverter device 1 is changed. The determined gate signal is input.

However, in the structure of FIG. 1, for example, as shown in FIG. 4, in each phase wiring between the inverter 1 and the induction motors 3a, 3b, 3c, 3d connected in parallel, the induction motor ( The case where one line of W phase of 3a) is disconnected is demonstrated. In FIG. 3, the waveform example of each phase current Iu, Iv, Iw and a torque calculation result Tqcal in that case is shown.

As can be clearly seen from Fig. 3, the waveforms of the phase currents Iu, Iv, and Iw are almost unchanged from those of the normal waveform shown in Fig. 2, but the torque calculation result shows that Tqcal is twice the frequency of each phase current. Fluctuates. Moreover, since the absolute value of torque fluctuation range (DELTA) Tqcal becomes larger than torque fluctuation range reference value (DELTA) Tqref, as shown in the said logic table, a disconnection detection signal turns into "1". When the disconnection detection signal "1" is input, the vector control unit 2 stops the gate signal, and stops power supply from the inverter device 1 to the induction motors 3a, 3b, 3c, and 3d.

In addition, the process of the vector control part 2, the torque calculating part 5, the torque fluctuation calculating part 6, and the comparator 7 is normally performed by digital calculation using a microcomputer, a digital signal processor, etc.

As described above, according to the present invention, based on the q-axis current I1q, the d-axis current I1d, the q-axis voltage command E1qr, the d-axis voltage command E1dr, and the inverter angular frequency ωinv obtained by the vector control unit. Note that the torque of the induction motor is calculated, and the result of the torque calculation changes when only one phase of one induction motor is disconnected in a system in which a plurality of induction motors are connected in parallel with one inverter device under vector control. Since the torque fluctuation range and the torque fluctuation reference value were compared to detect disconnection, only one phase of one induction motor could be detected in a system in which a plurality of induction motors were connected and driven in parallel by one vector-controlled inverter device. Can be.

In addition, when the present invention is used, the torque calculation result greatly varies even in a state where the gate signal is lost or in the disconnection state of the inverter device output, so that such an abnormality can be detected.

In the above description, the number of induction motors has been described as four, but not limited to this case, but may be one, two, five, six, or the like. 1 and 4, each phase current detection CT is assumed to be three phases, but this is not limited to this case, and only two phases, for example, 4a and 4b for detecting Iu and Iv, may be used. do. In this case, Iw is calculated in the vector control unit 2 as Iw = − (Iu + Iv).

The time width Tw at the time of calculating the torque fluctuation may be any value as long as it is an appropriate time width, but may be determined as follows. As can be clearly seen from Fig. 3, the result of torque calculation, the variation frequency of Tqcal is twice the frequency of the phase current. In consideration of this, the time width Tw at the time of calculating the torque fluctuation range is set to 1/2 or more of the phase current period at the time of calculation. In this way, since the time width Tw is always equal to or more than the torque fluctuation period, the torque fluctuation range DELTA Tqcal can be calculated accurately.

According to the present invention, the torque of the induction motor is based on the q-axis current I1q, the d-axis current I1d, the q-axis voltage command E1qr, the d-axis voltage command E1dr and the inverter angular frequency? Inv obtained by the vector control unit. Note that the torque calculation results vary when only one phase of one induction motor is disconnected in a system in which a plurality of induction motors are connected in parallel with one inverter device controlled by a vector. Since disconnection is detected by comparing the variation reference values, in a system in which a plurality of induction motors are connected and driven in parallel by one vector-controlled inverter device, only one phase of one induction motor can be detected.

Claims (3)

An electric vehicle control device for vector controlling an induction motor by an inverter device, A vector control unit for calculating the q-axis current I1q, d-axis current I1d, q-axis voltage command E1qr, d-axis voltage command E1dr, and inverter angular frequency ωinv of the induction motor; A torque calculating unit that calculates torque of the induction motor based on the q-axis current I1q, the d-axis current I1d, the q-axis voltage command E1qr, the d-axis voltage command E1dr, and the inverter angular frequency ωinv; A torque fluctuation calculator for calculating a torque fluctuation range from a maximum value and a minimum value of the torque calculation result in a preset time width based on the torque calculation result calculated by the torque calculation part; And a comparator for comparing the torque fluctuation range calculated by the torque fluctuation range calculating unit with a preset torque fluctuation range reference value and outputting a disconnection detection signal when the torque fluctuation range exceeds the torque fluctuation range reference value. The method according to claim 1, And the time width set in advance in the torque fluctuation calculator is set to 1/2 or more of a phase current period. The method according to claim 1 or 2, The torque calculating section uses the q-axis current I1q, the d-axis current I1d, the q-axis voltage command E1qr, the d-axis voltage command E1dr, and the inverter angular frequency ωinv to form the d-axis and q-axis primary magnetic flux of the induction motor. And d-axis and q-axis secondary currents, and calculating the torque from the d-axis and q-axis primary magnetic flux and the d and q-axis secondary currents.

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