JPS58103807A - Control system for electric rolling stock - Google Patents

Abstract

PURPOSE:To prevent an excessive exciting current from flowing by controlling the output frequency of an inverter in response to a set current value signal and controlling the output voltage of the inverter in response to the set current peak value signal or set current ripple signal. CONSTITUTION:A deviation amplifier 35 controls a voltage controlled oscillator 24 according to the deviation signal between the motor current command responding to the vehicle speed outputted from a motor current instruction unit 32 and the detected value of a current detector 34, and applies the frequency becoming the reference of an inverter frequency to a modulator 26. A current regulator 22 applies the output voltage command of the inverter to the modulator 26 so that the instantaneous current value from an instantaneous current detector 33 may not exceed the peak current value set by a setter 31 or the ripple value. In this manner, it can prevent the excessive exciting current from flowing.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control system for an electric vehicle that obtains power by driving a squirrel cage cast conduction ridge using a variable voltage/variable frequency inverter (hereinafter referred to as a VVVF inverter) using a thyristor or the like. This is a practical electrical method for controlling squirrel cage conduction motors and VVVF inverters so that the squirrel cage conduction motors and VVVF inverters are kept in a clear condition and an excessive negative current is not applied to the VVVR inverters. The aim is to provide a vehicle control system.

Fig. 1 shows the basic configuration of a vehicle system driven by a vvvy inverter applied to the present invention, in which 1 is a DC overhead wire, 2 is a pantograph, 3 is a switch, 4 is a filter reactor, and 5 is a filter capacitor, 6maro,
ab, . However, these are not limited to reverse conduction thyristors, and may be a general thyristor or a GTO thyristor, etc., and a diode in antiparallel. It is acceptable if it is an element case or an element pair that has the function of circulating the motor reactive current as a load when the thyristor is off. However, in the case of general thyristors and reverse conduction thyristors, it goes without saying that a commutation auxiliary circuit, which is not shown in Figure 1, is required.
are the positive and negative motherboards, 19 is the wheel, 10 is the rail, a llu, IIY, and IIW are the output AC paths of the v v v F inverter, and a plurality of three-phase squirrel cage electric motors *MteMm, ・. . . 0 connected to Mm. FIG. 2 shows the medium conductor power conversion element 6a shown in FIG.

sb, .
g is a GTO thyristor, @h is a feedback diode, 6k in FIG. 2(b) is an ordinary thyristor, and ah is a feedback diode similar to FIG. 2(a).

FIG. 3 is a known example showing a control block diagram of the main circuit system described in FIG. 1 or 2.
Reference numeral 20 is a traction motor torque or vehicle tension cover turn setting device, which is a block that generates a torque pattern commensurate with the vehicle speed as shown in the characteristic curve shown in FIG. Normally, it is used to synthesize signals from an oscillator 24, etc. 20 is a current command generator that generates a current command commensurate with the torque command given from the torque button setting device 20, and 20b is a current command generator that generates a current command commensurate with the torque command given from the torque command signal. The current command generator goa e slip frequency command II Rob, which is a slip frequency command generator that generates a slip frequency command commensurate with the current command, has a nonlinear function generation function as described in No. SvA. whom is the current command and slip frequency command of the output signal of the current command generator 20m and the slip frequency #L thrust command unit 0b when changing the traction motor torque T1, that is, acceleration or load.The slip frequency and current value are as follows: Even for the same torque T1, the temperature rise value of the 8th order resistance of the induction motor causes a wide change as shown by the broken line, and without compensating for this, this type of drive system may not be practical. .

To explain Fig. 3, electric ms+generator 201
The output of is fed back from two current feedback signal inclusion circuits (
Find the value of the difference between the actual electric spa amount value and the current that amplifies the deviation from the actual value through the algebraic addition point
! It is converted into a voltage command by the Il generator 22, and is added as one of the inputs to the modulation circuit 26 having a vvvr inverter output voltage adjustment function.The slip frequency command output from the slip frequency command generator 26b is also output from the tachogenerator! Motor-linked expansion series II from 9
The motor rotation speed fed back through the signal matching circuit 30 is added at the addition point 23 to generate one torque.The signal obtained by adding the sliding frequency to the actual speed is sent to the voltage controlled bullet oscillator 24. In addition, a frequency that becomes a reference for the desired VVVF inverter wave ridge is generated. 1!6 is a frequency divider, which appropriately divides the oscillation frequency of the voltage controlled bullet oscillator 24 to obtain vvv.
Perform processing suitable for the operation of the r inverter 28. The output of the frequency divider 2s is added as another input to the modulation circuit 26. The output of the modulation circuit 26 is applied to two current feedback circuits and a VVVF inverter 28 as shown. The VVVF inverter of the first IEI described above is an example of a device that performs so-called PWM control, and mixes the output of the modulation circuit 6 and the output of the voltage-controlled bullet oscillator 24 to control the output voltage during the pulse, thereby controlling the VVVF inverter output current. Figure 7 (1) for controlling the stabilization generation torque
An example of the output-to-voltage waveform of a 4ζvvvr inverter is shown below, but in general, the number of pulses during a half cycle is low speed and low frequency is high (to prevent the magnetic circuit from becoming saturated).
For convenience, one way to avoid increasing the VVVF inverter frequency is to change the number of half-cycle pulses in some way depending on the vehicle speed, but this technology is already well known and will be omitted here. Now, 3-phase squirrel cage trout conduction motor" * * Ms#...
, Mn's primary current varies non-linearly depending on the motor load as shown in FIG.
voltage signal and modulation circuit! ! If the frequency signals from 6 and 6 are not matched, there are drawbacks such as a large amount of reactive current resulting in no torque, or an overexciting current with a high desired value flowing, resulting in increased noise and vibration.

P7 The present invention has been made with attention to this point, and the present invention will be explained below with reference to the control block shown in FIG. 4. In addition, in the figure, the same numbers and symbols are given to block parts that have the same functions as those in the known control block diagram of FIG. 3. The difference between FIG. 4 and FIG. 3 is that in diagram 4 there is no current pattern generator to generate the desired torque. That is, in the control block diagram of the present invention shown in FIG. 4, the current peak value IP, ripple value 1. On the output line of the modulation circuit 26, an instantaneous current value detector 33 detects the instantaneous current value, and the detected signal is sent to the current feedback signal matching circuit 27 to set the above-mentioned setting. The current peak value 1. The current −
Adjuster 22 makes the adjustment. The current regulators 1 and 2 are used to generate regulated voltage command signals, and the output signal of the current regulator 22 controls the PWM pulse width of the VVVF inverter, and thus the voltage average value, as mentioned above. It is similar to the current regulator 22 in Figure 3. Additionally, a voltage control target value proportional to the frequency is provided in advance, and the current peak value I, 13 pull value I, etc. are set so as not to exceed a predetermined value. It is also effective to use it as a compensation element. For example, this system can avoid troubles in which the voltage 8 frequency of the VVVF inverter output is unbalanced and excessive excitation current flows due to changes in motor resistance due to temperature or wheels 9 idling.

Also, the motor current command device 32 is similar to the slip frequency command generation * sob shown in FIG. be.

The motor current command output from the motor current command device 32 is soft-calculated with the detected value of the current detector 34 at the addition point 23, and the deviation amplification -35 is activated so that one command and the detected value are equal to each other.
Deviation increase width 111! The output of I controls the voltage-controlled vibrator 24 in the same way as in the case of FIG.
indicates the vvvr inverter input current (direct a), but it is also possible to detect the electric current mIr and Ir as shown in the input waveform.

Applying a constant excitation current regardless of the speed and providing a slip frequency commensurate with the desired torque are the basics of conductive motor control.According to the method of the present invention, the basic principle can be achieved using a relatively simple method. It is possible to perform control close to

[Brief explanation of the drawing]

Fig. 1 is a main circuit configuration diagram of a vehicle system driven by a VVVF inverter applied to the present invention, and Fig.
A diagram showing a power conversion element pair of another configuration example used in the power converter shown in the figure, both SvA and 4WA are control block diagrams, FIG. 3 is a known example, and FIG. The explanatory diagram, Figure 6, shows the vehicle speed and tensile force (torque) commonly used in electric cars. Current force characteristics - diagram, Figure 6 is a diagram of characteristics such as primary current and slip frequency of induction motor with respect to torque 1, Figure 7 (1), (b) and (C) are VVVF inverter FIG. 3 is a waveform chart showing the output voltage, current, and input current of. l...DC overhead wire, 2...pantograph, 3
...Switch, 4...Filter reactor, 5...Filter capacitor, 6a to 6f...Tei conductor power conversion element, 9... ... Wheel s 20 ... Torque pattern setter, 201 ... Current command generator, 20b ... Slip frequency command device, 22 ...
...Current regulator, 24...Voltage control token,
2S... Frequency divider, 26... Modulation circuit,
2F...Current feedback signal matching circuit, 28...
...vvvy inverter, 30...Motor speed feedback signal alignment circuit, 31...Setter, 32...
...Motor current command, 33...'IIE
Current instantaneous value detector, '34...Current detector s 8
B... Deviation amplification device. Atsushi Doi, representative of Toyo Denki Seizo Co., Ltd., the applicant for the approval! - Section 2 (g) (b) Tame 4 figure θ γ Lua cho 1 hair 71 sword

Claims (1)

[Claims] Predetermined torque six turns according to vehicle speed Electric fIt value setting + power and electric s mechanical electric tIt411 [output means, current peak value setting means or current ripple setting means corresponding to IIIk'WLtIt value when air gap magnetic flux is appropriate, and electric rlLil
In an electric vehicle drive system that drives a squirrel-cage casting main motor by a variable voltage/variable frequency inverter having at least an 11 o'clock value detection means, the slip frequency of the inverter is controlled so that the desired current value flows, and the current An electric vehicle control system in which the voltage division of the inverter is performed as %IIE so that the peak value is similar to the current peak value setting means or the current ripple setting means.