JP2667291B2 - Control method of voltage type VVVF inverter for driving DC electric vehicle - Google Patents

Description

The present invention relates to a control method of a voltage source VVVF (variable voltage variable frequency) inverter for driving a DC electric vehicle.

[Prior Art] The applicant has previously proposed a VVVF inverter system using a voltage source inverter in which a DC input side is connected in series.

FIG. 5 is a schematic diagram showing such a proposed system, and FIG.
The figure is an operation waveform diagram for explaining the operation. Fifth
In the figure, 1 is a pantograph, and 2 is an inverter input circuit including a switch and a reactor. Reference numerals 31 to 34 denote inverter units including an input capacitor, and reference numerals 41 to 44 denote vehicle drive motors, to which vehicle drive wheels (not shown) are connected. 310 to 340 are shunt circuits composed of a series circuit of a resistor and a chopper (transistor chopper).
41 is a resistance and 312-342 are choppers. This shunt circuit shunts the current flowing into the inverter (equal to the current in the input circuit of the inverter) when the output of the inverter unit decreases due to slipping or sliding of the wheels. In other words, when the wheels spin or slide, the input current to the inverter unit decreases, but the pantograph 1
Since the same current continues to flow in from, the chopper of the shunt circuit is operated to divide the difference.

 The operation will be described with reference to FIG.

Until the time t ₁ of FIG. 6 is a normal operation, the input current i _d1 through i _d4 of the inverter unit 31 to 34 is the same as the inverter input circuit current i _d0. The wheel coupled to the motor 41 at time t ₁ (not shown) is idle, the input current i _d1 of the inverter unit 31 becomes substantially zero, the current i _d0 is flowing continuously into the shunt circuit 310 Inflow. The transistor chopper 312 adjusts the conductivity according to the magnitude of the shunt current i _d0 , and passes the current i _R1 to the shunt circuit. At this time, the input currents i _{d2 to} i _d4 of the other inverter units are i
Same as _d0 . When the idling behavior at time t ₂ is extinguished, also becomes zero current of the input current is also i _d0 next shunt circuit of the inverter unit 31.

FIG. 7 is an explanatory diagram for explaining a frequency operation in a case where idling occurs in one of the plurality of series-connected inverters.

In this case, each inverter unit is individually controlled, and the output frequency of each inverter is a value corresponding to the load (wheel). If the wheels do not spin, the inverter frequency has a value proportional to the vehicle speed. However, if the wheels spin, the inverter frequency becomes irrelevant to the vehicle speed. That is, the symbol A (dotted line) in FIG. 7 indicates the inverter frequency driving a wheel with idling, and the symbol B (solid line) indicates the inverter frequency driving a wheel with no idling (healthy shaft). Is shown. That is, when idling at time t ₁ is assumed to have occurred, the wheel speed of the generated torque idling the axis motor soared, reaching a maximum frequency f _max at time t _10. f _max
Is equivalent to the inverter frequency limit, so that the inverter frequency does not rise any further. After that, when the slipping phenomenon disappears at time t _2, the frequency of the idle shaft also returns to rapidly and to the frequency of the sound axis.

Note that in the case of gliding, the operation is the same as above _except that the frequency becomes zero instead of fmax.

[Problems to be solved by the invention]

In such a system as described above, when idling or gliding occurs on one axis, the frequency of the corresponding inverter becomes the maximum frequency (for gliding) or zero (for gliding). Thereafter, when the idling or sliding phenomenon disappears, the idling or sliding axis rapidly returns to the frequency of the sound axis, but at this time, the following problem occurs.

i) Since the rotation speed of the drive shaft changes rapidly, a large torque is applied to the shaft, and the shaft is damaged and the wheels and the rail surface are damaged.

ii) Since the inverter frequency changes rapidly, the inverter control cannot follow and the control becomes unstable.

[Means for solving the problem]

In order to solve the above problems, the present invention relates to a voltage type VVVF inverter which collects power from a DC train line and drives a motor for a DC electric vehicle by connecting a plurality of voltage type unit inverters in series on the DC input side and individually controlling the voltage type unit inverters. When idling or sliding occurs in the driving wheels connected to the electric motor, the output frequency of the unit inverter that drives the driving wheels, and in the case of idling, the frequency of the unit inverter that drives the non-idling driving wheels A unit that drives a non-sliding drive wheel in the case of skidding by controlling the frequency so that it does not become higher than the frequency obtained by adding a predetermined constant value to either the average value, the maximum value, or the minimum value. The inverter frequency is controlled so that it does not become lower than the frequency obtained by subtracting a predetermined constant value from the average value, the maximum value or the minimum value of the inverter frequency.

[Action]

Even if slipping or skidding occurs, the inverter frequency does not rise or fall unnecessarily, so even if the slipping or skidding phenomenon disappears and returns to the frequency of a healthy shaft, the change in the rotation speed is small, and as a result In addition, there is little damage to the drive shaft, wheels or rails, and control becomes easy.

〔Example〕

FIG. 1 is a schematic diagram showing a DC electric vehicle system in which the present invention is implemented, and FIG. 2 is an explanatory diagram for explaining the operation of the present invention.

In FIG. 1, reference numerals 51 to 54 denote rotational speed detectors of the electric motors 41 to 44, 61 to 64 denote inverter output current detectors, and 71 to 74 denote inverter input voltage detectors. Reference numerals 101, 102, and 103 denote detection lines for sending these detected values to the inverter control device 100. The inverter control device 100 performs predetermined control based on these values. In addition, 104 is a control line of the inverter, 105 is a chopper control line, and the others are the same as FIG.

 The operation of the present invention will be described with reference to FIGS.

First, the motor rotation speed, the inverter output current and the inverter input voltage are detected from the detection lines 101, 102 and 103, respectively, thereby detecting the slipping axis and the sliding axis in which the slip or the sliding has occurred. At this time, the rotation speed (or inverter frequency) of the non-spinning shaft and the non-sliding shaft is also detected. The frequency of the idle inverter tends to rise sharply, but here a frequency limit slightly higher than the frequency of the non-idle shaft is imposed. The situation at this time is shown as Δf (+) in FIG.

On the other hand, the frequency of the sliding inverter tends to decrease sharply, but here a frequency limit slightly lower than the frequency of the non-sliding axis is applied. The situation at this time is shown in FIG.
Shown as f (-).

Note that Δf (+) and Δf (−) are appropriately selected,
In any case, the value that takes this into account is the specified value (expected error or load fluctuation in either the average value, the maximum value, or the minimum value of the frequency of the unit inverter driving the wheels that are not spinning or skidding). However, the value does not exceed a certain value).

Then, at time t ₂ , when the slipping or gliding phenomenon disappears,
Immediately remove such a limitation and return to the frequency of the sound axis. In addition, such control is performed by the inverter control device 100 through the control line 1
Will be done via 04. In addition, in the above, Idling, gliding 3
Although the detection is performed by using one type of signal, the detection may be performed using one or two types of signals.

By the way, in order to continue the normal operation of the other healthy axis even if one axis slips or slides, a shunt circuit including a resistor and a chopper is required on the input side of the inverter. Therefore, focusing on the fact that if the output of the inverter is reduced, the input current can be reduced, and if the idling or sliding occurs even in one axis, the output of the inverter of the healthy axis is immediately reduced, so that the shunt circuit can be formed. It turns out that it can be made unnecessary.

FIG. 3 is a schematic diagram showing a system for realizing such a method, FIG. 3A is a partially detailed diagram thereof, and FIG. 4 is an operation waveform diagram for explaining its operation.

As is clear from FIG. 3, the system configuration is almost the same as that shown in FIG. 1, and the difference is that the chopper control line is omitted because the shunt circuit is not required. Details are also omitted. The inverter units 31 and 32 in FIG. 3 are configured by unit inverters 301 and 302 and input capacitors 401 and 402, for example, as shown in FIG. 3A.

Next, the operation will be described with reference to FIG. 3A and FIG. 4. Here, it is assumed that the wheels connected to the electric motor 41 idle and the other wheels are sound. The symbols of the input current are the same as those in FIGS. 5 and 6.

Now, when idling at time t ₁ shown in FIG. 4 it is assumed that occurred, the unit inverter 301 of the inverter unit 31
Of the input current i _d1 decreases from i _d0 to i _d0 ′ corresponding to almost zero. The difference current between i _d0 and i _d0 ′ becomes i _C1 and flows through the input capacitor 401. The voltage of the input capacitor 401 rises due to this current. However, detectors 51, 61, 71
Thus, at 51, the rotation speed is detected, at 61, the current is reduced, and at 71, the voltage is detected. Times of Day
When this is detected at t _10, (in this case 32) healthy inverter is not idling to reduce the output current of, reduces the inverter input current from the i _d0 to i _d0 '.
Since the input current of each inverter unit becomes i _d0 ′, the current of the input circuit (corresponding to the input current of the VVVF inverter system) i _d also decreases to i _d0 ′, and the input capacitor 401
Does not become overvoltage. Then, at the same time increasing the output of all the inverter at time t ₂ when the idle phenomenon disappears, returns the input current from the i _d0 'to i _d0.

〔The invention's effect〕

According to the present invention, when slipping or sliding occurs even in one axis, the inverter frequency is limited so as not to be higher or lower than necessary. I) The rotation speed change width when the slipping or sliding phenomenon disappears is small. Therefore, stress on the drive shaft is small and damage to the axle and rail surface can be eliminated.

ii) Since the change of the inverter frequency is small, the control can be stably performed.

iii) Since the time required for the idling and sliding axes to return to normal is shortened, so-called re-adhesion characteristics are greatly improved.

Advantages such as are obtained.

In addition, if slipping or sliding occurs even in one axis, the output of the inverters of other healthy axes can be reduced to a) eliminate the resistor and chopper shunt circuits that were required in the past, thus reducing the weight of the VVVF inverter system. It can be made smaller, more compact, or cheaper.

b) Even with one shaft, if the vehicle runs idle and slides, the inverter output decreases to the healthy shaft, but this is the same as the conventional system in which a single inverter drives a plurality of electric motors, and does not cause any particular reduction in performance.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a system to which the present invention is applied, FIG. 2 is an explanatory diagram for explaining its operation, FIG. 3 is a schematic diagram showing another system to which the present invention is applied, and FIG. FIG. 4 is a partially detailed diagram, FIG. 4 is an operation waveform diagram for explaining the operation, FIG. 5 is a schematic diagram showing the proposed system, and FIG.
FIG. 7 is an explanatory diagram for explaining the shunt operation during idling in FIG. 5, and FIG. 7 is an explanatory diagram for explaining the frequency operation during idling in FIG. Description of symbols 1 ... pantograph, 2 ... inverter input circuit, 31-
34 …… Inverter unit, 41-44 …… Electric motor, 51-54
…… Rotation speed detector, 61-64 …… Current detector, 71-74 ……
Voltage detector, 100: Inverter control device, 101: Rotation speed detection line, 102: Current detection line, 103: Voltage detection line, 10
4 ... Inverter control line, 105 ... Chopper control line, 301,
302 Unit inverter, 401, 402 Input capacitor, 310 to 340 Shunt circuit, 311 to 314 Resistance, 312 to 3
42 ... Chopper (transistor chopper).

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shigenori Kinoshita 1-1, Tanabe-Nitta, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture Inside Fuji Electric Co., Ltd. No. 1 Inside Fuji Electric Co., Ltd. (72) Michio Iwahori 1-1, Tanabe Nitta, Kawasaki-ku, Kawasaki City, Kanagawa Prefecture Inside Fuji Electric Co., Ltd. (72) Naoto Yoshinori No. 1, Tanabe Nitta, Kawasaki-ku, Kawasaki City, Kanagawa Prefecture No. 1 Inside Fuji Electric Co., Ltd. (72) Inventor Hideaki Ishibashi 1-1-1, Tanabe-Nitta, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture Inside Fuji Electric Co., Ltd. (56) References JP-A-4-46502 (JP, A) JP-A-3-261307 (JP, A) JP-A-59-136004 (JP, A) JP-A-56-132186 (JP, A) JP-A-50-114431 (JP, A)

Claims (2)

(57) [Claims] 1. A voltage type VVVF inverter which collects power from a DC train line and drives a motor for a DC electric vehicle by connecting in series at a DC input side thereof and individually controlling the voltage type VVVF inverters. In the event of a slip or gliding of the drive wheel, the output frequency of the unit inverter driving the drive wheel is used. In the case of a slip, the output frequency of the unit inverter driving the non-slip drive wheel is averaged, Control so that the frequency does not become higher than the frequency obtained by adding a predetermined constant value to either the value or the minimum value.In the case of gliding, the average of the frequency of the unit inverter driving the non-sliding drive wheel is controlled. DC electric vehicle drive characterized in that control is performed so that the frequency does not become lower than a frequency obtained by subtracting a predetermined constant value from one of a value, a maximum value and a minimum value. Method of controlling the voltage-type VVVF inverter. 2. A voltage type VVVF inverter, which collects power from a DC train line and drives a motor for a DC electric vehicle by connecting in series on a DC input side thereof and individually controlling the voltage type VVVF inverter, is connected to the motor. A voltage-type VVVF inverter for driving DC electric vehicles, characterized in that, when a slip or gliding occurs on a driving wheel, the output current of all unit inverters driving the driving wheel without slip or gliding is reduced. Control method.