JPH03155305A - Ac motor driving system for internal combustion engine - Google Patents

Abstract

PURPOSE:To obviate the necessity of auxiliary circuit generator and auxiliary internal combustion engine by constructing a VVVF inverter with low loss transistors having good frequency characteristics. CONSTITUTION:Since a transistor has lower loss and better frequency characteristics than a GTO thyristor, over speed change control is performed individually for respective main motors 22-36 through PWM control upto a high vehicle speed region while maintaining the output voltage of a main generator 12 constant over the entire speed region. Since over speed change control is not required for the voltage of the main generator 12, a stabilized power source can be obtained. Since transistor inverters 50-70 are inexpensive compared with a GTO thyristor inverter, overall cost does not increase even when an inverter is provided for each of the main motors 22-36.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to an AC generator for an internal combustion engine vehicle in which a generator is operated by an internal combustion engine mounted on the vehicle, and the generated power is converted inside the vehicle to drive an induction motor. Regarding electric motor drive system.

[Conventional technology]

Conventionally, the system shown in Figure 2 is known as an AC motor drive system for vehicles equipped with this type of internal combustion engine, and when applying induction motor drive to a vehicle equipped with such an internal combustion engine, there are economical considerations. Electric motor for driving each axis (main motor)
A method is adopted to control the functions as collectively as possible. As a constituent element of a variable voltage variable frequency inverter (hereinafter referred to as an inverter), a gate turn-off (hereinafter referred to as GTO) thyristor, which is a self-extinguishing semiconductor element having high withstand voltage and large current characteristics, is used due to the device capacity. Reference numeral 10 in FIG. 2, which is often used, is a driving internal combustion engine, and this driving internal combustion engine 10 drives a main generator 12, and the output power of the main generator 12 is generated by a three-phase diode bridge. It is forward converted by the main rectifier 14 of the configuration. The forward-converted output of the main rectifier 14 is supplied all at once to the main motor 22.24.26 via an inverter 20 consisting of a GTO thyristor.
Similar GTO thyristor inverters 3 connected in parallel
The main electric motors 32, 34 and 36 are also supplied together via 0. Furthermore, during braking, this series circuit is connected in parallel to the inverter 20.30 in order to perform dynamic braking in which the energy of the main motor is consumed in the series circuit of the brake chopper 18 and the brake resistor 16. Also,
The vehicle is further equipped with an auxiliary internal combustion engine 40, which drives an auxiliary generator 42 and supplies generated electric power to an auxiliary circuit (not shown).

For such a configuration, a control method shown in FIG. 3 is adopted. Figure 3 shows the relationship between the main generator voltage, the inverter output voltage, the inverter output frequency, and the vehicle speed. @ (PWM) control is performed, and a method is adopted in which the voltage of the main generator is controlled by one pulse control between vehicle speeds vA and ■1 which are medium speeds or higher. Here, the reason why the PWM control is limited to the low speed region is to suppress heat generation due to switching loss of the GTO thyristor.

[Problem U that the invention seeks to solve]

However, according to the above-mentioned AC motor drive system for internal combustion locomotives, when the vehicle speed is medium speed or higher, the main generator voltage changes significantly because the main generator voltage is controlled to change the inverter output frequency. do. Therefore, the main generator cannot be used as a power source for auxiliary circuit equipment that requires constant voltage and constant frequency, such as lighting and air conditioning inside the vehicle.For this reason, in the conventional system, a separate dedicated generator for auxiliary circuits is required. This required an internal combustion engine and a generator, making the vehicle as a whole expensive.

In addition, since the configuration is such that multiple traction motors are collectively controlled by one inverter, for example, if a wheel is spinning or skidding, the inverter will reduce the output voltage, but if the wheel that is not spinning or skidding is healthy, the inverter will reduce the output voltage. Also, the output voltage has to be narrowed down, which poses a problem of degraded performance.

Therefore, an object of the present invention is to be able to reduce the cost of auxiliary circuit equipment such as lighting and air conditioning and the auxiliary internal combustion engine, and to replace each shaft drive electric motor with a separate inverter without increasing the cost of the entire vehicle. An object of the present invention is to provide an AC motor drive system for an internal combustion locomotive that can be driven by an internal combustion engine.

[Means to solve the problem]

The AC motor drive system for internal combustion locomotives according to the present invention operates a main generator using an internal combustion engine mounted on the vehicle, converts the generated power into direct current using a main rectifier inside the vehicle, and then converts the generated power into direct current via a variable voltage variable frequency inverter. AC electric motor IIWI for internal combustion engine vehicles that performs speed control operation of multiple shaft drive main motors.
In the A-driving system, the main generator voltage is kept constant, variable voltage variable frequency inverters using transistors as switching elements are installed in each of the plurality of main motors, and pulse width modulation control of the inverters is performed over the entire speed range. The present invention is characterized in that the speed control operation of the main motor is performed by the above-described method, and the constant voltage output of the main generator is used as an auxiliary power source in the vehicle.

[For production]

According to the AC motor drive system for internal combustion locomotives according to the present invention, the variable voltage variable frequency inverter has a transistor configuration with low loss and good frequency characteristics, thereby making the main generator output a constant voltage and driving the shaft drive motor. Speed control can be PWM controlled over the entire vehicle speed range. Therefore, the constant voltage output of the main generator can also be used as an auxiliary circuit power source within the vehicle.

Further, an inverter is installed in each shaft driving electric motor, so that speed control can be performed for each electric motor.

〔Example〕

Next, an embodiment of the AC motor drive system for an internal combustion engine vehicle according to the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a system configuration diagram of an AC motor drive system for an internal combustion engine vehicle, showing an embodiment of the present invention. For convenience of explanation, the same reference numerals are given to the same components as those shown in the conventional example shown in FIG. 2. In FIG. 1, reference numeral 10 indicates an internal combustion engine, and the internal combustion engine 10 drives a main generator 12 at constant rotation.

The constant voltage output of the main generator 12 is supplied to an auxiliary circuit (not shown), and is forward converted by a main rectifier 14 having a three-phase diode bridge configuration. The forward-converted DC output of the main rectifier 14 is transferred to inverters 50, 60, . . . with transistors connected in parallel. ..., 70. Each inverter 50, 60. . . , 70 has one main motor 22, 24 . ..., 36
will be installed. Further, a series circuit of a brake resistor 16 and a brake chopper 38 is connected in parallel to the output end of the main rectifier 14.

For a system configured in this way, each inverter 50,60 configured with a transistor as a switching element
．． . . , 70 adopts a control method as shown in FIG. In other words, in this control method, the transistor is G 'T'
Since it has low loss and excellent high frequency characteristics compared to an O thyristor, the output voltage of the main generator 12 is held constant over the entire speed range, and the PW
Each main motor 22, 24 . ..., 3
Variable speed control is performed individually for every 6. Therefore, since there is no need to control the voltage of the main generator 12 at variable speed as in the conventional example, it can be used as a stable power source for the auxiliary circuit. Also, transistor inverter 50.6
0. ..., 70 is the GTO thyristor inverter (
20, 24. Even if one inverter is installed in each of the main electric motors 22, 24, 24, . ..., 36, inverters 50, 60, ..., 70, the brake resistor 16 and the brake chopper 38, and are consumed as heat.

〔Effect of the invention〕

As is clear from the embodiments described above, according to the AC motor drive system for internal combustion engine vehicles of the present invention, PWM control is possible over the entire speed range by employing an inverter using low-loss transistors. The main generator is driven by the internal combustion engine to a constant rotation speed and can maintain the main generator output voltage at a constant value, so it can be used as a stable power source for auxiliary circuits such as lighting and air conditioning in the vehicle. can. Therefore, an auxiliary internal combustion engine and an auxiliary generator are not required, and since an inexpensive transistor inverter is used, the vehicle as a whole can have a simple configuration and an inexpensive system.

In addition, since each shaft drive traction motor is controlled by an individual inverter, the output voltage can be narrowed down only to the traction motor whose wheels are spinning or skidding, for example, and healthy wheels can be This eliminates the disadvantage of reducing the performance of the main electric motor ts by reducing the output voltage, and rather improves the performance.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and it goes without saying that various design changes can be made without departing from the spirit of the present invention.

[Brief explanation of the drawing]

FIG. 1 is a system configuration diagram showing an embodiment of an AC motor drive system for internal combustion locomotives according to the present invention, FIG. 2 is a system configuration diagram showing a conventional AC motor drive system for internal combustion locomotives, and FIG. A diagram of the relationship between the main generator output voltage, inverter output voltage/frequency, and vehicle speed showing the vehicle speed control method of the conventional system configuration. FIG. 4 shows the main generator 'CAR' in the vehicle speed control method according to the embodiment shown in FIG. FIG. 3 is a characteristic diagram showing the relationship between the output voltage, the inverter output voltage/frequency, and the vehicle speed. 42... Auxiliary power supply 50.60.70... Variable voltage variable frequency inverter 10... Drive internal combustion engine 12... Main generator 14... Main rectifier 16... Brake resistor 18...・Brake chopper 20...Variable voltage variable frequency I 22.24.26...Main motor 30...Variable voltage variable frequency I 32.34.36...Main motor 38...Brake chopper 40...・Auxiliary internal combustion engine inverter Fl (3

Claims (1)

[Claims] (1) After the main generator is operated by the internal combustion engine mounted on the vehicle and the generated power is converted to DC by the main rectifier inside the vehicle, the speed of the main motors for driving multiple shafts is controlled via the variable voltage variable frequency inverter. In an AC motor drive system for internal combustion locomotives, the main generator voltage is kept constant, and a variable voltage variable frequency inverter using a transistor as a switching element is installed in each of the plurality of main motors to operate the main motor over the entire speed range. An AC motor drive system for an internal combustion engine, characterized in that the speed control operation of the main motor is performed by pulse width modulation control of the inverter, and the constant voltage output of the main generator is used as an auxiliary power source in the vehicle.