JPH0767389A - Motor driving device - Google Patents

Abstract

PURPOSE:To prevent a motor from being stopped frequently due to overheat when a motor drive device is miniaturized and light by protecting a power switch element from overheat by stopping the drive of the motor when detecting the overheat of an inverter and at the same time issuing an alarm externally at a lower temperature than that reaching the stop. CONSTITUTION:In a motor driving device 2 by an inverter 13, a temperature switch A15 and a temperature switch B16 are laid out and fixed closer to an inverter 13 of a cooler 12 and the state of temperature switches A15 and A16 is monitored by a CPU 14. Then, when the temperature of the cooler 12 rises for example above 80 deg.C, the temperature switch A15 operates first, the CPU 14 recognizes it as overheat, and then an external communication means 11 gives a warning. Further, when temperature exceeds for example 90 deg.C, the temperature switch B16 operates and the CPU 14 recognizes it as an abnormal overheat, thus stopping the drive of a motor 3. Therefore, overheat can be protected as needed without stopping operation, thus achieving miniaturization and reducing weight.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor drive device using an inverter or a chopper.

[0002]

2. Description of the Related Art If a motor is driven by using an inverter or a chopper, the voltage applied to the motor and the drive frequency can be varied as desired, so that it is often used as a driving method for induction motors, DC motors, brushless DC motors and the like. ing. As an inverter or chopper switch,
Thyristor, bipolar transistor, MOS-FE
Semiconductor power switch elements such as T and IGBT are used. In the motor drive device, the power switch is configured as a three-phase bipolar, three-phase unipolar, two-phase bipolar, or chopper according to the application, as well as a pre-drive circuit section for driving and controlling the power switch element, and internal power switch element by energization It is composed of a radiator for dissipating heat generated from the loss of heat to the outside of the apparatus, a control unit for driving and controlling the motor, an external communication means with an external system, and the like. The heat radiator is designed so that the power switch element will not be destroyed by heat in accordance with the worst conditions such as the operating temperature, the inverter loss, and the operating time even under the normal motor operating conditions. ,
In most cases, the above-mentioned conditions are extremely rare in the worst case. That is, the maximum operating temperature is 60 ° C
This is because the design is performed under conditions of 80 ° C., the inverter loss is 3 times at the maximum in the rated operation, and the worst continuous operation in the operation time. Still abnormal overload,
Alternatively, when overheating of the inverter is detected due to an abnormal rise in ambient temperature or the like, motor driving is stopped to protect the power switch element from damage due to overheating.

[0003]

Conventionally, in the radiator, the required thermal resistance of the radiator is calculated from the maximum loss as an inverter, the maximum operating temperature range, and the operating time required from the motor operating conditions. The size of the radiator and cooling methods such as natural air cooling, forced air cooling and forced water cooling are designed. However, the radiator and drive device designed as described above have a large or complicated cooling structure and are not suitable for mounting on a moving body such as an electric vehicle. That is, in the case of an electric vehicle that uses a battery as a power source, it is required that the equipment mounted in order to maximize the power performance be small, lightweight, and highly energy efficient. With respect to these requirements, the conventional structure increases the volume and weight of the radiator. Alternatively, energy loss for driving the blower or the like always occurs due to forced cooling. Alternatively, piping and a system for flowing cooling water are required, which leads to an increase in weight. There was a problem such as. Further, simply reducing the size and weight is not preferable because the drive device is frequently stopped due to overheating.

[0004]

The motor drive device of the present invention, which has been made in view of the above problems, has means for detecting the temperature of the inverter, and a protection function for stopping the drive of the motor when the inverter is overheated. It is characterized in that it has an external communication means for warning that the inverter is overheated, and that the external communication means issues an alarm to the outside at a temperature lower than a temperature at which motor driving is stopped due to overheating of the inverter.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a block diagram for explaining the structure of the motor drive device of the present invention. The motor drive device includes an inverter block including a smoothing capacitor 17, an inverter 13, a current sensor 18, and the like, and a control circuit block including a CPU 14, a gate circuit, an inverter drive circuit, a system reset circuit, and the like. Is used as a power source to drive and control the motor 3. The inverter blocks are arranged and fixed to the radiator 12, and the heat generated by the loss generated by the inverter 13 is
It is mainly radiated to the outside of the driving device through the radiator. The temperature switch A15 and the temperature switch B16 are arranged and fixed on the radiator so as to be close to the inverter, and are connected to the CPU, respectively, and the CPU monitors the state of each temperature switch. The temperature switch A is a switch that opens when the temperature exceeds 80 ° C., and the temperature switch B is a switch that opens when the temperature exceeds 90 ° C. When the loss of the inverter is large, the temperature of the radiator rises, and the temperature of each temperature switch rises accordingly. When the temperature exceeds 80 ° C., the state of the temperature switch A first changes from conduction to open, the CPU recognizes the state change, recognizes that it is overheated, and issues a warning by the external communication means.

When the temperature exceeds 90 ° C., the temperature switch B
State changes from conduction to open state, the CPU recognizes the state change, recognizes abnormal overheating, and stops driving the motor.

Although an example using two temperature switches has been described here, a thermistor and a resistance voltage conversion circuit may be used. Further, the temperature setting is determined by the installation relationship between the inverter, the radiator, and the temperature switch, the thermal resistance, and the set temperature difference between the temperature switch A and the temperature switch B is determined by the heat capacity of the driving device. It is not limited to.

FIG. 2 is a block diagram illustrating the configuration of an air conditioning system for an electric vehicle using the motor drive device of the present invention. The battery 1 is connected to the motor driving device 2, and the motor driving device drives and controls the motor 3 according to a command from the system controller 4. The compressor 5 is disposed coaxially with the motor, and has an exterior heat exchanger 6, an expansion valve 8,
A refrigeration cycle is formed with the vehicle interior heat exchanger 7.
The expansion valve 8, the fan 9 and the fan 10 can be adjusted in capacity by a command from the system controller 4. The motor drive device and the system controller are connected by the communication means 11, and the system controller sends a motor start / stop command and a rotation speed command, while the motor drive device transmits overload, overheat, and current rotation speed information. Has been sent. When the system controller receives an overheat alarm from the motor drive device, the capacity of the fan 9 is increased and the opening degree of the expansion valve 8 is increased to reduce the load on the motor and reduce the overheat of the motor drive device. continue. Other methods for reducing overheating of the motor drive device include reducing the capacity of the fan 10, reducing the rotation speed of the motor, and forcibly cooling the motor drive device by a fan (not shown).

[0010]

As described above, according to the present invention,
Since the motor drive device can be protected by the inverter overheating as needed without stopping the operation, the margin when designing the radiator can be estimated to be small, and the radiator can be downsized, and in turn, the motor drive device can be downsized. Weight reduction can be achieved.

[Brief description of drawings]

FIG. 1 is a block diagram illustrating a configuration of a motor drive device of the present invention.

FIG. 2 is a block diagram illustrating the configuration of an air conditioning system for an electric vehicle using the motor drive device of the present invention.

[Explanation of symbols]

 1. Battery 2. Motor drive device 3. Motor 4. System controller 5. Compressor 6. Heat exchanger outside the vehicle 7. Heat exchanger for passenger compartment 8. Expansion valve 9.10. Fan 11. Communication means 12. Radiator 13. Inverter 14. CPU 15. Temperature switch A 16. Temperature switch B 17. Smoothing capacitor 18. Current sensor

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication H02P 7/29 G 4238-5H

Claims (1)

[Claims] 1. A motor drive device comprising means for detecting the temperature of an inverter, a protection function for stopping the drive of the motor when the inverter is overheated, and external communication means for warning the operator of overheating. The motor drive device, wherein the external communication means issues an external warning at a temperature lower than a temperature at which the motor drive is stopped due to overheating of the inverter.