JPH07322563A - Cooling protective unit for electric apparatus - Google Patents

Abstract

PURPOSE:To protect an electric apparatus by actuating a cooling means when a predictive decision means makes a decision that the temperature of the electric apparatus reaches a predetermined level thereby predicting the temperature of the electric apparatus earlier. CONSTITUTION:The conduction amount of a motor 1 is detected through a current sensor 4 in the form of a voltage value which is then compared through a voltage comparator 6 with a threshold voltage generated from a voltage generator 5. The threshold voltage is set at a level corresponding to a threshold value for causing overheat if an electric automobile is accelerated with current conduction amount. A substantially constant current is fed to the motor when the automobile is running at a constant speed with relatively low current but since it is lower than a threshold value, switches 10, 11 are turned OFF by means of the voltage comparator 6. Upon abrupt acceleration, the conduction amount increases abruptly and the temperatures of the motor 1 and an inverter 2 vary gradually. When the conduction amount exceeds a threshold, the switches 10, 11 are turned ON to actuate fans 7, 8 thus cooling the motor 1 and the inverter 2. This constitution can protect an electric apparatus more quickly.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling protection device for electric equipment, and more particularly to a technique for predicting a temperature rise of the electric equipment and cooling the electric equipment.

[0002]

2. Description of the Related Art An electric device operates by being supplied with an electric current, and an electric device in which overheating is a problem has conventionally been provided with a cooling protection device. A typical example of an electric device in which overheating is a problem is an electric motor or an inverter having a large current semiconductor.

In a conventional cooling protection device, a thermosensor is provided in a problematic part of a target electric device, and a temperature signal detected by the thermosensor is guided to a comparator as it is, which is a reference corresponding to a temperature at which a protection operation is to be executed. The necessary operation is performed by comparing with the voltage (threshold value), or the signal level of the thermosensor is converted into a digital value by the A / D converter and taken in, and the signal level of the thermosensor indicates the temperature at which the protection operation should be performed. The CPU determines whether or not the necessary operation is performed by the software.

[0004]

However, in the conventional cooling protection device for electric equipment, the thermosensor does not respond in real time to the temperature change of the electric equipment in question, and depending on the mounting method of the sensor and its position. In the actual situation, there may be a considerable delay from the sudden increase in the energizing current to the detection of the temperature rise.

Therefore, even if the temperature of the electric device in question reaches the threshold value required for temperature protection, the necessary protection operation cannot be executed immediately, and the operation is executed with a slight delay. In the meantime, there is a risk that the temperature rises above the threshold value and adversely affects, so the fact is that the threshold value for executing the protection operation is lowered. However, if the threshold value is lowered, then the temperature protection operation frequently occurs, and for example, the cooling fan motor is frequently turned on and off, so lowering the threshold value causes power loss and noise generation. It also becomes.

The present invention has been made in view of such conventional problems, and an object of the present invention is to provide a protective cooling device for an electric device by predicting a temperature rise of the electric device earlier and protecting the electric device. .

[0007]

Therefore, in the protective cooling apparatus for electric equipment according to the invention of claim 1, cooling means for cooling the electric equipment and current detecting means for detecting the amount of current flowing through the electric equipment are provided. A prediction determination unit that determines whether or not the temperature of the electric device reaches a predetermined temperature at which the electric device should be cooled based on the detection value of the current detection unit; and a temperature of the electric device is determined by the prediction determination unit. And a control means for operating the cooling means when it is determined that the temperature is reached.

According to another aspect of the invention, there is provided a protection and cooling apparatus for electric equipment, wherein the current detecting means is composed of a current sensor which outputs a voltage proportional to the amount of energizing current, and the predicting judging means has a predetermined threshold voltage. Comparing the voltage generation means to generate, the detection voltage of the current sensor with a predetermined threshold voltage generated by the voltage generation means, when the detection voltage of the current sensor is equal to or higher than the predetermined threshold voltage, a comparator that outputs a control signal, The control means is constituted by a switch means for energizing the cooling means when a control signal is output from the comparator.

In the electric equipment protection and cooling apparatus according to the third aspect of the present invention, the current detecting means is composed of a current sensor for outputting a voltage proportional to the amount of energizing current, and the predictive judging means is a detection of the current sensor. An A / D converter for converting the voltage into a digital value, a storage means for storing a predetermined threshold voltage,
The detected voltage of the current sensor converted into a digital value by the A / D converter is compared with a predetermined threshold voltage stored in the storage means, and when the detected voltage of the current sensor exceeds a predetermined threshold voltage, the temperature of the electric device And a comparing and judging means for predictively judging that a predetermined temperature for cooling the electric equipment will be reached and outputting a control signal, and the controlling means cools when the control signal is outputted from the comparing and judging means. The switch means is configured to energize the means.

According to a fourth aspect of the present invention, there is provided a protective cooling device for an electric device, which comprises an outside air temperature detecting means for detecting an outside air temperature, while the predictive judging means detects the detected value of the current detecting means and the outside air temperature detecting means. Based on the determined outside air temperature, it is configured to predict and determine whether or not a predetermined temperature at which the electric device should be cooled is reached. In the electric equipment protection and cooling apparatus according to the fifth aspect of the present invention, the power supply for driving the electric equipment and the power supply for control of the prediction determination means and the control means are separately provided.

[0011]

According to the above construction, in the electric equipment protection and cooling apparatus according to the invention of claim 1, the current detecting means detects the amount of current flowing through the electric equipment, and the predicting determining means uses the detected value of the current detecting means. When it is determined that the temperature of the electric device has reached the predetermined temperature at which the electric device should be cooled based on the control, the cooling device is controlled and operated by the control device to cool the electric device. Therefore, it is possible to predict whether or not the temperature of the electric device reaches the temperature to be protected, depending on the amount of current flowing through the electric device, and thus it is possible to cool and protect the electric device earlier.

According to the second aspect of the present invention, in the protective cooling apparatus for an electric device, the voltage proportional to the amount of energized current is output from the current sensor, and in the comparator, the detected voltage of the current sensor is the predetermined threshold value generated by the voltage generating means. The voltage is compared with the voltage, and when the voltage exceeds a predetermined threshold voltage, the cooling means is energized by the switch means. As a result, the current detection unit, the prediction determination unit, and the control unit are configured by hardware including the current sensor, the voltage generation unit, the comparator, and the switch unit.

In the electric equipment protection and cooling apparatus according to the third aspect of the present invention, the voltage proportional to the amount of the energizing current output from the current sensor is converted into a digital value by the A / D converter,
It is compared with a predetermined threshold voltage stored in the storage means, and when it becomes equal to or higher than the predetermined threshold voltage, it is predicted that the temperature of the electric equipment will reach a predetermined temperature at which the electric equipment should be cooled, and the switching means energizes the cooling means. To be done. As a result, it becomes possible to make a prediction judgment by software.

In the electric equipment protection and cooling apparatus according to the fourth aspect of the present invention, the outside air temperature is detected by the outside air temperature detecting means, and the predicting judgment as to whether or not the electric equipment reaches a predetermined temperature for cooling is performed by the current detecting means. Since it is performed based on the detected value of and the outside air temperature detected by the outside air temperature detecting means,
Even when the predetermined temperature for cooling the electric device is affected by the outside air temperature, the prediction determination can be accurately performed.

In the protective cooling device for electric equipment according to the fifth aspect of the present invention, the control power source and the traveling power source are independent of each other,
The cooling control is no longer influenced by the driving conditions.

[0016]

Embodiments of the present invention will be described below with reference to FIGS. First, the first embodiment will be described. This is a cooling protection device for electric equipment, which is composed of hardware. In FIG. 1 showing the present embodiment, an electric motor 1
Is an electric device that is supplied with electric power from the traveling power source 3 via the inverter 2 and drives, for example, an electric vehicle.

The inverter 2 includes a power control semiconductor,
It is an electric device that converts direct-current power from the traveling power supply 3 into alternating-current power. The current sensor 4 is a sensor that is interposed between the traveling power source 3 and the inverter 2 and that generates and outputs a voltage proportional to the energization amount of the energization current. The energization amount of the electric motor 1 and the inverter 2 is macroscopic. Are considered to be the same and have only one current sensor 4.

The voltage generator 5 generates a constant or regulated comparison voltage having a predetermined threshold voltage, and corresponds to a voltage generating means. The voltage comparator (comparator) 6 compares the voltage from the current sensor 4 with the threshold voltage generated by the voltage generator 5. The blower 7 is supplied with electric power from the control power supply 9 through the switch 10 and blows cooling air to the inverter 2 to cool it.

The blower 8 includes a control power source 9 and a switch 11
Power is supplied to the motor 1 to blow cooling air to the motor 1 for cooling. The blowers 7 and 8 correspond to cooling means. The switches 10 and 11 are turned on / off according to the comparison result of the voltage comparator 6. The switches 10 and 11 correspond to switch means and control means.

The control power source 9 is provided separately from the traveling power source 3 so that the cooling control is not influenced by the traveling state, and operates the voltage comparator 6, the voltage generator 5, and the blowers 7 and 8. It is a power source for It should be noted that the traveling power source 3 and the control power source 9, for example, the cathode is the control power source 9
By connecting via the diode on the side, the traveling power source 3 can replenish the control power source 9 with electric power.
The current may not flow backward from the control power supply 9 to the traveling power supply 3.

Next, the operation of the cooling protection device for electric equipment will be described with reference to FIG.
The operation will be described with reference to the operation explanatory diagram. In addition, the upper part of FIG.
It is a diagram comparing the temperature characteristics in the case of performing the cooling protection based on the energization amount of the present embodiment, the temperature characteristics in the case of performing the cooling protection based on the temperature signal of the thermosensor, the lower stage, the time of the present embodiment It is a figure showing the relation between the energization amount of energization current.

The electric current i and the energization amount i of the energizing current are detected as a voltage value by the current sensor 4, and the detected value is compared with the threshold voltage generated by the voltage generator 5 by the voltage comparator 6. This threshold voltage is set to a value corresponding to a threshold i _b that will eventually overheat when the electric vehicle is accelerated with the current energization amount. When the electric vehicle is traveling at a constant speed with a relatively small current, a substantially constant current is applied to the electric motor 1 as shown in FIG. 2, and the energization amount i _a at this time is greater than the threshold value i _b . Since it also becomes low, the switches 10 and 11 are controlled to be turned off by the voltage comparator 6, and the blowers 7 and 8 do not operate.

When the electric vehicle is suddenly accelerated from this state, it is observed that the energization current sharply rises from the energization amount i _a , but when it is less than the threshold value i _b , the blowers 7 and 8 do not operate. The temperatures of the electric motor 1 and the inverter 2 gradually change compared with the change of the energization amount i. When the energization amount i exceeds the threshold value i _b , the switches 10 and 11 are turned on based on the comparison result of the voltage comparator 6. As a result, the blowers 7 and 8 are operated and the electric motor 1 and the inverter 2 are cooled. When the protection operation is started, the energization amount i is strong after that.
Even when the temperature reaches _c , the temperatures of the electric motor 1 and the inverter 2 smoothly change to the temperature threshold value θ _th and converge as shown in the upper part of FIG.

As shown in the upper part of FIG. 2, when the protection operation is executed by the output of the thermosensor, the temperature detected by the thermosensor is delayed from the actual temperature of the electric motor 1 and the inverter 2, so the protection operation is performed. It is understood that the temperature of the electric motor 1 and the inverter 2 reaches a temperature higher than the temperature threshold value θ _th when the start of. In the present embodiment, the control power source 9 is provided in addition to the traveling power source 3. However, if the traveling power source 3 is also used for control, the timing at which temperature protection is required is almost the same. In the case of, the point at which a large current suddenly started to flow, and there is a phenomenon that the power supply voltage suddenly drops at that time due to the limit of the discharge capacity of the storage battery. Cause

Therefore, as in this embodiment, the traveling power source 3 is used.
In addition to the above, by providing the control power supply 9, stable control accuracy is ensured. According to this configuration, in the electric device, when the cause of overheating is mainly due to the energizing current, the temperature rise is predicted instead of measuring the temperature and performing cooling or the like in order to control the temperature. By setting the alternative threshold value as the current value and controlling the blowers 7 and 8,
The problem of delayed execution of the protection operation is solved, and a reliable and durable product can be completed.

Further, by separately providing the traveling power source 3 and the control power source 9, the control power source 9 is not affected even if the voltage of the traveling power source 3 is lowered, and stable control accuracy is obtained. Is also secured. In this embodiment, the electric motor 1
Macroscopically, the energization amount of the inverter 2 is considered to be the same macroscopically, and only one current sensor 4 is provided. However, there are other devices that may be overheated by the electric current, and the energization amount is When they differ, a current sensor and a voltage comparator are provided independently.

Next, the second embodiment will be described. This is configured so that the software makes a prediction decision and executes a protection operation. FIG. 3 is a diagram showing the configuration of the second embodiment. The A / D converter 12 uses the current sensor 4
The analog signal from is converted into a digital value and output to the central processing unit 14.

The signal input device 13 inputs a sensor signal from a sensor or the like for detecting the outside air temperature, converts it into a digital value, and outputs it to the central processing unit 14. Central processing unit 14
The current data, which is a digital value, is input from the A / D converter 12, and the outside air temperature data and the like is input from the signal input device 14. The ROM 15 stores software for executing the protection operation, preset threshold values, and data of the current value i _b , and the central processing unit 14 stores the work area in the RAM 16 based on these input data. The software that controls the switches 10 and 11 is executed while ensuring the above.

With such a configuration, the protection operation similar to that of the first embodiment can be executed by software.

[0030]

As described above, in the protective cooling apparatus for an electric device according to the invention of claim 1, when it is predicted that the temperature of the electric device reaches the temperature at which the electric device should be cooled, the electric device is Since it is cooled, the electric device can be cooled and protected more quickly, the problem of delay in execution of the protection operation can be solved, and reliability and durability can be improved.

The protective cooling device for electric equipment according to the second aspect of the present invention can be configured by hardware. In the protective cooling device for an electric device according to the third aspect of the present invention, the prediction determination can be performed by software. With the protective cooling apparatus for an electric device according to the fourth aspect of the present invention, even if the predetermined temperature for cooling the electric device is affected by the outside air temperature, the prediction determination can be accurately performed.

In the electric equipment protection and cooling apparatus according to the fifth aspect of the present invention, the electric equipment protection operation can be executed without affecting the running state.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment in which a protective cooling device for an electric device according to the present invention is configured by hardware.

FIG. 2 is an operation explanatory diagram of FIG.

FIG. 3 is a configuration diagram showing an embodiment in which a protective cooling device for an electric device according to the present invention is configured by software.

[Explanation of symbols] 1 motor 2 inverter 3 power supply for running 4 current sensor 5 voltage generator 6 voltage comparator 7, 8 blower 9 control power supply

Claims (5)

[Claims] 1. A cooling unit for cooling an electric device, a current detecting unit for detecting an amount of current flowing through the electric device, and a temperature of the electric device based on a detected value of the current detecting unit.
Prediction determining means for predicting whether or not a predetermined temperature for cooling the electric device is reached, and control means for activating the cooling means when the prediction determining means determines that the temperature of the electric device reaches the predetermined temperature. And a cooling protection device for an electric device. 2. The current detecting means is composed of a current sensor which outputs a voltage proportional to the amount of energized current, and the prediction determining means includes a voltage generating means for generating a predetermined threshold voltage and a detected voltage of the current sensor. And a comparator that outputs a control signal when the detected voltage of the current sensor is equal to or higher than a predetermined threshold voltage, compared with the predetermined threshold voltage generated by the voltage generating means, wherein the control means controls the comparator. The cooling protection device for an electric device according to claim 1, wherein the cooling protection device is constituted by a switch means for energizing the cooling means when a signal is output. 3. The current detecting means is composed of a current sensor that outputs a voltage proportional to the amount of energized current, and the prediction determining means is an A / D converter that converts the detected voltage of the current sensor into a digital value. And comparing the detection voltage of the current sensor converted to a digital value by the storage means for storing the predetermined threshold voltage with the predetermined threshold voltage stored in the storage means, and the detection voltage of the current sensor is determined by the predetermined threshold voltage. When the voltage becomes equal to or higher than the voltage, the temperature of the electric device is made up of a comparison and determination unit that predictively determines that the temperature will reach a predetermined temperature at which the electric device should be cooled, and outputs a control signal. 2. The cooling protection device for an electric device according to claim 1, wherein the cooling protection device is constituted by a switch unit that energizes the cooling unit when a control signal is output from the cooling unit. 4. The outside air temperature detecting means for detecting the outside air temperature is provided, while the prediction determining means cools the electric equipment based on the detected value of the current detecting means and the outside air temperature detected by the outside air temperature detecting means. The cooling protection device for an electric device according to any one of claims 1 to 3, wherein the cooling protection device is configured to predict and determine whether or not a predetermined temperature should be reached. 5. The power supply for driving the electric equipment and the power supply for control of the prediction determination means and the control means are separately provided, and the power supply for power supply is separately provided. Cooling protection device for electrical equipment.