JPH09260166A - Driver for contactless power transmission coupler - Google Patents

Abstract

(57) 【Abstract】 PROBLEM TO BE SOLVED: To provide an external device which is not affected by changes in heat radiation and heat generation due to changes in load conditions or operating conditions of a contactless power transmission coupler and which does not cause errors in burnout prevention operation. (EN) Provided is a drive device provided with an unnecessary burnout prevention means. A contactless power transmission coupler driving apparatus includes a current detecting unit that detects a current value from an output of the driving apparatus, an absolute value converting circuit that converts the current value into an absolute value, and an effective value of the current value. A burnout prevention means including an effective value conversion circuit 6 for changing the temperature, a temperature estimation means 8 for estimating the temperature of the coupler based on the effective value of the current, and a power supply determination means 11 for making a power supply determination according to overheating of the coupler 1. It is characterized in that it is a device which is provided with the power supply according to the judgment of the power supply judging means 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coupler driving device for transmitting electric power to an electric load without contact.

[0002]

2. Description of the Related Art Conventionally, a coupler for contactless power transmission using magnetism receives electric power from a driving device for driving a power feeding side coil of the coupler. Due to the hysteresis loss of the side core, the power supply side coupler generates a considerable amount of heat. For example, if a coupler has a very small thermal conductance when it radiates heat to the outside, and the amount of heat generated by the coupler itself is considerably large compared to the amount of heat radiated to the surroundings of the coupler, it will become overheated and it will transmit a large amount of power, especially for a long time. In that case, the coupler will burn out. Therefore, in order to prevent burnout, the drive device is equipped with a burnout prevention device such as a mechanical thermal relay that detects the output current of the drive device and shuts off the main power supply when an excessive output current flows. Have been proposed.

[0003]

However, in the above-mentioned prior art, the coupler for contactless power transmission has a heat radiation state and a cooling state depending on, for example, a mounting state on a rotating shaft having an electric machine load, a load condition or an operating condition. Since the conditions change, every time the heat radiation and heat generation of the coupler changes, it is necessary to use a mechanical thermal relay with specifications that are adapted to them, and there is an error in the burnout prevention operation due to the temperature depending on the mounting location of the thermal relay. Problems such as
Alternatively, there is a problem that an external burnout prevention device different from the drive device is required. Therefore, the present invention is not affected by changes in the state of heat radiation and heat generation due to changes in the load conditions or operating conditions of the coupler, does not require an external device, and does not cause errors in the burnout prevention operation of the coupler.
An object of the present invention is to provide a drive device for a contactless power transmission coupler.

[0004]

In order to solve the above-mentioned problems, the present invention detects the output current of a drive device for driving a power supply side coil of a coupler which transmits power in a contactless manner, and prevents the coupler from being burned. In a drive device for a contactless power transmission coupler having a burnout prevention means, the burnout prevention means detects a current value from the output of the drive device and a current value obtained from the current detection means. Absolute value converting means for converting into an absolute value, effective value converting means for converting the current value into an effective value, and overheating of the coupler based on the effective value of the current obtained from the effective value converting means. And an overheat determining unit that determines power supply according to the above, and supplies power according to the determination of the overheat determining unit.
The overheat determination means estimates a temperature of the coupler from an effective value of the current obtained from the effective value conversion means and a preset thermal constant of the coupler, and estimates from the temperature estimation means. Power supply determination means for determining whether to supply power by comparing the estimated temperature value with the temperature setting value based on the temperature of the coupler.
Further, the driving device is provided with a microcomputer having an arithmetic function therein, and at least the overheat judging means of the burnout prevention means is provided in the microcomputer.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a drive device for a power transmission coupler provided with a burnout prevention unit according to an embodiment of the present invention. FIG. 2 is a block diagram of a drive device for a power transmission coupler provided with a burnout prevention unit according to another embodiment of the present invention. Reference numeral 1 is a power transmission coupler for transmitting power in a contactless manner, 2 is a power module for exciting a power supply side coil of the power transmission coupler 1, and 3 is a drive circuit for driving a power module 2. Is a CT for detecting an output current flowing from the power module 2 to the power transmission coupler 1, and 5 is a CT
An absolute value conversion circuit composed of an electronic circuit for converting the detected current value into an absolute value, 6 is an effective value conversion circuit composed of an electronic circuit for converting the absolute value of the current value into an effective value, and 7 is An AD conversion circuit that performs AD conversion of the effective current, 8 is a coupler temperature estimation means that calculates the current temperature rise from the AD-converted effective current and the preset thermal constant of the power transmission coupler 1, and 9 is shown in the figure. No coupler 1 preset in memory
Set value of the temperature rise of 10 is a comparison means for comparing the current temperature rise of the coupler 1 obtained by the coupler temperature estimation means 8 with the temperature rise preset by the set value 9, 11
Is a power supply determination means for determining whether or not to supply power to the power transmission coupler 1 when the current temperature rise of the power transmission coupler 1 becomes larger than the set value 9 according to the comparison means 10, and 12 is a power supply determination. This is an alarm for causing an abnormality of the power transmission coupler 1 based on the means 11. Of these, the coupler temperature estimating means 8, the set value 9 and the comparing means 10, the error
The frame 12 is provided in the microcomputer.

In FIG. 1, the output current transmitted from the power module 2 to the power transmission coupler 1 is detected by the CT 4 provided therebetween, converted into an absolute value by the absolute value conversion circuit 5, and further effective. After being converted into an effective value by the value conversion circuit 6, the effective value is AD-converted by the AD conversion circuit 7 and is also taken into the microcomputer. Also,
Inside the microcomputer, the current temperature rise of the coupler 1 can be calculated in real time based on the effective current value fetched from the AD conversion circuit 7. Letting the effective current value be I and the current temperature rise of the coupler 1 be ΔT, these relationships can be expressed by the following relational expressions. However, the resistance of the power supply side coil of the coupler (not shown) is R, the thermal conductance of the coupler when radiating heat to the outside air is C, the heat quantity of the coupler is Q, the heat capacity of the coupler is G, the current temperature rise of the coupler is ΔT, and the time is t and d are differential operators. The heat conductance C and the heat capacity G of the coupler when the coupler radiates heat to the outside air are setting parameters. dQ / dt = I ² · R−ΔT · C (1) ΔT = Q / G (2) First, an arbitrary initial heat quantity Q is given to the inside of the microcomputer. , (2), when the coupler heat quantity Q is divided by the heat capacity G of the coupler, the current temperature rise ΔT with respect to the surroundings of the coupler is obtained. Next, increase this temperature ΔT by (1)
Substituting into the equation, the heat radiation amount is calculated by the thermal conductances C and ΔT with respect to the surroundings of the coupler, and the heat radiation amount of the coupler based on the effective current value I at the next sampling time t is subtracted from this heat radiation amount to obtain the coupler heat amount Q. Calculated and dividing this Q by the heat capacity G of the coupler, the temperature difference ΔT from the current surroundings of the coupler is ΔT.
Is obtained. By repeating this calculation many times, the algorithm is such that the current temperature of the coupler is instantaneously calculated in real time. Further, the preset maximum rated value of the temperature rise of the coupler 1 is stored as a set value 9 in a memory (not shown) in the micro computer, and the present value of the coupler 1 for power transmission obtained by the coupler temperature estimating means 8 is obtained. The comparison means 10 compares the temperature rise of 1 with the maximum rated value stored in the set value 9.
On the other hand, FIG. 2 is a block diagram of a drive device equipped with a burnout prevention unit showing an embodiment different from FIG. In place of the absolute value converting circuit 5 and the effective value converting circuit 6 shown in FIG. 1, absolute value converting means 51 and effective value converting means 61 are provided in the microcomputer. With such a configuration, the absolute value and the effective value of the current value may be calculated by software in the microcomputer.

Next, the operation will be described with reference to FIG.
In the configuration described above, if the power module 2
When an excessive output current starts to flow from the power supply coupler 1 to the power supply side coil, the output current detected by CT4 passes through the absolute value conversion circuit 5, the effective value conversion circuit 6 and the AD conversion circuit 7 with the passage of time. Then, the effective current value I is input to the coupler temperature estimation means 8 and is sequentially calculated from the calorific value of the coupler to the current temperature rise value with the surroundings, and the current temperature rise is the maximum temperature rise moment by moment. The value approaches the rated value and is compared with the maximum rated set value 9 by the comparison means 10. Here, a power transmission coupler 1 calculated from the output current
If the current temperature rise of the battery is higher than the maximum rating as compared with the set value 9, the power supply determining means 1 in the microcomputer 1
1 issues an alarm 12 and the power supply determining means 11
According to the judgment of (1), a signal for stopping the power supply is sent to the power module drive circuit 3 to stop the power supply from the power module 2 to the power transmission coupler 1. Therefore,
The present invention estimates the heat generation amount of a power transmission coupler from the output current, and estimates the coupler temperature from the estimated heat generation amount of the coupler and the two parameters of the heat capacity of the coupler and the heat conductance at the time of heat radiation of the coupler. Since the overheat can be detected and the power supply to the coupler can be stopped to prevent the burnout in advance, it is possible to cope with couplers having different characteristics by changing these parameters.

[0008]

As described above, according to the present invention, it is possible to achieve stable operation without an external device and without being affected by changes in heat radiation and heat generation due to changes in the load conditions or operating conditions of the coupler. Can perform burnout prevention operation,
There is an effect that a highly reliable contactless power transmission coupler driving device is obtained.

[Brief description of drawings]

FIG. 1 is a block diagram of a drive device for a power transmission coupler including a burnout prevention unit according to an embodiment of the present invention.

FIG. 2 is a block diagram of a drive device of a power transmission coupler including a burnout prevention unit according to another embodiment of the present invention.

[Explanation of symbols]

 1: Power transmission coupler 2: Power module 3: Power module drive circuit 4: CT 5: Absolute value conversion circuit 51: Absolute value conversion means 6: Effective value conversion circuit 61: Effective value conversion means 7 : AD conversion circuit 8: Coupler temperature estimation means 9: Set value 10: Comparison means 11: Power supply determination means 12: Alarm

Claims (3)

[Claims] 1. A non-contact power transmission coupler driving method for detecting an output current of a driving device for driving a power feeding side coil of a coupler for transmitting electric power in a non-contact manner and having a burnout prevention means for preventing the burnout of the coupler. In the device, the burnout prevention unit is a current detection unit that detects a current value from the output of the drive unit, an absolute value conversion unit that converts the current value obtained from the current detection unit into an absolute value, and an absolute value conversion unit. Based on the effective value of the current obtained from the effective value converting means for converting the effective current value into an effective value,
A contactless power transmission coupler driving device, comprising: an overheat determining unit that determines power supply according to overheating of the coupler; and a device that supplies power according to the determination of the overheat determining unit. 2. The temperature estimation means for estimating the temperature of the coupler from the effective value of the current obtained from the effective value conversion means and a preset thermal constant of the coupler, Based on the temperature of the coupler estimated from the temperature estimating means, a power supply determining means for determining whether to supply power by comparing the temperature estimated value and the temperature setting value, and The drive device for the contactless power transmission coupler according to claim 1. 3. The drive device comprises a microcomputer having an arithmetic function therein, and at least the overheat judging means of the burnout prevention means is provided in the microcomputer. The drive device for a coupler for contactless power transmission according to claim 1 or 2.