JPH11355959A - Temperature protecting apparatus for rotating electric machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a rotating electric machine small-sized and light-weight for an output required by building a map of a rotational speed and a protecting temperature preset in a temperature control flow, determining a temperature protection set value automatically on occasion, and performing comparison with a coil end temperature signal and performing heating protection. SOLUTION: As temperature detecting means for a synchronous motor for electric cars, a thermistor sensor 12 is fitted to a stator coil end, and another thermistor sensor 13 is fitted to a spot near the rotor of the end surface of a stator core. Besides, a temperature protection set value is automatically determined on occasion, by building-in a map of the rotational speed and a protecting temperature beforehand, and taking in a rotational speed signal of a rotating electric machine. And heating protection is performed by comparing this set value with a coil temperature signal from a temperature detecting means fitted to the coil end of the rotating electric machine. Here, the rotational speed- protecting temperature map is set from temperature increase data etc., at each rotational speed, and the difference between limit values at individual parts is taken into consideration.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a temperature protection device for a rotating electric machine. In particular, it is suitable for protecting the temperature of rotating electric machines used in a wide operating speed range such as electric motors for electric vehicles. It is necessary to prevent stator coil burning and permanent magnet demagnetization like permanent magnet type synchronous motors. The present invention relates to a temperature protection device for a rotating electric machine.

[0002]

2. Description of the Related Art A conventional temperature protector for a rotating electric machine determines a protection set value from a load state used by the rotating electric machine and a maximum point of temperature rise of each part, and a temperature state from a temperature detecting means attached to the rotating electric machine. Generally, a warning signal or an output cutoff signal is issued by a signal. Therefore, since the temperature is set to be protected in the worst case for the rotating electric machine, the temperature protection specification may have a sufficient margin except at the temperature protection set load point. In a rotating electric machine such as an electric vehicle that requires a small size and light weight and has a wide operating load range, it may not be economical.

[0003] For this reason, it is reasonable to adopt a contrivance to extend the protection operation start point to the last according to the temperature state of the protection target machine. This is the same not only in the rotating machine but also in the control base of the rotating electric machine.
As described in Japanese Patent No. 22387, there is also an overheat monitoring method in which when a detected temperature of a temperature sensor attached to a target machine exceeds a predetermined temperature, an output of an alarm is determined based on a change in temperature over time of the detected temperature. . In this way, a measure is taken to closely monitor the temperature by using the timer and expand the operable area.

[0004]

However, there are cases where it is not sufficient to monitor a change in temperature detected by a timer over a certain period of time, and it is desired to monitor the temperature in accordance with the load state.

An object of the present invention is to attach a single temperature detecting means to a rotating electric machine in the same manner as in the prior art, and to take out the output up to the full capacity of the rotating electric machine having various temperature rises and different temperature limit values in various load states. It is an object of the present invention to provide a temperature protection device for a rotating electric machine that can perform the above-described operations.

Another object of the present invention is to provide a temperature protection signal when both a temperature detection signal attached to a stator coil end and a temperature state signal of a temperature detection means attached to an end face of a stator core reach a preset threshold value. So that the temperature protection of each part of the rotating electrical machine varies depending on the operating state of the rotating electrical machine and the temperature protection operates properly according to the temperature rise limit, and the output is taken out to the full capacity of the rotating electrical machine under various load conditions It is an object of the present invention to provide a temperature protection device for a rotating electric machine that can perform the above-described operations.

[0007]

In order to achieve the above object, a preset rotation speed and a protection temperature map are incorporated in a temperature protection control flow, and a rotation speed signal of the rotating electric machine is taken in. The overheat protection is performed by automatically determining a set value and comparing the set value with a coil temperature signal from a temperature detecting means attached to a coil end of the rotating electric machine. Also, a plurality of temperature detecting means are attached to the coil end and the end face of the stator core, etc.
The overheat protection is performed when the temperature state of each of these parts reaches the threshold value.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 2 is a structural view of a drive motor for an electric vehicle, and particularly shows a permanent magnet type synchronous motor in which predetermined permanent magnets are arranged in a rotor core as shown in a rotor sectional view of FIG. A permanent magnet 4 is inserted into a slot 3 of a laminated rotor core 2 made of an electromagnetic steel plate fixed to a shaft 1. A stator coil 6 is incorporated in a laminated stator core 5 made of an electromagnetic steel sheet facing the rotor core 2 with an appropriate gap to form an armature. The stator 5 is press-fitted and fixed to a stator frame 7, and end brackets 8 and 9 are fixed to both sides of the stator frame 7. Bearing boxes in which the bearings 10 inserted at both ends of the shaft 1 are incorporated are formed on both end brackets 8 and 9. A magnetic pole position sensor 11 is attached to the opposite output shaft of the end bracket 9.

As the temperature detecting means of the synchronous motor for an electric vehicle having such a configuration, one is provided with a thermistor sensor 12 at the end of the stator coil, and the other is provided with a thermistor sensor 13 at a position near the rotor on the end face of the stator core. It is attached. Here, an example is shown in which two thermistor sensors are mounted in the motor, but generally only one is mounted on the stator coil end.

It is obvious that the temperature limits of each part of the synchronous motor for electric vehicles are different. The thermistor sensor 12 attached to the stator coil end is intended to prevent burning of the stator coil 6, and the thermistor sensor 13 attached to the end face of the stator core is intended to prevent thermal demagnetization of the permanent magnet 4 incorporated in the rotor core 2. is there. The heat resistant temperature of the coil wire and the permanent magnet material are naturally different. In addition, the ratios of copper loss and iron loss at various operating points of the synchronous motor for electric vehicles are naturally different, and mainly the output signal of the thermistor sensor 12 attached to the stator coil end for mainly detecting heat generated by the copper loss. Thermistor sensor 1 attached to the end face of the stator core to detect heat generated by iron loss
It has been confirmed that the relationship between the output signals of FIG. 3 is as shown in FIG.

FIG. 3 shows, by way of example, a case in which 35
The temperature rise situation at the time of kW output is shown. (A) is 3000 rp
m, (b) is 6000 rpm, (c) is 100
Shows the case of 00 rpm. As is apparent from this figure, the thermistor sensor 12 is higher or the thermistor sensor 13 is higher depending on the operating rotational speed even at the same output. Therefore, when only one temperature detecting means is installed in the rotating electric machine and it is to be protected at a certain temperature, it is necessary to set the temperature to be equal to or less than the upper limit of the temperature of each part in each operating state, and it is necessary to set a narrow operating output allowable range. It was common not to get.

A description will now be given of a temperature protection device according to an embodiment of the present invention, in which only one temperature detecting means is mounted in a rotating electric machine and has a wide allowable operating output range. FIG. 1 shows a control flow of overheat protection by detecting coil end temperature according to the present invention. The feature of this control flow is to incorporate and set a preset rotation speed and protection temperature map,
By taking in the rotation speed signal of the rotating electrical machine, the temperature protection set value is automatically determined at any time, and this is compared with the coil temperature signal from the temperature detecting means attached to the coil end of the rotating electrical machine to perform overheat protection. That is. The rotation speed and the protection temperature map are set based on the temperature rise data at each rotation speed in FIG. 3 described above, and needless to say, the difference in the temperature limit value of each part is taken into account. .

In another embodiment, it is obvious that the same temperature protection control can be realized by incorporating a threshold function based on the rotation speed in the program instead of the rotation speed and the protection temperature map.

As another embodiment, a thermistor sensor 1 attached to a stator coil end of a rotating electric machine is described.
2 and the temperature protection control of a device having a thermistor sensor 13 attached at a position near the rotor on the end face of the stator core. This thermistor sensor 1
Although not shown, the flow of the temperature protection control in response to the temperature state signals from the units 2 and 13 is such that the overheat protection is performed when the temperature state of each of these parts reaches the threshold value. It goes without saying that each threshold value is determined from the temperature limit of each component.

[0015]

According to the present invention, by mounting only one temperature detecting means on the rotating electric machine, it is possible to increase the temperature of each part and protect the temperature of the rotating electric machine having different temperature limit values, and to achieve the full capacity in various load states. Since the output can be extracted up to the required output, there is an effect that a small and lightweight rotating electric machine can be provided for the required output.

[Brief description of the drawings]

FIG. 1 is a diagram showing a control flow of overheat protection control based on coil end temperature detection according to an embodiment of the present invention.

FIGS. 2A and 2B are a sectional view of a rotor of a permanent magnet type synchronous motor for an electric vehicle and an upper half sectional view of the motor.

FIGS. 3A to 3C show 35 kW at each rotation speed.
FIG. 4 is a temperature characteristic diagram showing a temperature rise state during output operation.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... shaft, 2 ... rotor core, 3 ... slot, 4 ... permanent magnet, 5 ... stator core, 6 ... stator coil, 7 ...
Stator frame, 8 Front end bracket, 9
... Rear end bracket, 10 ... Bearing, 11 ... Magnetic pole position sensor, 12,13 ... Thermistor sensor, T ₀ ...
Protection set temperature, Tc: coil end detection temperature, Tm: core end detection temperature, N: motor rotation speed.

Claims (5)

[Claims] An apparatus for performing temperature protection of a rotating electric machine based on a temperature state signal from a temperature detecting means attached to the rotating electric machine, wherein a protection operation is performed by changing a threshold for shifting to protection control depending on an operation load state of the rotating electric machine. Characteristic temperature protection device for rotating electric machines. 2. The method according to claim 1, wherein the temperature detecting means is attached to a stator coil end as a thermistor sensor, and a preset rotation speed and protection temperature map are incorporated in a temperature protection control flow, and a rotation speed signal of the rotating electric machine is transmitted. A temperature protection device for a rotating electric machine, wherein a temperature protection set value is automatically determined at any time by taking in the temperature, and the temperature protection set value is compared with a coil temperature signal from a temperature detecting means to perform overheat protection. 3. An apparatus for protecting the temperature of a rotating electric machine by a temperature state signal from temperature detecting means attached to the rotating electric machine, wherein a plurality of temperature detecting means are attached to the rotating electric machine. apparatus. 4. An apparatus for protecting the temperature of a rotating electric machine based on a temperature state signal from temperature detecting means attached to the rotating electric machine, wherein the temperature detecting means attached to the rotating electric machine is attached to a stator coil end and an end face of a stator core. Temperature protection device for rotating electric machines. 5. An apparatus for protecting the temperature of a rotating electric machine by a temperature state signal from a temperature detecting means attached to the rotating electric machine, wherein the temperature detecting means attached to a stator coil end and the temperature detecting means attached to an end face of a stator core. A temperature protection device for a rotating electric machine, wherein a temperature protection signal is generated when both of the signals reach a preset threshold.