KR20180080049A

KR20180080049A - A generator comprising a rotor and a combined heat and power generating system comprising the generator

Info

Publication number: KR20180080049A
Application number: KR1020170000941A
Authority: KR
Inventors: 하승형; 김상영; 김재연
Original assignee: 엘지전자 주식회사
Priority date: 2017-01-03
Filing date: 2017-01-03
Publication date: 2018-07-11
Also published as: KR101940533B1

Abstract

An objective of the present invention is to provide a generator including a rotor which reduces a torque ripple and cogging torque. According to an embodiment of the present invention, the generator including a rotor comprises: a rotor iron core where steel plates as a whole are stacked in a pillar form; a rotary shaft insertion hole formed on the center of the rotor iron core; a permanent magnet accommodation hole formed on a portion corresponding to each edge of a polygon formed around the center of the rotor iron core; a permanent magnet inserted into the permanent magnet accommodation hole; and a plurality of slits formed on the outer circumferential portion of the permanent magnet accommodation hole in parallel. The plurality of slits are formed to be tilted by a prescribed angle in a counterclockwise direction with respect to a polarity center in the upper half of the rotor iron core, and are formed to be tilted by a prescribed angle in a clockwise direction with respect to the polarity center in the lower half of the rotor iron core.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a generator having a rotor and a cogeneration system having the same,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a generator having a slit formed rotor and a cogeneration system having the same.

A cogeneration system is a system that generates electricity from a generator by operating an engine with gas fuel, and converts the heat generated by the engine into hot water or the like to supply it to the customer.

In this cogeneration system, an air conditioner is connected to supply power and heat or hot water to the air conditioner.

The engine turns the generator to produce power.

The power generated by the generator can be converted to commercial power converted from current, voltage, frequency, etc. in the power converter and supplied to power consumers such as buildings or air conditioners.

A generator with a permanent magnet insertion structure causes a cogging torque in a no-load state when the rotor rotates due to the tooth slot structure of the stator. Cogging torque acts as the load of the engine when the generator starts, and it causes vibration and noise of the generator at the time of load operation.

In order to reduce the cogging torque of the generator, it is common to give a skew to each layer when the rotor core is laminated.

If the pole pieces are twisted in the lamination direction of the rotor, the upper and lower cogging torques can be offset or reduced from each other.

However, when the rotor is manufactured by applying the skew, the manufacturing process of the rotor becomes complicated, and a phenomenon that the generated magnetic flux of the permanent magnet leaks in the stacking direction occurs, there was.

An object of the present invention is to provide a generator in which a cogging torque and a torque ripple are reduced by forming a plurality of slits formed by stacking rotors and inclined at a predetermined angle with respect to a diameter at an outer peripheral portion.

According to an aspect of the present invention, there is provided a generator including a rotor, the rotor including a rotor iron core in which a steel plate is stacked in a column as a whole, a rotating shaft insertion hole formed in the center of the rotor iron core, A plurality of slits formed parallel to each other on the outer periphery of the permanent magnet accommodating hole, and a plurality of slits formed in parallel to each other on the outer periphery of the permanent magnet accommodating hole, Wherein the plurality of slits in the upper half of the rotor iron core are formed to be inclined at a predetermined angle counterclockwise with respect to the center of the pole, Angularly inclined.

The inclined angle of the plurality of slits is preferably 20 to 30 degrees.

It is preferable that the current phase with respect to the q-axis of the generator is controlled to be larger than that in the case where there is no slit.

The current phase is preferably controlled to be 156 to 160 degrees.

According to another aspect of the present invention, there is provided a generator including a rotor, comprising: a rotor iron core formed by stacking a steel plate as a whole in a columnar shape; a rotating shaft insertion hole formed in the center of the rotor iron core; A plurality of slits formed parallel to each other in an outer peripheral portion of the permanent magnet accommodating hole; and a plurality of slits formed in parallel with each other in the outer peripheral portion of the permanent magnet accommodating hole, The slit is formed to be inclined at a predetermined angle in the direction opposite to the rotation direction with respect to the center of the pole.

The inclined angle of the plurality of slits is preferably in the range of 35 to 20 degrees in a direction opposite to the rotation direction.

It is preferable that the current phase is controlled at 152 to 156 degrees.

A cogeneration system according to one aspect of the present invention includes an engine using gas as fuel, a generator as described above which is driven by the engine to produce electric power, a cooling water circulation line for cooling the engine, And a hot water heat exchanger installed in the line and generating hot water by heat exchange with water supplied separately.

According to the generator having the rotor of the present invention, by forming a plurality of slits which are inclined in opposite directions from each other in the upper half portion and the lower half portion of the rotor, the cogging torque and the torque ripple can be reduced and the performance of the generator can be improved.

By forming a plurality of slits in the outer circumferential portion of the rotor in a direction opposite to the rotational direction, the torque ripple can be reduced and the performance of the generator can be improved.

Also, although the no-load voltage and the generated torque can be reduced by a plurality of sloped slits, it is possible to control to raise the voltage and increase the generated torque through the adjustment of the current phase angle.

1 is a conceptual diagram schematically showing a cogeneration system.
2 is a perspective view showing a rotor according to a first embodiment of the present invention.
Fig. 3 is a plan view showing an upper half (a) and a lower half (b) of the rotor of Fig. 2;
4 is a graph showing changes in cogging torque and unloaded counter electromotive force according to slit angles.
5 is a view showing a magnetic flux flow according to a slit angle inclined to the left.
6 is a graph showing the cogging torque (a) in the upper and lower halves when the slit angle is 20 degrees and the cogging torque (b) in comparison with the slitless model.
7 is a graph showing torque ripple (b) compared with the torque ripple (a) and the no-slit model in the upper half and lower half when the slit angle is 20 degrees.
FIG. 8 is a diagram showing the current phase (a) at a slit angle of 20 degrees and the resulting torque and the like in comparison with a no-slit model (b).
FIG. 9 is a graph showing torque ripple (b) compared with the torque ripple (a) and the slipless model in the upper half and lower half when the current phase is further changed when the slit angle is 20 degrees.
FIG. 10 is a graph showing a comparison between the current phase (a) and the torque according to the slit angle of 20 degrees, which is more greatly changed, compared with the no-slit model (b).
11 is a perspective view showing a rotor according to a second embodiment of the present invention.
12 is a plan view showing a slit angle that is inclined relative to the rotational direction of the rotor.
13 is a view showing a magnetic flux flow according to an angle of a slit inclined in a rotating direction.
14 is a view showing a magnetic flux flow according to an angle of a slit inclined in a direction opposite to a rotating direction.
FIG. 15 is a graph showing changes in induced voltage a and torque ripple b according to slit angles.
16 is a graph showing torque ripple when a slit angle of -30 degrees is applied in comparison with a no-slit model.
FIG. 17 is a view showing the current phase (a) at the slit angle of -30 degrees and the resulting torque and the like in comparison with the no-slit model (b).
FIG. 18 is a graph showing the torque ripple compared with the no-slit model when the current phase is further changed when the slit angle is -30 degrees.
FIG. 19 is a diagram showing a comparison between the current phase (a) and the torque according to the slit angle -30 degrees, which is more greatly changed, compared with the no-slit model (b).

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a conceptual diagram schematically showing an example of a cogeneration system.

The cogeneration system 100 refers to a system that generates electricity from a generator by operating an engine with gas fuel, converts heat generated by the engine into hot water or the like, and supplies the heat to the customer.

In the cogeneration system 100, an air conditioner is connected to supply power, heat, or hot water to the air conditioner.

The gaseous fuel can be supplied by the zero governor 12 while maintaining a constant outlet pressure regardless of the shape of the inlet input or the change in flow rate. The zero governor 12 is capable of obtaining a stable outlet pressure over a wide range and has a function of adjusting the pressure of the gaseous fuel supplied to the engine to almost constant at atmospheric pressure. In addition, the zero governor 12 is provided with two solenoid valves to shut off the supplied fuel.

The air can be filtered and supplied with clean air through an air cleaner 14. The air cleaner 14 can block the mixing of moisture and oil in the form of dust and mist using external air supplied to the engine as a filter.

The gas fuel and the air supplied as described above can be sucked into the engine by a mixer having a constant mixture ratio of air and fuel by a mixer (16).

Between the zero governor 12 and the mixer 16, a fuel valve 13 for regulating the flow rate of fuel flowing into the mixer 16 may be provided.

A turbocharger 20 can compress the mixer to a high temperature and high pressure state. The turbocharger 20 is a device that rotates the turbine by the force of the exhaust gas, compresses the intake air by its rotational force, and sends the compressed air to the cylinder of the engine to increase the output.

The turbocharger 20 is a combination of a turbine and a supercharger. The turbocharger 20 is composed of a turbine and an air compressor connected directly to the turbine. The turbine wheel is rotated by the energy of the exhaust gas The air sucked by the air compressor can be compressed and sent to the cylinder.

The turbocharger 20 has a structure in which a turbine wheel in which a blade is installed and an impeller of an air compressor are connected to one shaft and each surrounds the housing, and can be disposed near the exhaust manifold of the engine.

The mixer is cooled by the intercooler 25 and then introduced into the engine 30 through the intake manifold 32 because the temperature of the mixture is compressed by the turbocharger 20. [ The intercooler 25 can cool the mixer to increase the density, thereby increasing the absolute amount of the mixer introduced into the engine and improving the engine output.

The intercooler 25 may comprise an air-cooled heat exchanger that cools with air or a water-cooled heat exchange path that cools with water. The water-cooled intercooler can use cooling water as a medium, and it has a separate heat exchanger and pump to discard the calories from the compressed mixer to the outside.

An ETC valve (Electronic Throttle Control Valve) 29 is provided at the inlet side of the intake manifold 32 to regulate the amount of the mixer introduced into the engine. When a large number of mixers are supplied, the engine output becomes large.

The control unit 110 controls the operation of the engine 30 by adjusting the opening of the fuel valve 13 and the opening of the ETC valve 29. As the opening degree of the fuel valve 13 and the opening degree of the ETC valve 29 become larger, the engine speed will increase.

The engine 30 is an internal combustion engine that operates the mixer introduced through the intake manifold 32 through four strokes of suction, compression, explosion, and exhaust.

Exhaust gas generated as the engine 30 is operated is discharged through the exhaust manifold 34, at which time the impeller of the turbocharger 20 is rotated.

The engine 30 rotates the generator 40 to produce electric power. To this end, a belt may be connected between a pulley 36 provided at one end of the rotating shaft of the engine 30 and a pulley 46 provided at one end of the rotating shaft of the generator 40.

The pulley 36 of the engine 30 and the pulley 46 of the generator 40 may be provided so that the rotation ratio thereof is approximately 1: 3. That is, when the engine 30 rotates at 1000 rpm, the generator 40 can rotate at about 3000 rpm.

The power generated by the generator 40 may be converted into a commercial power converted from a current, a voltage, a frequency, etc. in the power converter 90 and supplied to a power consumer such as a building or an air conditioner.

On the other hand, since the engine 30 generates considerable heat during operation by gas combustion, it circulates the cooling water and performs heat exchange to absorb the heat of high temperature generated in the engine.

In the automobile, the radiator is installed in the cooling water circulation flow path to discard all of the waste heat of the engine. In the cogeneration system 100, however, the heat generated by the engine can be absorbed to generate hot water.

To this end, a hot water heat exchanger (50) is provided in the cooling water circulation channel so that heat is exchanged between water supplied separately from the cooling water so that the water receives heat from the high temperature cooling water.

The hot water generated by the hot water heat exchanger (50) is stored in the hot water storage tank (51) and can be supplied to hot water consumers such as buildings.

In the case where hot water is not used in the hot water consumer, water is not supplied to the hot water heat exchanger 50, and the temperature of the cooling water rises. To prevent this, a separate heat radiator 70 is installed, You can throw away.

The radiator 70 dissipates heat by exchanging heat with the air by means of a plurality of fins, and the heat dissipating fan 72 may be provided to accelerate heat dissipation.

The cooling water flow path from the engine 30 is branched into the hot water heat exchanger 50 and the radiator 70 and a three-way valve 53 is provided at the branch point to control the flow direction of the cooling water according to the situation . The cooling water can be sent only to the hot water heat exchanger 50 or only to the radiator 70 by the three-way valve 53 or can be divided into the hot water heat exchanger 50 and the radiator 70 at a predetermined ratio depending on the situation.

Way valve 53 and radiating from the radiator 70 can be combined with the cooling water that has passed through the three-way valve 53 and passed through the hot water heat exchanger 50 and then introduced into the engine 30.

The cooling water circulating passage is provided with a cooling water pump 55 to adjust the flow rate of the cooling water. This cooling water pump 55 can be installed downstream of the hot water heat exchanger 50 and the radiator 70 and upstream of the engine 30 in the cooling water circulation flow path.

On the other hand, the exhaust gas flowing through the exhaust manifold 34 of the engine 30 operates the turbocharger 20 described above. However, the exhaust gas heat exchanger 60 may be provided to recover the waste heat of the exhaust gas. have.

The exhaust gas heat exchanger 60 is arranged between the cooling water pump 55 and the upstream side of the engine 30 in the cooling water circulating flow passage and can be configured to exchange heat between the exhaust gas discharged through the turbocharger 20 and the cooling water . The exhaust heat of the exhaust gas can be recovered through the exhaust gas heat exchanger (60).

The cooling water is heated to some extent while flowing through the exhaust gas heat exchanger 60 and flows into the engine 30 in a lukewarm state, but the cooling water can sufficiently cool the engine 30.

Exhausted gas passing through the exhaust gas heat exchanger 60 passes through the muffler 80 and the exhaust side noise of the engine can be reduced by the muffler 80. [

The exhaust gas that has passed through the muffler 80 can be discharged to the outside after passing through the drain filter 85. The drain filter 85 has a built-in hydride filter for purifying the condensed water generated in the muffler 80, the exhaust gas line, etc., so that the acidic condensed water can be purified and neutralized and flow out to the outside.

FIG. 2 is a perspective view showing a rotor according to a first embodiment of the present invention, and FIG. 3 is a plan view showing an upper half (a) and a lower half (b) of the rotor of FIG.

The rotor 200 includes a rotor iron core 210 in which a steel plate is stacked in a column as a whole. A stator (not shown) is disposed on the outer circumferential surface of the rotor 200. When the rotor 200 is rotated by the engine 30, current flows through the conductor of the stator to generate electric power.

A rotation axis insertion hole 220 is formed at the center of the rotor core 210 so that the rotation axis can be inserted.

A plurality of bolt fastening holes 230 may be formed on the outer side of the rotary shaft insertion hole 220.

The permanent magnet receiving hole 240 may be formed at a portion corresponding to each side of the polygon centered on the center of the rotor iron core 210.

In the illustrated embodiment, six permanent magnet receiving holes 240 are formed in the permanent magnet receiving hole 240 at positions corresponding to the respective sides of a regular hexagon, but the length of the regular polygonal sides is not limited thereto.

The permanent magnet receiving hole 240 is formed in a substantially rectangular elongated rectangular column shape, and two permanent magnets 250 can be inserted into each of the permanent magnet receiving holes 240.

A plurality of slits 270 formed parallel to each other are formed on the outer circumferential portions 260 of the permanent magnet receiving hole 240. A plurality of slits 270 are formed parallel to each other in one peripheral portion 260 and are formed to be inclined at the same angle with respect to the center of the pole.

3, a plurality of slits 270 are formed at an upper half of the rotor core 210 so as to be inclined at a predetermined angle counterclockwise with respect to the center of the pole, The plurality of slits 270 are preferably formed to be inclined at a predetermined angle in the clockwise direction with respect to the center of the poles.

The upper half slit of the rotor 200 is formed to be inclined in the counterclockwise direction with respect to the center of the pole and the lower half slit is inclined in the clockwise direction with respect to the pole center so that slits at different angles in the upper half and lower half can give a cogging torque phase difference So that the synthetic cogging torque can be reduced.

The torque ripple is influenced not only by the correlation between the magnetic flux due to the current and the magnetic flux due to the permanent magnet, but also by the saliency of the rotor. As described above, when the slits are formed, sloped slits in the upper and lower halves interfere with the q-axis magnetic path, so that the salient polarity of the rotor is reduced and the torque ripple can be reduced.

4 is a graph showing changes in cogging torque and no-load electromotive force according to slit angles.

It can be seen that as the slit angle increases to 20 degrees, the rate of decrease in cogging torque (DELTA) is large, but the rate of decrease in no-load back electromotive force (&squ;) is not large.

That is, the cogging torque (Δ) was reduced from 40% to 5% when the slit angle was 0 ° and 45% when the slit angle was 20 °. However, the unloaded counter electromotive force (□) was decreased from 99% to 98% Able to know.

It can be seen that when the slit angle changes from 20 degrees to 30 degrees, the cogging torque (DELTA) decreases by only 1%.

Therefore, the angle of inclination of the plurality of slits 270 is preferably 20 to 30 degrees, and more preferably 20 degrees.

5 is a view showing a magnetic flux flow according to a slit angle inclined to the left.

5 (a) is a view in which the slit angle is inclined by 10 degrees counterclockwise, FIG. 5 (b) is inclined by 20 degrees, FIG. 5 (c) is inclined by 30 degrees, It is also tilted.

As shown in the figure, the magnetic flux generated in the permanent magnet varies depending on the slit angle.

6 is a graph showing the cogging torque (a) in the upper and lower halves when the slit angle is 20 degrees and the cogging torque (b) in comparison with the slitless model.

6 (a), it can be seen that a predetermined phase difference occurs between the upper half cogging torque and the lower half cogging torque of the rotor, and the composite cogging torque of the upper half and the lower half is shown in Fig. 6 (b).

The synthetic cogging torque is obtained by adding the upper half cogging torque and the lower half cogging torque to the instantaneous value, and when a phase difference is generated between the upper half cogging torque and the lower half cogging torque, the total cogging torque is decreased.

6 (b), the cogging torque is reduced to about 40% as compared with the model without the slit in the case of the model in which the slit angle of 20 degrees is applied.

FIG. 7 is a graph showing torque ripple (b) in comparison with torque ripple (a) and no-slit model in the upper and lower halves when the slit angle is 20 degrees, FIG. 8 is a graph showing current ripple (B) comparing with a no-slit model.

Fig. 7 (a) shows the upper side load torque and the lower side load torque, and Fig. 7 (b) shows the combined load torque.

In FIG. 7 (b), the torque ripple of the combined load torque is decreased in the case of the model using the slit angle of 20 degrees as compared with the slitless model.

However, when the current phase is controlled to be the same as the mu slit model at 146 degrees as shown in FIG. 8, the output voltage of the generator decreases and the absolute value of the generated torque decreases due to the decrease of the q-axis inductance.

This is because the no-load voltage and the pole polarity decrease as the slit is formed, so that when the current is controlled at the same current phase, the generated torque is reduced as compared with the slitless model.

In order to prevent this, it is preferable that the current phase with respect to the q-axis of the generator is controlled to be larger than that in the case where there is no slit.

FIG. 9 is a graph showing torque ripple (b) in comparison with the torque ripple (a) and the no-slit model in the upper and lower halves when the current phase is further changed when the slit angle is 20 degrees, (B) comparing the current phase (a) and the torque according to the current phase (a) and the slit model.

9 (a) shows the upper side load torque and the lower side load torque, and Fig. 9 (b) shows the combined load torque.

For example, when the current phase is controlled to be 158 degrees rather than 146 degrees as in FIG. 10 (a), the combined load torque in FIG. 9 (b) is larger than that of the slitless model It can be seen that the absolute value of the generated torque becomes larger while the torque ripple is reduced.

10 (b), the torque ripple is 4.6% smaller than that of the no-slit model, the generated torque is -58.6 Nm, and the fundamental wave output voltage is 38.7 V, Which is almost the same or larger than that of the first embodiment.

FIG. 11 is a perspective view showing a rotor according to a second embodiment of the present invention, and FIG. 12 is a plan view showing slit angles that are inclined with respect to a rotating direction of the rotor.

In the rotor of the second embodiment, the inclined angle of the slit 270 is formed in the same direction as that of the first embodiment, not the upper half and the lower half.

In Fig. 12, when the rotational direction of the rotor is counterclockwise as shown by an arrow, the inclination angle of the slit 270 is the same as the rotational direction, and " + [theta] " θ "(b).

In the case of the rotor of the second embodiment, as shown in Fig. 12 (b), the plurality of slits are formed to be inclined by a predetermined angle in the direction opposite to the rotation direction with respect to the center of the poles.

FIG. 13 is a view showing a magnetic flux flow according to an angle of a slit inclined in a rotating direction, and FIG. 14 is a view showing a magnetic flux flowing with an angle of a slit inclined in a direction opposite to a rotating direction.

It can be seen that the flow of the magnetic flux generated in the permanent magnet changes according to the angle of the slit.

FIG. 15 is a graph showing changes in induced voltage a and torque ripple b according to slit angles.

15 (a) shows the upper side peak of the generator induced voltage when a load is applied. When the slit angle is -30 degrees, the fifth and seventh harmonic components are the smallest, which can minimize torque ripple.

15 (b), when the slit angle is from about -40 degrees to about -30 degrees, the torque ripple decreases to the minimum, the torque ripple increases from about -20 degrees, and the torque ripple increases continuously to +40 degrees .

Therefore, it is preferable that the angle of inclination of the plurality of slits is 35 to 20 degrees in the direction opposite to the rotation direction. When the slit angle is -35 to -20 degrees, the torque ripple can be less than about 2%.

FIG. 16 is a graph showing torque ripple when a slit angle of -30 degrees is applied to a no-slit model. FIG. 17 is a graph comparing the current phase a with the slit angle- (b).

16, it can be seen that the torque ripple is reduced in the case of the model in which the slit angle is applied at -30 degrees as compared with the slitless model.

However, when the current phase is controlled to be the same as the mu slit model at 146 degrees as shown in FIG. 17, the output voltage of the generator decreases and the absolute value of the generated torque decreases due to the decrease in q-axis inductance.

FIG. 18 is a graph showing torque ripple in comparison with a no-slit model when the current phase is further changed when the slit angle is -30 degrees. FIG. 19 is a graph showing the current phase (a) And the torque and the like are compared with the no-slit model (b).

For example, when the current phase is controlled to be 158 degrees rather than 146 degrees as in FIG. 19 (a), the combined load torque in FIG. 18 shows a torque ripple And the absolute values of the generated torques are almost the same.

19 (b), the torque ripple is 1.7%, which is smaller than the slitless model, the generated torque is -58.4 Nm, and the fundamental wave output voltage is 316.0 V, Which is almost the same as the case of Fig.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, Changes will be possible.

12: Zero Governor 14: Air Cleaner
16: Mixer 20: Turbocharger
30: engine 40: generator
50: hot water heat exchanger 60: exhaust gas heat exchanger
70: Radiator 80: muffler
90: power converter 100: cogeneration device
200: rotor 210: rotor iron core
220: rotating shaft insertion hole 230: bolt fastening hole
240: permanent magnet receiving hole 250: permanent magnet
260: outer circumferential portion 270: slit

Claims

A rotor iron core in which a steel plate as a whole is stacked in a columnar shape;
A rotating shaft insertion hole formed at the center of the rotor iron core;
A permanent magnet accommodation hole formed at a portion corresponding to each side of a polygon centered on the center of the rotor iron core;
A permanent magnet inserted into the permanent magnet accommodating hole; And
And a plurality of slits formed parallel to each other on an outer peripheral portion of the permanent magnet receiving hole,
Wherein the plurality of slits at an upper half of the rotor iron core are formed to be inclined at a predetermined angle counterclockwise with respect to the center of the pole,
Wherein the plurality of slits in the lower half of the rotor iron core are formed to be inclined at a predetermined angle clockwise with respect to the center of the pole.

The method according to claim 1,
Wherein an angle of inclination of the plurality of slits is 20 to 30 degrees.

3. The method of claim 2,
Wherein the current phase with respect to the q-axis of the generator is controlled to be greater than that with no slit.

The method of claim 3,
Wherein the current phase is controlled at 156 to 160 degrees.

An engine using gas as fuel;
The generator according to any one of claims 1 to 4, which is driven by the engine to produce electric power.
A cooling water circulation line for cooling the engine; And
And a hot water heat exchanger installed in the cooling water circulation line and generating hot water by heat exchange with water supplied separately.

A rotor iron core in which a steel plate as a whole is stacked in a columnar shape;
A rotating shaft insertion hole formed at the center of the rotor iron core;
A permanent magnet accommodation hole formed at a portion corresponding to each side of a polygon centered on the center of the rotor iron core;
A permanent magnet inserted into the permanent magnet accommodating hole; And
And a plurality of slits formed parallel to each other on an outer peripheral portion of the permanent magnet receiving hole,
Wherein the plurality of slits are formed to be inclined at a predetermined angle in a direction opposite to a rotation direction with respect to the center of the poles.

The method according to claim 6,
Wherein an angle of inclination of the plurality of slits is 35 to 20 degrees in a direction opposite to a rotation direction.

8. The method of claim 7,
Wherein the current phase with respect to the q-axis of the generator is controlled to be greater than that with no slit.

9. The method of claim 8,
Wherein the current phase is controlled at 152 to 156 degrees.

An engine using gas as fuel;
A generator according to any one of claims 6 to 9, which is driven by the engine to produce electric power;
A cooling water circulation line for cooling the engine; And
And a hot water heat exchanger installed in the cooling water circulation line and generating hot water by heat exchange with water supplied separately.