JP2007330062A - Power generating apparatus and heat pump device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To secure stability with respect to load torque fluctuation in a motor. <P>SOLUTION: An inverter circuit 110 is stabilized by changing a phase of output voltage in a direction where transitional speed fluctuation generated by fluctuation of a load angle of the motor 108 is absorbed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a power generation device and a heat pump device used for various electric appliances for business use, general household use, and business use.

  Conventionally, in this type of power generation device, the control means controls so that the phase of the voltage and current supplied from the inverter circuit to the motor, or the reactive current becomes a predetermined value (see, for example, Patent Document 1).

FIG. 10 shows a block diagram of a conventional power generator described in Patent Document 1. In FIG. As shown in FIG. 10, the AC power 1 is converted into DC power by the rectifier circuit 2, the motor 4 is driven by the inverter circuit 3, the output current of the inverter circuit 3 is detected by the current detection means 5, and the reactive current is set. The rotation speed is controlled to be a predetermined value, and the sine wave drive can be performed without detecting the position of the motor 4 (position sensorless) while having a simple configuration.
JP 2005-204431 A

  However, in the conventional configuration, even when the load torque of the motor 4 changes, the magnitude of the supply voltage to the motor 4 is controlled so that the value of the reactive current becomes a predetermined value, whereby the inverter circuit The phase of the rotor of the motor 4 with respect to the voltage supplied from the motor 3 changes, that is, the load angle changes, so that the operating point after the load torque fluctuation is naturally followed. As for the frequency and phase of the voltage supplied to the motor 4, since the operation of the synchronous motor is given by a signal completely independent of the actual rotation of the motor 4, the rotational speed of the motor 4 before and after the fluctuation of the load torque This results in transient speed fluctuations accompanying changes in the load angle. The speed and load angle are also related to various constants such as the moment of inertia of the mechanical system and the damper resistance. Were those damping vibration is intended to occur.

  FIG. 11 shows the relationship between torque and load angle δ when the conventional motor 4 is operated at 6000 revolutions per minute, and the inverter is set so that the reactive current value is always 1A. The characteristic is under the condition that the magnitude of the voltage supplied from the circuit 3 to the motor 4 is controlled.

  The load angle δ is 40 degrees at the operating point A operating stably at a load torque of 0.6 Nm. When the load torque is increased to 0.85 Nm from this state, the reactive current value is always set to 1 A. , The generated torque of the motor 4 changes as shown in the curve, that is, in order for the motor 4 to output 0.85 Nm, the load angle δ needs to be 52 degrees, and δ = If it remains at 40 degrees, the torque is insufficient and δ increases due to a temporary decrease in speed, and moves to point B. However, when point B is reached, the speed is considerably lower. The operating point moves further to the upper right.

  In order to give kinetic energy corresponding to the synchronous speed to the mechanical moment of inertia, the load angle δ temporarily becomes a considerably large value after reaching the point C at which S2 substantially equal to the area S1 is obtained, and then the mechanism By the action of the resistance component (dump component) that suppresses typical vibrations, after damped vibrations, they converge to point B.

  FIG. 12 shows the change of the load torque in (a) and the change in the load angle δ in (a). When the load torque is increased stepwise from 0.6 Nm to 0.85 Nm at time t1, the load angle is Damping vibration is performed by the mechanism described above.

  Here, the period of the damped vibration is a value obtained by differentiating the torque generated by the motor 108 with respect to the load angle, that is, the inclination is the restoring force, and is the vibration period of the mechanical system with the moment of inertia of the load including the motor 108. Compared to the response period, there is a tendency to have a long period. Especially when the load inertia moment is large, the period becomes quite long. It becomes a situation of pulling.

  Further, when such a condition of a transiently large load angle is passed, there is a possibility of stepping out at that time, and it is often difficult to maintain a stable operation.

  In particular, when the load torque increases abruptly, even if the magnitude of the voltage is controlled so that the reactive current value is maintained at a predetermined value, the rotor is once delayed considerably with respect to the voltage, that is, the load The problem was that the corners became excessive and the possibility of step-out was high.

  For example, when used in a compressor of a heat pump device, there is a feature that the moment of inertia is small although the fluctuation of the load torque is large, so the problem becomes large, and the control that advances the phase of the current to the rotor However, in this state, the maximum torque value with respect to the load angle is small, which makes it easy to step out. It was a serious problem.

  The present invention solves the above-described problem. By suppressing a transient speed change caused by a change in the load angle when the load torque fluctuates, the load torque fluctuation, such as a compressor of a heat pump device, is suppressed. Even when driving a large load, an object is to provide a power generation device that prevents an out-of-step due to an excessive value of the load angle and can perform a stable drive with a simple configuration.

  In order to solve the above problems, a power generation device according to the present invention includes an electric motor including a permanent magnet and a winding, and an oscillating unit that generates a signal having a frequency corresponding to the speed of the electric motor. An inverter circuit for supplying an alternating current, wherein the inverter circuit absorbs a transient speed fluctuation caused by a fluctuation in a load angle of the electric motor and absorbs a phase of an inverter circuit output voltage with respect to an output signal of the oscillation means. Is something that changes.

  As a result, when the load torque of the motor fluctuates, the load angle fluctuates, but the inverter circuit changes the voltage phase in such a direction as to suppress the speed fluctuation that occurs transiently due to the load angle fluctuation. As a result, it is possible to reduce the damping vibration of the load angle and speed that occurs after the fluctuation of the load torque, sufficiently reduce the possibility of step-out, and perform stable operation.

  Although the present invention has a simple configuration, the possibility of step-out due to fluctuations in load torque is suppressed, and a highly stable power generation device can be realized.

  1st invention has an inverter circuit which has an electric motor provided with a permanent magnet and a coil, an oscillation means which generates a signal of a frequency corresponding to the speed of the motor, and supplies an alternating current to the coil The inverter circuit changes the load torque fluctuation by changing the phase of the inverter circuit output voltage with respect to the output signal of the oscillating means in a direction to absorb the transient speed fluctuation caused by the fluctuation of the load angle of the electric motor. It is possible to reduce the damped vibration of the load angle and speed that occur later, and to sufficiently reduce the possibility of step-out and perform stable operation.

  2nd invention has an electric motor provided with the permanent magnet and the coil | winding, and the inverter circuit which supplies an alternating current to the said coil | winding, The said inverter circuit is an oscillation means which outputs the frequency corresponding to the speed of the said motor And a phase shift means for shifting the phase of the oscillating means, and the inverter circuit controls the voltage supplied to the electric motor so that the reactive current supplied to the electric motor becomes a predetermined value. By setting the voltage phase supplied to the windings to a value corresponding to the output of the phase shift means, performance equivalent to vector control can be obtained without a position sensor, and operation with high stability against load torque fluctuations can be achieved. It can be done.

  In particular, the third aspect of the invention provides a phase shift means of the second aspect of the invention that is advanced in phase as the voltage supplied to the motor is higher, so that the load angle generated when the load torque fluctuates while having a relatively simple configuration. It is possible to effectively prevent the step-out associated with the fluctuations of.

  In the fourth aspect of the invention, in particular, the oscillation means of the second aspect of the invention controls the output frequency so that the effective current supplied to the electric motor becomes a predetermined value, so that even when the load torque fluctuation is particularly large, Drive control according to the actual speed is performed, and more stable operation is possible.

  In particular, the fifth invention has speed setting means for outputting a set value of the speed of the electric motor in addition to the configuration of the fourth invention, so that the output frequency of the oscillation means becomes equal to the output of the speed setting means. In addition, by changing the predetermined value of the effective current, even when the load torque fluctuation is particularly large, high stability is achieved, and speed control is performed with high accuracy so that the actual motor speed is close to the set speed. Will be able to.

  In particular, the sixth invention includes a compressor having the power generation device according to any one of the first to fifth inventions, a refrigerant, and a heat exchanger, wherein the power generation device compresses the refrigerant, By configuring a heat pump device that performs heat exchange with the refrigerant, the heat exchanger has a relatively simple configuration, but there is no out-of-step even when using a compressor with large load fluctuation and small moment of inertia. Thus, sufficient driving stability can be ensured.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a block diagram of a power generation device according to a first embodiment of the present invention. In FIG. 1, a rotor 101 has permanent magnets 102a, 102b, 102c, and 102d, and a stator 104 has a three-phase winding 105, 106, and 107, and an electric motor 108 is configured. The inverter circuit 110 that supplies an alternating current to the windings 105, 106, and 107 is connected.

  Here, the permanent magnets 102a, 102b, 102c, and 102d are all made of rare earth neodymium and are embedded in the rotor 101 made of a magnetic material. In this state, the revolving torque is used together with the reluctance torque, so that it can be operated efficiently. However, it is not absolutely necessary to use an embedded magnet. It does not matter as a configuration.

  The inverter circuit 110 generates an oscillation unit 111 that generates a signal having a frequency corresponding to the speed of the electric motor 108, counts an output signal of the oscillation unit 111, and counts an electrical angle with a resolution of 1 degree, and an oscillation unit 111. Is added to the electrical angle counted by the electrical angle counter 112 to provide a phase shift means 113 for shifting the phase, and the phase shift means 113 uses an amplifier 114 and an addition means 115. Thus, θ is output as an output signal.

  The rotation conversion means 118 receives a θ signal that changes within a range of 0 to 360 degrees, and corresponds to the magnitude of the voltage output from the Va input to the windings 105, 106, 107 of each phase, and the electrical angle θ The instantaneous value corresponding to the phase of the signal is output to the PWM inverter 119 as each signal of Vu, Vv, and Vw. The PWM inverter 119 is 15.625 kHz, that is, a triangular wave carrier signal having a period of 64 microseconds. By digitally comparing the magnitude, PWM modulation is performed, and an inverter having a three-phase, six-stone structure is turned on and off with a drive signal including an appropriate dead time.

  The PWM inverter 119 detects each of the three-phase output currents by the current detection means 121. As a specific configuration of the current detection means 121, there are three low-potential-side elements used in the prior art. The voltage generated in the three resistors connected in series to the emitter terminal of the switching element is detected during the ON period of each switching element, and the current values Iu, Iv, Iw of each phase are detected. However, in addition to such a configuration, for example, a configuration using magnetic current detection parts having frequency characteristics from a direct current component, such as DCCT, or the emitter terminals of three low potential side switching elements Are connected in common, and the voltage of one current detection resistor connected between the DC input terminal on the low potential side is detected at a predetermined timing. Ri, in which like can also be used that detects a current value of each phase of the three phases.

  The three-phase currents Iu, Iv, and Iw detected by the current detection unit 121 are input to the reactive current detection unit 122, and as a result of performing a multiplication process with a trigonometric function according to the simultaneously input θ value, The current of the component orthogonal to the voltage vector input to the electric motor 108, that is, the value of the reactive current Ir is calculated.

  On the other hand, the reactive current setting means 124 is capable of covering the range of the load torque of the electric motor 108 at the driving speed and setting and outputting the value of the reactive current that allows the electric motor 108 to realize high efficiency. In this embodiment, the reactive current value Ir * of 1 A is set.

  The subtracting means 125 obtains the difference between the output Ir * of the reactive current setting means 124 and the output Ir of the reactive current detection means 122, and the difference is amplified by the PI amplifier 127 by a proportional element and a time integration element. , Va value is output to the rotation conversion means 118.

  With the above configuration, the inverter circuit 110 according to the present embodiment controls the voltage Va supplied to the electric motor 108 so that the reactive current Ir supplied to the electric motor 108 becomes a predetermined value Ir *. Further, regarding the voltage phase supplied to the windings 105, 106, 107, since the output θx of the amplifier 114 is added, the electrical angle corresponds to the output θ (= θ0 + θx) of the phase shift means 113.

  As for θx, in this embodiment, the magnitude Va of voltage supplied from the inverter circuit 110 to the windings 105, 106, 107 of the electric motor 108 is input to the amplifier 114, and the larger the value is, the larger the value is θx. Since the output is made, the phase shift means 113 advances the phase greatly as the voltage supplied to the electric motor 108 is higher.

  FIG. 2 is an operation waveform diagram of the phase shift means 113 in the present embodiment. (A) is the output signal θ0 of the electrical angle counter 112, (A) is the output signal θ of the phase shift means 113, and (C) is the output signal θ. The waveform of the U-phase voltage Vu output from the PWM inverter 119 is shown.

  Vu has a waveform obtained by performing a SIN function on the θ signal, but Vv and Vw have the same amplitude as Vu, respectively, and are sine wave waveforms with phases delayed by 120 degrees and 240 degrees, respectively. ing.

  As described above, since the three-phase voltages are sine waves whose phases are shifted, the line voltages (U-V, V-W, and W-U) are all substantially sine waves. However, for example, two-phase modulation, superposition of 3rd order harmonics, 3n order harmonics, etc. are generally used, and such a waveform is output because of the effect of improving the voltage utilization rate. In any case, an almost sinusoidal voltage is applied to the three-phase windings 105, 106, and 107, and a waveform with relatively little distortion can be obtained with respect to the current waveform.

  FIG. 3 shows the torque generated by the motor 108 and the load angle δ (no-load induced electromotive force and terminal voltage when the reactive current Ir is kept constant in a state where the motor 108 is operated at 6000 rpm. It is a graph showing the relationship between the two vectors.

  In the present embodiment, since the permanent magnets 102a, 102b, 102c, and 102d are embedded in the rotor 101 of the electric motor 108, reluctance torque due to the difference between the q-axis inductance and the d-axis inductance is taken into account. The generated torque is shown.

  When the value of the reactive current Ir is kept at 1 A, the peak of the torque of 1.25 Nm is present at about δ = 73 [degrees] as shown by the curve m, and the reactive current set value is adjusted Are curves as indicated by 0A, 0.5A, and 1.5A (all broken lines), respectively.

  The value of the peak torque (maximum torque) increases as the reactive current is increased, and the torque peak load angle is larger as the reactive current value is larger.

  When the load torque is stably operated at 0.6 Nm, the operation is performed at the operating point indicated by the point A, but when the load torque is increased to 0.85 Nm, the operating point is operated at the point B. As a result, the load angle δ increases from 40 degrees to 52 degrees, and the difference increases by 12 degrees.

  Therefore, when the phase of the voltage supplied to the motor 108 is not changed, the load angle δ increases due to the shift from the point A to the point B, so that the speed decreases transiently. This causes the phenomenon of vibration (with damping) at the load angle and speed described in the prior art.

  FIG. 4 is a characteristic graph showing the relationship between the voltage Va and the torque supplied to the electric motor 108 under the same conditions as in FIG. 3, that is, in a state where the reactive current is kept at 1 A at 6000 rpm. In the range normally used (the range where the load angle is smaller than the peak point of torque), Va increases as the torque increases. In this case, the value of Va increases from 77V to 110V.

  Therefore, in the present embodiment, by changing the output voltage phase from the inverter circuit 110 with respect to the voltage magnitude Va in a state where the reactive current is kept at 1A which is a predetermined value, The structure prevents the vibration phenomenon that occurs.

  FIG. 5 is a graph showing the characteristics of the amplifier 114 of the present embodiment. The phase shift value θx with respect to the voltage setting value Va applied to the electric motor 108 changes, and the Va value increases from 77V to 110V. In response to this state, the θx value output from the amplifier 114 is increased from 40 degrees to 52 degrees by the difference of 12 degrees, that is, the phase shift means 113 supplies the motor 108 with the difference. The higher the voltage Va, the higher the phase advance characteristic.

  In the present embodiment, the relationship between the voltage Va and the shift phase θx is determined by a substantially linear function, but if necessary, a curve may be provided. Further, it is possible to switch to a plurality of curves according to the speed, or not only to determine θx as a function of the instantaneous value of Va, but also to have a PI characteristic to which a time integration element is added.

  With the above configuration, in the present embodiment, even when the operating point shown in FIG. 3 moves from point A to point B, the load angle δ increases by 12 degrees, but the voltage phase is advanced by 12 degrees. As a result, a transient decrease in speed does not occur, and the same characteristics as if moving to the point E of the curve e in FIG. 3 can be obtained.

  As described above, when the load torque fluctuates, the load angle fluctuates. However, in the present embodiment, the voltage phase is changed by the phase shift means 113. As a result, the load torque fluctuation is changed. As a result, the fluctuation of the transient speed is suppressed, and the vibration of repeating acceleration and deceleration so that the speed catches up to the original speed (that is, the synchronous speed) is greatly reduced, that is, the load angle δ of the motor 108 is reduced. The phase of the inverter circuit output voltage with respect to the output signal of the oscillating means 111 is changed in a direction to absorb the transient speed fluctuation generated by the fluctuation.

  In particular, in the present embodiment, the voltage value Va is controlled so that the value of the reactive current becomes the predetermined value 1A. Therefore, the operation without the position sensor can be performed with a substantially sine wave current waveform, and the reactive current Ir By appropriately setting the set value, it is possible to keep the current vector on the dq plane in a phase that allows the motor 108 to operate efficiently, as in vector control, with a relatively simple configuration. Nevertheless, a great effect can be obtained.

  However, it is not absolutely necessary to keep the reactive current at a predetermined value. For example, the power factor is set to a predetermined value, that is, the phase difference between the voltage input from the inverter circuit 110 to the motor 108 and the current vector is constant. It may be configured so as to be controlled, and further, it may be driven by a predetermined voltage Va value as in the case of a synchronous motor transmitted from ancient times. Since δ changes with the fluctuation of the load torque, the inverter circuit output voltage with respect to the output signal from the oscillating means 111 in the direction of absorbing the transient speed fluctuation caused by the fluctuation of the load angle δ. The configuration that changes the phase of the motor works effectively as a configuration that reduces vibration of the load angle and speed when the load fluctuates and suppresses step-out. It becomes.

  FIG. 6 shows the waveforms of (a) load torque, (b) load angle δ, and (c) voltage shift phase θx in the present embodiment. At time t1, the load torque is reduced from 0.6 Nm to 0. .85 shows a case where the step changes.

  When the load angle δ starts to increase immediately after the load torque increases at t1, as a result of the control to keep the reactive current constant, the phase shift means 113 shortens θx as the voltage Va increases promptly. Since it increases from 40 degrees to almost 52 degrees in time, even if the voltage phase advances and the load angle δ increases, the required torque of 0.85 Nm continues without causing a transient decrease in speed. Then, the vibration while the speed and the load angle δ are attenuated can be suppressed to almost zero.

  Therefore, since the operating point at a transient large load angle δ is not passed, the possibility of step-out can be suppressed to a very low level, and an extremely stable operation can be performed.

  Incidentally, in contrast to FIG. 6, FIG. 7 shows (a) load torque, (b) load angle δ, when the phase shift means 113 is configured to delay the phase when the load angle is large and the Va value is large. (C) Although it is θx, when this is done, the load angle and the damped vibration of the speed will be larger than in the prior art.

(Embodiment 2)
FIG. 8 is a block diagram of an inverter circuit 129 of the power generation device according to the second embodiment of the present invention.

  In FIG. 8, connection from the output UVW of the inverter circuit 129 is not described, but the same electric motor 108 as in the first embodiment is connected. In FIG. 8, a three-phase / two-phase conversion means 130 capable of detecting both the effective current Ia and the reactive current Ir is provided, and the trigonometric function of the electrical angle θ is matrix-calculated into Iu, Iv, and Iw, The voltage applied to the electric motor 108 is decomposed into an in-phase component and a quadrature component and output, so that the output is performed while the component is decomposed into an effective current and a reactive current.

  Among these, as for the signal output of the reactive current Ir, as in the first embodiment, the set value of the magnitude Va of the voltage applied to the motor 108 is output from the error from the output Ir * of the reactive current setting means 124. It has become.

  On the other hand, in the case of the present embodiment, the effective current Ia has a meaning of a value that senses the state of the torque of the electric motor 108, and the oscillation means 131 includes the effective current setting means 132 and Ia. The frequency ω0 is set by inputting a difference from the value, that is, a value obtained by calculating the error by the subtracter 133. Therefore, the oscillation means 131 has an effective current Ia supplied to the motor 108 having a predetermined value. The output frequency ω0 is controlled to be equal to the value Ia *.

  In addition, speed setting means 135 for outputting the set value ω * of the speed of the electric motor 108 is further provided, and the difference from the output frequency ω 0 of the oscillation means 131 corresponding to the actual speed, that is, the speed error is subtracted 136. Since the effective current setting means 132 outputs the set value Ia * of the effective current based on the difference, the speed of the motor 108, that is, the output frequency ω0 of the oscillation means 131 is obtained as a result. The effective current Ia is controlled so as to be equal to the output ω * of the speed setting means 135.

  Therefore, in the present embodiment, the configuration is slightly more complicated than that in the first embodiment, but the speed is controlled by the set value ω *, and the synchronous motor that has been used for a long time is used. Unlike the state of being connected to an AC power supply having a voltage and frequency that is irrelevant to the operating state of the motor, the load can be flexibly adapted to the situation such as load torque. Therefore, even a situational change such as a sudden change in load torque becomes even more excellent, and the possibility of causing problems such as step-out can be eradicated.

(Embodiment 3)
FIG. 9 is a block diagram of a heat pump apparatus according to the third embodiment of the present invention. In FIG. 9, the power generation device 155 uses the one described in the first embodiment, and the compressor 156 rotates the cylinder 160 connected to the output shaft of the electric motor 108 of the power generation device 155. The refrigerant 157 using the alternative chlorofluorocarbon 134a is compressed.

  The refrigerant 157 compressed by the compressor 156 heats the air passing therethrough in a heat exchanger 161 also called a condenser, and is then reduced in pressure by the expansion valve 162 to become a low temperature. At 163, the refrigerant 157 that takes heat from the passing air and is vaporized is compressed again by the compressor 156, and is in a state called a refrigeration cycle. The air flowing from the intake pipe 165 It is cooled by the exchanger 163, and then heated by the heat exchanger 161 and comes out of the blower tube 166, but when it passes through the heat exchanger 163, the moisture contained in the passing air is reduced. Since the dew condensation and the generated water are discharged from the drain pipe 167, the dehumidifying operation is performed.

  However, the type of the refrigerant 157 is not limited to chlorofluorocarbon or alternative chlorofluorocarbon. For example, the refrigerant 157 may be used by compressing carbon dioxide gas to a supercritical condition. About the heat exchanger 161, the thing of a structure called a gas cooler etc. may be used.

  In such a compressor 156, the configuration of the cylinder 160 is called, for example, a two-piston configuration, and when viewed from the electric motor 108, there are many cases in which a load characteristic with a large torque fluctuation with respect to the rotation angle is exhibited.

  Therefore, the provision of the power generation device 155 shown in the first embodiment provided with a change in voltage phase with respect to a change in load torque can increase the effect of preventing load angle and speed vibrations. Therefore, there is no problem such as step-out, and stable operation is possible.

  As described above, in the power generation device according to the present invention, the phase of the inverter circuit output voltage with respect to the output signal of the oscillating means is such that the inverter circuit absorbs the transient speed fluctuation caused by the fluctuation of the load angle of the motor. By changing, the load angle and speed damped oscillations that occur after fluctuations in the load torque can be reduced, the possibility of step-out can be reduced sufficiently, and a stable power generator can be provided.

1 is a block diagram of a power generation device according to Embodiment 1 of the present invention. (A) Signal waveform diagram of the electric counter of the phase shift means of the power generation device (A) Signal waveform diagram of the phase shift means (C) Voltage waveform diagram of the U phase Same as above, load angle and torque characteristics graph of power generator Same as above, voltage Va and torque characteristics graph of power generator Same as above, characteristic graph of phase shift means 113 of power generator (A) Same as above, (a) Same as above, (B) Same as above, (C) Same as above, (C) Same as above, (C) Same as above, Same as above (A) Same as above, (a) Same as above, (A) Same as above, (A) Same as above, (C) Same as above, (C) Same as above, Operation waveform diagram Block diagram of a power generation device according to Embodiment 2 of the present invention Block diagram of a heat pump apparatus in Embodiment 3 of the present invention Block diagram of a conventional power generator Same as above, graph of power generator torque and load angle δ (A) Same as above, Operation waveform diagram of load torque of power generator (I) Same as above, Operation waveform diagram of load angle

Explanation of symbols

102a, 102b, 102c, 102d Permanent magnet 105, 106, 107 Winding 108 Electric motor 110, 129 Inverter circuit 111, 131 Oscillating means 113 Phase shift means 135 Speed setting means 155 Power generator 156 Compressor 157 Refrigerant 161, 163 Heat exchange vessel

Claims (6)

An electric motor having a permanent magnet and a winding; and an oscillating means for generating a signal having a frequency corresponding to the speed of the electric motor, and having an inverter circuit for supplying an alternating current to the winding; A power generator for changing a phase of an inverter circuit output voltage with respect to an output signal of the oscillating means in a direction to absorb a transient speed fluctuation generated by a fluctuation of a load angle of the electric motor. An electric motor having a permanent magnet and a winding; and an inverter circuit for supplying an alternating current to the winding, the inverter circuit outputting a frequency corresponding to a speed of the electric motor, and a phase of the oscillating means And the inverter circuit controls the voltage supplied to the motor and the voltage supplied to the winding so that the reactive current supplied to the motor has a predetermined value. A power generation device that sets the phase to a value corresponding to the output of the phase shift means. The power generation device according to claim 2, wherein the phase shift means advances the phase as the voltage supplied to the electric motor is higher. The power generation device according to claim 2, wherein the oscillating means controls the output frequency so that the effective current supplied to the electric motor becomes a predetermined value. 5. The power generation according to claim 4, further comprising speed setting means for outputting a set value of the speed of the electric motor, wherein the predetermined value of the effective current is changed so that the output frequency of the oscillation means becomes equal to the output of the speed setting means. apparatus. A compressor having the power generation device according to any one of claims 1 to 5, a refrigerant, and a heat exchanger, wherein the power generation device compresses the refrigerant, and the heat exchanger includes the refrigerant. A heat pump device that exchanges heat.