JP2008029116A - Single-phase permanent magnet motor controller, fan and pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a single-phase permanent magnet motor controller, especially, an inexpensive low vibration and low noise single-phase permanent magnet motor controller having flat output torque, and to provide a fan and a pump employing it. <P>SOLUTION: The single-phase permanent magnet motor controller comprises single-phase permanent magnet motor including a rotor having a permanent magnet and a stator having a single-phase winding and having a mechanism for generating cogging torque by magnetic action of them, a converter for supplying an AC current to the permanent magnet motor from a DC power supply, and a controller for controlling it. The single-phase permanent magnet motor controller is further provided with a controller for controlling the converter with waveform information of induced voltage and cogging torque of the single-phase permanent magnet motor. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a single-phase permanent magnet motor control device, and more particularly, to a low-cost, low-vibration, low-noise single-phase permanent magnet motor control device with a low output torque, and a fan and a pump using the same.

  A single-phase permanent magnet motor controller is used as a fan drive source because of its low cost. In principle, a single-phase permanent magnet motor generates a zero or negative torque region twice in one electrical angle cycle in the rotational direction at least in the rotational direction due to the current flowing through the single-phase winding and the magnetic flux of the permanent magnet. For this purpose, the gap length in the circumferential direction of the stator core is changed, and the zero or negative torque is compensated by the cogging torque by the stator core and the permanent magnet so that no negative torque is generated, or the stator The shape of the iron core is devised.

  This single-phase permanent magnet motor control device requires only one set of windings (three sets for three phases) and one hall element (three for three phases) compared to a general three-phase motor, and Since the conversion circuit is also an H-bridge, the number of components is four (6 for three phases), and the price merit is great. On the other hand, due to the above-described restrictions, the output torque during operation is not easily flattened and vibration noise is likely to occur.

  Moreover, as a use, there exists a tendency for the application to the pump mainly used for motor vehicles other than the said fan. As an improvement in automobile fuel efficiency, it is possible to achieve power-saving control by controlling the motor instead of pump driving by the engine, or the pump driving by the engine is restricted by the implementation of idle stop. This is a major reason for the adoption and expansion of the drive. In this case, a low price is very important, and in the case of a fan or a pump, a large starting torque is not required, and there is no problem such as a difficulty of generating a starting torque, which is a large defect of a single-phase permanent magnet motor. For this reason, it is a point which is easy to employ | adopt a single phase permanent magnet motor.

  A typical control disclosure example of a single-phase permanent magnet motor is shown in Japanese Patent Application Laid-Open No. 2004-88870. In Japanese Patent Laid-Open No. 2004-88870, in order to reduce torque pulsation of a single-phase permanent magnet motor, torque pulsation is reduced by providing a restriction at two places where the current increases in the electrically anti-cycle of the motor. An example to be disclosed is disclosed.

JP 2004-88870 A

  Japanese Patent Application Laid-Open No. 2004-88870 has an effect of reducing torque ripple to some extent with a simple configuration.

  However, when the number of revolutions changes, when the load changes, or when the temperature changes, it is not possible to cope with it sufficiently, and torque ripple may occur, which may cause vibration and noise.

  The present invention solves the above-described problems of the conventional example, reduces torque ripple to some extent even when the load fluctuates, and thereby provides a low-vibration, low-noise, low-cost single-phase permanent magnet motor control device and The fan and pump used are provided.

  One feature of the present invention is that electric power for driving a single-phase permanent magnet motor having a rotor having a permanent magnet and a stator having a single-phase winding and generating cogging torque by the magnetic action of both of them. A single-phase permanent magnet motor control device having a converter, which has waveform information of cogging torque and induced voltage of the single-phase permanent magnet motor.

  It is possible to provide a low-vibration, low-noise, low-cost single-phase permanent magnet motor control device, and a fan and a pump using the same.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 shows a configuration of a single-phase permanent magnet motor control device according to an embodiment of the present invention. FIG. 2 shows the details of the main part. FIG. 3 is a diagram for explaining the operation.

In FIG. 1, a single-phase permanent magnet motor control device 1 includes a single-phase permanent magnet motor 2, a converter 5 having a function of supplying AC power from a DC power source Edc to the single-phase permanent magnet motor 2, and an output of the converter 5. And a control circuit 6 for controlling the current.

  The single-phase permanent magnet motor 2 includes a stator 3 and a rotor 4. Here, a so-called outer rotation type motor in which the stator 3 is the inner periphery and the rotor 4 is disposed on the outer periphery will be described, but the same applies to the inner rotation motor or other motors. Further, although the rotor 4 is shown as an example in which the number of poles of the permanent magnet is 4, the effect of the present invention does not depend on the number of poles.

  In FIG. 1, the stator 3 includes a stator core 9, a stator winding 10 wound around the stator core 9, and a support device (not shown here). In general, the stator core 9 is formed by punching and laminating thin silicon steel plates, but it is generally used. However, the stator core 9 may be made of a dust core or the like. As shown in the figure, the number of salient poles of the stator core 9 is four, which is equal to the number of permanent magnets 7 of the rotor 4. The four stator windings 10 are connected in series and connected to the converter 5 as shown.

  The rotor 4 is arranged on the outer periphery of the permanent magnet 7 and constitutes a magnetic circuit of the permanent magnet 7 and has a role of mechanical connection to a shaft (not shown) as an output shaft. 8. Here, a ferrite rubber magnet or a plastic magnet is generally used because of its low cost.

  In FIG. 1, the gap between the rotor core 4 and the stator 3 is substantially constant in the rotation direction on the gap surface of the stator core 9, and the counter-rotation direction (here, the rotor 4 rotates counterclockwise). In this case, the gap length is large as shown by 91 in the counter-rotation direction of the stator core 9, and the gap length is small and constant as shown by 92 in the rotation direction. To do. In principle, a single-phase permanent magnet motor generates a zero or negative torque region twice in one electrical angle cycle in the rotational direction at least in the rotational direction due to the current flowing through the single-phase winding and the magnetic flux of the permanent magnet. By adopting the above shape, cogging torque that can compensate for the zero or negative torque can be effectively generated, and low vibration and noise can be achieved.

  At the shaft end of the permanent magnet 7 of the rotor 4, a position detector 11 (generally, a Hall element is used to detect the magnetic flux of the permanent magnet 7) is arranged on the stator 3, and thereby permanent The position of the magnet 7 is detected, and the single-phase permanent magnet motor 2 is supplied with an effective current through the converter 5. The stator winding 10 or the converter 5 of the single-phase permanent magnet motor has a current sensor 18 so that the current supplied to the stator winding 10 is constantly monitored.

  The control circuit 6 controls the converter 5 that supplies power to the single-phase permanent magnet motor from the information of the position detector 11 and the current sensor 18 described above, the cogging torque information 13 and the induced voltage information 14 stored in advance. .

  The angle conversion unit 12 is an arithmetic unit that estimates the electrical angle θ of the rotor 4 based on the information of the position detector 11, and the average speed of the rotor 4 in the cycle of switching between positive and negative of the output signal of the position detector 11. And the angle of the rotor can be calculated and estimated based on the passage of time in the control cycle. Further, the sign of the energization method of the converter 5 is determined by the sign information of the position detector 11.

  FIG. 2 shows the details of the main part of one embodiment of the present invention. The pulsating torque calculation means 16 includes an output torque calculation means 17 for calculating an output torque from the output of the current sensor 18, the output of the angle conversion unit 12, the cogging torque information 13, and the induced voltage information 14, and the output torque calculation means 17. The average torque calculating means 19 for calculating the average value of the pulsating torque and the pulsating torque calculating means 20 are included.

  Hereinafter, a method for calculating the pulsation torque will be described in detail.

  First, the electromagnetic torque Tw (θ) between the magnetic flux generated by the permanent magnet and the current flowing through the stator winding can be expressed by the following equation.

ここで、ωは回転角速度の情報を
Ｅ０（θ）は各速度ωにおける角度θに対する誘起電圧情報を
Ｉ（θ）は電流センサにより得られた電流情報を示す。
ωは回転角速度の情報を示す。

Where ω is the rotational angular velocity information
E0 (θ) is the induced voltage information for the angle θ at each speed ω.
I (θ) indicates current information obtained by the current sensor.
ω indicates information on the rotational angular velocity.

  Therefore, the total torque Tt (θ) generated by the single-phase permanent magnet motor is

ここで、Ｔｃｏｇ（θ）は回転角に対するコギングトルクを示す。

Here, Tcog (θ) represents the cogging torque with respect to the rotation angle.

  On the other hand, the average torque Tav can be calculated by the following equation by taking an average of one cycle of electrical angle of the total torque Tt (θ) (possibly even a half cycle if necessary).

  Therefore, the pulsation torque component Tac (θ) can be expressed by the following equation.

  In FIG. 1, the single-phase permanent magnet motor is generally controlled by the speed control means 15 so as to become a speed command Ns. As described above, control is performed using proportional-integral control or the like as necessary based on the speed feedback information calculated from the cycle of one electrical angle cycle of the position detector 11. On the other hand, the correction signal is generated by finely dividing one cycle of the position detector 11 based on the pulsating torque information calculated by the pulsating torque calculating means 16. The correction signals from the speed control means 15 and the pulsation torque calculation means 16 are combined by the drive signal calculation creation circuit 51 to control the converter 5. Accordingly, it is possible to flatten the output torque of the single-phase permanent magnet motor by performing correction control.

FIG. 3 is a diagram for explaining the operation of the control according to the present invention.
(A) shows the output signal of the position detector 11. It is also possible to advance the induced voltage shown in (c). The speed information of the permanent magnet rotor can be calculated from the half cycle of this signal or the cycle of the signal of one cycle.
(B) is a terminal voltage of the motor. Basically, a positive voltage signal is applied at the zero cross point from the negative to the positive of the position detector. The height of the voltage is adjusted by PWM (Pulse width Modulation) or the like. By delaying from the zero crossing point for a certain time, it is possible to advance or delay the induced voltage shown in (c).
(C) is the induced voltage information with respect to the rotating electrical angle. In general, the induced voltage is stored as an induced voltage constant obtained by dividing the induced voltage by the rotational speed, and can be converted into an induced voltage by multiplying the rotational speed.
(D) is current information, which is information fetched from the current sensor 18. Sequentially measure and store in memory.
(E) shows the cogging torque information with respect to the rotating electrical machine angle. Measure and store in memory in advance.
(F) is an electromagnetic torque Tw (θ) between the magnetic flux (induced voltage) by the permanent magnet and the current flowing in the stator winding, and is obtained by the equation (1).
(G) indicates the total torque, which is the torque expressed by the formula (2) as the sum of the above-described torque Tw (θ) and cogging torque.
(H) indicates pulsation torque and is calculated by the equations (3) and (4).

A signal for controlling the converter 5 is generated by synthesizing the output from the speed control means 15 and the output from the pulsating torque calculation means 16 by the drive signal calculation creation circuit 51. With the above control, the torque ripple shown in FIG. 3G is corrected, and a single-phase permanent magnet motor control apparatus with less torque ripple can be provided.

  The above control is a fan and pump control, and since the response frequency of the control is very slow at several hertz or less, the control is stably performed.

  The speed control cycle can be electrically performed every cycle, and the pulsation torque can be corrected every integer multiple thereof. Further, it is possible to stop the control at the time of a transient in which the speed command Ns signal is largely changed as necessary.

  As shown in FIG. 1, the single-phase permanent magnet motor has one set of windings and one hall element as compared with a general three-phase motor as shown in FIG. In addition, since the conversion circuit can be an H-bridge, the number of components is four and the cost advantage is great. On the other hand, the operation torque can be flattened by the control as described above, which is inferior to the three-phase motor. There can be provided a low noise, low vibration permanent magnet motor control device.

  With the above configuration, the cogging torque information 13 and the induced voltage information 14 are information that is proportional to or proportional to the square of the gap magnetic flux density, and the gap magnetic flux density is information proportional to the temperature. If a temperature sensor is provided in the motor control device to thereby correct the cogging torque information 13 and the induced voltage information 14, more accurate control can be performed.

  Further, by controlling the speed control every half cycle of the electrical angle and dividing the cycle into a plurality of times and performing pulsation torque correction control, high-precision control is possible.

  Also, considering the accuracy and temperature dependence of each constant in pulsating torque correction control, the deviation remains more than zero deviation control by integral control, but even if proportional control alone can achieve stable control, it is also selected it can.

  By adopting and providing this single-phase permanent magnet motor control device for an electric fan and an electric pump, an electric fan and an electric pump with a simple structure, low cost, small size, light weight, low noise and low vibration are provided. It is possible.

  Next, another embodiment of the present invention will be described.

  FIG. 4 shows the details of the essential parts of another embodiment of the present invention. FIG. 5 is a diagram for explaining the operation of another embodiment of the present invention.

  Only the 16 pulsating torque calculation means are different from the above-described invention.

  The pulsation torque shown in FIG. 4H can be calculated by the same control as described above.

  In this embodiment, the pulsation torque is decomposed into frequency components and controlled for each frequency. Here, a method of reducing torque pulsation of two frequencies, for example, a double component and a quadruple component of a fundamental wave of an electrical frequency is shown.

  Basically, the phase and magnitude of two frequency components in the pulsating torque are calculated, and proportional and integral control is performed for each frequency, thereby reducing the pulsation of the total torque.

  Hereinafter, specific embodiments and operations will be described with reference to the drawings.

  In the configuration according to another embodiment of FIG. 4, the pulsation torque calculation means 16 outputs the output torque from the output of the current sensor 18, the output of the angle conversion unit 12, the cogging torque information 13, and the induced voltage information 14. The torque calculating means 17 comprises an average torque for calculating an average value of the output torque calculating means 17 and a pulsating torque calculating means 20 for calculating a pulsating torque. This can be decomposed as shown in (h) of FIG. For example, the phase and magnitude of the pulsating torque can be calculated by means of the phase and magnitude calculating means 21 having a component twice the fundamental frequency using Fourier integration. The correction signal generating means 22 for the double component of the fundamental wave is a control for setting the target of the double component of the fundamental wave to 0, and a correction torque for the double component of the fundamental wave of the pulsating torque calculated thereby is generated. Thereby, it is possible to selectively suppress the pulsation of the double component of the fundamental wave of the pulsation torque.

  Similarly, the phase and magnitude of the quadruple component of the fundamental frequency of the pulsating torque can be calculated by the calculation means 23 using Fourier integration. Furthermore, the correction signal generating means 24 for the fundamental wave quadruple component performs control to set the target of the quadruple component of the fundamental wave to 0, and generates a correction torque for the quadruple component of the fundamental wave of the calculated pulsation torque. Let me. Furthermore, torque pulsations of two frequency components can be selectively suppressed by controlling the correction signal synthesis means 25.

  FIG. 5 (i) shows the torque of the double component and the quadruple component of the fundamental frequency obtained by analyzing the pulsation torque of (h) shown in FIG. 5, and the phase and magnitude of the double component of the fundamental frequency. The output component of the calculation means 21, the phase of the quadruple component of the fundamental frequency, and the magnitude calculation means 23 is shown. From this, it is possible to reduce torque pulsation by creating an effective correction signal.

  In general, vibrations and noises generated in electric pumps, electric fans, etc. are often based on factors that are an integral multiple of the electrical angle. Therefore, this method, which can reduce the factors for each frequency, is considered effective. .

1 shows a single-phase permanent magnet motor drive circuit according to an embodiment of the present invention. The detail of the principal part of one Example of this invention is shown. Operation | movement explanatory drawing of one Example of this invention is shown. The detail of the principal part of the other Example of this invention is shown. Operation | movement explanatory drawing of the other Example of this invention is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Single phase permanent magnet motor control apparatus, 2 ... Single phase permanent magnet motor, 3 ... Stator, 4 ... Rotor, 5 ... Converter, 6 ... Control circuit, 7 ... Permanent magnet, 8 ... Rotor core, 9 DESCRIPTION OF SYMBOLS ... Stator core, 10 ... Stator winding, 11 ... Position detector, 12 ... Angle conversion part, 13 ... Cogging torque information, 14 ... Induction voltage information, 15 ... Speed control means, 16, 20 ... Pulsating torque calculation means , 17 ... output torque calculating means, 18 ... current sensor, 19 ... average torque calculating means, 21 ... phase and magnitude calculating means for twice the fundamental frequency, 22 ... correction signal generating means for twice the fundamental wave component , 23: Phase and magnitude calculation means for a quadruple component of the fundamental frequency, 24: Correction signal generation means for quadruple component of the fundamental wave, 25: Correction signal synthesis means, 51: Drive signal calculation creation circuit, Edc: DC Power supply, 91 ... Large gap length on stator core surface Min, 92 ... gap length small portion of the stator core surface.

Claims (7)

A single-phase permanent that controls a power converter that drives a single-phase permanent magnet motor that has a rotor having a permanent magnet and a stator having a single-phase winding and generates cogging torque by the magnetic action of both. A magnet motor control device,
A single-phase permanent magnet motor control device comprising waveform information of cogging torque and induced voltage of the single-phase permanent magnet motor.   2. The single-phase permanent magnet motor control device according to claim 1, wherein the shape of the gap surface of the stator core of the single-phase permanent magnet motor is made different depending on the rotation direction.   The single-phase permanent magnet motor control device according to claim 1, which has a temperature detection function and thereby has a function of correcting cogging torque and induced voltage information according to temperature.   2. The single-phase permanent magnet motor control device according to claim 1, wherein the output torque and the output power are calculated, subjected to frequency analysis, and then controlled for each frequency.   2. The single-phase permanent magnet motor control device according to claim 1, wherein the circumferential direction is divided into a plurality of sections, and control is performed for each section.   2. The single-phase permanent magnet motor control device according to claim 1, wherein the control does not include integral control. A fan and a pump comprising the single-phase permanent magnet motor control device according to claim 1.

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