JP2008029115A - Single-phase position sensorless permanent magnet motor controller - 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: In a DC power supply, a converter for converting DC into AC, a controller for controlling the converter, and a single-phase permanent magnet motor controller being driven by it, a motor current measuring means, a terminal voltage measuring means, a means for correcting impedance drop of motor constants, and a means for determining an induced voltage by that control are provided, and the direction of the terminal voltage is determined by the value of induced voltage thus determined. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a single-phase position sensorless permanent magnet motor control device, and more particularly, to control operation of a single-phase permanent magnet motor without a position sensor, and thereby, low vibration, low noise, small size, light weight, and low speed suitable for in-vehicle use. A cost-effective single-phase position sensorless permanent magnet motor controller is provided.

  A single-phase permanent magnet motor controller is used as a fan drive source because of its low cost.

  This single-phase permanent magnet motor controller has one set of windings (three sets for three-phase) and four conversion elements (three-phase) because it requires only one set of windings (three sets for three-phase) and a conversion circuit. In this case, the cost advantage is great. In addition, when a position detector is attached, only one hall element is required (three for three phases), which has a price advantage over a three-phase motor.

  On the other hand, the sensorless drive of a single-phase permanent magnet motor is opposite to the sensorless drive of an established three-phase motor in order to perform sensorless drive where the starting torque of a fan or the like is not large and the rise time is slow. There is a problem to be complicated.

  Furthermore, the single-phase permanent magnet motor is, in principle, twice as many as the torque caused by the current flowing through the single-phase winding and the magnetic flux of the permanent magnet at least in the rotational direction, with one electrical angle cycle. There is a problem of generating a zero or negative torque region. On the other hand, 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 generated by the stator core and the permanent magnet so that no negative torque is generated. Or, the shape of the stator core is devised to deal with it.

  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 problems such as difficulty in generating a starting torque, which is a problem of a single-phase large permanent magnet motor, do not become a problem. For this reason, it is a point which is easy to employ | adopt a single phase permanent magnet motor.

  Japanese Patent Publication No. 7-63232 discloses a typical control disclosure example of sensorless driving of a single-phase permanent magnet motor having this price merit.

  In Japanese Patent Publication No. 7-63232, an energization stop period is provided in the vicinity of the switching point between the positive and negative of the induced voltage of the single-phase permanent magnet motor, the induced voltage is generated between the windings, and the polarity of the rotor is determined by determining the polarity. The position (switching point of applied voltage) is detected.

Japanese Patent Publication No. 7-63232

  In the above Japanese Patent Publication No. 7-63232, an energization stop period is provided in the vicinity of the switching point between the positive and negative of the induced voltage of the single-phase permanent magnet motor, the induced voltage is generated between the windings, and the rotation is determined by the positive / negative discrimination. Since the position of the child is detected, and the polarity of the applied voltage that can always generate positive torque can be confirmed, sensorless driving can be performed. However. Since this method basically provides a pause period for the current that causes the induced voltage to be output on the windings, the efficiency decreases and the pulsation torque increases, which may result in a motor with high noise and vibration. .

  The present invention provides a low-noise, low-vibration single-phase permanent magnet motor control device with little reduction in efficiency and a fan or pump using the same, excluding the problems of the conventional examples described above.

  One feature of the present invention is that in a single-phase position sensorless permanent magnet motor control apparatus for controlling a power converter that drives a single-phase permanent magnet motor, motor current measuring means, terminal voltage measuring means, motor constant impedance drop And a means for obtaining an induced voltage by the control thereof, and the polarity of the terminal voltage is determined by the value of the obtained induced voltage.

  A low-noise, low-vibration, high-efficiency single-phase position sensorless permanent magnet motor with little torque pulsation can be provided.

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

  In FIG. 1, a single-phase position sensorless permanent magnet motor control device 1 includes a single-phase permanent magnet motor 2, a conversion circuit 5 having a function of supplying AC power from a DC power supply Edc to the single-phase permanent magnet motor 2, and outputs of the conversion circuit 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 conversion circuit 5 as shown in the figure.

  Further, the rotor 4 is disposed 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. It consists of. Here, a ferrite rubber magnet or a plastic magnet is generally used because of its low cost.

  In FIG. 1, when the gap between the rotor 4 and the stator 3 is in the rotation direction, the surface of the stator core 9 in the rotation direction has a small gap length and is substantially constant as indicated by 92. In addition, the direction of rotation is selected so as to gradually increase in the counter-rotating direction (here, the rotor 4 rotates counterclockwise). 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-mentioned shape, a cogging torque that can compensate for the zero or negative torque can be effectively generated, and low vibration and low noise can be achieved.

  In a general single-phase permanent magnet motor, a position detector is used for the stator 3 at the shaft end of the permanent magnet 7 of the rotor 4 (generally, a Hall element is used to detect the magnetic flux of the permanent magnet 7). ) Is arranged, thereby detecting the position of the permanent magnet 7 and having the role of supplying an effective current to the single-phase permanent magnet motor 2 via the conversion circuit 5. However, in applications such as automobiles, the use environment is high, and the Hall element may not be used. Further, when it is difficult to mount the position detection element and the circuit, a sensorless driving method as shown in the disclosure example can be considered.

  In the present invention, as the control circuit 6, the induced voltage for calculating the induced voltage of the single-phase permanent magnet motor 2 from the information of the current sensor 16, the winding resistance information 11 and the inductance information 12 of the stator winding 10 stored in advance. It is characterized by having a calculation means 14, a speed control circuit 13, and a drive signal calculation creation circuit 15 that synthesizes the former signal. In the present invention, the position of the rotor is determined based on the information obtained by the induced voltage calculation means 14, and the timing of the applied voltage is determined. Thereby, continuous energization is possible, and single-phase sensorless operation with less torque pulsation is possible. Accordingly, the magnetic pole position detector is not required and the sensorless operation can be performed.

  The operation of the present invention will be described below with reference to FIG.

FIG. 2 is a diagram for explaining the operation of the control according to the present invention.
(A) shows the terminal voltage Et (θ) of the motor. Here, the magnitude of the terminal voltage is PWM
(Pulse width modulation) etc. In general, PWM between positive and negative half cycles is constant. In addition, it is possible to advance with respect to the induced voltage shown in FIG. The value of the terminal voltage Et (θ) can be held in the microcomputer.
(C) shows the induced voltage with respect to the rotating electrical angle.
The induced voltage is characterized by having a left-right non-target waveform depending on the shape on the gap surface of the stator core. Here, the induced voltage E0 (θ) is calculated by the induced voltage calculation means 14 using information on the terminal voltage Et (θ), the current sensor i (θ), the resistance r of the winding, and the inductance L of the winding. It can be calculated from the following formula.

ここで、Ｅｔ（θ）は（ａ）で示した端子電圧である。
ｒは巻線の抵抗を示す。
Ｌは巻線のインダクタンスを示す。
ｉ（θ）は電流センサ１６によって測定された電流値である。
（ｂ）は電流ｉ（θ）であり、電流センサ１６より取り込まれる情報である。
（ｄ）はコギングトルクＴｗ（θ）を示す。これは、固定子鉄心の空隙面の形状，固定子突極間のスリットの大きさ等と、永久磁石の磁束分布との磁気的な作用によって発生するものである。
（ｅ）は永久磁石による磁束（誘起電圧）と固定子巻線に流れる電流との電磁気的なトルクＴｗ（θ）で次式で算出できる。

Here, Et (θ) is the terminal voltage shown in FIG.
r represents the resistance of the winding.
L represents the inductance of the winding.
i (θ) is a current value measured by the current sensor 16.
(B) is the current i (θ), which is information taken in from the current sensor 16.
(D) shows the cogging torque Tw (θ). This is caused by the magnetic action of the shape of the gap surface of the stator core, the size of the slit between the stator salient poles, and the magnetic flux distribution of the permanent magnet.
(E) is an electromagnetic torque Tw (θ) between the magnetic flux (induced voltage) generated by the permanent magnet and the current flowing through the stator winding, and can be calculated 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
（ｆ）は全体トルクＴｔ（θ）を示し、上述のトルクＴｗ（θ）とコギングトルク
Ｔｃｏｇ（θ）の和として次式で算出できる。

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 (f) indicates the total torque Tt (θ), and can be calculated by the following equation as the sum of the above-described torque Tw (θ) and cogging torque Tcog (θ).

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.

  In the present invention, in FIG. 1, the single-phase permanent magnet motor is generally controlled by the speed control circuit 13 so as to become the speed command Ns. In order to control the speed, the speed information of the single-phase permanent magnet motor is required. As described above, the speed feedback calculated from the induced voltage information obtained by the induced voltage computing means 14 from the cycle of one electrical angle cycle. It is assumed that constant speed control is performed using information and using proportional-integral control or the like according to the speed error as necessary. With the above control, the motor can be controlled to a speed of Ns.

  Further, in the present invention, the positive / negative switching of the terminal voltage Et (θ) is performed based on the induced voltage information obtained by the induced voltage calculation means 14 according to the expression (1). As an example, the terminal voltage is switched from positive to negative when the induced voltage drops from a positive maximum part and becomes a certain value or less. The terminal voltage shown in FIG. 2A is controlled in this way.

  Here, the voltage is controlled to be constant until the next switching point, but it is also possible to add a voltage change such as a rising part or a falling part in the vicinity of the switching as necessary. By such control, the current can be continuously controlled.

  FIG. 3 shows an operation principle diagram by conventional control.

  By providing a current pause section to detect the terminal voltage during a half cycle, a steep torque fluctuation of the output torque occurs, and by providing a current stop section, the current in other energized sections can be reduced. There is a need to increase, resulting in reduced efficiency.

  With the above control, a low noise, low vibration, high efficiency single phase permanent magnet motor with less torque pulsation can be provided.

  As described above, in the present invention, in a DC power supply, a converter that converts DC to AC, a control device that controls the converter, and a single-phase permanent magnet motor control device that is driven by the motor current measurement means, A terminal voltage measuring means and a means for correcting the impedance drop of the motor constant, and a means for obtaining an induced voltage by the control thereof, and determining the polarity of the terminal voltage according to the value of the induced voltage obtained. By using a single-phase position sensorless permanent magnet motor control device characterized in that, for a three-phase motor, as shown in FIG. Since only one (three for three phases) is required and the conversion circuit is an H-bridge, the number of constituent elements is four, and the cost merit is great. On the other hand, the control as described above can flatten the operating torque, and provide a permanent magnet motor control device with low noise and low vibration comparable to that of a three-phase motor.

  By adopting and providing this single-phase permanent magnet motor control device for an electric fan and an electric pump, the electric fan and electric pump (for example, a vehicle) with a simple configuration, low cost, small size, light weight, low noise, and low vibration can be obtained. When it is deployed in a guest room, it is possible to provide low noise and a low price as a great weapon.

  The above description has been made with a system using a microcomputer as the control circuit 6 in mind. However, even if the control circuit 6 includes a discrete circuit such as an amplifier, a resistor, a capacitor, etc. A position sensorless permanent magnet motor control device can be realized. In this case, it can be realized with a cheaper configuration.

  In addition, there is no information on the induced voltage at start-up, and the method of energizing the voltage is unknown, but it has a mechanism to energize the stator windings, and this determines the current direction in which the rotor can produce positive torque Stable start-up can be enabled by using polarity discrimination.

1 shows a single-phase position sensorless 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.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Single phase position sensorless permanent magnet motor control apparatus, 2 ... Single phase permanent magnet motor, 3 ... Stator, 4 ... Rotor, 5 ... Conversion circuit, 6 ... Control circuit, 7 ... Permanent magnet, 8 ... Rotor core , 9 ... Stator core, 10 ... Stator winding, 11 ... Winding resistance information, 12 ... Inductance information, 13 ... Speed control circuit, 14 ... Induced voltage calculation means, 15 ... Drive signal calculation creation circuit, 16 ... Current Sensor: 91: A portion with a large gap length on the surface of the stator core, 92: A portion with a small gap length on the surface of the stator core, Edc: DC power supply.

Claims (5)

In a single-phase position sensorless permanent magnet motor control device that controls a power converter that drives a single-phase permanent magnet motor,
A motor current measuring unit; a terminal voltage measuring unit; a unit for correcting an impedance drop of a motor constant; and a unit for determining an induced voltage by the control thereof. The terminal voltage is determined by a value of the determined induced voltage. A single-phase position sensorless permanent magnet motor control device characterized by determining the polarity of the motor.   The single-phase position sensorless permanent magnet motor control device according to claim 1, wherein a current is passed through the single-phase permanent magnet motor and the terminal voltage direction is determined at the time of startup. Position sensorless permanent magnet motor controller. In a single-phase position sensorless permanent magnet motor control device that controls a power converter that drives a single-phase permanent magnet motor,
A motor current measuring means; a terminal voltage control means; a means for correcting an impedance drop of the motor constant; and a means for obtaining an induced voltage by the control; and an energization current depending on the value of the obtained induced voltage. A single-phase position sensorless permanent magnet motor control device characterized by performing continuous control. In a single-phase position sensorless permanent magnet motor control device that controls a power converter that drives a single-phase permanent magnet motor,
A motor current detecting means, a terminal voltage control means, a means for correcting an impedance drop of a motor constant, and a means for obtaining an induced voltage by the control, a position where the absolute value of the obtained induced voltage is high A single-phase position sensorless permanent magnet motor control device characterized in that the terminal voltage is switched between positive and negative. A fan and a pump comprising the single-phase position sensorless permanent magnet motor control device according to claim 1.

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