JP4899485B2 - Motor drive control device - Google Patents

Description

  The present invention relates to a motor drive control device that controls a voltage applied to a stator winding.

The control of the AC motor is performed by an inverter connected to the stator winding. In particular, the instantaneous winding current of the stator is determined in consideration of the position and rotational speed of the rotor, which is called vector control, and the instantaneous torque is thereby calculated. In the control method to control, it is indispensable to measure the instantaneous current of each winding, and it is necessary to install a current sensor or a magnetic flux sensor for each winding.
JP 2004-297881 A

  In a current sensor, the main conductor to be measured is called a magnetic flux balance type, and the magnetic flux in the core induced by this is adjusted by adjusting the current of the secondary winding wound around the same core. In general, a method is used in which a secondary winding current value necessary for the cancellation is used as a current measurement value. In this method, the current sensor is a composite part that assembles the core (ferromagnetic material), secondary winding, core magnetic flux measuring element (hall element), secondary winding control circuit, etc. It is difficult to control durability and reliability. The problem caused by the current sensor becomes a larger problem in proceeding with the multiplexing of windings (Patent Document 1).

  On the other hand, a system using a magnetic flux sensor instead of a current sensor is also conceivable. The magnetic flux sensor can be reduced in cost and size as compared with the current sensor. Since the motor vector control synthesizes the circumferential magnetic flux distribution of the gap between the rotor and stator with respect to the rotor, a large number of magnetic flux sensors are installed in the gap in order to directly measure the gap magnetic flux. However, because it is installed in the gap, there are problems such as installation location and wiring.

  The present invention has been made in view of such problems, and an object of the present invention is to use a large number of magnetic flux sensors in the gap between the rotor and the stator without using a large and high-cost current sensor. An object of the present invention is to provide a motor drive control device capable of performing vector control without being installed.

To achieve the above object, according to the present invention, in a motor having concentrated windings, magnetic flux sensors are embedded in back yoke portions between the centers of adjacent coil sets, and magnetic pole magnetic flux detection is performed with a difference from the adjacent magnetic flux sensor. The magnetic flux detected value is compared with the magnetic pole magnetic flux command value, and the voltage applied to the magnetic pole winding is controlled. The magnetic flux sensor is preferably embedded in the back yoke on the side opposite to the rotor, on the rotor side of the back yoke, or in the central portion in the thickness direction of the back yoke.

  In the present invention, a magnetic flux sensor is embedded in the back yoke portion of the motor, and the feedback control is performed by manipulating the voltage applied to the winding by the signal from the magnetic flux sensor. Therefore, without using a large and expensive current sensor, The vector control of the motor can be performed without installing the magnetic flux sensor near the gap between the rotor and the stator, which is difficult to install.

  Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a schematic configuration of a motor used in the present invention. Here, a radial gap type motor will be described. The motor 11 includes a stator 12, a power conversion unit / control unit 16 disposed on the outer periphery of the back yoke of the stator 12, a rotor 13 having a permanent magnet, and a substantially cylindrical case 15. The rotating shaft 14 of the rotor 13 adjacent to the stator 12 via the rotation gap is supported by the case 15 via a bearing (not shown).

  The control unit / power conversion unit 16 controls the switch unit of the power conversion unit in accordance with a control signal (for example, PWM) from the control unit, so that the DC current supplied from the DC power supply 17 is n-phase, here Convert to 3-phase AC current.

  Next, a first embodiment of the stator configuration will be described with reference to FIG. FIG. 2 shows a schematic configuration of a part of the stator. The stator includes a back yoke 21 including a magnetic pole core 22 protruding toward the rotor 13 and a winding (coil) 23 wound around the magnetic pole core 22. In reality, nine magnetic pole cores 22 are equally provided in the circumferential direction, but only three are shown in the figure. The winding (coil) 23 is formed by concentrated winding. Here, since the motor is driven by a three-phase alternating current, three magnetic cores 22 having the same phase exist for each phase.

  In FIG. 2, the power conversion unit / control unit 16 is disposed on the outer peripheral portion of the back yoke 21 of the stator, and the winding 23 wound around the magnetic pole core 22 and the power conversion unit / control unit 16 are connected to the winding feeder 26. At the same time, magnetic flux sensors 27a and 27b are embedded between the magnetic pole cores of the back yoke 21 and the magnetic pole cores on the outermost periphery (opposite side of the rotor) of the back yoke 21, and power conversion is performed with the magnetic flux sensors 27a and 27b. The unit / control unit 16 is connected. In FIG. 2, the power conversion unit / control unit 16, the winding feeder 26, and the magnetic flux sensors 27 a and 27 b are displayed for only one magnetic pole portion, but these are actually arranged for each magnetic pole. As the magnetic flux sensors 27a and 27b, for example, a Hall element, a magnetoresistive element or the like can be used. In the case of an axial gap type motor, the magnetic flux sensors 27a and 27b are installed on the back surface of the back yoke.

  FIG. 3 shows a system configuration diagram of the motor drive control device of the present invention. The motor drive control device of the present invention includes a magnetic pole core, a winding, a back yoke, a magnetic flux sensor embedded in the back yoke, and a power conversion unit / control unit for each winding (power semiconductor chip and driver / control). The component) is an integral module, and the magnetic flux control system is configured. FIG. 3 shows a single magnetic pole module, which is one module, and the number of modules increases or decreases according to the number of magnetic poles and the number of phases of the motor.

  Next, the operation of the magnetic pole 1 module will be described. The magnetic flux sensors embedded between the magnetic core and magnetic core of the back yoke are denoted by 1A and 1B, respectively. The magnetic flux command value calculation unit has a magnetic flux command value table with the instantaneous rotor angle and rotor angular velocity as arguments for the motor torque command value, and when the motor torque command value is given to the magnetic flux command value calculation unit The motor torque command value is converted from the rotor position, the rotor speed (further field current if there is a field winding), etc., to the magnetic flux command value of each winding. Upon receiving the magnetic pole magnetic flux command value, the control unit of the magnetic pole 1 module uses the difference between the detection signals of the magnetic flux sensor 1A and the magnetic flux sensor 1B embedded in the back yoke portion of the magnetic pole 1 module as the magnetic pole magnetic flux detection value. The operation amount to the power conversion unit is calculated from the deviation from the magnetic pole magnetic flux command value. The power converter generates an ON / OFF signal for the semiconductor element according to the operation amount, and controls the voltage applied to the winding, thereby controlling the magnetic flux of the magnetic pole.

  Adjacent magnetic pole modules can share the magnetic flux sensor. Therefore, when the magnetic flux sensors embedded in the magnetic core between the magnetic pole cores of the back yoke of the magnetic pole 2 module are 2A and 2B, the detected value of the magnetic flux sensor 2A is obtained in the magnetic pole 1 module. It can also be used as a detection value of the magnetic flux sensor 1B. In an N-phase motor, there are N of these magnetic pole modules, and 2N magnetic flux sensors are embedded in the back yoke. However, it is possible to consolidate the magnetic flux sensors into N magnetic flux sensors by sharing the previous sensor. Here, the N-phase motor means a motor having N circuits capable of flowing independent currents regardless of concentrated winding or distributed winding motors. In the case of a concentrated winding radial gap motor, N It is a pole motor.

  In general, since the total value of the magnetic flux is always zero including the sign, the N-th magnetic flux sensor is used by using the first to (N−1) -th magnetic flux sensor detection values φ1 to φ (N−1). The detected value φN can also be calculated as φN = −φ1−φ2−φ3... −φ (N−1). Therefore, in an N-phase motor (N-pole motor in the case of a concentrated winding radial gap type motor), at least (N-1) magnetic flux sensors need only be embedded in the back yoke, and a large number of magnetic fluxes are placed in the gap portion where the magnetic flux sensor is difficult to install. The magnetic flux distribution in the gap can be detected without installing a sensor.

  In the first embodiment of the stator configuration, the case of the motor of the concentrated winding stator configuration has been described, but the present invention can also be applied to the case of the motor of the distributed winding stator configuration. In the case of the distributed winding stator configuration, a magnetic flux sensor is installed at the intermediate back yoke portion between the center of the coil set that is distributed and the center of the adjacent coil set. The average magnetic flux density detection value of the gap magnetic flux between the magnetic flux sensors is used.

  In the first embodiment of the stator configuration, there is a magnetic flux sensor between the magnetic pole core and the magnetic pole core of the back yoke 21 and on the outermost periphery of the back yoke 21 (opposite the rotor). Wiring (wiring of signal lines and power supply lines) becomes easy. In addition, since the internal wiring is completed and a module that completes the control function is created and combined, the stator part of the motor can be obtained, so there is no need to install a sensor or perform wiring work after assembling the iron core. As a result, it is possible to improve assembly and reliability.

  Next, a second embodiment of the stator configuration will be described. FIG. 5 shows a schematic configuration of a part of the stator. In the second embodiment, the stator has a configuration in which the magnetic flux sensors 27a and 27b are embedded in the innermost circumference (rotor side) of the back yoke 21 between the magnetic core and the magnetic core of the back yoke 21. Is the same as in the first embodiment. In the case of an axial gap type motor, the magnetic flux sensor is installed on the rotor side. In the second embodiment, since the magnetic flux is detected in the portion having the highest magnetic flux density in the back yoke, it is possible to detect a signal with a good S / N ratio.

  Next, a third embodiment of the stator configuration will be described. FIG. 6 shows a schematic configuration of a part of the stator. In the third embodiment, the stator is between the magnetic pole iron core and the magnetic pole iron core of the back yoke 21, and is at an intermediate portion between the outermost periphery and the innermost periphery of the back yoke 21 (the central portion in the thickness direction of the back yoke). The configuration is such that the magnetic flux sensors 27a and 27b are embedded, and the others are the same as in the first embodiment. In the third embodiment, since the magnetic flux density in the central portion of the back yoke in the thickness direction is close to the average magnetic flux density in the back yoke portion, stable magnetic flux detection is possible even when the magnetic flux density distribution in the back yoke is not uniform. It is.

It is a figure which shows schematic structure of the motor used for this invention. It is a partial schematic block diagram of the stator which shows the 1st Example of a structure of a stator. It is a system block diagram of the motor drive control apparatus of this invention. It is a partial schematic block diagram of the stator which shows the 2nd Example of a structure of a stator. It is a partial schematic block diagram of the stator which shows the 3rd Example of a structure of a stator.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Motor 12 Stator 13 Rotor 14 Rotating shaft 15 Case 16 Power conversion part / control part 17 DC power supply 21 Back yoke 22 Magnetic pole core 23 Winding (coil)
26 Winding feeders 27a, 27b Magnetic flux sensor

Claims (7)

In a motor having concentrated windings, a magnetic flux sensor is embedded in each back yoke portion between the centers of adjacent coil sets, and the difference from the adjacent magnetic flux sensor is used as a magnetic pole magnetic flux detection value. A motor drive control device that controls a voltage applied to a magnetic pole winding by comparing with a command value.   In a motor having distributed windings, a magnetic flux sensor is embedded in the back yoke portion between the center of the coil set that is distributed and the center of the adjacent coil set, and the magnetic flux is obtained with a difference from the adjacent magnetic flux sensor. A motor drive control device characterized by controlling a voltage applied to a winding by using a detected value and comparing the detected magnetic pole magnetic flux value with a magnetic pole magnetic flux command value.   3. The motor drive control device according to claim 1, wherein at least (N−1) magnetic flux sensors are embedded in a back yoke portion in a motor having N circuits capable of flowing independent currents.   The stator core, winding, back yoke, magnetic flux sensor embedded in the back yoke portion, and power conversion unit / control unit for controlling the voltage applied to the winding are formed as an integrated module. 4. The motor drive control device according to any one of 3.   5. The motor drive control device according to claim 1, wherein the magnetic flux sensor is embedded on a side of the back yoke opposite to the rotor.   The motor drive control device according to claim 1, wherein the magnetic flux sensor is embedded on a rotor side of a back yoke.   The motor drive control device according to any one of claims 1 to 4, wherein the magnetic flux sensor is embedded in a central portion in a thickness direction of a back yoke.

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