JPH09215396A - Permanent magnet ac generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate a reactor and a capacitor from the internal flux control means of a permanent magnet AC generator and, further, widen the control range of a reactive power. SOLUTION: In a permanent magnet AC generator 1 which has a permanent magnet and AC windings, an auxiliary winding 13 which is an AC winding for the control of internal flux and a pole position detector 8 which detects the pole position of the permanent magnet are provided. The detection output of the pole position detector 8 is connected to an active AC excitation inverter 15 which supplies an AC excitation current to the auxiliary winding 13 in accordance with a terminal voltage, a load current and a load power factor to control a reactive power.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic flux control technique for reactive power control of a permanent magnet AC generator.

[0002]

2. Description of the Related Art A conventional magnetic flux control technique for a permanent magnet AC generator will be described. In adjusting the terminal voltage of a conventional permanent magnet AC generator, the reactive power cannot be controlled only by the AC generator because of constant excitation by the permanent magnet.Therefore, in order to control the reactive power by the magnetic flux inside the AC generator, the AC winding is used. A magnetic flux control device consisting of a passive reactor and a capacitor is connected to the line to control the reactive power of the AC generator output.
FIG. 2 is a block diagram showing the configuration of a conventional magnetic flux control device for a permanent magnet AC generator. In the figure, 20 is a permanent magnet AC generator having a permanent magnet rotor 21, a main winding 22, and an auxiliary winding 23, and the main winding 22 is connected to a load (not shown). A magnetic flux controller 24 is composed of an automatic voltage regulator 25 and a reactive power controller 26.

In the automatic voltage regulator 25, the voltage detecting unit 32 detects the output terminal voltage of the permanent magnet AC generator 20, and the detected value is compared with the setting value of the voltage setting unit 31 by the voltage control unit 33. The difference between the two is calculated and output to the phase control unit 34. The phase control unit 34 controls the firing angle of the thyristor control device 35 with a phase according to the voltage deviation. The reactive power control device 26 includes a thyristor control device 35 connected to the auxiliary winding 23 of the permanent magnet AC generator 20, and a reactor 36 (three-phase power supply device) having one end connected to the thyristor control device 35 and the other end connected to a three-phase power supply. Only one of the phases is shown). Since the alternating-current excitation of the auxiliary winding 23 is controlled by the magnetic flux controller 24 according to the deviation between the voltage setting value and the detection terminal voltage, the terminal voltage of the permanent magnet alternating-current generator 20 can be adjusted.

[0004]

In the above-mentioned prior art, the reactor and the capacitor are required depending on the load power factor and the load factor, which makes the device large and expensive. In addition, there are problems associated with temperature rise due to heat generated by the reactor and the capacitor and electromagnetic noise. Therefore, it is required to eliminate the reactor and the capacitor and to have a wider control range of the reactive power. In order to solve the above problems, the present invention is to connect an inverter to an auxiliary winding instead of a reactor and a capacitor, detect a magnetic pole position, and perform an appropriate AC excitation by the auxiliary winding to generate a permanent magnet AC generator. The purpose is to control the internal magnetic flux.

[0005]

In view of the above-mentioned drawbacks of the prior art, the present invention provides an auxiliary winding for controlling internal magnetic flux as an AC winding in a permanent magnet AC generator comprising a permanent magnet and an AC winding, and An active type having a magnetic pole position detector for detecting the magnetic pole position of a permanent magnet, and supplying an alternating excitation current to the auxiliary winding based on the detection output of the magnetic pole position detector, the terminal voltage, the load current and the load power factor. The AC exciting inverter is connected to control the reactive power. The permanent magnet AC generator is originally a constant excitation by a permanent magnet,
The induced voltage due to the internal magnetic flux is constant, and as it is, the generator terminal voltage changes due to changes in the active power and the reactive power that are the load of the generator. In order to control the generator terminal voltage at a constant level, it is necessary to control the internal magnetic flux according to changes in the load power and adjust the internal induced voltage. In order to control the excess or deficiency of the internal magnetic flux, reactive power is transferred and received by the exciting current from the AC excitation inverter to the auxiliary winding to control the reactive power of the generator and control the terminal voltage.

With this structure, the reactive power can be continuously controlled over a wide range, and thus the degree of freedom in designing the permanent magnet AC generator is expanded. In addition, a large space is required, and an expensive reactor and capacitor are unnecessary.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. In the figure, 1 is a permanent magnet AC generator having two windings of a main winding 2 and an auxiliary winding 3 which are stator windings and a permanent magnet rotor 4, and the main winding 2 and the auxiliary winding Three
Is a three-phase AC winding. The AC generator 1 is connected to a load that supplies active power and reactive power, or is used as a commercial power supply system. Reference numeral 8 is a magnetic pole position detector for detecting the magnetic pole position of the permanent magnet rotor 4.
As a power source of the magnetic pole position detector 8, a tacho generator connected to the permanent magnet AC generator 1 or a pulse generator connected to a separately prepared DC power source is used. Reference numeral 5 denotes a magnetic flux controller, which includes an automatic voltage regulator 6 and a reactive power controller 7.

The automatic voltage regulator 6 includes a voltage detector 11, a current detector 12, a voltage detector 10 for detecting the output terminal voltage and current of the permanent magnet AC generator 1, a voltage setter 10, and the detector and the setter. It has a control unit 13 that receives an output, and a phase control unit 14 that controls the reactive power control device 7 based on the output of the control unit 13. The reactive power control device 7 has an AC excitation inverter 15 having one end connected to the auxiliary winding 3 of the permanent magnet AC generator 1 and the other end connected to the output end of the permanent magnet AC generator 20. Next, the operation of magnetic flux control with such a configuration will be described. When the permanent magnet rotor 4 is rotated by an external force, a voltage is induced in the main winding 2. This induced voltage is determined by the electric power required by the load and the magnetomotive force of the permanent magnet rotor 4, and does not always become the voltage required by the load. Therefore, in order to induce the voltage required by the load, in the present embodiment, the excess or deficiency of the magnetomotive force of the permanent magnet rotor 4 is energized by AC-exciting the auxiliary winding 3.

In the automatic voltage regulator 6, the terminal voltage and the output current of the permanent magnet AC generator 1 are detected by the voltage detection unit 11 and the current detection unit 12, and the control unit 13 determines the set value of the voltage setting unit 10 from the detection result. And the voltage deviation, the load power factor angle between the voltage and the current, and the generator internal impedance drop, and the deviation of the internal induced voltage. Based on this, the required magnetomotive force in the auxiliary winding 3 is calculated, and the calculation result Output to the phase controller 14. The phase control unit 14 outputs a magnetomotive force magnitude command (current command) by the auxiliary winding 3 and a magnetomotive force phase command by the auxiliary winding 3 based on the output of the control unit 13 and the magnetic pole position output from the magnetic pole position detector 8. It is sent to the AC excitation inverter 15. In the reactive power control device 7,
The alternating current excitation inverter 15 uses the auxiliary winding 3 from the phase control unit 14 to request the magnitude of the required magnetomotive force (current command),
The control is executed based on the phase command of the magnetomotive force by the auxiliary winding 3 to excite the auxiliary winding 3. The inverter 7 for AC excitation supplies the same amount of current as the frequency of the permanent magnet AC generator 1 for AC excitation of the excess and deficiency of the magnetic flux by the auxiliary winding, and its phase is the same as the vector of the magnet rotor. Phase.

The strength of the magnetomotive force of the auxiliary winding 3 is determined by the current generated by the AC exciting inverter 7, and the phase of the rotating magnetic field of the auxiliary winding 3 is determined by the phase of the AC exciting inverter 7. In this way, the magnetic pole position detector 8 detects the magnetic pole position of the permanent magnet rotor 4, and the phase of the rotating magnetic field of the auxiliary winding 3 is controlled by the phase of the AC excitation inverter 7 based on the magnetic pole position detection signal. Further, by controlling the current of the AC excitation inverter 7 with the output from the control unit 13, the power and voltage required by the load can be supplied by the appropriate excitation of the auxiliary winding 3 by the AC excitation inverter 7.

[0011]

As described above, according to the present invention, the reactor and the capacitor for the reactive power are eliminated, the control of the reactive power and the voltage can be continuously performed over a wide range, and the design of the permanent magnet alternator is possible. This has the effect of increasing the degree of freedom. Since the reactor and the condenser are eliminated, the device can be downsized and the cost of the device can be reduced.
Further, it is possible to eliminate the problem associated with the temperature rise due to the heat generation of the reactor and the capacitor. The auxiliary winding can be excited without using a slip ring, which is advantageous for high-speed machines.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a conventional example.

[Explanation of symbols]

 1 Permanent Magnet Alternator 2 Main Winding 3 Auxiliary Winding 4 Permanent Magnet Rotor 5 Magnetic Flux Control Device 6 Automatic Voltage Adjustment Device 7 Reactive Power Control Device 8 Magnetic Pole Position Detector 10 Voltage Setting Unit 11 Voltage Detection Unit 12 Current Detection Unit 13 Control Section 14 Phase Control Section 15 AC Excitation Inverter 20 Permanent Magnet AC Generator 21 Permanent Magnet Rotor 22 Main Winding 23 Auxiliary Winding 24 Flux Controlling Device 25 Automatic Voltage Adjusting Device 26 Reactive Power Controlling Device 31 Voltage Setting Unit 32 Voltage detection unit 33 Voltage control unit 34 Phase control unit 35 Thyristor control device 36 Reactor

Claims (1)

[Claims] 1. A permanent magnet AC generator having a permanent magnet and an AC winding, comprising an auxiliary winding as an AC winding for controlling internal magnetic flux, and a magnetic pole position detector for detecting a magnetic pole position of the permanent magnet, Detection output of the magnetic pole position detector,
A permanent magnet AC generator characterized in that an active AC exciting inverter for supplying an AC exciting current to the auxiliary winding is connected to the auxiliary winding based on a terminal voltage, a load current and a load power factor of the permanent magnet AC generator. .