JPS6169399A - 3-phase ac constant-frequency power source - Google Patents

Abstract

PURPOSE:To obtain a 3-phase AC constant frequency power source with a simple configuration by supplying an AC of the prescribed frequency to an exciter stator winding and rectifying the generator output synchronously with the prescribed frequency. CONSTITUTION:An inverter supplies the single phase AC power of the prescribed frequency to the exciter stator 10-1-1 of a high frequency generator 10. Thus, a main stator 10-2-1 outputs a 3-phase AC having a frequency modulated by the high frequency decided by the number of poles and the rotating speed of a rotor in the exciter frequency. A synchronous rectifier 30 rectifies the 3-phase AC outputs from the main stator synchronously with the exciter frequency and outputs the rectified output through a filter 30-1.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a constant frequency power supply device, and particularly to a three-phase AC constant frequency power supply device.

(Prior Art) Conventional constant frequency power generation systems can be roughly classified into the following three types.

(a) C3D (constant speed drive) system (b) DC (direct current) link system (c) cycloconverter system All of these systems are DC excitation systems, and their respective configurations are as follows.

(a) C3D method This method is a method in which a synchronous generator is driven by a constant speed device driven by a drive source to obtain constant frequency power.

0) DC link method In this method, AC power generated by a synchronous generator driven by a drive source is connected to an A/D converter, that is, a converter.
This is a method of obtaining constant frequency power by converting the FL to DC and then converting it to AC using a D/A converter, ie, an inverter.

(c) Cycloconverter method, 1.□ This method is a method for obtaining constant frequency power from AC power generated by a synchronous generator driven by a drive source via a cycloconverter.

(Problem to be solved by the invention) ”-The action of the force distribution equation is as follows.

In all of the above three systems, the generator used is a synchronous generator, and the generated frequency f is expressed by the following equation.

Here, P is the number of magnetic poles of the generator (a value determined by the generator), and N is the rotation speed (r, p, +n,) of the generator. In other words, in order to keep the frequency f constant, the rotational speed N of the generator must be
must be kept constant. Therefore, in the C3D method, a mechanical constant speed device is attached to a drive machine whose rotational speed is undefined, and a generator is driven at a constant rotational speed to obtain constant frequency power.

Furthermore, without using such a constant speed device, the AC power generated by a single generator at an undefined frequency is electrically converted into DC, which is then further converted into AC with a constant frequency.
It is a C-link system.

The cycloconverter method is a method for directly obtaining constant frequency alternating current power from variable frequency alternating current power generated by a generator by controlling the firing angle using a thyristor.

The C3D method has disadvantages in that maintenance and inspection are complicated because it uses many parts that are subject to mechanical wear, and the structure is complicated.

Furthermore, the DC link method requires many electrical parts in the A/D converter and the D/A converter, and has the disadvantage that the system tends to be complicated.

Furthermore, the psychroconverter method uses thyristor firing angle control, but requires firing at a high voltage.
Therefore, there are disadvantages in that surge voltage is likely to occur and it is difficult to control it.

(Means for Solving the Problems) Therefore, the present invention has been made in view of the two prior art techniques. , an inverter section whose output current or voltage or both can be changed according to the output voltage of the power supply device, a three-phase alternating current generator section, and a synchronous rectifier section. The generator section includes an exciter section and a main section disposed corresponding to the exciter section, and the exciter includes an exciter stator section having a winding connected to the inverter section and driven by the output of the inverter section. and an exciter rotor part, the main part having a main rotor part having each winding electrically connected to each winding of the exciter rotor part correspondingly, and a main stator part outputting a generator output. The synchronous rectifier rectifies the output of the generator in synchronization with the excitation waveform to the exciter stator winding, and outputs an AC output at a desired output frequency.

The exciter rotor section L and the main rotor section are fixedly attached to the same drive shaft, preferably a permanent magnet generator section is attached to the drive shaft, and the output of the permanent magnet generator section drives the inverter section. to drive.

(Example) The present invention will be described in detail below with reference to the drawings.

Referring to FIG. 1, the three-phase AC constant frequency power supply according to the present invention includes a three-phase AC generator section 1O and an inverter section 20 whose output current and/or voltage can be varied according to the output voltage of the power supply. and a synchronous rectifier 30. The generator section 10 includes an exciter section 10-1 and a main section 10 disposed corresponding to the exciter section 1O-1.
-2, and the exciter section 1O-1 has an exciter stator section 10-1- which is connected to the inverter section 20 and has a winding driven by the output of the inverter section 20.
1 and an exciter rotor part 10-1-2, the main part 10-2 having each winding electrically connected to each winding of the exciter rotor part 10-12 in a corresponding manner. -2-2 and a main stator section 10-2-1 having a winding that outputs a generator output, and the synchronous rectifier section 30 has a main stator section 10-2-1 that has a winding that outputs a generator output.
The generator output is rectified in synchronization with the excitation waveform applied to the winding t, and an AC output with a desired output frequency is output. Synchronous rectifier 3
0 may be, for example, a three-phase thyristor rectifier as is known, -'a of the exciter stator 10-11;
A control signal for controlling the firing angle of the thyristor in synchronization with the excitation waveform to the line is provided to the synchronous rectifier 30 by a thyristor control circuit 50 associated with the inverter 20.

As clearly shown in FIG. 2, the exciter rotor section 10-1-2 and the main rotor section 10-2-2 are
A permanent magnet generator section (hereinafter abbreviated as PMG) 10-4 is fixedly mounted on the same drive shaft 10-3, and preferably a permanent magnet generator section (hereinafter abbreviated as PMG) 10-4 is mounted on the drive shaft 10-3.
-4 output is used as a power source 40 to drive the inverter section 20. However, the power source 40 that drives the inverter section 20 is not limited to the PMG 40, and may be any known power source.

This configuration will be described in more detail below.

(1) Generator section This generator section IO is a high-frequency special winding generator. As indicated by L and as shown in FIG. 1, this includes an exciter section 10-1, a main section 10-2, and preferably a PMG 10-4.

Particular differences between this high-frequency special winding generator 10 and a normal generator are as follows.

In the case of a normal generator, the exciter section 1O-1 is excited by, for example, a direct current obtained by rectifying the output of a PMG.
The high-frequency special winding generator 10 according to the present invention is driven by a three-phase alternating current output by an inverter section 20, or a waveform obtained by independently full-wave rectifying the three-phase alternating current. (The exciter section 10-1 of this generator is preferably driven by current.) Therefore, the number of poles of the exciter section 1O-1 is an integral multiple of three.

Rotor In the case of a normal generator, the output frequency is determined by the number of poles of the rotor and the input rotation speed, so there is a limit to the number of poles of the rotor, but in the case of the high frequency special winding generator 10 according to the present invention, The purpose is to output a desired frequency modulated with a high frequency and demodulate it to obtain a desired constant frequency output, and the number of poles of the rotor can be determined independently of the output frequency of the generator. It is designed to have as many poles as possible.

As shown in FIGS. 3(A) and 3(B), the number of poles of the exciter rotor section 10-1-2 and the main rotor section 10-2-2 are the same and correspond, and the number of poles of the corresponding poles is the same. The windings are electrically connected to each other, but the windings of uncorresponding poles are not electrically connected to each other.

The relationship between the stator section exciter stator section 10-1-1 and the main stator section 10-2-1 is as follows. Basically, the poles of the exciter stator section and the poles of the main stator section are
As shown in FIG. 4, especially FIG. 6, they are arranged at corresponding positions (same location when viewed from the axial direction).

The positional relationship between the stator windings and rotor windings of the exciter section 1O-1 and the main section 10-2 is as shown in FIG. 4, and the relationship between the currents flowing therein is as shown in FIG. 5. That is, as shown in FIG. 5, an alternating current waveform as shown in FIG. 5(A) is applied to the windings of the exciter stator section to-t-t. What is shown in FIG. 5(^) is the waveform of one of the three phases, and the other two phases have waveforms that differ in phase by 120°. Since an alternating current waveform is applied to the windings of the exciter stator section 10-11, the windings of the exciter rotor section 10-12, and therefore the windings of the main rotor section 10-2-2 are shown in FIG. 5(B). like,
A waveform is produced in which the exciter drive frequency is modulated by a high frequency determined by the number of poles and rotational speed of the rotor.

Therefore, as shown in FIG. 5(C) of the current waveform generated in the winding of the main stator 10-2-1, the modulation waveform becomes similar to the rotor current waveform.

If you want to particularly improve the output waveform, you can increase the number of poles in the rotor section as much as possible and increase the frequency determined by this number of poles. However, the point to be especially careful here is that if the angle occupied by the poles of the exciter section or the stator section of the main section becomes too large compared to the angle occupied by one pole of the rotor section, the current generated on the rotor side will decrease and the volume will increase. This means that when the efficiency deteriorates, it becomes less efficient.

(2) Synchronous rectifier The synchronous rectifier 30 is a known rectifier using a semiconductor power control element 1, for example, a thyristor, as shown in FIG. The modulated waveform is rectified in synchronization with the drive of the exciter by an exciter signal provided from the inverter section 20 via the thyristor control device 50, which is known per se. The result of rectification is a waveform as shown in FIG. 7(B). This waveform diagram shows the waveform of only the l phase.

A simple filter 30-1 is included in the output of the synchronous rectifier 30 to filter out high frequency components modulating the output waveform. As a result, the current waveform output from the synchronous rectification section 30 is transferred to the exciter section 10-1 by the inverter section 20.
It has the same frequency as the current waveform that drove it. Therefore, if the drive waveform of the exciter section 10-1 is controlled to have a desired frequency, the current waveform output from the synchronous rectifier section 30 will have the desired frequency.

(3) Inverter section with control The power source 40 of the inverter section 20 with control is supplied from the PMG 10-4 built in the generator IO. However, this power source 40 is not limited to the PMG 10-4, and may be from any other power source. The inverter section 20 has a built-in oscillator with an output frequency desired by the three-phase AC room frequency power supply device according to the present invention, and applies its output to the exciter section 1O-It as an exciter drive current for the generator section IO. The output voltage of the generator section 10 is controlled by increasing or decreasing the exciter drive current. Therefore, this inverter section 20 has a function of controlling its output current by the output voltage of the device, that is, the output voltage of the synchronous rectifier section.

(Effects of the Invention) (1) The three-phase AC room frequency power supply device according to the present invention has fewer mechanical parts than the C3D (constant speed drive) method described in - in the conventional device, so it has a long life.1. N.

(2) The three-phase AC room frequency power supply device according to the present invention requires simple filling and is therefore lighter in weight than the above-described DC (direct current) link method or cycloconverter method in conventional devices.

(3) The three-phase AC room frequency power supply device t according to the present invention has a simpler circuit configuration than the conventional device using the DC (direct current) link method or cycloconverter method described above.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of a three-phase AC room frequency power supply device according to the present invention, and FIG. 2 shows a rotor section of a generator section in an embodiment of the three-phase AC room frequency power supply device according to the present invention. A schematic perspective view showing the positional relationship of the stator section, Fig. 3 (
A) is a schematic perspective view showing the positional relationship between the magnetic poles of the exciter part and the main part in the rotor part, FIG. 3(B) is a conceptual diagram showing the correspondence between the windings of the exciter part and the main part, and FIG. Similarly, a conceptual diagram showing the correspondence between the windings in the rotor and stator parts, Figure 5 is a current waveform diagram in each winding in the rotor and stator parts, and Figure 6 is a diagram showing the magnetic poles of the exciter part and the main part in each stator part. FIG. 7 is a waveform diagram showing the relationship between the output waveform of the generator section and the output waveform of the synchronous rectification section in one embodiment of the three-phase AC room frequency power supply device according to the present invention. Explanation of symbols 10. ,,, Generator section, 10-1. -, exciter section,
10-2. ,,,Main part, 10-3. ,,,drive shaft,
10-4. ,,, P M G, 20. , , Inverter section, 30, , Synchronous rectifier section.

Claims (4)

[Claims] (1) In a three-phase AC constant frequency power supply device, a three-phase AC generator section, an inverter section whose output current and/or voltage can be changed according to the output voltage of the power supply device;
the generator section includes an exciter section and a main section disposed corresponding to the exciter section, and the exciter section is connected to the inverter section and driven by the output of the inverter section. an exciter stator section and an exciter rotor section each having a winding connected to the exciter rotor section; and a main stator section having a winding that outputs an AC output at a desired output frequency, and the synchronous rectifier section rectifies the generator output in synchronization with an excitation waveform to the exciter stator winding and outputs an AC output at a desired output frequency. A three-phase AC constant frequency power supply device comprising: (2) The three-phase AC constant frequency power supply device as set forth in claim 1, wherein the exciter rotor section and the main rotor section are fixedly mounted on the same drive shaft. (3) In the statement of claim 2, the generator section has a permanent magnet generator section attached to the drive shaft, and the inverter section is energized by the output of the permanent magnet generator section. A three-phase AC constant frequency power supply device characterized in that: (4) The three-phase alternating current constant according to claim 1, wherein the exciter section is excited by a three-phase alternating current or a waveform obtained by individually full-wave rectifying each phase thereof. frequency power supply