JPS6096158A - Noise reducing device of rotary electric machine - Google Patents

Abstract

PURPOSE:To suppress the noise and the vibration by constructing to absorb high frequency components by a capacitor to eliminate to flow the components to a rotary electric machine. CONSTITUTION:A noise reducing unit 2 is connected between an inverter 3 of nonsinusoidal wave power source and a rotary electric machine 1. This unit 2 is composed of a reactor 4 and a capacitor 5 connected in parallel with the reactor 4. Part 1a of the windings of the machine 1 is connected in series with a reactor 5. Frequency components which are higher than the operating frequency of the machine 1 contained in the output of the inverter 3 are absorbed by the capacitor 5, and substantially the operating frequency component is merely applied to the rotary machine 1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a noise reduction device for a single-rotation motor such as an induction motor or a synchronous traction motor driven by a non-sinusoidal power source such as an inverter.

[Technical background of the invention and its problems]

Recently, non-sinusoidal power sources such as inverters have been used as variable frequency power sources to control the variable speed operation of Kagosugi electric motors. However, this is different from the case of a commercial power supply; the output voltage and electric crystal are not sine waves, but rectangular waves or a collection of them. Therefore, compared to the case of commercial power supply, there are many high frequencies, and in particular, many modulated frequency components and components that are integral multiples of the frequency are included as shown in FIG.

When such a non-sinusoidal power source 3 is connected as shown in Fig. 2 to drive the rotating IIT machine 1, a problem arises in that the high frequency electromagnetic noise and vibration of the rotating electric machine 1 are extremely increased due to the high frequency components. .

In addition, such high frequencies have the disadvantage of increasing loss, especially iron loss, in the rotating electric machine, resulting in an excessive temperature rise.

Conventionally, there has been a method of reducing the magnetic flux density of the iron core in order to solve these problems, but this method has the disadvantage that if the noise is reduced to a certain extent, the output of the rotating electric machine is also reduced.

As another countermeasure, the above problem can be alleviated to some extent by connecting an AC reactor between the rotating electric machine and the non-sinusoidal wave source 3 to smooth the voltage l or current waveform. However, 1! due to modulation frequency components and frequency components that are integral multiples of them! L magnetic noise did not decrease much, and the effect was small.

These harmonic components can also be removed by connecting a capacitor between the terminals of the rotating electrical machine, but the charge on the capacitor may cause line-to-line shorts to the PL or semiconductor devices that have caused problems in the operation of semiconductor devices such as inverters. In some cases, this element could be destroyed by passing current, making the capacitor unusable in many cases.

[Purpose of the invention]

An object of the present invention is to provide a device that reduces electromagnetic noise and vibration of a rotating electrical machine that is driven at variable speed by a non-sinusoidal power source such as an inverter, and also reduces the increase in iron loss caused by high frequencies. I'm in the middle of the day.

[Summary of the invention]

If a capacitor that absorbs high frequency components is connected in parallel to the windings of the rotating electric machine between the non-sinusoidal wave power source, which is a variable frequency power source for variable speed operation, and the rotating electric machine, the capacitor will be connected in parallel to the windings of the accelerator and the rotating electric machine. A noise reduction device for rotating electrical machines that connects some parts in series to absorb high-frequency components into a capacitor and prevent them from flowing into the rotating electrical machine, thereby reducing noise and vibration.

[Embodiments of the invention]

An embodiment of the present invention will be described with reference to FIGS. 3 to 14. FIG. 3 is a layout diagram of equipment employing the noise reduction device of the present invention, and FIG. 4 is a complete wiring diagram of the device of the present invention.

1 is a rotating electric machine, and 2 is an inverter which is a device of the present invention and has three non-sinusoidal wave sources. As shown in FIG. 4, the inside of the device 2 of the present invention consists of a reactor 4 and a capacitor 5 connected in parallel, to which a portion 1a of the winding of the rotating electrical machine I is connected in series with the reactor 5. This noise reduction device 2 is connected between the non-sinusoidal power source 3 and the rotating type 4jAl.

By employing the noise reduction device 2 of the present invention, the rotation frequency included in the output of the inverter 3 is higher than the operating frequency of the parked aircraft l.
The capacitor 5 absorbs the six frequency components, and the rotating electric machine 1 applies almost only the operating frequency components. This noise reduction device 2 consists of an intance component of a capacitor 5 and an axle 4 that takes the winding of the rotating electric machine 1.Generally, the circuit that connects the capacitor 5 and the reactor 4 to the groove 5X is called a filter positive circuit. Here, a low-pass filter A is constructed by including part 1a of the winding of the rotating electric machine 1.

Moreover, the AH frequency of this circuit is 3 to 4 times the operating frequency or more, that is, 200 to 1000 Hz or more.
A reactor 4 and a capacitor 5 having a (71-') tank are selected. Inverter 3VC has 1 semiconductor element
However, since this noise reduction device 2vc has an inductor noise component, the electric charge accumulated in the capacitor 5 when the inverter 3's inverter element is not energized escapes the semiconductor element and is discharged, causing damage to the semiconductor element. No defects such as damage to the equipment will occur.

The value of inductance is determined by taking into account the danger of short circuits, variations in no-voltage time, etc., and also from the resistance and inductance of part of the winding 1a of the rotating electric machine l, which constitutes the inductance component, and the axle 4, based on experiments etc. The determined time constant must be at least 5 times the no-voltage time. Furthermore, the ratio of inductance due to part of the winding 1a of the rotating electric machine 1 and the reactor 4 is experimentally and empirically determined to be 1 to 2:10. High-frequency magnetic flux is generated in the iron core of the rotating electric machine 1 due to the inductance caused by a part of the winding 1a of the rotating winding 1, but because the number of turns of the part of the winding 1a that constitutes the filter ÷ action is small. The high frequency magnetic flux density is also low, and the electromagnetic noise caused by high frequencies is small.

Further, the equivalent circuit for one phase of the circuit including the noise reduction device 2 of the present invention and the rotating IT machine 1fc is shown as VC as shown in FIG. This figure 5 VC'J? where lb is the inductance of the winding of the rotating electric machine, 1c is the resistance, and if the current flowing through the capacitor 5 is I C (AJ) and the current flowing through the rotating electric machine is 1 N, then the value of the capacitor 5 is the inductance of the rotating electric machine 1. Due to the relationship with /Pida/S, it is necessary to satisfy the following conditions.

(1) At operating frequency The ratio of current holes in the operating frequency component satisfies equation (1).

１０ Since the value of each constant of the equivalent circuit differs depending on the output rating, the value of the capacitor 5 differs depending on the output rating.

Generally, the current component of the operating frequency is IM=(20~3
It is preferable to select the value of the capacitor 5 such that Ic = (20 to 30) x IM as the current component of the modulation frequency.

Examples will be described below. In the case of a 4-pole 0.75KW rotating electrical machine, the conditions stated above and formulas (1) and (2) are satisfied, and the cutoff frequency is higher than the operating frequency and lower than the modulation frequency, that is, 200Hz to 1000Hz.
The inductance at this time is lomH,
The capacitance of the capacitor was selected to be 15 μF, and the inductance values of the part of the winding 1a of the rotating electric machine 1 and the axle 4 were set to 2 mH and 8 mH, respectively. It can be seen that the output current waveform of the inverter 3 and the current waveform of the capacitor 5, which are the results of this experiment, are different from the current waveform of the rotating electric machine 1. In this way, the high frequency component in the output of the inverter 3 is reduced, so the magnetic noise in a part of one rotating machine is reduced, and when comparing the case where the present invention is adopted and the case where it is not used, the dotted line of the conventional example is shown in Figure 12. In contrast to B, in the case of the present invention shown by solid line A, the noise is reduced by 8 to 12 dB. FIG. 13 is a frequency analysis characteristic diagram of noise of the conventional example, and FIG. 14 is a noise frequency analysis characteristic diagram of the present invention. It can be seen that the electromagnetic noise component in the vicinity of 1000 to 6000 kHz due to the modulation frequency component has been significantly reduced.

In addition, as shown in Figures 4 and 5, high-frequency current also flows through a portion of the winding 1aK of the rotating electric machine, but the number of turns in this part is smaller than the number of turns of the entire winding of the rotating electric machine. Therefore, the magnetic flux caused by this is also small, so the noise caused by the high frequency current has almost no effect on the whole. In addition, the rotating electric machine
Since the high frequency component of the current decreases by 1.- within 2, the iron loss due to this decreases, the efficiency of the rotating electric machine improves, and there is no drop in output. In addition, rotation V! It is necessary to change each constant of the noise reduction device of the present invention depending on the magnitude of the output of the machine, but the table below shows an example. Note that the capacitor connection may be Y or Δ connection, or Of course, the same effect can be obtained even if the connection order of the part 1a of the winding of the rotating electric machine 1 and the reactor 4 is reversed.

〔Effect of the invention〕

As described above, according to the present invention, the electromagnetic noise of a rotating electrical machine driven by a non-sinusoidal power source such as an inverter is significantly reduced, harsh noise is eliminated, iron loss of the rotating electrical machine is also reduced, and efficiency is improved. .

Also, since a part of the winding of the rotating IL 4M is used as part of the inductance, the reactor can also be made smaller.

Furthermore, FIGS. 15 and 16 are wiring diagrams showing other embodiments of the present invention, in which high frequency components are Current can be adjusted.

[Brief explanation of drawings]

Figure 1 is a frequency analysis characteristic diagram of inverter output and current.
Fig. 2 is a block diagram showing the connection between a conventional non-sinusoidal power source and a rotary rocker, Fig. 3 is a block diagram of the noise reduction device of the present invention, and Fig. 4 is a wiring diagram of the equipment of the present invention. , FIG. 5 is a front side circuit diagram of the device of the present invention - phase component, FIG. 6 is a waveform diagram of the inverter output current adopted by the present invention, FIG. 8 is a waveform diagram of the capacitor current adopted by the present invention, and FIG. The figure is a frequency analysis characteristic diagram of the output current of the inverter, Figure 10 is a frequency analysis characteristic diagram of the rotating electric machine current, Figure 11 is a frequency analysis characteristic diagram of the capacitor current, and Figure 12 is the rotation % ISO of the present invention and the conventional example. Fig. 13 is a noise frequency analysis characteristic diagram of a conventional rotating electric machine.
FIG. 14 is a noise frequency analysis characteristic diagram of a rotating machine employing the present invention, and FIGS. 15 and 16 are connection diagrams of other embodiments of the present invention. ■...Rotating electrical machine 1a... Rotating part lb of the winding of the rotating electrical machine... Inductance lc of the rotating electrical machine... Resistance of the rotating electrical machine 2... Noise reduction device 3.
...Non-sinusoidal power supply = Inverter 4...Reactor 5...Capacitor 6...Resistor IM...Current flowing to the rotating electric machine Ic...Current flowing to Co/De/Sa. Agent Patent attorney Kensuke Chika (and 1 other person) Figure 1 Figure 2, Figure 3 Figure 5 Figure 7 Figure 9 pj I, 5 Pl number I straight - Ifl liquid ridge - 1 i 15 skin soft Figure 12 Figure 13 Figure 14 □1!1 Liquid ridge Figure 15 Figure 16

Claims (1)

[Claims] (1) In a rotating electric machine driven by a non-sinusoidal power source such as an inverter, part of the winding of the rotating machine and the winding of the axle are connected in series to the non-sinusoidal power source, and the rotating machine is parked. Rotation 1 is characterized by connecting a capacitor in parallel to the rotating electric machine side of a part of the winding! Rocky shore noise reduction device. (The ratio of the rotating electric machine current IM to the capacitor current Ic for some of the windings of the 22-rotating electric machine is IM≧1 (i x Ic, and for the modulation frequency component Ic≧10 The noise reduction device for a rotary parking aircraft according to claim 1, wherein the cutoff frequency is selected to be 200 to 1000H2Ic.