JPS59185166A - Synchronization switching device of multiple current type inverter and commercial power source - Google Patents

Abstract

PURPOSE:To enable to accurately synchronously switch by detecting the phase coincidence when a multiplexed inverter power source and a commercial power source, sequentially setting the phases of the respective inverters at the prescribed interval, thereby synchronizing it. CONSTITUTION:A commercial power source 1 is connected through a contactor K2, and addition outputs of unit inverters 2-4 are connected through a contactor K1 to a motor 9. The signal of a frequency instruction unit 10 is formed to pulses of phases of +20 deg., 0 deg., -20 deg. corresponding to the respective inverters via a V/F converter 12, applied to input pulse selectors 13-15 together with pulses of the phases of +20 deg., 0 deg., -20 deg. of a synchronizing pulse generator 28 connected to the power source 1, the selectors 13-15 are sequentially set on the basis of the outputs of frequency coincidence and phase coincidence detectors 25, 26, thereby controlling the inverters 2-4. Accordingly, the synchronization is performed without phase mistake, thereby switching between the commercial power source and the inverter.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a circuit responsible for synchronous switching between a commercial power source and a multiple current source inverter.

For example, when controlling the air volume of a fan blower, etc.
When the output is high, it is operated using commercial power, and when the operation is stopped, the inverter (the output frequency is set considerably lower than the commercial frequency) is used to drive at low speed or stop in preparation for the next operation. There is.

In such a driving method, it is necessary to completely switch the power supply from the inverter to the open lh source, or vice versa.

By the way, in order to switch the drive motor of a fan or blower from inverter operation to curved operation, it is necessary to match the frequency, voltage, and phase of the two, and without this, an inrush current will flow and the load motor will Abnormal torque is fully generated. In particular, inrush current is strongly affected by phase difference, and matching one phase is an important requirement for power supply switching.

On the other hand, when the motor load is fully driven by a large capacity current source inverter, since the inverter output is a rectangular wave, there are many harmonic components and large torque pulsations. In order to compensate for this, the output f of several current source inverters is located symmetrically on the left and right with one waveform as the center. All multiplexing means of shifted current source inverters are used to make the waveform of the load current as close to the trace wave as possible.

Now, regarding the multiplexing of this current source inverter.

Each unit inverter must have a certain phase difference depending on the number of multiplexed units. Accordingly, it is necessary to ensure that the phase of each unit inverter does not change even when switching in synchronization with the commercial N'6M. By sequentially setting the phase of each unit of the inverter at regular intervals and synchronizing, it is possible to eliminate phase errors. Accurately prevents and enables synchronous switching,
The purpose is to maintain equal capacity sharing among each unit of the inverter at the time of switching.

The illustrated embodiment will be specifically described below. 1st
The figure is a circuit diagram of a 5-multiplex 18-phase inverter.
02, 3 and 4 are the commercial power supply, and 02, 3 and 4 are TI type unit inverters, respectively, which have a forward conversion section and an inverse conversion section. is applied. And each unit inverter 2.3
The outputs of the inverse converters 6 and 4 are respectively connected to separate transformers 6 and 7.
and 8 to obtain a total addition output, which is then supplied to the load motor 9 through the contactor 1.

Further, the commercial power supply is connected to the load motor 91C through two contacts. lO is a frequency command setter,
The output signal is led to a V-F converter 12 via a ramp function generator 11. 13.14 and 15 are input pulse selection circuits for the unit inverters 2.3 and 4, respectively, and are for the V-F converters 12 and 20, respectively.
It receives pulse signals with phases of °, Oo, and -200, and also receives +
200. All pulses having a phase of O, -200 are used to prompt switching of pulses to be used sequentially based on a phase one cycle and a wave number matching signal, which will be described later.

This manual pulse selection circuit 13.14. Specific circuit 1-1 of l'5 As shown in FIG. 2, a timing circuit 13a
, 14a.

15a and switching circuits 13b, 14b, 15
b) 16.Constructed with the connections shown in the diagram. 1'7 and 18 are pulse distributors for controlling the inverse converters of the unit inverters 2, 3.4, respectively, and control the inverse converters of the unit inverters 2, 3.4, respectively. A synchronization signal is sequentially supplied to ensure that the R, S, and T thread forces of the pulse distributors 16, 17, and 18 match in phase. 2
2 is a power factor angle detection circuit, which obtains the output current, output voltage, and voltage of the unit inverter 3 from the transformer 23 and the current transformer 24, and detects the jJ factor. Based on the comparison between the pulse frequency regulated by the input voltage to the V-F converter 12 and the commercial frequency, if the image frequencies match, the entire output signal is obtained.

26 is a phase-integration output circuit which obtains the output of the unit inverter 3 via the transformer 23, obtains the commercial power supply voltage via the transformer 3o, and converts the phase power of both voltages by known means; When there is a match, you will get the result.

2F is an AND gate, and the frequency-scattering output circuit 25,
The output signals of the phase-scattering output circuit 26 are ANDed and supplied as a pulse switching command to the input pulse selection circuit 13. 28 is a synchronous pulse generation circuit which inputs the output from the transformer 5 via the transformer 29, simultaneously receives input from the power factor angle detection circuit 22, and generates pulses synchronized with the commercial power supply voltage based on each input. Each manual pulse selection circuit 13, 14, and 15 has a phase difference of y +200. Oo
, -200k a is supplied. and.

The specific configuration of this synchronous pulse generation circuit is shown in FIG. 3, which includes filter circuits Fl, F2 . F3. The filter circuit Fl,
Zero cross circuit Zl that connects all outputs from F2゜F3,
Z2. Z3゜The zero cross circuit Zl, Z2. Z
3 differentiating circuits H1, F2 . F3
, the differentiating circuits H1, F2 . The waveform shaping circuit W responsible for shaping the human-powered waveform from F3 receives the power factor signals from the waveform shaping circuit 'l@W and the power factor detection circuit 22, respectively. Oo, the pulse that stands at -200'
t On the Noho pulse generation circuit P obtained, P2. P3i≧
It consists of

In the above configuration, 1 is normally used (1 is closed to the izu contactor at the time of starting during evening driving).

All load motors 9 are connected to the 2 and 3° 4 sides of the load motors, and V-F conversion 2S is performed with the action of the ramp function generator 4 until the frequency reaches the frequency corresponding to the output of the 5 frequency setter 10.
The nok pulse period gradually becomes shorter from 12. At this time, each person's power (pulse selection time 1 master worker 3, 14 degrees i, 5
fTj respectively +20°]ζrus from V-F converter 12.

By setting to select O0 pulse and -200 pulse, each unit inno (-ta 2, 3)
゜4 are pulse distributors 16.1'7.18 and 1 respectively
It is traced by Sowidth 2 soybean 9°20.2, and the unit inno (-t3 waveform is middle) and the 20° advanced waveform (unit inno (-t2 waveform) and 20° It operates so that the delayed waveform (waveform of unit inverter 4) and the waveform of the unit inverter 4 are integrated and approximated to the positive wave.In this operation, each <Rus distributor 16.l'7.18 sequentially matches the phase t.
Signals are transmitted accordingly. In this way, the load motor 9 is connected to the transformer 6+ 7. from each unit inverter 2, 3.4. On top of s and contactor? The inverter power will be supplied sequentially.

Now, the power supply to the load motor 9 from such a unit inno (-2.3°4) is less efficient than the power supply from a commercial power supply, especially during low speed operation of about 90% or less. In order to save energy, it is necessary to switch to using commercial power for normal operation, except for the following cases.However, we will explain the transition from inverter operation to operation using commercial power in a step-by-step manner.

First, close 1 to the contactor and unit inlet ζ
l When the load motor 9ft is connected to the 3 and 4 sides, the output level of the frequency setter 10, that is, the input level to the V-F converter, is adjusted so that the period of the output pulse of the V-F converter is commercially It is set to correspond to the power supply frequency. At this time, when the frequency of the unit inverter 2.3.4 and the commercial frequency match, a frequency match signal is supplied from the frequency-integration output circuit 25.

Then, the output voltage phase and bending % of unit inverter 3
When the phase matches the phase of Shiro 4410, the phase-scattering output circuit 2
Output (switching command) is issued from 6, and AND gate 27f
Through the timing circuit 13 of each manual pulse selection circuit 13
υ0 is added to a.

By the way, before the switching command is issued from the AND gate 27, the synchronizing pulse generating circuit 2B.

A +20° phase pulse, a 00 phase pulse, and a -20° phase pulse are created with respect to the commercial frequency by each component shown in FIG. Therefore, when a switching command is input to the manual pulse selection circuit 13, the timing circuit selects, for example, +20 from the -F converter 12.
Falling point of 0 phase pulse U iron synchronous pulse generation circuit 2
The output is switched to +200 synchronization pulses from B.

Next, a command from the switching circuit 1' 413b gives a command to the timing circuit 14a in the manual pulse selection circuit 4, and the V-F converter 12 outputs a commercial synchronizing pulse of 00 phase at the falling edge of the 00° phase pulse. Simultaneously with the switching, a switching command is issued to the timing circuit lea. This f'L causes the switching circuit 15b to apply a 1200-phase commercial synchronous pulse to the pulse distributor 1 at the same pulse falling timing as described above, and also to supply a synchronous switching permission signal. By closing the contactor 2 in response to this synchronization switching permission signal, the commercial power supply 1 and the inverter power from each unit inverter 2, 3.4 are connected to the contactor 2. It wraps through Kl' and supplies power to the load motor 9. After this lap operation is performed for some time, the contactor Klft is opened (this operation can be done automatically or manually), and the load motor 9 receives power from the commercial power source 1.

In addition, in the above explanation, an example of a 3-multiplex 18-phase inverter is used. As shown, it is generally applicable to n multiplexing (n is a natural number excluding lft).Furthermore, the phase difference of each unit inverter can be arbitrarily set to a value other than 200.

As described above, the synchronous switching device between a multiple current source inverter and a commercial power source according to the present invention operates a plurality of unit inverters with a desired phase difference, multiplexes multiple current sources, and supplies power to a load. In the type inverter, each unit inverter is equipped with an input pulse selection circuit that selects one of the two input pulses by a side leg command, and each manual pulse selection circuit is equipped with an input pulse selection circuit that selects one of the two input pulses by a side leg command. The current source inverter receives the pulses generated at the corresponding frequency and the desired phase difference, and the pulses synchronized with the commercial power supply and has the same phase difference as above as the total input signal, and obtains the output from each unit inverter. When the overall output (when the number of unit inverters is an odd number, the output of the unit inverter centered at 0° phase is also acceptable) and the output of the commercial power supply have the same frequency and phase, the selection pulse of one input pulse selection circuit Switch.

Sequentially switch the selection pulses of the remaining input pulse selection circuits 7 and then start lamp operation after switching of all input pulse selection circuits is completed. The power source is then switched over. Based on this configuration, ■ Even in multiple current type inverters, switching between pulses from the inverter control V-F converter and commercial synchronous pulses for each unit inverter is possible when switching synchronously between the inverter power supply and the commercial power supply. Since this is performed sequentially for each unit, synchronization can be achieved without causing phase errors. Since the unit inverter in this device switches between the pulses of each unit inverter in a short time of about 2000, there is no room for the capacity sharing of each unit inverter to be disrupted, so it has all the effects such as sagging.

[Brief explanation of drawings]

Figure 1 is a circuit diagram showing all the embodiments of this invention, Figures 2 and 3.
The figure is a circuit diagram showing a part of FIG. 1 in detail. 1...Commercial power supply 2.3,4a◆Unit inverter 9...Load motor 10...Frequency setter 12
...V-F converter 13, l'4.15...Input pulse selection circuit 25.
...Frequency coincidence detection circuit 26...Phase coincidence detection circuit 2 days...Synchronization pulse generation circuit Applicant Shinko Electric Co., Ltd. Agent Patent attorney Haruya Saito No. 1 Figure 2

Claims (1)

[Claims] 1 Multiple unit inverters? A multiple current source inverter operates with a desired phase difference and multiplexes the outputs of these unit inverters to supply power to the load. , has an input pulse selection circuit for controlling each of the unit inverters, and each of the manual pulse selection circuits receives a pulse signal generated from a frequency setting device at a frequency corresponding to the human power level and having a desired phase difference sound;
circuit means for providing as an input signal a pulse having the same frequency as the commercial power supply voltage and the same phase difference as the above phase difference;
When the overall output of the current source inverter obtained from the above unit inverter output and the output of the commercial power supply have the same frequency and the same phase, the selection pulse of one manual pulse selection circuit is switched - 1 sequentially to the remaining input pulses Synchronization between a multiple current source inverter and a commercial power supply, which is characterized by having a circuit means that switches the selection pulses of the selection circuit and supplies all power supply switching permission commands when the switching of all input pulse selection circuits is completed. Switching device.