JPS58157342A - Inverter phase control system for dc stationary power source control - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a phase control method for a power generation system inverter that is operated interconnected with a commercial grid via a self-excited inverter from a DC fixed voltage power source such as a solar cell, a fuel cell, or a storage battery. be.

This type of power generation system requires active power control that can adjust any output depending on the operating state, and reactive power control that reduces reactive power to zero in order to suppress disturbances to the grid as much as possible.

Therefore, as a means to perform the active power control and reactive power control at the same time, a configuration has been proposed in which two self-excited inverters are used, and the outputs of each self-excited inverter are added vectorially by a transformer and connected to the grid. be done. However, in this case, the two self-excited inverters must simultaneously satisfy the above-mentioned requirements for active power control and reactive power control, and to achieve this, the phase angle of the two self-excited inverters is changed from leading to It must be possible to change the delay at will.

From this point of view, in conventional power generation systems that use self-excited inverters, a controlled rectifier or chopper that serves as a variable DC voltage power source is installed at the input stage of the self-excited inverter to increase self-excitation and the output of the self-excited inverter. Reactive power control was performed by installing a phase advance capacitor, phase adjuster, or compensator on the side.

Therefore, active power control and reactive power control using a self-excited inverter in a conventional power generation system has the disadvantage that not only the configuration is complicated, but also the adjustment work of various devices for proper control is complicated.

Therefore, the inventors of the present invention conducted various studies in order to solve all the problems of active power control and reactive power control in the conventional power generation system mentioned above, and as a result, they connected a self-excited inverter in parallel to a fixed DC power source. In a power generation system that connects t″L to a commercial grid, when controlling active power and reactive power using the self-excited inverter, analog outputs obtained from the active power control system and the reactive power control system are mutually added and subtracted. It has been found that by doing so, an appropriate phase control signal can be obtained, and by controlling the phase angle of each self-excited inverter using this phase control signal, the above-mentioned problem can be overcome.

Therefore, an object of the present invention is to provide a power generation system that performs active power control and reactive power control using self-excited inverters connected in parallel, and to easily perform simultaneous power control by controlling the phase angle of each inverter. There are a whole range of phase control methods that can be provided.

In order to achieve the above object, the present invention provides a power generation system in which a self-excited inverter is connected in parallel to a DC fixed power source and connected to a commercial grid, and an active power control system and a reactive power control system are provided. The analog outputs of the respective power control systems are mutually added and subtracted to obtain a phase control signal 1, and these phase control signals cause the self-excited inverter tf! It is assumed that the I control is t-%.

In the above phase control method, the active power control system consists of an active power setter, a power regulator, and a TFT regulator, and compares the active power set value with the detected active power value obtained from the automatic inverter output, and calculates the obtained power. The deviation active power thus obtained is supplied to a power regulator, the output of this power regulator is compared with the detected current value obtained from the self-excited inverter output, and the obtained deviation current value is sent to the central angle via the current regulator. ψ. It is preferable to configure the system to obtain an analog output that defines .

The reactive power control system includes a reactive power setting device, a reactive power regulator, and a voltage regulator, and compares the reactive power setting value with the reactive power detection value obtained from the self-excited inverter output.
The obtained deviation reactive power is supplied to a reactive power regulator, the output of this reactive power regulator is compared with the voltage detection value obtained from the self-excited inverter output, and the obtained deviation voltage value is sent via the voltage regulator. It is preferable to configure the structure so that an analog output defining the opening angle Δψ is obtained.

Next, an embodiment of a phase control method for an inverter for controlling a DC fixed power supply according to the present invention will be described in detail with reference to the accompanying drawings.

The gt diagram is a system diagram of a power generation system using the control method of the present invention. In FIG. 1, reference numeral 10 indicates a DC power source, which is composed of a fuel cell and a fixed voltage source in a power storage mode. This DC power supply 10 includes two self-excited inverters 12.141.
The self-excited inverters 12 and 14 are connected in parallel, and the outputs of the self-excited inverters 12 and 14 are connected to the commercial grid 20 via the transformer 16 and the coupling reactor 18. In this power generation system, this is realized by active power control, reactive power control, and phase angle control of the t-inverter for both self-excited inverters 12 and 14. FIGS. 2(1) and 2(2) are vector diagrams illustrating the control operation state of such an inverter. That is, in f12 diagram (1), (21, Vl.

v2 is each output voltage of the self-excited inverter 12.14,
These magnitudes are always equal and constant; only the phase changes. Then, the composite vector of the output voltages V, V2 is expressed as Vi, which becomes the total output voltage of the inverter system.

The magnitude and phase of the output voltage V1. Determined by the phase of V2. Therefore, Fig. 2 (1) shows the vector phase relationship of the output voltages V, , V2, and the second
Figure ■ shows the vector phase relationship of the output voltages V, , V2 of each self-excited inverter when the total output voltage Vi is large.As is clear from Figure 2 (1), θ), proper active power control and reactive power In order to control the system voltage Vs
It turns out that it is sufficient to perform phase control so that a current of a desired magnitude flows in the same phase. At this time, as is clear from the vector diagram shown in Fig. 2, the relationship shown in the following equation holds true.

However, X: Inverter output side reactance including coupled reactor or V Todoro = A Shuundo = Vs v 脣- ...fight...■ I However, x = -: Reactance drop is Formula (1) above, ■ From the relationship, the phase control angle of each self-excited inverter needs to change according to the control of active power and reactive power, and the phase angle of the self-excited inverter 12.14 is set to ψ1. If ψ2 is the central angle ψ. and the opening angle Δ from this
The following relationship holds true with respect to ψ.

Based on the above formula 〇)K, the phase angle ψ1. of the self-excited inverter 12.14 is determined. In order to control ψ2, a control circuit consisting of an active power control system and a reactive power control system as shown in FIG. 3 is used.

That is, in the control circuit shown in FIG.

The active power control system includes an active power setting device 22 and a power regulator 2.
4 and a current regulator 26, and the reactive power control system includes a reactive power setter 28, a reactive power regulator 30, and a voltage regulator 62. However, in the active power control system, ′i? Then, the active power setting value Psoll set by the active power setting device 22 is compared with the active power detection value P ist detected as the output of the transformer 616, and the obtained deviation active power is sent to the power regulator 24. By comparing the output of the power regulator 24 with the detected current value Iist detected as the output of the transformer 16, and supplying the obtained deviation current value to the current-tube unit 26, angle ψ
. Obtain an analog output that specifies the On the other hand, in the reactive power control system, the reactive power set value Qsoll set by the reactive power setting device 28 is compared with the reactive power detected value Qiit detected as the output of the transformer 16, and the obtained deviation reactive power t- is supplied to the reactive power regulator 30, the output of the reactive power regulator 50 is compared with the voltage detection value Vist detected as the output of the transformer 16, and the obtained deviation voltage value is supplied to the voltage regulator 32tK- By supplying an analog output defining the opening angle Δψ. Therefore, the analog output ψ of these active power control systems. By adding and subtracting the analog output Δψ of the reactive power control system and the analog output Δψ of the reactive power control system by crossing them, the self-excited inverter 1
2.14 phase angle ψ1. A control signal defining ψ2 can be obtained.

In addition, as a means for detecting the control number 15 used in the control circuit shown in FIG. #I3 from the output of the transformer 16, as shown in FIG. A voltage detection value V ist is obtained from the potential transformer 34, and a current detection value l1st is obtained from the current transformer 36. Then, an active power and reactive power detector 681 which inputs each output of the instrument transformer 34 and the current transformer 36 is provided, and the active power detected value P i
st and the detected reactive power value Q it can be obtained.

As is clear from the above embodiments, according to the present invention,
By adding and subtracting the outputs of each analog automatic control system regarding active power and reactive power to each other to obtain a phase control signal for each self-excited inverter, it is possible to appropriately control the phase of two self-excited inverters with a simple circuit configuration. can. Therefore,
The phase control method of the present invention is applicable to a stone power generation system using two self-excited inverters connected to a fixed DC voltage source.
Control of active power and reactive power can be applied to.

It is also possible to install many self-excited inverters of this type in parallel, each with two
The present invention can be similarly applied to a power generation system divided into groups. Further, as a self-excited inverter to which the control method of the present invention is applied, it can also be applied to a self-extinguishing inverter that can commutate even in phase leading to the system, such as a transistor inverter or a GTO inverter.

Although the preferred embodiments of the present invention have been described above, it is of course possible to make various design changes without departing from the spirit of the present invention.

[Brief explanation of the drawing]

Fig. 1 is a block circuit diagram of a power generation system that implements the phase control method of an inverter for controlling a DC fixed power supply according to the present invention, and Fig. 2 (1) and ■ indicate the output voltage of the self-excited inverter shown in Fig. 1. Vector diagram showing the phase relationship with the total output voltage,
FIG. 3 is a diagram of a phase control circuit implementing the phase control method of the present invention, and FIG. 4 is a diagram of a signal detection circuit for obtaining a control signal for controlling the control circuit shown in FIG. 3. 10...DC 1t# 12.14...Self-excited inverter 16...Transformer 18...Coupling reactor 2
0...Commercial system 22...Active power setting device 24...Power regulator 26...Current regulator 28...
・Reactive power setting device 30...Reactive power controller 32・
...Voltage regulator 34...Instrument transformer 36...
Current transformer 38...Patented active power and reactive power detector
Kansai Electric Power Co., Inc. Fuji Electric Manufacturing Co., Ltd. FIG, I FIG, 2 (1) (2) FIG 3 151 FIG 4 2

Claims (2)

[Claims] (1) In a power generation system consisting of a fixed DC source, self-excited inverters connected in parallel and connected to the commercial grid,
An active power control system and a reactive power control system are provided, analog outputs of the respective power control systems are mutually added and subtracted to obtain a phase control signal, and a self-excited inverter is controlled from these phase control signal pressures. Features a phase control method for inverters for controlling DC fixed power supplies. (2) % Allowance In the phase control method described in claim 1, the active power control system includes an active power setter and a power FA.
Compare the active power setting value between the moderator and the current regulator and the active power detection value obtained from the self-excited inverter output,
The obtained deviation active power is supplied to a power regulator, the output of this power regulator is compared with the detected current value obtained from the self-excited inverter output, and the obtained deviation current value is sent to the power regulator via the current regulator. Central angle ψ. A phase control method for an inverter for controlling a DC fixed power supply that is configured to obtain an analog output that specifies the G) In the phase control method according to claim 1, the reactive power control system includes a reactive power setting device, a reactive power regulator, and a voltage regulator, and a reactive power setting value and a self-excited inverter output. The obtained reactive power detection value is compared with the voltage detection value obtained from the self-excited inverter output, and the obtained deviation reactive power is supplied to a reactive power regulator. The deviation voltage value is the voltage vI4
A phase control system for an inverter for controlling a DC fixed power supply, which is configured to obtain an analog output t- which defines an opening angle Δψ via a moderator.