JPH01190225A - Parallel operation control method for charger - Google Patents

Abstract

PURPOSE:To achieve uniform operating condition of respective chargers and to shorten the interval of varying output operation, by setting the number of operating chargers and an operating sequence corresponding to loads. CONSTITUTION:Operating conditions of plurality of chargers CH1-CHn to be operated in parallel include a constant time constant output operation, a varying output operation, and stoppage. A sequential start selecting circuit SCJ for commanding modification of the sequence of the operating conditions of respective chargers CH1-CHn is provided. The sequential start selecting circuit SCJ operates to bear the load, which can not be born on the constant output recharger, onto a single variable output recharger and modifies the operating conditions of respective chargers CH1-CHn every specific time.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for controlling parallel operation of a plurality of constant voltage chargers.

[Conventional technology]

Conventional parallel operation control methods of this type include an equal sharing method in which the total load is applied equally to each charger, and a sequential start-up method in which the chargers are operated according to priorities, but the operating status is not sequentially changed depending on time conditions. In the above-mentioned conventional equal sharing method, as the number of chargers increases, the control circuit for equally distributing the load to each charger becomes complicated, resulting in a relative decline in the reliability of the control device and an increase in price. Furthermore, since the amount of load distributed to each charger does not necessarily match the optimal output of each charger, there is a possibility that the charger operation efficiency will decrease. There was a problem in averaging the lifespan of each charger because the operation was biased towards the charger with higher priority.In view of the above, the present invention provides a method for parallel and parallel operation of chargers that solves the above problems easily and inexpensively. The operating states of the multiple chargers are set to three types: constant output operation for a fixed period of time, variable output operation, and stop, and the load that cannot be borne by the constant output charger is borne by one variable output charger. A sequential startup selection means is provided to sequentially change and repeat the operating state of the chargers at specific time intervals.In other words, a plurality of chargers connected in parallel are selected according to the total load state of each charger parallel system. In the parallel operation control method for a plurality of chargers that are activated in sequence, the operation states of each charger are set to three types: constant output operation for a fixed period of time, variable output operation, and stop, and a comprehensive sequence activation command is issued to the parallel charger system. Specify the number of chargers to be operated in the constant output operation according to the total load and their operation order, and calculate the rated output value by bearing the difference between the total load and the total output of the constant output operation chargers. One charger that performs variable output operation is designated below, and a stop command is issued to the remaining chargers, and thereafter, the variable output charger The present invention is characterized in that the three types of operating states of each of the chargers are sequentially changed and repeatedly controlled in accordance with an appropriate combination of the elapsed power at the elapsed time so that the designation of the three types of operating states is sequentially changed.

[Effect]

For a plurality of chargers operated in parallel, it is desirable to average the output level and operation time of each charger in order to average the lifespan of each charger. Further, in terms of operating efficiency, each of the chargers is preferably operated near the rated output, and the constant voltage positive charger is preferably operated near the rated current. Therefore, when a fluctuating load is borne by a plurality of chargers operated in parallel, the plurality of chargers are connected to a constant output charger that is operated at an optimum constant output for a specific period;
The variable output charger bears the difference between the variable load and the total output of each of the constant output chargers, and the charger is placed in a stopped state. By sequentially switching the motion state of each charger at specific time intervals, it is possible to average the operating states including minimizing the period during which each charger is carrying a fluctuating load. The present invention includes specifying the number of chargers to be operated at constant output according to the fluctuating load and the order of operation thereof, specifying the chargers corresponding to the three types of operation states, and continuing constant output operation for each of the chargers thereafter. A sequential activation selection circuit that instructs to sequentially change the operating state of each of the chargers so that the designation of the variable output charger is sequentially changed at each time point; and a sequential activation selection circuit that instructs the load bone to be borne by the variable output charger. A current bias circuit is installed to control the parallel operation of multiple chargers to average out the operating status of each charger.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

Fig. 1 is a circuit diagram showing an embodiment of the present invention, and Fig. 2 is a circuit diagram showing an embodiment of the present invention.
It is a sequential switching operation waveform diagram when three chargers in the figure are operated in parallel. In FIG. 1, pst ~PS,
is an AC power supply, and CH, ~CHn are voltage control signals V, respectively.
A charger that outputs the DC specified by cl~vcfi, L and -L are DC output smoothing reactors of each charger, D and -Dfi are diodes for preventing backflow when each charger is operated in parallel, and DCCT , ~DCCT, l is an isolated DC current transformer for detecting the output DC current of each of the chargers CH, ~CH, and SH is a DC shunt for detecting the total output DC current when each of the chargers is operated in parallel. and each current detector D
The current detection values by CCT, ~DCCT, and SH are respectively 11-11 and It as shown in the figure. Also AC
R, -ACR, 1 are respectively the front chargers C) (l~CH
, and the respective current input signals are the current detection values ■, ~I7 and the current set values t's~Ins for the current detection values ■, ~■7, and the respective output signals V+S~ ■7. is automatic voltage regulator AVR,~AV
This is the operating voltage setting value for R. Further, the output signals VCI to vcfi of each automatic voltage regulator are connected to each of the chargers CH.
.

The ignition phase control signal becomes the ignition phase control signal for the control switching element of ~CH, and the output DC current of each charger CH, ~CH, becomes I j = I js between the respective detected value and set value.
Vj = Vjs between the output voltage at the illustrated position of each charger and its set value so that (j = 1 to n)
(j=1 to n). Next, the SCT is a sequential startup selection circuit that performs relay operations such as designating the operating state of each charger and switching the current setting value for each charger, and also sets the current of each charger during constant output operation. The value Ijsr (j=1 to n) is specified. CP is a comparison calculator, which determines the various current quantities. The integer m gives the number of constant output operation chargers in operation, and the selection circuit SCT uses the integer m to select m constant output operation chargers and one variable output charger from a total of n chargers. (n-m-1) out-of-operation chargers are sequentially designated every time the designated operation time of each of the constant output operation chargers elapses. Note that the current setting value 1jsv (j=1 to n) of the one variable output charger is set to a value below the rated current value of the charger. Therefore, the current set value 1js becomes both the 1jsr and ljsv values, which are sequentially switched by the selection circuit SCT. The sequential switching operation diagram in FIG. 2 is for n=3 in the above explanation. This corresponds to the case where m=1°n-m-1=1, and shows the case where the number is changed in the order of No. 1 -> No. 2 - No. 3 - No. 1 -.

〔Effect of the invention〕

According to the present invention, in parallel operation of a plurality of chargers, a fixed time constant output operation charger and one variable output operation charger are used to charge the plurality of chargers in a fixed time constant output operation charger whose operation number and operation order are specified according to the load. Equalize the operating status of each charger by classifying the operation into three types: charger and stop charger, and sequentially changing the specified operating status of each charger every time the specified operating time of each charger elapses. As a result, the lifespan of each charger can be equalized and the operating efficiency can be improved.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing an embodiment of the present invention, and Fig. 2 is a circuit diagram showing an embodiment of the present invention.
In the figure, when three chargers are operated in parallel (n=3)
FIG. 3 is a sequential switching operation waveform diagram. CH, ~CH, 1... Charger, D CCT, -D
C.C.T. ...DC current transformer, D+""Di...Diode, L
l~LL1...Reactor, SH...DC shunt, AVR1~AVR,...Automatic voltage regulator, AC
RI~ACR. ...Automatic current regulator, CP...Comparison calculator, OP
+~OP1... Calculation for current bias amplifier, SCT
...Sequential startup selection circuit. 1. Do-Representative Patent Attorney Iwao Yamaguchi' Figure 1

Claims (1)

[Claims] 1) In a method for controlling parallel operation of a plurality of chargers in which a plurality of chargers connected in parallel are activated in sequence according to the state of the total load of each charger parallel system, the operation state of each charger is fixed for a fixed period of time. There are three types of operation: output operation, variable output operation, and stop, and designation of the number of chargers to be operated and the order of operation thereof according to the total load according to the total order start command to the charger parallel system. , designation of one charger that carries the difference between the total load and the total output of the constant output operation chargers and performs variable output operation below its rated output value, and a stop command for the remaining chargers. After that, the designation of the variable output charger is sequentially changed every time the predetermined constant output operation duration time of each charger elapses. A method for controlling parallel operation of a charger, characterized in that the three types of operating states of the charger are sequentially changed and repeatedly controlled.