JPH0440929B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical field to which the invention pertains] The present invention relates to a power supply switching control device between a power supply comprising an inverter device that adjusts the output voltage according to the amount of load current and a commercial power supply.

[Prior art and its problems]

Conventionally, this type of switching control device detects the voltage difference between the inverter output voltage and the commercial voltage.
The differential voltage can be used to adjust the inverter's output voltage to the commercial voltage and then wrap it for a short period of time to switch the inverter's output voltage to the commercial voltage. Devices that switch after matching are known.

However, in such a device, the detection voltage of the two power supplies becomes the same from the moment the wrap occurs, making it impossible to detect the difference in voltage during the wrap, making it impossible to wrap for a long time, or changing the output depending on the load current. When the voltage is changing and the inverter output voltage setting is not equivalent to the actual output voltage,
It is not possible to simply use the set value as a substitute, and therefore, there is a drawback that it is difficult to match the voltage values of both power supplies.

[Purpose of the invention]

This invention changes the differential voltage detection between the inverter and the commercial power supply according to the amount of load (output) current, makes it possible to detect the differential voltage even during a wrap, and makes the inverter output voltage match the commercial voltage. It is an object of the present invention to provide a power supply switching control device that enables switching while keeping the power supply closed for a long time.

[Key points of the invention]

This invention was made based on the fact that the output voltage detection value of an inverter is equivalent to the sum of the internal voltage setting value and the load (output) current amount.In short, the output voltage setting value plus the load current This method detects the difference voltage between the added value and the detected commercial voltage value, inputs the difference voltage as a correction input even during lapping, and attempts to switch the inverter's output voltage while matching it with the commercial voltage. .

[Embodiments of the invention]

FIG. 1 is a block diagram showing an embodiment of the present invention. In the figure, 1 is a power source such as an inverter device, 2 is an output voltage setter, 3 is an output voltage detector,
4 is a commercial voltage detector, 5 is an output voltage regulator, 6,
7 is a switch, 8 is an output current detector, and 9 and 10 are comparators.

When power is being supplied from the inverter 1 to the load, the switch 6 is closed, and the outputs of the output voltage setter 2, output voltage detector 3, and output current detector 8 are matched by the comparator 9, and the output is The voltage regulator 5 controls the inverter output voltage by adding an amount corresponding to the output current amount to the set value voltage. When switching from this state to the commercial side, the actual inverter output voltage and the commercial The difference voltage ΔV from the inverter output voltage is inputted as a correction input to the output voltage regulator 5 via the comparator 10, thereby controlling the inverter output voltage to match the commercial voltage. Note that ΔV here is zero when the inverter output current is zero and the commercial voltage is 100%, but when the inverter output voltage is 2 depending on the output current.
%up, even if the commercial voltage is 100%, an amount that lowers ΔV by 2% is sent. When the inverter output voltage matches the commercial voltage, switch 7 closes and both power supplies are wrapped. As a result, the output voltage detector 3 is regulated to the commercial voltage, but ΔV
The internal induced voltage of the inverter matches the commercial voltage by the correction input. Therefore, even during a wrap, the inverter output voltage remains consistent with the commercial voltage. Furthermore, even if the commercial voltage fluctuates during lapping, ΔV is corrected accordingly, so it always matches the commercial voltage.

FIG. 2 is a block diagram showing another embodiment of the invention. This means that when trying to match the commercial voltage, the output current correction is turned off using switch 11.
The inverter output voltage is made to be equivalent to the internal voltage setting value, and the difference voltage ΔV between the voltage setting value and the detected commercial voltage value is input as a correction input to the regulator 5. The same effect as in FIG. 1 can also be expected.

〔Effect of the invention〕

According to this invention, since the difference voltage between the inverter voltage setting value plus the load current amount and the detected commercial voltage value is detected, even if the inverter output voltage is adjusted by the load current, the commercial voltage The voltage difference between the inverter and the commercial voltage can be detected extremely easily and accurately, making it possible to keep the inverter's output voltage consistent with the commercial voltage and keep it wrapped for a long time. In addition, even if the commercial voltage fluctuates during the lap, it will follow it, so
There is no need to worry about cross currents.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram showing an embodiment of this invention;
The figure is a configuration diagram showing another embodiment of the present invention. Code explanation, 1...Power supply (inverter), 2...
Output voltage setting device, 3... Output voltage detector, 4...
Commercial voltage detector, 5...Output voltage regulator, 6,
7, 11...Switch, 8...Output current detector,
9,10... Comparator.

Claims (1)

[Claims] 1. A commercial power supply and a power supply consisting of an inverter device equipped with a control means for controlling the output voltage based on the sum of the set value and the amount of output current, each of which supplies power to the load via a switch. In a power supply switching control device that is connected to a busbar and closes both switches when switching power, the switches wrap around each other without causing a momentary interruption of the power supply. A detection means is provided for detecting a deviation from a value obtained by adding the output current amount to a set voltage value, and when switching the power supply, the deviation is inputted as a correction signal to the control means, so that the voltages of both power supplies are made to match. A power supply switching control device characterized by switching the power supply at the time of a lap. 2. A commercial power source and a power source consisting of an inverter device equipped with a control means that controls the output voltage based on the sum of its set value and output current amount are connected to the power supply bus to the load through a switch, respectively, and the power source is In a power supply switching control device that closes both switches at the time of switching and wraps them together without causing a momentary interruption of the power supply, the voltage value of the commercial power supply and the set voltage value of the power supply consisting of an inverter device are A detection means for detecting a deviation is provided, and when switching the power supply, the deviation is inputted as a correction signal to the control means, and the control means of the power supply, which is an inverter device, calculates the sum of the output voltage setting value and the output current amount. What is claimed is: 1. A power supply switching control device characterized in that the voltages of both power supplies are matched by using only the output voltage setting value instead of using the output voltage setting value to switch the power supply at the time of a lap.