KR-20260065915-A - Uninterruptible Power Supply

Abstract

The converter (11) converts AC power from the AC power source (1) into DC power and supplies it to the DC line (12). The bidirectional chopper (13) receives DC power between the DC line (12) and the power storage device (3). The control device (16) controls the converter (11) and the bidirectional chopper (13) so that the DC voltage of the DC line (12) becomes the first reference voltage. The assist circuit (17) is connected in parallel with the converter (11) between the AC power source (1) and the DC line (12). When the DC voltage of the DC line (12) is lower than the first reference voltage and also higher than the threshold voltage, the assist circuit (17) is deactivated. When the DC voltage of the DC line (12) drops below the threshold voltage, the assist circuit (17) is activated. The assist circuit (17) converts the AC voltage input from the AC power source (1) into a DC voltage and outputs it to the DC line (12).

Inventors

• 이마니시 료고
• 야마모토 유신
• 기노시타 마사히로
• 나가노 히로타카

Assignees

• 가부시키가이샤 티마이크

Dates

Publication Date

20260511

Application Date

20240913

Claims (4)

1. A converter that converts AC power from an AC power source into DC power and supplies it to a DC line, and A capacitor connected to the above DC line, and A bidirectional chopper that receives and receives DC power between the above-mentioned DC line and the power storage device, and An inverter that converts DC power received from the above DC line into AC power and supplies it to a load, and A control device that controls the converter and the bidirectional chopper so that the DC voltage of the above DC line becomes a first reference voltage, and An assist circuit connected in parallel with the converter between the AC power source and the DC line is provided. If the DC voltage of the above DC line is lower than the first reference voltage and also higher than the threshold voltage, the assist circuit is deactivated, and When the DC voltage of the above DC line drops below the threshold voltage, the assist circuit is activated and converts the AC voltage input from the AC power source into a DC voltage and outputs it to the above DC line. Uninterruptible Power Supply
2. In paragraph 1, The above assist circuit is, A transformer having a primary winding connected to the above AC power source and a secondary winding, and converting a primary voltage applied to the primary winding from the above AC power source into a secondary voltage at a transformation ratio, It includes a diode rectifier connected between the secondary winding of the transformer and the DC line, which rectifies the secondary voltage of the secondary winding in full wave and outputs it to the DC line. The transformer ratio of the above transformer is set so that the amplitude of the secondary voltage is greater than or equal to the threshold voltage. Uninterruptible Power Supply
3. In paragraph 1 or 2, When the above AC power supply is healthy, the control device, The converter is controlled such that the phases of the input voltage and input current of the converter match, and the DC voltage of the DC line becomes the first reference voltage, and the bidirectional chopper is also controlled such that the voltage between the terminals of the power storage device becomes the second reference voltage, while When the DC voltage of the above DC line drops below the lower limit voltage, the bidirectional chopper is configured to be controlled so that the DC voltage of the above DC line becomes the first reference voltage, and The above threshold voltage is set to a value higher than the above lower limit voltage. Uninterruptible Power Supply
4. In paragraph 3, In the event of a power outage of the above AC power source, the control device, Along with stopping the operation of the above converter, controlling the bidirectional chopper so that the DC voltage of the above DC line becomes the first reference voltage. Uninterruptible Power Supply

Description

Uninterruptible Power Supply The present disclosure relates to an uninterruptible power supply. For example, International Publication No. 2020/026430 (Patent Document 1) discloses an uninterruptible power supply comprising a converter, a capacitor, a bidirectional chopper, an inverter, and a control device. When the AC power source is healthy, the converter converts AC power supplied from the AC power source into DC power and supplies it to a DC line. The capacitor is connected to the DC line. The bidirectional chopper receives DC power between the DC line and a power storage device. The inverter converts DC power received from the DC line into AC power and supplies it to a load. When the AC power source is healthy, the control device controls the converter so that the DC voltage of the DC line becomes a first reference voltage, and at the same time controls the bidirectional chopper so that the voltage between the terminals of the power storage device becomes a second reference voltage. FIG. 1 is a circuit block diagram of an uninterruptible power supply according to an embodiment of the present disclosure. Figure 2 is a block diagram showing an example of the hardware configuration of a control device. Figure 3 is a block diagram showing the configuration of the part related to the control of the converter in the control device. Figure 4 is a block diagram showing the configuration of the part related to the control of the bidirectional chopper in the control device. Figure 5 is a circuit diagram showing an example of the configuration of a converter and an assist circuit. Figure 6 is a diagram illustrating the design of an assist circuit. Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In addition, identical or substantial parts in the drawings are given the same reference numerals below, and their descriptions will, in principle, not be repeated. FIG. 1 is a circuit block diagram of an uninterruptible power supply device according to an embodiment of the present disclosure. The uninterruptible power supply device (10) according to the present embodiment actually receives a three-phase AC voltage from a commercial AC power source (1) and supplies a three-phase AC voltage to a load (2), but in order to simplify the drawing and description, only the part related to the one-phase AC voltage is shown in FIG. 1. As illustrated in FIG. 1, the uninterruptible power supply (10) is equipped with an AC input terminal T1, a battery terminal T2, and an AC output terminal T3. The AC input terminal T1 receives AC power of commercial frequency from a commercial AC power source (1). The battery terminal T2 is connected to a battery (3). The AC output terminal T3 is connected to a load (2). The uninterruptible power supply (10) also includes switches S1 to S3, capacitors C1 to C3, reactors L1 to L3, current detectors CD1 to CD3, a converter (11), a DC line (12), a bidirectional chopper (13), an inverter (14), an operating unit (15), and a control device (16). Switch S1 and reactor L1 are connected in series between the AC input terminal T1 and the AC node (11a) of the converter (11). Switch S1 is controlled by a control device (16). When AC power is supplied normally from the commercial AC power source (1) (when the commercial AC power source (1) is healthy), switch S1 is turned on. When AC power is not supplied normally from the commercial AC power source (1) (when the commercial AC power source (1) is in power outage), switch S1 is turned off. Current detector CD1 detects the current Ii flowing between the commercial AC power source (1) and the converter (11) and outputs a signal Iif representing the detected value to the control device (16). The instantaneous value of the AC input voltage VI appearing at the AC input terminal T1 is detected by the control device (16). The control device (16) determines whether a power outage has occurred based on the detected value of the AC input voltage VI. Additionally, the control device (16) controls the converter (11), etc., based on the detected value of the AC input voltage VI. Capacitor C1 is connected between node N1 between switch S1 and reactor L1 and neutral point NP. Capacitor C1 and reactor L1 form an AC filter. This AC filter is a low-pass filter that passes AC power of commercial frequency and prevents a signal of switching frequency generated in the converter (11) from passing to the AC input terminal T1. The converter (11) is a well-known type comprising a plurality of transistors and a plurality of diodes and is controlled by a control device (16). When the commercial AC power source (1) is healthy, the converter (11) converts the AC power received by the AC node (11a) into DC power and outputs it to the DC node (11c). The DC node (11c) is connected to the DC line (12). The output voltage of the converter (11) can be controlled to a desired value. When the commercial AC power source (1) is depleted, th