Power supply system and control method of power supply system

Abstract

To provide a power supply system and a controlling method of the same, which prevent a load from compensating for an excessive voltage in voltage compensation control for compensating for a voltage of the load after completion of opening of a switch.SOLUTION: A power supply system is a power supply system that supplies a power from a power system to a load L when a power system S is normal, cuts off the power supply from the power system to the load when the power system is abnormal, and supplies the power from a DC power supply to the load, and comprises: a switch 2 that is provided in a power line P for supplying the power from the power system to the load and is opened when the power system is abnormal; a power converter 4 that is connected to the power line and converts the DC power from the DC power supply into an AC power; and a power converter control part 85 that controls a voltage output by the power converter when the power system is abnormal. The power converter control part comprises a voltage compensation control part 852 that performs a voltage compensation control, which is control for compensating the load voltage based on a deviation between a target value of the load voltage and a measured value, after the opening of the switch is completed when the power system is abnormal.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a power supply system and a method for controlling a power supply system. [Background technology]

[0002] A conventional power supply system, as shown in Patent Document 1, for example, includes a circuit breaker provided on a power line for supplying power from a power system to a load, and a power converter connected to the load side of the circuit breaker and converting energy from an energy storage unit into AC power.

[0003] In this power supply system, when the power grid is normal, the circuit breaker is closed, power is supplied from the power grid to the load via the transformer, and the power converter is stopped. On the other hand, when an abnormality occurs in the power grid, the circuit breaker is opened to cut off the power supply from the power grid to the load. Since the load voltage drops when the circuit breaker is opened, after the circuit breaker is opened, the power converter converts the DC power from the energy storage unit into AC power and supplies that AC power to the load. In this way, the above power supply system performs voltage compensation control to compensate for the load voltage when an abnormality occurs in the power grid.

[0004] Here, in the voltage compensation control, the power supply system compensates the load for the drop in the system voltage from the power converter based on the deviation between the measured value of the system voltage, which is the voltage of the power system, and the target value of the load voltage, which is the voltage of the load.

[0005] However, conventional power supply systems perform voltage compensation control using measured values ​​of the grid voltage rather than measured values ​​of the load voltage, which can result in excessive voltage compensation to the load, which can cause overcurrent to flow from the power converter or increase power consumption in the DC power supply. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 6677916 Summary of the Invention [Problem to be solved by the invention]

[0007] Therefore, the present invention has been made in consideration of the above problems, and its main objective is to prevent excessive voltage from being compensated to the load in voltage compensation control that compensates for the voltage of the load after the switch has been opened. [Means for solving the problem]

[0008] That is, the power supply system of the present invention is a power supply system that supplies power from the power system to a load when the power system is normal, cuts off the power supply from the power system to the load when there is an abnormality in the power system, and supplies power to the load from a DC power supply, and is characterized by comprising: a switch that is provided on a power line for supplying power from the power system to the load and that opens when there is an abnormality in the power system; a power converter that is connected to the power line and converts DC power from the DC power supply into AC power; and a power converter control unit that controls the voltage output by the power converter when there is an abnormality in the power system, and is characterized by comprising a voltage compensation control unit that performs voltage compensation control, which is control to compensate for the load voltage, by causing the power converter to output a compensation voltage calculated based on the deviation between a target value of a load voltage, which is the voltage of the load, and a measured value of the load voltage, after the opening of the switch is completed when there is an abnormality in the power system.

[0009] In such a power supply system, when voltage compensation control is performed, the voltage compensation control unit causes the power converter to output a compensation voltage calculated based on the deviation between the target value of the load voltage and the measured value of the load voltage, so that excessive voltage is not compensated for to the load. As a result, it is possible to prevent overcurrent from flowing from the power converter and to reduce power consumption of the DC power supply more than with conventional voltage compensation control.

[0010] It is preferable that the power supply device further includes a power restoration determination unit that determines whether a system voltage, which is the voltage of the power system, has recovered in the event of an abnormality in the power system, and that before the power restoration determination unit determines that the system voltage has recovered, the voltage compensation control unit sets the target value of the load voltage to a rated voltage, and after the power restoration determination unit determines that the system voltage has recovered, the switch is turned on and the voltage compensation control unit changes the target value of the load voltage to the measured value of the system voltage.

[0011] With this configuration, after the grid voltage is restored, the measured grid voltage is changed to the target load voltage, so the load voltage and the grid voltage become equal. As a result, even if the grid voltage fluctuates when the power is restored and the switch is turned on, the potential difference between the switch terminals is zero, so it is possible to prevent a short-circuit current from occurring between the power converter and the switch. Furthermore, before the system voltage recovers, the load voltage is feedback-controlled with the rated voltage as the target value of the load voltage, so that the load voltage can be maintained at the rated voltage before the system voltage recovers. As a result, when the system voltage recovers to the rated voltage, both the system voltage and the load voltage are at the rated voltage, so that it is possible to prevent a potential difference from occurring in the voltage between the terminals of the switch when the switch is turned on.

[0012] It is preferable that the voltage compensation control unit controls the power converter so that the target value of the load voltage becomes the lower limit value of an allowable range of the load voltage.

[0013] With this configuration, the power converter control unit controls the power converter so that the target value of the load voltage is the lower limit of the allowable range of the load voltage, thereby reducing the power consumption of the DC power supply during voltage compensation control and achieving energy savings in the DC power supply. In particular, when the power converter is connected to a power line via, for example, an injection transformer or an interconnection reactor, the target value of the load voltage is set to the lower limit of the allowable range of the load voltage, so that only the necessary voltage can be compensated to the load regardless of the circuit conditions.

[0014] A specific embodiment of the lower limit of the allowable range of the load voltage is preferably 90% of the rated voltage of the load.

[0015] A control method for a power supply system that supplies power from the power system to a load when the power system is normal, cuts off the power supply from the power system to the load when the power system is abnormal, and supplies power to the load from a DC power source, wherein the power supply system includes a switch that is provided on a power line for supplying power from the power system to the load and that is opened when the power system is abnormal, and a power converter that is connected to the power line and converts DC power from the DC power supply into AC power, and the control method for the power supply system includes, after the switch has been opened when the power system is abnormal, performing voltage compensation control that compensates for the load voltage by causing the power converter to output a compensation voltage that is calculated based on the deviation between a target value of a load voltage, which is the voltage of the load, and a measured value of the load voltage.

[0016] With this configuration, it is possible to obtain the same effects as the above-described power supply system. [Effects of the Invention]

[0017] According to the present invention configured in this manner, in voltage compensation control that compensates for the voltage of the load after the switch has been opened, it is possible to prevent excessive voltage from being compensated for in the load. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a schematic diagram showing the configuration of a power supply system according to an embodiment of the present invention; [Figure 2] FIG. 2 is a diagram showing functional blocks of a control device according to the present embodiment. [Figure 3] FIG. 2 is a schematic diagram showing functional blocks of a power converter control unit in the present embodiment. [Figure 4] 10 shows the results of a simulation in this embodiment. [Figure 5] 10 shows the results of a simulation in a conventional example. [Figure 6]10 shows the results of a simulation in this embodiment. [Figure 7] 10 shows the results of a simulation in a conventional example. DETAILED DESCRIPTION OF THE INVENTION

[0019] An embodiment of a power supply system according to the present invention will be described below with reference to the drawings. Note that, for ease of understanding, some parts may be omitted or exaggerated in schematic form in all of the drawings shown below. Identical components are designated by the same reference numerals, and their descriptions will be omitted where appropriate.

[0020] <Device configuration> The power supply system 100 in this embodiment is provided between an electric power system S and a load L, and when an abnormality occurs in the electric power system S, such as a short circuit accident in the electric power system S, the power supply from the electric power system S to the load L is cut off, and then the voltage of the load L is compensated for. Note that in this embodiment, the power supply system 100 is a three-phase circuit, but the number of phases is not particularly limited.

[0021] Specifically, as shown in FIG. 1 , the power supply system 100 includes a switch 2 that cuts off the power supply from a power system S to a load L, a DC power supply 3 that outputs DC power, a power converter 4 that converts the DC power of the DC power supply 3 into AC power and supplies it to a power line P, a system voltage measurement unit 5 that measures the system voltage that is the voltage of the power system S, a load voltage measurement unit 6 that measures the load voltage that is the voltage of the load L, a switch current measurement unit 7 that measures the switch current that is the current flowing through the switch 2, and a control device 8 that controls the switch 2 and the power converter 4.

[0022] The switch 2 is provided on a power line P for supplying power from the power system S to the load L, and opens and closes the power line P. Specifically, when the switch 2 is opened, the supply of AC power from the power system S to the load L is cut off, and when the switch 2 is closed, AC power is supplied from the power system S to the load L. Note that the switch 2 in this embodiment may be a semiconductor switch or a mechanical switch.

[0023] The DC power supply 3 is a battery such as a lead storage battery or a capacitor that stores DC power when the power system S is normal. When the power system S is abnormal, the DC power supply 3 discharges and outputs DC power.

[0024] The power converter 4 is connected in series to the power line P and converts DC power from the DC power supply 3 into AC power to supply the power to the load L. In this embodiment, as shown in FIGS. 1 and 3, the AC power output from the power converter 4 is supplied to the power line P via an interconnection reactor and an injection transformer T. Note that although the power converter 4 is a single-phase inverter in this embodiment, it may also be a three-phase inverter.

[0025] The system voltage measurement unit 5 is connected to the power lines P of each phase via a system transformer (not shown) and measures the system voltage. The measured system voltage measured by the system voltage measurement unit 5 is output to a parameter acquisition unit 81, which will be described later. In this embodiment, the system voltage measurement unit 5 measures the voltage on the power system S side relative to the switch 2 so that an opening command output unit 82, which will be described later, can detect an abnormality in the power system S early.

[0026] The load voltage measuring unit 6 is provided on the low-voltage side of the switch 2. The measured load voltage measured by the load voltage measuring unit 6 is output to a parameter acquiring unit 81, which will be described later.

[0027] The switch current measuring unit 7 is provided on the power line P of each phase and measures the switch current. The switch current measured by the switch current measuring unit 7 is output to a parameter acquiring unit 81, which will be described later.

[0028] The control device 8 is a dedicated or general-purpose computer equipped with a CPU, internal memory, an input / output interface, an A / D converter, etc., and controls the switch 2 and the power converter 4 when an abnormality occurs in the power system S. Specifically, as shown in FIG. 2 , the control device 8 includes a parameter acquisition unit 81 that acquires various parameters, an opening command output unit 82 that outputs an opening command to open the switch 2 when an abnormality in the power system S is detected, a power restoration determination unit 83 that determines whether the system voltage, which is the voltage of the power system S, has recovered, a switch control unit 84 that controls the opening and closing of the switch 2, and a power converter control unit 85 that controls the power converter 4.

[0029] The parameter acquisition unit 81 acquires various parameters measured by each measurement unit. In this embodiment, the parameter acquisition unit 81 acquires at least one of the measured system voltage measured by the system voltage measurement unit 5, the measured load voltage measured by the load voltage measurement unit 6, and the switch current measured by the switch current measurement unit 7. When compensating for the voltage of the load L, it is sufficient for the parameter acquisition unit 81 to acquire at least the measured load voltage.

[0030] The open command output unit 82 determines whether an abnormality has occurred in the power system S based on the system voltage, and if it determines that an abnormality has occurred in the power system S, it outputs an open command to the switch control unit 84. Specifically, if the measured system voltage falls below a predetermined value, the open command output unit 82 determines that an abnormality has occurred in the power system S, and outputs an open command to the switch control unit 84. The predetermined value here is a voltage value for detecting a momentary sag.

[0031] When it is determined that the power system S has recovered from the abnormality, the power restoration determination unit 83 outputs an abnormality recovery signal indicating that the power system S has recovered from the abnormality to the switch control unit 84 and a voltage compensation control unit 852 (described later). Specifically, when the system voltage becomes equal to or higher than a predetermined value (for example, a rated voltage) over multiple cycles after the switch 2 has been opened, the power restoration determination unit 83 determines that the power system S has recovered from the abnormality and outputs the abnormality recovery signal.

[0032] The switch control unit 84 uses a drive circuit (not shown) to control the opening and closing of the switch 2. Specifically, the switch control unit 84 receives an opening command and performs control to open the switch 2. When the opening of the switch 2 is complete, the switch control unit 84 outputs an opening completion signal, which is a signal indicating that the opening of the switch 2 is complete.

[0033] Furthermore, the switch control unit 84 receives the abnormality recovery signal and performs control to close the switch 2. Then, when the closing of the switch 2 is completed, the switch control unit 84 outputs a closing completion signal indicating that the closing of the switch 2 is completed.

[0034] 3, the power converter control unit 85 has a current interruption control unit 851 that performs current interruption control, which is control to interrupt the load L from the power system S, when an opening command is output, a voltage compensation control unit 852 that performs voltage compensation control, which is control to cause the power converter 4 to output a compensation voltage that is a voltage that compensates for the voltage of the load L that has dropped due to the current interruption control, after the opening of the switch 2 is complete, and a control switching unit 853 that switches between the current interruption control and the voltage compensation control. Note that the case where the opening of the switch 2 is complete here refers to the case where the switch control unit 84 outputs an opening completion signal.

[0035] In response to the output of the opening command, the current cut-off control unit 851 performs feedback control of the current output from the power converter 4 so that the current flowing through the switch 2 becomes zero. Specifically, the current cut-off control unit 851 subtracts the switch current acquired by the parameter acquisition unit 81 from a switch current command value that makes the current flowing through the switch 2 zero. The current cut-off control unit 851 then multiplies the difference by a proportional gain Kp and causes the power converter 4 to output a voltage calculated by the switch current command value.

[0036] The voltage compensation control unit 852 performs feedback control of the voltage output by the power converter 4 by calculating a compensation voltage based on the difference between a voltage command value to be output by the power converter 4 so as to make the load voltage a predetermined voltage and the load voltage measured by the load voltage measurement unit 6. Specifically, the voltage compensation control unit 852 performs dq / uvw conversion on the load voltage measured by the load voltage measurement unit 6 and calculates the deviation between the converted load voltage and the voltage command value. Then, the voltage compensation control unit 852 performs PI control and dq / uvw conversion on the calculated deviation to calculate the output voltage which is the voltage to be output by the power converter 4.

[0037] Here, the voltage compensation control unit 852 sets the target value of the measured load voltage to the rated voltage from the start of voltage compensation control until the power restoration determination unit 83 outputs the abnormality recovery signal. Therefore, the voltage compensation control unit 852 feedback controls the voltage output by the power converter 4 so that the measured load voltage becomes the rated voltage from the start of voltage compensation control until the power restoration determination unit 83 outputs the abnormality recovery signal.

[0038] On the other hand, after the power restoration determination unit 83 outputs the abnormality recovery signal, the voltage compensation control unit 852 changes the target value of the load voltage from the rated voltage to the system voltage measured by the system voltage measurement unit 5. Therefore, after the power restoration determination unit 83 outputs the abnormality recovery signal, the voltage compensation control unit 852 feedback controls the voltage output by the power converter 4 so that the measured load voltage and the measured system voltage become equal.

[0039] The control switching unit 853 switches from the current cutoff control to the voltage compensation control after the current cutoff control is completed. Here, "after the current cutoff control is completed" refers to the completion of opening the switch 2 in the current cutoff control.

[0040] <Power supply system control operation> Next, the control operation of the power supply system 100 will be described.

[0041] (1) Normal operation of power system S The measured system voltage measured by the system voltage measuring unit 5 is output to the opening command output unit 82. The opening command output unit 82 compares the measured system voltage with a predetermined value.

[0042] When the power system S is normal, the switch 2 is turned on, and AC power is supplied from the power system S to the load L.

[0043] (2) When an abnormality occurs in power system S For example, if a voltage sag occurs and the system voltage falls below a predetermined value, the opening command output unit 82 determines that an abnormality has occurred in the power system S, and outputs an opening command to the switch control unit 84.

[0044] When the open command is output, the switch control unit 84 performs control using the drive circuit to open the switch 2. Furthermore, the current cut-off control unit 851 controls the current output from the power converter 4 so that the current flowing through the switch 2 becomes zero.

[0045] Then, when the opening of switch 2 is completed, switch control unit 84 outputs a switch completion signal. When the switch completion signal is output, control switching unit 853 switches from current cut-off control to voltage compensation control. As a result, current cut-off control unit 851 completes the current cut-off control, and voltage compensation control unit 852 calculates a compensation voltage and starts voltage compensation control.

[0046] Until the power restoration determination unit 83 determines that the abnormality in the power system S has been recovered, the voltage compensation control unit 852 sets the target value of the measured load voltage to the rated voltage and feedback controls the power converter 4 so that the measured load voltage becomes the rated voltage.

[0047] When the power restoration determination unit 83 determines that the power system S has recovered from the abnormality, the power restoration determination unit 83 outputs an abnormality recovery signal. In response to the output of the abnormality recovery signal, the switch control unit 84 performs control to turn on the switch 2. Furthermore, the voltage compensation control unit 852 changes the target value of the measured load voltage from the rated voltage to the measured system voltage, and performs feedback control of the power converter 4 so that the measured load voltage and the measured system voltage become equal.

[0048] When the closing of the switch 2 is completed, the switch control unit 84 outputs a closing completion signal. Upon receiving the output of the closing completion signal, the voltage compensation control unit 852 completes the voltage compensation control.

[0049] <Simulation results> Next, we will show the voltage waveforms and current waveforms in various power supply systems through simulations. The accident condition in the following simulations is a three-phase short-circuit accident with a momentary sag in which the voltage of the power system S drops by 100%.

[0050] 4 shows the results of a simulation in which the voltage compensation control unit 852 sets the target value of the load voltage to the rated voltage before it is determined that power has been restored and performs feedback control on the power converter 4, and then changes the target value of the load voltage to the grid voltage after it is determined that power has been restored and performs feedback control on the power converter 4. In addition to a three-phase short-circuit fault, this simulation also covers an event in which the grid voltage drops by several percent after the power restoration determination unit 83 determines that power has been restored and starts controlling the closing of the switch 2.

[0051] When it is determined that power has been restored, the voltage compensation control unit 852 controls the power converter 4 so that the load voltage and the system voltage are equal, and therefore the power converter 4 does not apply a potential difference between the terminals of the switch 2. As a result, as shown in Fig. 4, even if the system voltage drops by several percent after it is determined that power has been restored and control to close the switch 2 has started, no overcurrent will flow from the power converter 4.

[0052] Fig. 5 shows the results of a simulation in which the drop in grid voltage is compensated for by the power converter 4 to the load L based on the deviation between the grid voltage and the target value (rated voltage) of the load voltage, as in the past. In this simulation, as in Fig. 4, in addition to a three-phase short-circuit fault, the simulation also covers an event in which the grid voltage drops by several percent after the power restoration determination unit 83 determines that power has been restored and starts controlling the closing of the switch 2.

[0053] If the grid voltage drops by several percent after it is determined that power has been restored, power converter 4 applies a potential difference between the terminals of switch 2 based on the deviation between the grid voltage and the target value of the load voltage. As a result, an overcurrent flows from power converter 4, as shown in Figure 5.

[0054] <Effects of this embodiment> According to the power supply system 100 of this embodiment, when voltage compensation control is performed, the voltage compensation control unit 852 causes the power converter to output a compensation voltage calculated based on the deviation between the target value of the load voltage and the measured load voltage, so that an excessive voltage is not compensated for to the load L. As a result, it is possible to prevent an overcurrent from flowing from the power converter 4 and to reduce the power consumption of the DC power supply 3 more than with conventional voltage compensation control.

[0055] According to the power supply system 100 of this embodiment, after the system voltage is restored, the measured system voltage is changed to the target value of the load voltage, so that the measured load voltage and the measured system voltage become equal. As a result, even if the system voltage fluctuates when power restoration is determined and switch 2 is turned on, the potential difference between the terminals of switch 2 is zero, so that it is possible to prevent a short-circuit current from occurring between the power converter 4 and switch 2. Furthermore, before the system voltage recovers, the rated voltage is set as the target value of the load voltage and the power converter 4 is feedback-controlled, so that when the system voltage recovers to the rated voltage, both the system voltage and the load voltage become the rated voltage. As a result, it is possible to prevent a potential difference from occurring in the voltage between the terminals of the switch 2 when the switch is turned on.

[0056] <Other embodiments> The present invention is not limited to the above-described embodiment.

[0057] In the above embodiment, the voltage compensation control unit 852 sets the target value of the load voltage to the rated voltage before it is determined that power has been restored, and sets the target value of the load voltage to the system voltage after it is determined that power has been restored, but this is not limited to this. For example, the voltage compensation control unit 852 may perform voltage compensation control so that the target value of the load voltage is the lower limit of the allowable range of the load voltage. The allowable range of the load voltage here refers to, for example, between 90% and 110% of the rated voltage of the load voltage, but is not limited to this. Furthermore, the lower limit of the allowable range of the load voltage refers to, but is not limited to, 90% of the rated voltage.

[0058] FIG. 6 shows the results of a simulation in which voltage compensation control section 852 feedback controls power converter 4 so that the load voltage is 90% of the rated voltage, which is the lower limit of the allowable range of the load voltage.

[0059] 6, the voltage compensation control unit 852 performs voltage compensation control based on the load voltage, thereby controlling the load voltage to 90% of the rated voltage. As a result, the voltage output by the power converter 4 is smaller than when the load voltage is controlled to be the rated voltage, thereby reducing the energy consumption of the DC power supply 3. As a result, resource conservation of the DC power supply 3 can be achieved.

[0060] 7 shows the results of a simulation in which, as in the past, voltage compensation control section 852 causes power converter 4 to output the voltage drop caused by the impedance of the interconnection unit, which is made up of an injection transformer T, an interconnection reactor R, and the like, provided between power converter 4 and switch 2, and the system voltage drop. Here, the voltage drop caused by the impedance of the interconnection unit is a fixed value.

[0061] 7, the voltage drop due to the impedance of the grid-connected unit and the drop in the grid voltage are added together, resulting in an excessive voltage being output from the power converter 4. As a result, even though the load voltage is within the allowable range (for example, 90% to 110% of the rated voltage), the load voltage becomes excessive, resulting in increased energy consumption by the DC power supply 3.

[0062] In the above embodiment, the power supply system 100 is configured to include a system voltage measurement unit 5, a load voltage measurement unit 6, and a switch current measurement unit 7, but the system voltage measurement unit 5, the load voltage measurement unit 6, and the switch current measurement unit 7 may be provided separately from the power supply system 100.

[0063] Furthermore, the present invention is not limited to the above-described embodiment, and it goes without saying that various modifications are possible without departing from the spirit of the present invention. [Explanation of symbols]

[0064] 100 Power Supply System 2 Switch 3...DC power supply 4. Power Converter 5. System voltage measurement section 6. Load voltage measurement section 7 Switch current measurement section 8. Control device 81 Parameter acquisition section 82...Open command output section 83...Power restoration determination unit 84 Switch control section 85 Power converter control section 851 Current cutoff control unit 852 Voltage compensation control section 853 Control switching unit S...Power system L...Load P...power line

Claims

1. A power supply system that supplies power from a power system to a load when the power system is normal, and cuts off power supply from the power system to the load when an abnormality occurs in the power system, and supplies power to the load from a DC power supply, a switch that is provided on a power line for supplying power from the power system to the load and that is opened when an abnormality occurs in the power system; a power converter connected to the power line and converting DC power from the DC power supply into AC power; a power converter control unit that controls a voltage output by the power converter when an abnormality occurs in the power grid, The power converter control unit a voltage compensation control unit that performs voltage compensation control, which is control to compensate for the load voltage, by causing the power converter to output a compensation voltage calculated based on a deviation between a target value of a load voltage, which is the voltage of the load, and a measured value of the load voltage, after the switch has been opened in the event of an abnormality in the power system.

2. a power recovery determination unit that determines whether a system voltage, which is a voltage of the power system, has recovered when an abnormality occurs in the power system; 2. The power supply system according to claim 1, wherein before the power restoration determination unit determines that the grid voltage has been restored, the voltage compensation control unit sets the target value of the load voltage to a rated voltage, and after the power restoration determination unit determines that the grid voltage has been restored, the switch is turned on and the voltage compensation control unit changes the target value of the load voltage to the measured value of the grid voltage.

3. 3. The power supply system according to claim 1, wherein the voltage compensation control unit performs the voltage compensation control so that the target value of the load voltage becomes a lower limit value of an allowable range of the load voltage.

4. 4. The power supply system according to claim 3, wherein the lower limit of the allowable range of the load voltage is 90% of the rated voltage.

5. A control method for a power supply system in which power is supplied from a power system to a load when the power system is normal, and power supply from the power system to the load is cut off when an abnormality occurs in the power system, and power is supplied from a DC power supply to the load, comprising: The power supply system includes: a switch that is provided on a power line for supplying power from the power system to the load and that is opened when an abnormality occurs in the power system; a power converter connected to the power line to convert DC power from the DC power supply into AC power, The method for controlling a power supply system includes: a control method for a power supply system, wherein after the opening of the switch is completed when an abnormality occurs in the power system, a voltage compensation control is performed, which is a control to compensate for the load voltage, by causing the power converter to output a compensation voltage calculated based on a deviation between a target value of a load voltage, which is the voltage of the load, and a measured value of the load voltage.

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