JPWO2018163397A1 - Uninterruptible power supply and test method for uninterruptible power supply - Google Patents

Abstract

When performing an electric test of the uninterruptible power supply (100) in a state where no load is connected to the fourth terminal (T4), the control device (4) includes the first and second switches (S2, S3). Is turned on, and the output current of the inverter (2) is controlled according to the current command value. The control device (4) is configured to execute a voltage command based on a deviation between the d-axis current command value and the q-axis current command value obtained by performing coordinate conversion on the current command value and the d-axis current value and the q-axis current value obtained by performing coordinate conversion on the output current. Generate a value. The control device generates a control signal for the inverter (2) based on the voltage command value. The control device controls the frequency of the control signal such that the phase of the AC voltage generated by the inverter (2) according to the control signal is synchronized with the phase of the AC power supply (5).

Description

  The present invention relates to an uninterruptible power supply and a method for testing the uninterruptible power supply.

  In order to meet the demand for reliability of the uninterruptible power supply, an electric test for confirming the performance of the uninterruptible power supply is performed. For example, Japanese Patent Laying-Open No. 2009-232541 (Patent Document 1) discloses a test method for performing an electrical test of an uninterruptible power supply without connecting a simulated load device to an AC output terminal.

JP 2009-232541A

  In the test method of the uninterruptible power supply described in Patent Literature 1, the AC power generated by the inverter is regenerated to the AC power via the bypass circuit without using the simulated load device. Thereby, the power required for the electrical test can be suppressed to the loss occurring in the power route described above.

  On the other hand, in the test method described in Patent Document 1, the inverter is controlled such that the detected value of the three-phase AC current output from the inverter matches the current command value. Since the rated frequency of the three-phase alternating current is superimposed on the control gain in this current control, the control gain needs to be high. Therefore, there is a problem that control is complicated in order to realize high-speed response and high control accuracy.

  SUMMARY OF THE INVENTION Therefore, a main object of the present invention is to provide an uninterruptible power supply and a test method of the uninterruptible power supply capable of performing an electrical test with high speed response and high control accuracy by easy control.

  According to one aspect of the present invention, an uninterruptible power supply includes a first terminal connected to an AC power supply, a second terminal connected to an AC power supply, a third terminal connected to the power storage device, a fourth terminal, a converter, , An inverter, first and second switches, and a control device. The converter is configured to convert AC power supplied from the AC power supply via the first terminal to DC power. The inverter is configured to convert DC power generated by the converter or DC power of the power storage device into AC power. The first switch is connected between an output node of the inverter and a fourth terminal. The second switch is connected between the second terminal and the fourth terminal. When performing an electric test of the uninterruptible power supply with no load connected to the fourth terminal, the control device turns on the first and second switches and adjusts the output current of the inverter according to the current command value. Configured to control. The controller generates a voltage command value based on a deviation between the d-axis current command value and the q-axis current command value obtained by performing coordinate conversion on the current command value and the d-axis current value and the q-axis current value obtained by performing coordinate conversion on the output current. I do. The control device generates a control signal for the inverter based on the voltage command value. The control device controls the frequency of the control signal such that the phase of the AC voltage generated by the inverter according to the control signal is synchronized with the phase of the AC power supply.

  According to the present invention, the electric test of the uninterruptible power supply can be performed with easy control and high-speed response and high control accuracy.

FIG. 1 is a circuit block diagram showing a configuration of an uninterruptible power supply according to an embodiment of the present invention. FIG. 3 is a block diagram illustrating a configuration of a portion related to control of a converter in the control device. FIG. 3 is a block diagram illustrating a configuration of a portion related to control of an inverter in the control device. It is a figure explaining the setting method of a d-axis current command value and a q-axis current command value. FIG. 4 is a waveform chart for explaining control of an inverter during an electric test. FIG. 2 is a circuit block diagram for explaining a test method of the uninterruptible power supply according to the embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The same or corresponding portions have the same reference characters allotted, and description thereof will not be repeated.

  FIG. 1 is a circuit block diagram showing a configuration of an uninterruptible power supply according to an embodiment of the present invention. The commercial AC power supply 5 supplies AC power of a commercial frequency to the uninterruptible power supply 100. The uninterruptible power supply 100 actually receives three-phase AC power from the commercial AC power supply 5, but for simplification of the drawing and the description, FIG. 1 shows only one phase circuit.

  The uninterruptible power supply 100 includes an input terminal T1, a bypass terminal T2, a battery terminal T3, and an output terminal T4. The input terminal T1 and the bypass terminal T2 are connected to the commercial AC power supply 5. The output terminal T4 can be connected to a load (not shown). The load is driven by AC power of a commercial frequency supplied from the uninterruptible power supply 100.

  Battery terminal T3 is connected to storage battery 6. The storage battery 6 is a battery capable of charging and discharging DC power. The storage battery 6 corresponds to an embodiment of a “power storage device” that stores DC power. A capacitor (electric double layer capacitor, electrolytic capacitor, etc.) may be connected to the battery terminal T3 instead of the storage battery 6.

  The uninterruptible power supply 100 further includes switches S1 to S3, reactors L1 and L2, converter 1, capacitors C1 and C2, bidirectional chopper 3, current detectors CD1 and CD2, voltage detectors VD1 to VD5, and controller 4. Is provided. Switch S1, reactor L1, converter 1, inverter 2, reactor L2, and switch S2 are connected in series between input terminal T1 and output terminal T4.

  Switch S1 has one terminal connected to input terminal T1, and the other terminal connected to an input node of converter 1 via reactor L1. The capacitor C1 is connected to the other terminal of the switch S1. The output node of converter 1 is connected to the input node of inverter 2 via DC bus 7 and to battery terminal T3 via bidirectional chopper 3. Capacitor C3 is connected to DC bus 7.

  The output node of inverter 2 is connected to one terminal of switch S2 via reactor L2, and the other terminal of switch S2 is connected to output terminal T4. The capacitor C2 is connected to one terminal of the switch S2.

  The switch S1 is normally closed (ON) when AC power is normally supplied from the commercial AC power supply 5, and is opened (OFF) at the time of maintenance of the UPS 100, for example. The on / off of the switch S1 is controlled by the control device 4.

  The capacitor C1 and the reactor L1 constitute an AC filter F1. The AC filter F1 is a low-pass filter that allows the passage of AC power of a commercial frequency supplied from a commercial AC power supply and cuts off a signal of a switching frequency generated by the converter.

  Converter 1 is configured to convert AC power supplied from commercial AC power supply 5 to DC power during normal times when AC power is supplied from commercial AC power supply 5. DC power generated by converter 1 is output to DC bus 7. At this time, converter 1 outputs a DC current to DC bus 7 so that voltage V3 of DC bus 7 becomes a predetermined reference voltage V3R. Power conversion in converter 1 is controlled by control device 4. During a power outage when the supply of AC power from commercial AC power supply 5 is stopped, operation of converter 1 is stopped. Converter 1 is controlled by control device 4. Capacitor C3 smoothes voltage V3 of DC bus 7.

  The bidirectional chopper 3 is configured to execute bidirectional DC voltage conversion (step-up and step-down). Normally, bidirectional chopper 3 stores DC power generated by converter 1 in storage battery 6. During a power outage, the bidirectional chopper 3 supplies the DC power of the storage battery 6 to the DC bus 7. The bidirectional chopper 3 is controlled by the control device 4. The bidirectional chopper 3 corresponds to one embodiment of “DC / DC converter”.

  Inverter 2 is normally configured to convert the DC power generated by converter 1 into AC power at a commercial frequency. At the time of a power failure, the inverter 2 is configured to convert the DC power of the storage battery 6 into AC power of a commercial frequency. The inverter 2 is controlled by the control device 4.

  Converter 1 and inverter 2 are constituted by semiconductor switching elements. As the semiconductor switching element, for example, an IGBT (Insulated Gate Bipolar Transistor) is applied. As a control method of the semiconductor switching element, PWM (Pulse Width Modulation) control can be applied.

  Reactor L2 and capacitor C2 constitute AC filter F2. The AC filter F <b> 2 is a low-pass filter, and passes the AC power of the commercial wave number generated by the inverter 2, and blocks a signal of the switching frequency generated in the inverter 2. In other words, the AC filter F2 converts the waveform of the output voltage of the inverter 2 into a sine wave.

  The switch S2 (first switch) is turned off in the bypass power supply mode and turned on in the inverter power supply mode. The bypass power supply mode is a mode in which AC power from the commercial AC power supply 5 is supplied to a load. A circuit that connects the bypass terminal T2 and the output terminal T4 is also referred to as a “bypass circuit”. The inverter power supply mode is a mode in which the AC power generated by the inverter 2 is supplied to a load.

  The switch S3 (second switch) is turned on in the bypass power supply mode and turned off in the inverter power supply mode. The on / off of the switches S2 and S3 is controlled by the control device 4.

  Voltage detector VD 1 detects an instantaneous value of AC voltage V 1 at input terminal T 1 (that is, an AC voltage supplied from commercial AC power supply 5), and provides a signal indicating the detected value to control device 4. Control device 4 determines whether or not AC power is normally supplied from commercial AC power supply 5 (that is, whether or not a power failure has occurred) based on the output signal of voltage detector VD1.

  Current detector CD1 detects an instantaneous value of alternating current I1 flowing through reactor L1 (that is, an input current of converter 1), and supplies a signal indicating the detected value to control device 4. Voltage detector VD3 detects an instantaneous value of DC voltage V3 of DC bus 7 and supplies a signal indicating the detected value to control device 4.

  Control device 4 controls converter 1 based on the output signals of voltage detectors VD1 and VD3 and current detector CD1. In other words, converter 1 normally supplies DC power to DC bus 7 so that DC voltage V3 of DC bus 7 becomes reference voltage V3R. During a power failure, the operation of converter 1 is stopped.

  Voltage detector VD4 detects an instantaneous value of DC voltage V4 at battery terminal T3 (that is, a voltage between terminals of storage battery 6), and provides control device 4 with a signal indicating the detected value. The control device 4 controls the bidirectional chopper 3 based on the output signals of the voltage detectors VD3 and VD4. In other words, the bidirectional chopper 3 normally supplies DC power to the storage battery 6 such that the DC voltage at the battery terminal T3 becomes a predetermined target battery voltage. During a power failure, the bidirectional chopper 3 supplies DC power to the DC bus 7 so that the DC voltage V3 of the DC bus 7 becomes the reference voltage V3R.

  Voltage detector VD2 detects an instantaneous value of AC voltage V2 at bypass terminal T2 (that is, an AC voltage supplied from commercial AC power supply 5), and provides a signal indicating the detected value to control device 4. The voltage detector VD4 detects an instantaneous value of the AC voltage V4 at the output terminal T4, and supplies a signal indicating the detected value to the control device 4.

  Current detector CD2 detects an instantaneous value of current I2 flowing through reactor L2 (that is, an output current of inverter 2), and supplies a signal indicating the detected value to control device 4. The control device 4 controls the inverter 2 based on the output signals of the voltage detectors VD2, VD4 and the current detector CD2.

  In particular, in the inverter power supply mode, control device 4 generates a voltage command value based on detection value V2 of voltage detector VD2 (that is, an AC voltage supplied from commercial AC power supply 5), and performs voltage detection on the voltage command value. Inverter 2 is subjected to voltage feedback control so that detection value V5 of detector VD5 (ie, the AC voltage at output terminal T4) matches, and inverter 2 is supplied so as to supply the current (load current) detected by current detector CD2. Performs current feedforward control.

[Electrical test of uninterruptible power supply]
In order to maintain the reliability of the uninterruptible power supply 100, an electrical test for confirming the performance of the uninterruptible power supply 100 is performed. When performing an electric test of the uninterruptible power supply 100, the uninterruptible power supply 100 is operated without using a load or a simulated load. Specifically, as shown in FIG. 1, the control device 4 operates the converter 1 and the inverter 2 with no load connected to the output terminal T4. In FIG. 1, the flow of electric power at the time of the electric test is shown using broken arrows.

  At this time, the control device 4 turns on the switches S2 and S3 to regenerate the AC power supplied from the inverter 2 to the commercial AC power supply 5 via the bypass circuit. By doing so, the electric power required for the electric test is only the loss generated in the electric power route shown in FIG. 1, so that the electric power supplied from the commercial AC power supply 5 can be suppressed to this loss.

  FIG. 2 is a block diagram showing a configuration of a portion of control device 4 related to control of converter 1. FIG. 2 shows the control of the converter 1 during the electric test.

  At the time of the electrical test, control device 4 controls converter 1 based on the output signals of voltage detectors VD1 and VD3 and current detector CD1, as in the inverter power supply mode. In other words, converter 1 supplies DC power to DC bus 7 so that DC voltage V3 of DC bus 7 becomes reference voltage V3R.

  Specifically, as shown in FIG. 2, the control device 4 includes a voltage reference generator 10, a voltage controller 12, a current controller 14, subtractors 11, 13 and a PWM controller 15. The voltage reference generator 10 generates a reference voltage V3R that is a target DC voltage of the DC bus 7.

  The subtracter 11 subtracts the DC voltage V3 (the detection value of the voltage detector VD3) from the reference voltage V3R to obtain a deviation V3R-V3 between V3R and V3.

  Voltage controller 12 generates current command value I1 * such that deviation V3R-V3 becomes zero. Voltage control unit 12 includes, for example, at least a proportional element (P: proportional element) and an integral element (I: integral element), and performs a proportional integral operation using deviation V3R-V3 as an input. Voltage control unit 12 generates current command value I1 * as the calculation result.

  The subtractor 13 subtracts the current I1 (the value detected by the current detector CD1) from the current command value I1 * to obtain a deviation I1 * -I1 between I1 * and I1.

  Current control unit 14 generates voltage command value V * such that deviation I1 * -I1 becomes zero. Current control unit 14 includes, for example, a proportional element and an integral element, and performs a proportional-integral operation using deviation I1 * -I1 as an input. The current control unit 14 generates a voltage command value V * as a calculation result.

  In the present embodiment, the PI control is used for the voltage control and the current control, but the PID control including the proportional element (P), the integral element (I), and the differential element (D: derivative element) may be used. Good. Alternatively, other general control methods may be used instead.

  When receiving the voltage command value V * from the current control unit 14, the PWM control unit 15 compares the voltage command value V * with a triangular carrier signal, thereby controlling the semiconductor switching element of the converter 1 to turn on and off the semiconductor switching element. Generate The control signal generated by the PWM control unit 15 is provided to the converter 1.

  FIG. 3 is a block diagram showing a configuration of a portion related to control of inverter 2 in control device 4. FIG. 3 shows the control of the inverter 2 during the electric test.

  At the time of the electric test, the control device 4 generates a current command value Ir based on a target value preset for the apparent power S [VA] and the power factor φ to be output by the uninterruptible power supply device 100. The control device 4 performs current feedback control of the inverter 2 so that the detected value of the current detector CD2 (that is, the output current I2 of the inverter 2) matches the generated current command value Ir.

  Specifically, referring to FIG. 3, control device 4 includes a d-axis current command generator 20, a q-axis current command generator 21, current controllers 24 and 25, coordinate converters 26 and 31, a voltage controller. 27, a PWM control unit 28, a frequency control unit 29, and a synchronization control unit 30.

  The d-axis current command generation unit 20 generates a d-axis current command value Idr which is a d-axis component of the current command value Ir. The q-axis current command generation unit 21 generates a q-axis current command value Iqr that is a q-axis component of the current command value Ir.

  Specifically, current command value Ir can be set, for example, based on maximum apparent power S [VA], which is the rated power of uninterruptible power supply 100. Assuming that the effective value of the AC voltage output from the uninterruptible power supply device 100 (that is, the AC voltage V5 of the output terminal T4) is V and the effective value of the current command value Ir is I, the maximum apparent power S [VA] is S = V × I.

  In the inverter power supply mode, the AC voltage V5 at the output terminal T4 is synchronized with the AC voltage V1 supplied from the commercial AC power supply 5. That is, the maximum apparent power S [VA] is represented by the product of the effective value V of the AC voltage (AC power supply voltage) V1 supplied from the commercial AC power supply 5 and the fundamental wave effective value I of the current command value Ir. Therefore, the current command value Ir can be calculated based on the maximum apparent power S [VA] and the effective value V of the AC power supply voltage V1.

  Next, the power factor φ of the uninterruptible power supply 100 is set. Power factor φ can be set, for example, to the power factor of a load that is scheduled to be connected to output terminal T4. In this way, it is possible to confirm the performance of the uninterruptible power supply 100 in a state where a load is substantially connected to the output terminal T4. Alternatively, it is also possible to set a plurality of power factors in advance, and perform an electrical test by switching the power factor φ. The maximum apparent power S [VA] multiplied by the power factor φ (S × φ) is the maximum active power of the UPS 100.

  When the power factor φ is set, as shown in FIG. 4, the current command value Ir can be converted into a d-axis current command value Idr and a q-axis current command value Iqr using the power factor φ. The specified d-axis current value Idr and the specified q-axis current value Iqr are given by the following equations (1) and (2), respectively.

Idr = Ir × cos φ (1)
Iqr = Ir × sinφ (2)
Given the current command value Ir and the power factor φ, the d-axis current command generation unit 20 generates the d-axis current command value Idr using Expression (1). The generated d-axis current command value Idr is provided to the subtractor 22. Given a current command value Ir and a power factor φ, the q-axis current command value 21 generates a q-axis current command value Iqr using Expression (2). The generated q-axis current command value Iqr is provided to a subtractor 23.

  By converting the current command value Ir into a d-axis current command value Idr and a q-axis current command value Iqr, the control device 4 sets the d-axis component Id and the q-axis component Iq of the output current I2 of the inverter 2 to d The current feedback control of the inverter 2 is performed so as to match the axis current command value Idr and the q-axis current command value Iqr.

  Here, in the conventional current feedback control, the inverter 2 is controlled such that the detection value I2 (three-phase alternating current) of the current detector CD2 matches the current command value Ir. Therefore, the rated frequency of the alternating current is superimposed on the control gain of the feedback control. In the case of FIG. 1, ωc = 314 rad / sec is superimposed on the response angular frequency of the control loop based on the frequency of the commercial AC power supply 5 (for example, 50 Hz). Therefore, the gain in the control loop needs to be high. Specifically, a gain that is at least one order of magnitude larger than ωc (that is, 3140 rad / sec or more) is required. In the voltage control (PWM control) according to the voltage command value generated by the current feedback control, a gain that is one digit larger (that is, 31400 rad / sec) is required. Therefore, there is a problem that complicated control is required to realize high-speed response and high control accuracy.

  On the other hand, in the present embodiment, as described above, the d-axis current Id and the q-axis current Iq can be independently controlled in the current feedback control. In the current feedback control of each component, since the current command value can be treated as a DC amount, the rated frequency of the AC current (that is, ωc) can be eliminated. Therefore, the gain in the control loop can be reduced. Therefore, high-speed response and high control accuracy can be easily realized.

  Hereinafter, the current feedback control in the control device 4 will be described in detail with reference to FIG.

  Synchronization control unit 30 detects phase θ of AC power supply voltage V1 based on a detection value of voltage detector VD1 (ie, AC voltage V1 supplied from commercial AC power supply 5). The synchronization control unit 30 is, for example, a PLL (Phase Locked Loop) circuit, and controls the phase difference between the output voltage V5 of the inverter 2 and the AC power supply voltage V1 to be zero. By synchronizing the phase of the output voltage V2 of the inverter 2 with the phase of the AC power supply voltage V1, as shown in FIG. 1, the AC power supplied from the inverter 2 is regenerated to the commercial AC power supply 5 via the bypass circuit. Can be done.

  The coordinate conversion unit 31 performs a coordinate conversion (three-phase / two-phase conversion) using the phase θ detected by the synchronization control unit 30 based on the detection value of the current detector CD2 (that is, the output current I2 of the inverter 2). , D-axis current Id and q-axis current Iq.

  The subtractor 22 subtracts the d-axis current Id from the d-axis current command value Idr generated by the d-axis current command generator 20 to obtain a deviation ΔId between Idr and Id. The subtractor 23 subtracts the q-axis current Iq from the q-axis current command value Iqr generated by the q-axis current command generator 21 to obtain a deviation ΔIq between Iqr and Iq.

  The current control unit 24 generates the d-axis voltage command value Vd * such that the deviation ΔId becomes zero. Specifically, the current control unit 24 obtains a control deviation by performing a proportional-integral operation with a predetermined gain on the deviation ΔId, and generates a d-axis voltage command value Vd * corresponding to the control deviation.

  Current control unit 25 generates q-axis voltage command value Vq * such that deviation ΔIq becomes zero. Specifically, the current control unit 25 obtains a control deviation by performing a proportional-integral operation with a predetermined gain on the deviation ΔIq, and generates a q-axis voltage command value Vq * according to the control deviation.

  The coordinate conversion unit 26 converts the d-axis voltage command value Vd * and the q-axis voltage command value Vq * into U-phase, V-phase, and W-phase by coordinate conversion (three-phase / two-phase conversion) using the phase θ of the AC power supply voltage. It is converted into each phase voltage command value Vu *, Vv *, Vw * of the phase. The AC voltage command value Vo * comprehensively indicates Vu *, Vv *, and Vw *.

  Thus, the voltage command value Vo * is generated by the current feedback control. Therefore, by performing PWM control on inverter 2 according to voltage command value Vo *, output current I2 of inverter 2 can be made to match current command value Ir.

  However, when starting the uninterruptible power supply 100 (inverter 2) for the electric test, the effective value of the voltage command value Vo * rapidly rises from 0, so that the control cannot follow, and the output voltage V2 of the inverter 2 becomes lower. There is a possibility that an overshoot that goes too far after the effective value reaches the effective value of the voltage command value Vo *, or hunting in which the effective value of the output voltage V2 oscillates around the effective value of the voltage command value Vo * may occur. As a result, there arises a problem that the electric test cannot be performed during a period from when the uninterruptible power supply device 100 is started to when the output voltage V2 is stabilized.

  In order to prevent overshoot and hunting of the output voltage V2, a method of gradually increasing the effective value of the voltage command value Vo * from 0 to the original target voltage when the uninterruptible power supply 100 is started can be adopted. . According to this, it is possible to cause the effective value of the output voltage V2 to follow the effective value of the voltage command value Vo *. However, on the other hand, during the period when the effective value of the voltage command value Vo * is increased, the effective value of the output current I2 of the inverter 2 is also lower than the effective value of the current command value Ir. The inability to do so remains unresolved.

  Therefore, in the present embodiment, when starting uninterruptible power supply 100, the effective value of voltage command value Vo * is linearly increased from 0, and the output frequency of inverter 2 is increased.

  Specifically, referring to FIG. 3, frequency control unit 29 receives a signal indicating phase θ of AC power supply voltage V1 from synchronization control unit 30, and receives a start instruction ST of uninterruptible power supply device 100. Start command ST is a command for starting converter 1 and inverter 2 of uninterruptible power supply 100. When an operation unit (not shown) is turned on in the electric test, a start command ST activated to an H (logic high) level is issued to control device 4.

  Receiving start command ST activated to the H level, frequency control unit 29 generates frequency command f♯ based on rated frequency f * of commercial AC power supply 5. Specifically, frequency control unit 29 increases frequency command f♯ from 0 to rated frequency f *. Frequency control section 29 gives generated frequency command f♯ to voltage control section 27 and PWM control section 28.

  Voltage control unit 27 generates voltage command value Vo # to be given to PWM control unit 28 based on voltage command value Vo * and frequency command f # generated by coordinate conversion unit 26. Voltage control unit 27 increases the effective value of voltage command value Vo # from 0 to Vo *. Thereby, the output frequency f of the inverter 2 and the effective value of the output voltage V5 of the inverter 2 can be simultaneously increased.

  The PWM control unit 28 generates a triangular carrier signal based on the frequency command f♯. The PWM control unit 28 is configured to include a voltage controlled oscillator (VCO). The voltage controlled oscillator adjusts the frequency of the triangular carrier signal so as to be an integral multiple of the frequency command f♯.

  The PWM control unit 28 generates a control signal for turning on and off the semiconductor switching element of the inverter 2 by comparing the voltage command value Vo # with the triangular carrier signal. The control signal generated by the PWM control unit 28 is provided to the inverter 2.

  FIG. 5 is a waveform diagram for explaining control of inverter 2 during the electric test. FIG. 5 shows the relationship between the start command ST, the effective value of the voltage command Vo #, and the effective value of the output current I2 of the inverter 2.

  Referring to FIG. 5, when start command ST is activated from L (logic low) level to H level at time t1, control device 4 turns on both switches S2 and S3, and sets current command value Ir And a voltage command value Vo * based on the power factor φ. Control device 4 further generates frequency command f♯ based on rated frequency f * of commercial AC power supply 5.

  Control device 4 increases frequency command f♯ at a predetermined rate of change, starting at time t1. Frequency command f♯ reaches rated frequency f *. At this time, control device 4 increases the effective value of voltage command value Vo # from 0, starting at time t1. The effective value of voltage command value Vo # increases and reaches Vo * at time t2.

  By doing so, the output frequency of the inverter 2 and the output voltage V5 change between the times t1 and t2. As described above, if only the output voltage V5 is reduced, the output current I2 of the inverter 2 is reduced. Therefore, the output frequency is also reduced corresponding to the output voltage V5. Thus, the electric test can be performed quickly and stably after starting the uninterruptible power supply 100 without causing overshoot and hunting of the output voltage V5.

  According to uninterruptible power supply device 100 of the present embodiment, it is also possible to perform an electric test assuming that the supply of AC power from commercial AC power supply 5 is stopped. As shown in FIG. 6, the control device 4 operates the inverter 2 in a state where no load is connected to the output terminal T4. At this time, control device 4 stops converter 1. In FIG. 6, the flow of electric power at the time of the electric test is shown using broken arrows.

  When the activation command ST is activated to the H level, the control device 4 turns on both the switches S2 and S3, and linearly changes the effective value of the voltage command value Vo♯ from 0 as in the above embodiment. At the same time, the frequency command f♯ of the inverter 2 is increased.

  The control device 4 controls the bidirectional chopper 3 based on the output signals of the voltage detectors VD3 and VD4. The bidirectional chopper 3 supplies DC power to the DC bus 7 so that the DC voltage V3 of the DC bus 7 becomes the reference voltage V3R.

  Thus, the DC power supplied from the storage battery 6 is converted into AC power by the inverter 2 and then regenerated to the commercial AC power supply 5 via the bypass circuit. Also in this case, the electric power required for the electric test is only the loss generated in the electric power route shown in FIG. 6, so that the electric power supplied from the commercial AC power supply 5 can be suppressed to this loss.

  As described above, according to the uninterruptible power supply according to the embodiment of the present invention, the current command value can be treated as a DC amount in the current feedback control at the time of the electric test, and therefore, the high-speed response can be achieved by the easy control. Also, an electrical test of the uninterruptible power supply can be performed with high control accuracy.

  Further, the output current of the inverter can be made to match the current command value immediately after starting the uninterruptible power supply for the electric test. Therefore, after starting the uninterruptible power supply, the electric test can be performed quickly and stably.

  The embodiments disclosed this time are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  DESCRIPTION OF SYMBOLS 1 Converter, 2 inverters, 3 bidirectional choppers, 4 control devices, 5 commercial AC power supplies, 10 voltage reference generators, 11, 13 subtractors, 12, 27 voltage controllers, 14 current controllers, 15, 28 PWM controllers , 20 d-axis current command generator, 21 q-axis current command generator, 24, 25 current controller, 26, 31 coordinate converter, 29 frequency controller, 30 synchronization controller, 100 uninterruptible power supply, T1 input terminal , T2 bypass terminal, T3 battery terminal, T4 output terminal, VD1-VD3 voltage detector, CD1, CD2 current detector.

Claims (6)

An uninterruptible power supply,
First and second terminals connected to an AC power supply;
A third terminal connected to the power storage device;
A fourth terminal;
A converter configured to convert AC power supplied from the AC power supply via the first terminal to DC power;
An inverter configured to convert DC power generated by the converter or DC power of the power storage device to AC power,
A first switch connected between an output node of the inverter and the fourth terminal;
A second switch connected between the second terminal and the fourth terminal;
When performing an electrical test of the uninterruptible power supply in a state where no load is connected to the fourth terminal, the first and second switches are turned on, and the output current of the inverter is changed according to a current command value. A control device configured to control,
The control device includes:
A d-axis current command value and a q-axis current command value obtained by performing coordinate conversion on the current command value using a predetermined power factor, and a d-axis current value obtained by performing a coordinate conversion on the output current using a phase of a voltage of the AC power supply. A voltage command value is generated based on a deviation from the q-axis current value, and
An uninterruptible power supply configured to generate a control signal for the inverter based on the voltage command value.   The control device further increases the effective value of the voltage command value from 0 to a predetermined voltage value when starting the inverter when performing an electrical test of the uninterruptible power supply device, and controls the frequency of the control signal. 2. The uninterruptible power supply according to claim 1, wherein the uninterruptible power supply is configured to increase from 0 to a frequency of the AC power supply.   3. The uninterruptible power supply according to claim 1, wherein the control device is configured to execute a coordinate transformation of the current command value using a power factor of the load to be connected to the fourth terminal. 4. Power supply. An uninterruptible power supply test method,
The uninterruptible power supply,
First and second terminals connected to an AC power supply;
A third terminal connected to the power storage device;
A fourth terminal;
A converter configured to convert AC power supplied from the AC power supply via the first terminal to DC power;
An inverter configured to convert DC power generated by the converter or DC power of the power storage device to AC power,
A first switch connected between an output node of the inverter and the fourth terminal;
A second switch connected between the second terminal and the fourth terminal,
When performing an electric test of the uninterruptible power supply in a state where the load is not connected to the fourth terminal, the test method includes:
Turning on the first and second switches;
A d-axis current command value and a q-axis current command value obtained by performing coordinate conversion on a current command value using a predetermined power factor, and a d-axis current value obtained by performing coordinate conversion on the output current of the inverter using the phase of the voltage of the AC power supply. And generating a voltage command value based on a deviation from the q-axis current value.
Generating a control signal for the inverter based on the voltage command value.   The test method further includes: when starting the inverter when performing an electric test of the uninterruptible power supply, increasing an effective value of the voltage command value from 0 to a predetermined voltage value, and changing a frequency of the control signal. 5. The method of testing an uninterruptible power supply according to claim 4, comprising a step of increasing from 0 to the frequency of the AC power supply.   The uninterruptible power supply according to claim 4 or 5, wherein, in the step of generating the voltage command value, coordinate conversion of the current command value is performed using a power factor of the load to be connected to the fourth terminal. Power supply test method.

Images