JP2018042428A - Power leveling device - Google Patents

Abstract

A power leveling device capable of narrowing an input voltage range and improving power conversion efficiency is provided. A power conversion unit (12) that converts AC power from an AC power supply (11) into DC power and supplies the load to a load, and a power storage unit (14) that supplies DC power to the output side of the power conversion unit. The discharge control unit 14b is connected between the storage element 14a and the output side of the storage element and the power conversion unit, and controls the discharge power according to the output current of the power conversion unit, and the charge control for charging the storage element The charging control unit converts the AC power into DC power and charges the power storage element at a constant power when the charging voltage of the power storage element becomes equal to or lower than a set value. [Selection] Figure 1

Description

  The present invention relates to a power leveling device that performs power leveling while suppressing fluctuations in load power.

  In recent years, with an increase in demand for cloud computing and big data analysis, systems in which a plurality of computers operate synchronously in a data center are increasing. Since the power consumption of a computer fluctuates instantaneously depending on the operating state of the CPU, etc., when a plurality of computers operate in synchronism, a large amount of power is instantaneously generated, placing a burden on the input system that supplies the power. (For example, excessive stress on power distribution equipment such as a beat of a transformer, a generator, or a cable or a breaker).

  On the other hand, the power consumption of the entire computer system has increased due to speeding up and large capacity, and there is a strong demand for reducing the loss of power conversion units such as power supply units (PSUs).

  In order to perform power leveling so as not to transmit the load power fluctuation to the input side, as shown in FIG. 6, the diode bridge circuit 100 converts AC power into DC power, and an active power factor correction circuit (PFC). The voltage is boosted by 101 and accumulated in the input capacitor 102, and the output of the capacitor 102 is output by the DC-DC converter 103 according to the load (for example, see Patent Document 1).

US Pat. No. 5,960,207

  By the way, generally, the narrower the input voltage range of the DC-DC converter 103, the higher the efficiency is possible (by increasing the transformer turns ratio, lowering the breakdown voltage of the secondary side parts, and suppressing the current of the primary circuit Effect). For example, comparing the case where the input voltage range of the DC-DC converter is 360 to 400V and the case where the input voltage range is 250 to 400V, the input voltage range is 250 to 400V. The efficiency is improved by about 2% compared to the case of ~ 400V.

  However, when the load fluctuation is large as in the above-described system in which a plurality of computers operate in synchronization, the DC-DC converter 103 needs to operate in a wide input voltage range, so that there is a problem that the conversion efficiency decreases. is there.

  That is, as shown by the solid line in FIG. 7A, when the load power changes periodically, the power that cannot be supplied by the power factor correction circuit 101 is supplied by the input capacitor 102 to absorb the fluctuation of the load power. The power fluctuation is not transmitted to the input side. For this reason, the voltage of the input capacitor 102 repeatedly decreases and increases periodically as shown by the broken line, and the voltage of the input capacitor 102 is supplied to the load after being stabilized by the DC-DC converter at the subsequent stage. In this case, the DC-DC converter 103 must be in a wide input range.

  However, in the above-described system in which a plurality of computers operate in synchronization, as shown by the solid line in FIG. 7B, the load power fluctuation is not periodic, for example, after a short-time power fluctuation occurs twice. In many cases, there is no load fluctuation for a while. In the case of such a load fluctuation, the voltage of the input capacitor 102 repeatedly decreases and increases according to the load fluctuation when the load fluctuation occurs as shown by a broken line, but when the load fluctuation does not occur, The output voltage of the power factor correction circuit 101 is held. For this reason, the power conversion efficiency of the DC-DC converter 103 is unnecessarily deteriorated during a period in which no load fluctuation occurs.

  Therefore, the present invention has been made paying attention to the problems of the above-described conventional example, and an object thereof is to provide a power leveling apparatus capable of improving the power conversion efficiency by narrowing the input voltage range. .

  In order to achieve the above object, one aspect of a power leveling apparatus according to the present invention includes: a power converter that converts AC power from an AC power source into DC power and supplies the power to a load; and an output side of the power converter. The power storage unit is connected between the power storage element and the output side of the power storage unit and the power conversion unit, and controls the discharge power according to the output current of the power conversion unit. A discharge control unit; and a charge control unit that charges the power storage element.

  According to one aspect of the present invention, the input voltage range of the power conversion unit is narrowed by covering the insufficient power that cannot be covered by the power conversion unit due to load power fluctuation by controlling the discharge power of the power storage unit by the discharge control unit. Thus, the input power can be leveled.

1 is a block diagram showing a first embodiment of a power leveling apparatus according to the present invention. It is a circuit diagram which shows the discharge control part of FIG. It is a circuit diagram which shows the charge control part of FIG. It is a block diagram which shows 2nd Embodiment of the power leveling apparatus which concerns on this invention. It is a block diagram which shows 3rd Embodiment of the power leveling apparatus which concerns on this invention. It is a block diagram which shows a prior art example. It is a time chart which shows the relationship between the load voltage fluctuation | variation and capacitor voltage of a prior art example.

  Next, an embodiment of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, the drawings are schematic.

  Further, the embodiment described below exemplifies an apparatus and a method for embodying the technical idea of the present invention, and the technical idea of the present invention describes the structure, arrangement, etc. of components as follows. It is not something specific. The technical idea of the present invention can be variously modified within the technical scope defined by the claims described in the claims.

  First, a first embodiment of a power leveling device representing one aspect of the present invention will be described with reference to FIGS. 1 and 2.

  As shown in FIG. 1, the power leveling device 10 includes an AC power source 11 that outputs, for example, 230 V AC power, and an AC / DC converter 12 as a power converter that receives AC power from the AC power source 11. And a load 13 to which output power from the AC / DC converter 12 is supplied, and a power storage unit 14 connected in parallel with the AC-DC converter 12.

  Here, the AC / DC converter 12 includes a power factor correction circuit (PFC) 12a and a DC-DC converter 12b. The power factor correction circuit 12a has a rectifying function for converting AC power into a DC voltage and an output limiting current so that the input current does not exceed a preset set current.

  The DC-DC converter 12b converts the DC power output from the power factor correction circuit 12a into a DC voltage required by the load 13, for example, 12V DC power, and outputs the DC power to the load 13 via the diode D1.

  The power storage unit 14 includes a power storage element 14 a, a discharge control unit 14 b that discharges the stored power stored in the power storage element 14 a to the output side of the AC / DC converter 12, and AC power input from the AC power supply 11. A charging control unit 14c for charging 14a.

  The storage element 14a is a chargeable / dischargeable element, and an electric double layer capacitor, a lithium ion capacitor, an electrolytic capacitor, various batteries (lead, alkali, lithium ion, etc.), and the like can be applied.

  As shown in FIG. 2, the discharge controller 14b includes an input terminal tin2 to which its own output voltage VA2 is input, and three voltage dividing resistors R11 and R12 connected in series between the input terminal tin2 and the ground. And a voltage dividing circuit 20 having R13, a current monitoring unit 21, and a discharge current control unit 22.

  The current monitoring unit 21 is a permissible upper limit current value output by the AC / DC converter 12 in which the current detection value IA1 input from the current detection unit CD that detects the output current of the AC / DC converter 12 as a voltage value is set in advance. An operational amplifier 21a that sucks current when IA1u or higher is provided. In the operational amplifier 21a, a current detection value IA1 having a voltage value is input to an inverting input terminal, and a reference voltage Vref1 corresponding to the allowable upper limit current value IA1u is input to a non-inverting input terminal. The output terminal of the operational amplifier 21a is connected to the cathode of the diode 21b, and the anode of the diode 21b is connected to the connection point of the resistors R11 and R12 of the voltage dividing circuit 20. Therefore, the operational amplifier 21a maintains a high level until the current detection value IA1 becomes equal to or higher than the set current value IA1u, and becomes a low level when the current detection value IA1 becomes equal to or higher than the set current value IA1u. Draw current from.

  The discharge current control unit 22 includes an operational amplifier 22a, a PWM signal generation circuit 22b, and a DC / DC converter 22c.

  In the operational amplifier 22a, the connection point of the resistors R12 and R13 of the voltage dividing circuit 20 is connected to the inverting input terminal, and the reference voltage Vref2 corresponding to 12V is input to the non-inverting input terminal. When the divided voltage Vd input from the operational amplifier 22a from the voltage dividing circuit 20 is equal to or higher than the reference voltage Vref2, a discharge control signal Vc that is at a low level is output, and when the divided voltage Vd becomes lower than the reference voltage Vref2. The discharge control signal Vc having a voltage level corresponding to the difference is output.

  The PWM signal generation circuit 22b includes a comparator that compares the discharge control signal Vc output from the operational amplifier 22a with the carrier signal Sca that is a triangular wave signal or a sawtooth wave signal input from the carrier signal generation unit CS. The comparator outputs a PWM signal that is turned on while the discharge control signal Vc is above the carrier signal Sca, and that is turned off while the discharge control signal Vc is below the carrier signal.

DC / DC converter 22c is connected between power storage element 14a and diode D2, and has a permissible range for charging voltage Vb of power storage element 14a with respect to voltage VA1 output from AC / DC converter 12 based on the PWM signal. The voltage is increased to a relatively high voltage VA2, and the storage element 14a can be discharged.
Here, the discharge current control unit 22 is controlled to be in an operation state or a stop state by an operation control signal Smc output from the current monitoring comparator 22d. In the converter 22d, the current detection value IA1 output from the current detection unit CD that detects the output current of the AC / DC converter 12 as a voltage value is supplied to the non-inverting input terminal, and the inverting input terminal is slightly more than the reference voltage Vref1. A reference voltage Vref6 set to a low voltage is supplied.

  Therefore, the comparator 22d outputs the low-level operation control signal Smc to the discharge current control unit 22 in a state where the current detection value IA1 is lower than the reference voltage Vref6, and the discharge current control unit 22 enters an operation stop state. On the other hand, in a state where the current detection value IA1 exceeds the reference voltage Vref6, a high-level operation control signal Smc is output from the comparator 22d to the discharge current control unit 22, and the discharge current control unit 22 enters an operation state. .

As illustrated in FIG. 1, the charging control unit 14 c includes a charging circuit 23 and a charging control circuit 24. The charging circuit 23 includes a power factor correction circuit 23a and a DC / DC converter 23b. When the power charging command Scc is input, the charging circuit 23 converts the AC power from the AC power source 11 into DC power to Charge.
As the charging mode at this time, when the storage element 14a is an electric double layer capacitor or a lithium ion capacitor, the constant current control is performed until the charging voltage Vb reaches the set voltage, and the constant voltage control is performed when the set voltage is reached. To do. In addition, when the storage element 14a is a battery, constant current / constant voltage control is performed in the same manner as the capacitor. Further, when the storage element 14a is an electrolytic capacitor, the DC / DC converter 23b is omitted. Constant power / constant voltage charging is performed only by the rate improving circuit 23a.

  The charging control circuit 24 monitors the charging voltage Vb of the storage element 14a, and when the charging voltage Vb drops below a preset normal set value Vbu (for example, 70% of the full charging voltage), the AC-DC converter 12 When the output current IA1 is less than the allowable charging current IA1s2 lower than the allowable upper limit current IA1s1, that is, when the power consumption of the load 13 is small, the power charging command Scc is output to the charging circuit 23.

  In addition, the charge control circuit 24 determines that the AC-DC converter 12 when the charge voltage Vb of the power storage element 14a has dropped below the required charge setting value Vbc (for example, 20% of the full charge voltage) lower than the normal setting value Vbu. The power charging command Scc is output to the charging circuit 23 regardless of the output current IA1.

  Here, as shown in FIG. 3, the charging control circuit 24 includes a storage voltage detection unit 25, a first control unit 26, a second control unit 27, and an OR circuit 28.

The storage voltage detection unit 25 includes a power supply terminal tin2 to which the charging voltage Vb of the storage element 14a is input, and a voltage dividing circuit having voltage dividing resistors R21, R22, and R23 connected in series between the power supply terminal tin2 and the ground. 25a.
A current monitoring unit 25b is connected to a connection point between the resistors R21 and R22 of the voltage dividing circuit 25a. Further, the stored voltage detection value Vbd is output from the connection point between the resistors R22 and R32 of the voltage dividing circuit 25.

  Here, the current monitoring unit 25b includes an operational amplifier 29 and a diode 30 similarly to the current monitoring unit 21 of the discharge control unit 14b. In the operational amplifier 29, the current detection value IA1 of the current sensor CD is supplied to the non-inverting input terminal, and the charging allowable current IA1s2 lower than the allowable upper limit current IA1s1 of the reference voltage Vref3 (the output current IA1 of the AC-DC converter 12) is supplied to the inverting input terminal. Is supplied). The diode 30 has an anode connected to the output terminal of the operational amplifier 29 and a cathode connected to a connection point between the resistors R21 and R22 of the voltage dividing circuit 25a.

  The first control unit 26 includes a comparator 26a. In the comparator 26a, the stored voltage detection value Vbd is input to the inverting input terminal, and the reference voltage Vref4 is supplied to the non-inverting input terminal. Reference voltage Vref4 is set to a voltage value corresponding to, for example, 70% of full charge voltage Vbmax of power storage element 14a. Therefore, a voltage drop detection signal Svr that changes from a low level to a high level when the stored voltage detection value Vbd falls below the reference voltage Vref4 is output from the comparator 26a to the OR circuit 28.

  The second control unit 27 includes a voltage dividing circuit 27a that divides the storage voltage Vb of the storage element 14a and a comparator 27b.

  The voltage dividing circuit 27a includes an input terminal tin3 to which the stored voltage Vb of the power storage element 14a is input, and voltage dividing resistors R24 and R25 connected between the input terminal tin3 and the ground. The stored voltage detection value Vbd2 is output from the connection point of the voltage dividing resistors R24 and R25.

  In the comparator 27b, the stored voltage detection value Vbd of the voltage dividing circuit 27a is input to the inverting input terminal, and the reference voltage Vref5 is input to the non-inverting input terminal. The reference voltage Vref5 is set to a voltage value corresponding to, for example, 20% of the full charge voltage Vbmax of the storage element 14a. Therefore, when the stored voltage detection value Vbd2 falls below the reference voltage Vref5 from the comparator 27b, a charge required detection signal Svc that changes from the low level to the high level is output to the OR circuit 28.

The OR circuit 28 charges the charge command signal Sc which becomes high level when either the voltage drop detection signal Svr of the first control unit 26 or the charge required detection signal Svc of the second control unit 27 becomes high level. Output to circuit CH.
Next, the operation of the first embodiment will be described.
Now, it is assumed that the charging voltage Vb of the storage element 14a is charged to a state close to the full charge pressure Vbmax.

  In this state, the charge control unit 14c of the power storage unit 14 is such that the divided voltage Vbd of the voltage dividing circuit 25a is equal to or higher than the reference voltage Vref4 of the comparator 26a of the first control unit 26, and the voltage drop detection signal output from the comparator 26a. Svr becomes low level. Further, the charge required detection signal Svc output from the comparator 27b of the second control unit 27 is also at a low level. For this reason, the power charging command Scc is not output from the OR circuit 28, and the charging circuit 23 stops operating.

If the power consumption of the load 13 is within a range that can be sufficiently covered by the DC power output from the AC / DC converter 12, the current IA1 output from the AC / DC converter 12 is the discharge controller 14b. Is lower than the reference voltage Vref6 of the current monitoring comparator 22d. For this reason, the operation control signal Smc output from the comparator 22d is at a low level, the discharge current control unit 22 is in an operation stopped state, and the DC / DC converter 22c is stopped in operation.
As a result, while the power consumption of the load 13 is small, only the AC / DC converter 12 is in an operating state when the charging process of the power storage element 14a is not performed.

From the stopped state of the DC / DC converter 22c, the current IA1 output from the AC / DC converter 12 increases and is higher than the reference voltage Vref6 of the current monitoring comparator 22d of the discharge control unit 14b. When the operation voltage is lower than the reference voltage Vref1 of the operational amplifier 21a of the current monitoring unit 21 (Vref6 <IA1 <Vref1), the operation control signal Smc output from the current monitoring comparator 22d becomes high level, and the discharge current control unit 22 The operating state is entered, and the DC / DC converter 22c enters the operating state.
However, in this state, the current IA1 output from the AC / DC converter 12 is lower than the reference voltage Vref1 of the operational amplifier 21a of the current monitoring unit 21 of the discharge control unit 14b. For this reason, the output of the operational amplifier 21a is maintained at a high level, and the current of the voltage dividing circuit 20 is not drawn through the diode 21b.

  Accordingly, the divided voltage Vd divided by the resistors R11 and R12 and R13 of the voltage dividing circuit 20 is supplied to the inverting input terminal of the operational amplifier 22a of the discharge current control unit 22. For this reason, the discharge control signal Vc having a low voltage level corresponding to the difference from the reference voltage Vref2 is output from the operational amplifier 22a. In response, a PWM signal corresponding to the voltage level of the discharge control signal Vc is output from the PWM signal generation circuit 22b to the DC / DC converter 22c, and the output voltage of the DC / DC converter 22c increases. The increase in the output voltage of the DC / DC converter 22c increases, for example, to 11V so that the diode D2 is not turned on when the voltage of the load 13 is 12V, and the power storage element 14a shares the power consumption of the load 13. Prepare for.

When the power consumption of the load 13 further increases from this state and the output current IA1 output from the AC / DC converter 12 becomes equal to or greater than the allowable upper limit current value IA1u that can be covered by the AC / DC converter 12, the discharge control unit 14b In the current monitoring unit 21, the output of the operational amplifier 21a becomes a low level, that is, the ground potential, and the current of the voltage dividing circuit 20 is drawn through the diode 21b.
For this reason, the divided voltage Vd output between the resistors R22 and R23 of the voltage dividing circuit 20 becomes sufficiently smaller than the reference voltage Vref2 of the operational amplifier 22a, and the voltage level of the discharge control signal Vc output from the operational amplifier 22a increases rapidly. To do. Therefore, a PWM signal having a wide ON state is obtained from the PWM signal generation circuit 22b, and this PWM signal is supplied to the DC / DC converter 22c.

  Therefore, the DC / DC converter 22c boosts the storage voltage Vb of the storage element 14a to the reference voltage VA2 in accordance with the width of the PWM signal in the on state. Therefore, the output current IA2 corresponding to the shortage of the power consumption of the load 13 is output from the power storage element 14a to the load 13 side through the DC / DC converter 22c of the discharge control unit 14b and further via the diode D2, and It is added to the output current IA1 of the DC converter 12 and supplied to the load 13.

  For this reason, the amount of current that cannot be covered by the AC / DC converter 12 can be covered by the amount of current from the storage element 14a. At this time, since the output voltage to the load 13 maintains the reference voltage VA1, the power consumption required by the load 13 can be supplied.

  Due to the power supply from the power storage unit 14, the charging voltage Vb of the power storage element 14a decreases, and falls below the reference voltage Vref4 of the first control unit 26 of the charging control unit 14c. At this time, when the output current IA1 of the AC / DC converter 12 monitored by the current monitoring unit 25b exceeds the charge allowable current IA1s2, the output of the operational amplifier 29 is at a high level.

  Therefore, current is supplied to the connection point between the resistors R21 and R22 of the voltage dividing circuit 25a via the diode 30, so that the divided voltage Vd at the connection point between the resistors R22 and R23 is higher than the reference voltage Vref4 of the operational amplifier 26a. The stored voltage drop detection signal Svr is at a low level.

  At this time, the charge-required detection signal Svc output from the comparator 27b of the second control unit 27 is also maintained at a low level, so that the power charging command Scc output from the OR circuit 18 is maintained at a low level. The charging process of the storage element 14a is not executed.

  In this state, when the power consumption of the load 13 decreases and the voltage value of the output current IA1 output from the AC / DC converter 12 decreases below the reference voltage Vref3, the output of the operational amplifier 29 becomes low level, and the voltage dividing circuit The supply of current to the connection point of the resistors R21 and R22 of 25a is stopped.

  For this reason, the current drop detection signal Svr output from the comparator 26 a of the first control unit 26 becomes high level, and a high level power charge command Scc is output from the OR circuit 28 to the DC / DC converter 23 b of the charging circuit 23. The For this reason, the charging circuit 23 converts the AC power from the AC power supply 11 into a DC current and steps down the voltage to charge the storage element 14a. At this time, when the storage element 14a is an electric double layer capacitor or a lithium ion capacitor, constant current control is performed when the charging voltage is less than the set voltage, and constant voltage control is performed when the set voltage is reached. Further, only the constant voltage control may be performed when the power storage element 14a is configured by a battery, and when the power storage element 14a is configured by an electrolytic capacitor, the DC / DC converter 23b is omitted to improve the power factor. Only the circuit 23a may be provided.

  Further, during the charging process by the first control unit 26, when the charging voltage Vb of the power storage element 14 further decreases and falls below the reference voltage Vref5 of the second control unit 27, that is, less than 20% of the full charging voltage Vbmax, A high level required charge detection signal Svc is output from the comparator 27 b of the second control unit 27 to the OR circuit 28.

  Therefore, the charging command is continuously output from the OR circuit 28, and the charging circuit 23 charges the power storage element 14a regardless of the value of the output current IA1 of the AC / DC converter 12.

  As described above, according to the first embodiment, the AC power of the AC power supply 11 is directly supplied to the AC / DC converter 12, and the AC power is full-wave rectified by the power factor improving circuit 12 a of the AC / DC converter 12. At the same time, a power factor improvement process is performed, and the DC / DC converter 12b steps down the voltage to a DC voltage required by the load 13 and outputs it to the load 13 via the diode D1. At this time, when the necessary current of the load 13 can be provided only by the AC / DC converter 12, only the AC / DC converter 12 is driven. Then, the current monitoring unit 21 of the discharge control unit 14 b monitors the current required by the load 13, and when the current required by the load 13 exceeds the current that can be provided by the AC / DC converter 12, When the discharge control unit 14b is driven to boost the storage voltage Vb of the storage element 14a to the set voltage VA2, a discharge current corresponding to the current exceeding the current that can be covered by the AC / DC converter 12 is supplied to the load 13. Is done.

  For this reason, it is not necessary to operate the AC / DC converter 12 so as to cover the entire current range required by the load 13, but only by performing power conversion so as to output a voltage and current that can be generated with constant input power. Well, it does not cause fluctuations in input power.

  As a result, the input voltage range of the AC / DC converter 12 can be narrowed to improve the power conversion efficiency, and at the same time, the current that cannot be covered by the AC / DC converter 12 due to fluctuations in the power consumption of the load 13 is stored. This can be covered by discharging the power stored in the element 14a. Therefore, the conversion efficiency when both the AC / DC converter 12 and the discharge control unit 14b of the power storage unit 14 are operating can be improved by about 1.0% with respect to the conversion efficiency of the conventional example described above. When the power consumption fluctuation of the load 13 can be covered only by the AC / DC converter 12, the conversion efficiency of the conventional example can be improved by 2.0%.

Therefore, according to the first embodiment, the power consumption fluctuation of the load does not affect the input side of the AC / DC converter 12, the input voltage of the AC / DC converter 12 can be leveled, Conversion efficiency can be improved.
Next, a second embodiment of the input power leveling apparatus according to the present invention will be described with reference to FIG.

  In the second embodiment, the storage element is charged using DC power output from the AC / DC converter.

That is, in 2nd Embodiment, as shown in FIG. 4, the charge control part 14c of the electrical storage part 14 is provided in parallel with the discharge control part 14b. For this reason, in the charging control unit 14c, the power factor correction circuit constituting the charging circuit 23 is omitted, and only the DC / DC converter 23b is configured. The DC / DC converter 23b has the same configuration as that of the first embodiment. It is controlled by a power charge command from the charge control circuit 24 it has. Further, the diode D2 is omitted.
Other configurations have the same configurations as those in the first embodiment described above with reference to FIGS.

  In the second embodiment, the input power is leveled in the same manner as in the first embodiment except that the power storage element 14a in the power storage unit 14 is charged by the output power of the AC / DC converter 12. be able to.

  For this reason, also in 2nd Embodiment, the effect similar to 1st Embodiment mentioned above can be acquired. Therefore, in the state where the AC / DC converter 12 and the discharge control unit 14b of the power storage unit 14 are operating, the power conversion efficiency can be improved by 1.0% as compared with the conventional example described above.

Furthermore, the power conversion efficiency when the power consumption of the load 13 can be covered only by the AC / DC converter 12 can be improved by 2.0%.
Next, a third embodiment of the power leveling apparatus according to the present invention will be described with reference to FIG.
In the third embodiment, the power factor correction circuit is shared.

  That is, in the third embodiment, as shown in FIG. 5, the AC power source 11 is made independent of the power factor improvement circuit provided in the AC / DC converter 12 and the charging control unit 14 c in the first embodiment. The first is except that the power factor improving circuit 31 is connected and the output of the power factor improving circuit 31 is supplied to the DC / DC converter in the DC / DC converter 12b and the charging control unit 14c of the power storage unit 14. It has the same configuration as the embodiment. Other configurations are the same as those in the first embodiment.

  According to the third embodiment, the output of the power factor improvement circuit in which the power factor improvement circuits provided separately in the AC / DC converter 12 and the charge control unit 14c in the first embodiment are made common and independent. Is distributed and supplied to the DC / DC converter 12b and the DC / DC converter 12b of the charging control unit 14c. Here, the electric power of the charging control unit 14c has a small capacity, and when a power factor correction circuit is provided independently, the charger efficiency is lowered. Therefore, with the configuration of the third embodiment, the large-capacity power factor correction circuit of the DC / DC converter 12b can be used as the power factor correction circuit of the charge control unit 14c, and the DC / DC converter The power conversion efficiency in the state where 12b and the discharge control unit 14b are operated simultaneously can be improved by 1.3% compared to the power conversion efficiency of the conventional example described above. Furthermore, the conversion efficiency during a period in which only the DC / DC converter 12b operates and there is no load fluctuation can be improved by 2.0%.

  In each of the above embodiments, the case where the power conversion system is one system has been described. However, the present invention is not limited to this, and the present invention is also applied to a case where the power conversion system is connected in parallel to a plurality of systems. Can be applied.

  DESCRIPTION OF SYMBOLS 10 ... Electric power leveling apparatus, 11 ... AC power supply, 12 ... AC / DC converter, 13 ... Load, 14 ... Power storage part, 14a ... Power storage element, 14b ... Discharge control part, 14c ... Charge control part, 20 ... Partial pressure Circuit 21... Current monitoring unit 21 a. Operational amplifier 22... Discharge current control unit 22 a. Operational amplifier 22 b... PWM signal generation circuit 22 c DC / DC converter 25 25 storage voltage detection unit 25 a. 25b ... Current monitoring unit, 26 ... First control unit, 26a ... Comparator, 27 ... Second control unit, 27a ... Comparator, 28 ... OR circuit, 31 ... Power factor improvement circuit

In order to achieve the above object, one aspect of a power leveling apparatus according to the present invention includes a power conversion unit that converts AC power from an AC power source into DC power and supplies the DC power to a load, and a DC on the output side of the power conversion unit. A power storage unit that supplies electric power, and the power storage unit is connected between the power storage element and the output side of the power storage unit and the power conversion unit, and controls discharge power according to the output current of the power conversion unit A control unit and a charge control unit for charging the power storage element, and the charge control unit converts the AC power to DC power when the charge voltage of the power storage element becomes equal to or lower than a set value to Charge.

In order to achieve the above object, one aspect of a power leveling apparatus according to the present invention includes a power conversion unit that converts AC power from an AC power source into DC power and supplies the DC power to a load, and a DC on the output side of the power conversion unit A power storage unit that supplies electric power, and the power storage unit is connected between the power storage element and the output side of the power storage unit and the power conversion unit, and controls discharge power according to the output current of the power conversion unit A control unit and a charge control unit for charging the power storage element, and the charge control unit converts the AC power to DC power when the charge voltage of the power storage element becomes equal to or lower than a set value to The charge and discharge control unit monitors the output current of the voltage dividing circuit and the power conversion unit, and draws the current from the voltage dividing circuit when the output current is larger than the set current, and the voltage dividing circuit of the voltage dividing circuit Discharge that generates a discharge command signal by comparing the voltage with the set voltage That comprise a flow controller.

Claims (8)

A power converter that converts AC power from an AC power source to DC power and supplies the load to the load;
A power storage unit for supplying DC power to the output side of the power conversion unit,
The power storage unit is connected between the power storage element and the output side of the power storage element and the power conversion unit, and controls the discharge power according to the output current of the power conversion unit, and the power storage element A power leveling device comprising: a charge control unit for charging the battery.   2. The charge control unit according to claim 1, wherein when the charging voltage of the power storage element becomes equal to or higher than a set value, the AC power is converted to DC power and the power storage element is charged with constant power. Power leveling device.   The said charge control part charges the said electrical storage element with the direct-current power output from the said power conversion part, when the charge voltage of the said electrical storage element becomes more than a setting value. Power leveling device.   The charge control unit sets a normal set value and a required charge set value smaller than the normal set value as set values, and when the charge voltage of the power storage element becomes equal to or lower than the normal set value, the power consumption of the load The power storage element is charged when the amount is small, and the power storage element is charged regardless of a power consumption amount of a load when a charge voltage of the power storage element is equal to or lower than the charge required setting value. The power leveling device according to claim 2 or 3.   2. The discharge control unit boosts a storage voltage of the power storage element to perform discharge control of the power storage element when an output current of the power conversion unit is equal to or greater than an allowable upper limit current. 5. The power leveling apparatus according to any one of items 1 to 4.   6. The power leveling apparatus according to claim 1, wherein the charge control unit is connected to the AC power source and charges the power storage element. 6.   6. The power leveling device according to claim 1, wherein the charge control unit is connected to an output side of the power conversion unit to charge the power storage element. 6. Equipped with a common power factor correction circuit to which AC power is input,
The power according to any one of claims 1 to 6, wherein an output of the power factor correction circuit is input to a power conversion unit configured by a DC / DC converter and also input to the charge control unit. Leveling device.

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