JP2014143794A - Power supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power supply device that stably supplies a current required by a load device and operates power supply units continuously at a current value implementing a desired load factor.SOLUTION: A power supply device 2 is connected to a power supply 1, a storage battery 8 and a load device 9, and the power supply device 2 includes one or more power supply units 3, a current sensor 4, a voltage sensor 5, a measurement section 6 and a control section 7. A combination of an output current of the power supply device and a charging/discharge current of the storage battery can stably supply a current required by the load device, and operate the power supply units continuously at a current value implementing a conversion-efficient load factor and operate the power supply device with high efficiency. This can feed high reliability power even to a load device with a great load power variation with high efficiency.

Description

  The present invention relates to a highly efficient power supply apparatus that supplies power to a server, a communication apparatus, or the like that requires an uninterruptible power supply.

  In recent years, the power consumption of information devices such as servers used in data centers has greatly changed according to the amount of load. For this reason, the operation time of the power supply device at an efficient load factor (output capacity of the power supply device / maximum output capacity of the power supply device) is reduced, and as a result, the power conversion efficiency of the power supply device is reduced. As a countermeasure, it has been proposed to use a method of switching the number of operating power supply units of a power supply device in accordance with fluctuations in load power in a power supply device including a plurality of power supply units.

JP 2007-135373 A

  However, when the power fluctuation of the load device is small relative to the output power capacity of the power supply unit and the power fluctuation of the load device falls within the threshold for switching the number of power supply units to be operated, the power supply follows the power fluctuation of the load device. Conversion efficiency cannot be improved by switching the number of operating units.

  Even when the power consumption of the load device is extremely small, that is, when the power consumption of the load device is smaller than the threshold for switching the number of operating power supply devices to 1, the conversion efficiency can be changed by changing the number of operating power supply units. Cannot be improved.

  Thus, in the conventional technology, when the power of the load device is small or when the power fluctuation of the load device is small compared to the power supply unit capacity of the power supply device, it is difficult to improve the efficiency by controlling the number of operating power supply units. is there.

  The present invention has been made in view of such problems, and an object of the present invention is to stably supply the current required by the load device and to always supply the power supply unit with a desired load factor. It is in providing the power supply device which can be drive | operated by.

  In order to solve the above-mentioned problems, the present invention is a power supply device, which converts power to a desired voltage or current and outputs the power, and can switch the number of operating units, and the power supply unit A storage battery connected to an output terminal; a current sensor for measuring an output current from the power supply unit and the storage battery to a load device; a voltage sensor for measuring a voltage of the storage battery; a current value measured by the current sensor; A control unit that controls the number of operating power supply units and the output control of each power unit based on the voltage value measured by the voltage sensor, and the control unit stops at least one of the power units. When the current required by the load device can be output and the storage battery can be charged or discharged, the power supply unit is set to a desired load factor. The number of power supply units operated is controlled and the power supply unit to be operated is determined so that the current as the sum of the output current when the current is controlled and the charge / discharge current of the storage battery is equal to the current required by the load device. It is characterized by current control.

  According to a second aspect of the present invention, in the power supply device according to the first aspect, the control device requests the power supply unit when at least one of the power units is stopped and the storage battery can be charged. The number of power supply units operated is set so that the output current when the constant current control is performed so that the load factor is greater than the current required by the load device and the number of power supply units operated is minimized. When the storage battery is charged with surplus current, when at least one of the power units is stopped and the storage battery is dischargeable, the power supply unit is controlled at a constant current so as to have a desired load factor. The number of operating power supply units is set so that the output current is smaller than the current required by the load device and the number of operating power supply units is the largest. The current lack characterized by discharging from the storage battery.

  According to a third aspect of the present invention, in the power supply device according to the first or second aspect, the control unit needs to be charged when a voltage value measured by the voltage sensor is lower than a predetermined first threshold value. If it is determined that the voltage is measured and the voltage value measured by the voltage sensor is higher than a predetermined second threshold, it is determined that the battery can be discharged.

  According to a fourth aspect of the present invention, in the power supply device according to the third aspect, the control unit stops at least one of the power units, and the voltage value measured by the voltage sensor is the first power unit. When larger than a threshold and smaller than the second threshold, the number of operating power supply units is maintained, and the current required by the load device is the sum of the output current of the power supply units and the charge / discharge current of the storage battery. The power supply unit is controlled at a constant current so as to be equal to.

  According to a fifth aspect of the present invention, in the power supply device according to any one of the first to fourth aspects, the control unit includes a communication unit that controls communication with an external network in place of the control unit. The apparatus can be used as the control unit.

  The present invention provides an effect of stably supplying a current required by a load device and allowing the power supply unit to be operated at a current value that always provides a desired load factor.

It is a block diagram of the power supply device which concerns on one Embodiment of this invention. It is a power supply device operation number determination table used in the power supply device which concerns on one Embodiment of this invention. It is a control flowchart used in the power supply device which concerns on one Embodiment of this invention. It is a figure which shows the load-conversion efficiency characteristic of a power supply unit. It is a driving | operation power supply unit determination table used in the power supply device which concerns on one Embodiment of this invention. It is a time chart in case there is no load fluctuation | variation which shows operation | movement of the power supply device which concerns on one Embodiment of this invention. It is a time chart in case there exists load fluctuation | variation which shows operation | movement of the power supply device which concerns on one Embodiment of this invention.

  The present invention improves conversion efficiency by utilizing charge / discharge of a storage battery in addition to control for switching the number of operating power supply units in accordance with the output current of the power supply device. That is, at the same time as performing control to switch the number of operating power supply units in accordance with load power fluctuation, the power supply unit is operated at a constant current with an output current value that increases the conversion efficiency of the power supply unit.

  Further, when the output current of the power supply device is insufficient with respect to the required current of the load device, the discharge current of the storage battery supplements the insufficient current to supply the necessary current to the load device. On the other hand, when the power supply device output current is larger than the required current of the load device, the power supply device supplies current to the load device and simultaneously charges the storage battery with the surplus current.

  As described above, by combining the output current of the power supply device and the charge / discharge current of the storage battery, the current value required for the load device can be stably supplied and the power supply unit always has a load factor with a high conversion efficiency. The power supply device can be operated with high efficiency. For this reason, it is possible to supply highly reliable power with high efficiency even to a load device having a large load power fluctuation.

  Hereinafter, embodiments of the present invention will be described in detail.

  FIG. 1 shows a configuration diagram of a power supply device according to an embodiment of the present invention. The power supply device 2 of the present invention is connected to a power supply 1, a storage battery 8, and a load device 9. The power supply device 2 includes one or more power supply units 3, a current sensor 4, a voltage sensor 5, a measuring unit 6, and a control unit 7. It is composed of In the present embodiment, the control unit 7 is built in the power supply device 2, but a communication device is mounted on the power supply device 2 instead of the control unit 7, and an external device is used as the control unit via the communication device. You can also.

  The power source 1 is an energy source such as a commercial power source or an emergency generator, a fuel cell, a wind power generation, and a solar cell.

  The power supply unit 3 has a function of converting electric power from the power supply 1 into electric power of a desired voltage / current. Further, the power supply unit 3 receives a control signal from the control unit 7, thereby turning on and off the power supply unit 3, switching between a constant voltage operation and a constant current operation method of the power supply unit 3, The set value of output voltage and output current can be changed.

  The current sensor 4 and the voltage sensor 5 each have a function of detecting the output current of the power supply device 2 and the voltage of the storage battery 8 and outputting them as analog signals. Assume that the output current of the power supply device 2 is equal to the current required by the load device 9 connected to the power supply device 2.

  The measuring unit 6 has a function of acquiring detection values of the current sensor 4 and the voltage sensor 5 and converting the acquired analog signal into analog / digital conversion. Further, it has a function of inputting the converted digital signal to the control unit 7.

  The control unit 7 includes the power supply device operation number determination table shown in FIG. 2 for determining the optimum operation number of the power supply units 3, and calculates the optimum operation number of the power supply units 3 by referring to this table. Based on the storage battery voltage value and power supply device output current value input from the measurement unit 6, the control unit 7 refers to the control flowchart of FIG. 3 and the control table of FIG. The number of operating units and the output current are determined. Further, by referring to the operation power supply unit determination table of FIG. 5, the function of determining the power supply unit 3 to be operated or stopped based on the number of operation determined by the above method and sending a control signal to each power supply unit 3 is provided. Have.

  The operation of the power supply device will be described based on the control flowchart of FIG.

  As an example, it is assumed that the power supply device 2 includes eight power supply units 3. Further, the output current capacity of each power supply unit 3 is 100 A, and the conversion efficiency of the power supply unit is maximized when the load factor is 60%, as shown in FIG. .

  First, it is assumed that all the power supply units 3 are operating in the constant voltage mode before the operation number control is started, and the control unit 7 sets the operation mode coefficient to N = 0 (S101). Here, the operation mode coefficient of N = 0 indicates a state in which the number control of the power supply units is not performed.

Next, in the control unit 7, the current sensor 4 detects the output current of the power supply device 2 (S102), and the output current value _Iload and the specified current value _In0 of the power supply device 2 converted into a digital signal by the measurement unit 6 are obtained. Compare (S103). The specified current value I _n0 is a current setting threshold at which the power supply device 2 switches the power supply units 3 to all-unit operation.

When I _load > I _n0 , the load factor of the power supply unit 3 is sufficiently high and the conversion efficiency of the power supply unit 3 is also high. Therefore, the number of operating power supply units 3 is not controlled (S109), and the power supply unit 3 is kept at a constant voltage. The mode is operated (S110). On the other hand, when I _n0 > I _load , it is possible to improve the load factor of the power supply unit 3 by controlling the number of operating power supply units 3. Therefore, the process for determining the method for controlling the number of operating power supply units 3 is determined. Proceed to

When I _n0 > I _load , the control unit 7 detects the voltage of the storage battery 8 by the voltage sensor 5 (S104), and the voltage value V _batt of the storage battery 8 converted into a digital signal by the measurement unit 6 and the storage battery threshold maximum The voltage V _H is compared with the storage battery threshold minimum voltage V _L (S104). When V _batt > V _H , the operation mode in which the number of operating the power supply units 3 and the output current are controlled so that the output of the power supply device 2 is smaller than the required current of the load device 9 and the storage battery 8 is discharged. The coefficient is switched to N = 1 (discharge mode) (S106). On the other hand, when V _L > V _batt , the number of operating power units 3 and the output current are controlled so that the output current of the power supply device 2 satisfies the required current of the load device 9, and the storage battery 8 is charged. Therefore, the operation mode coefficient N is switched to 2 (charge mode) (S108). In the case where V _H > V _batt > V _L , the value of the operation mode coefficient N is not changed, and the previous operation mode coefficient N is maintained (S107).

  When the processes of S106 and S108 are performed, the control unit 7 determines the number of operating power units 3 and the control method of the output from the current operation mode coefficient N (S111). When the operation mode determination coefficient N = 0, the power supply unit controller 7 operates in a constant voltage mode in which all the power supply units 3 mounted on the power supply device output a rated voltage. On the other hand, when the operation mode determination coefficient N = 1 or N = 2, the control unit 7 refers to the power supply unit operation number control table in FIG. 2 and determines the operation number and the output current value when operating in the constant current mode. decide.

For example, when the operation mode determination coefficient N = 1 and the output current value I _load of the power supply device 2 is 250 [A], the four power supply units 3 are set to operate in the constant current mode of the output current 60 [A]. Become. That is, when the storage battery 8 can be discharged, the power supply unit 3 is set so that the sum of the output currents of the power supply unit 3 operated at a load factor with good conversion efficiency is maximized in a range smaller than the output current value _Iload of the power supply device 2. Set the number of operating units.

On the other hand, when the operation mode determination coefficient N = 2 and the output current value I _load = 250 [A] of the power supply device 2 is set, the five power supply units 3 are set to operate in the constant current mode of the output current 60 [A]. Become. That is, when the storage battery 8 can be charged, the power supply unit 3 is such that the sum of the output currents of the power supply unit 3 operated at a load factor with good conversion efficiency is minimized in a range larger than the output current value _Iload of the power supply device 2. Set the number of operating units.

  After performing the processing of S110 and S111, the control unit 7 determines the power supply unit 3 to be operated and the power supply unit 3 to be stopped with reference to FIG. 5, and transmits a control signal to each power supply unit 3 (S112). Each power supply unit 3 is turned on / off of the operation of the power supply unit 3 based on the control signal from the control unit 7, the operation method of the constant voltage operation and the constant current operation of the power supply unit 3, the output voltage and output of the power supply unit 3 Switch the current.

By repeating the above control at regular intervals, the power supply device can always be operated with high efficiency. Note that the specified current value to be compared with the output current value I _load is different depending on the operation method of the power supply unit 3. When the voltage of the power supply unit is a constant voltage control, it is compared with the output current value I _load using I _n0 power unit 3 is the current set threshold to switch to full volume operated as prescribed current value (S103). On the other hand, in the case of constant current control after shifting to the discharge mode or charge mode, the specified current value is output using In ₁ which is the specified current value for constant current control, instead of In _{0 for} constant voltage control. Comparison with the current value I _load is performed (S114).

Next, a change in operation due to the presence or absence of load fluctuation will be described. FIG. 6 shows a time chart when there is no load fluctuation, and FIG. 7 shows a time chart when there is a load fluctuation. In FIG. 6, although the load device 9 is constant, the output current value I _load changes because the storage battery voltage V _batt fluctuates. The storage battery voltage V _batt is assumed to be equal to the voltage V _load at the output terminal of the power supply device 2.

First, a case where there is no load fluctuation as shown in FIG. 6 will be described. In the initial state, it is assumed that the power supply device 2 is operating in the discharge mode.
(1) Since the storage battery voltage V _batt becomes equal to or lower than the storage battery threshold voltage V _{L at} times T ₁ and T ₃ , the number of operating power supply units 3 is increased and the storage battery is charged.
(2) Since the storage battery voltage V _batt becomes the upper limit storage battery threshold voltage V _H at times T ₂ and T ₄ , the number of operating power supply units 3 is decreased and discharged from the storage battery.

Next, a case where there is a load variation as shown in FIG. 7 will be described. The control of the number of operating power supply units 3 when there is load power fluctuation is as follows. It is assumed that the initial state is operating in the discharge mode of the storage battery.
(1) At time T ₁ , the load current I _load is increased and thus exceeds the set threshold value. Therefore, the number of operating power supply units is increased.
(2) Since the storage battery voltage V _batt has reached the storage battery threshold V _{L at} time T ₂ , the power supply unit is increased and the storage battery is charged.
(3) Since the storage battery voltage V _batt has reached the storage battery threshold V _{H at} time T ₃ , the power supply unit is decreased and discharged from the storage battery.
(4) At time T ₄ , the load current I _load is decreased, so that the value falls below the set threshold value.
(5) Since the storage battery voltage V _batt has reached the storage battery threshold V _{L at} time T ₅ , the power supply unit is increased and the storage battery is charged.
(6) Since the storage battery voltage V _batt becomes the storage battery threshold V _{H at} time T ₆ , the power supply unit is decreased and discharged from the storage battery.
(7) At time T ₇ , since the load current I _load is increased and thus exceeds the set threshold, the number of units of the power supply device is increased.

DESCRIPTION OF SYMBOLS 1 Power supply 2 Power supply device 3 Power supply unit 4 Current sensor 5 Voltage sensor 6 Measurement part 7 Control part 8 Storage battery 9 Load apparatus

Claims (5)

A plurality of power supply units that can convert electric power into electric power of a desired voltage or current and output, and switch the number of operating units;
A storage battery connected to the output end of the power supply unit;
A current sensor for measuring an output current from the power supply unit and the storage battery to a load device;
A voltage sensor for measuring the voltage of the storage battery;
A control unit that controls the number of operating power units and the output control of each power unit based on the current value measured by the current sensor and the voltage value measured by the voltage sensor, and the control unit includes: When at least one of the power units is stopped and the current required by the load device can be output, and the storage battery can be charged or discharged, the power supply unit is set to a desired load factor. The number of operating power supply units is controlled and the power supply unit to be operated is controlled so that the current as the sum of the output current and the charge / discharge current of the storage battery when constant current control is performed is equal to the current required by the load device A power supply device characterized by constant current control. The control device includes:
When at least one of the power units is stopped and the storage battery is rechargeable, the output current when the power supply unit is controlled at a constant current so as to achieve a desired load factor is the current required by the load device Larger than that, and setting the number of operating power supply units so that the number of operating power supply units is minimized, and charging the storage battery with surplus current,
When at least one of the power units is stopped and the storage battery can be discharged, the output current when the power supply unit is controlled at a constant current so as to achieve a desired load factor is the current required by the load device 2. The power supply device according to claim 1, wherein the number of operating power supply units is set so as to be smaller and the number of operating power supply units is the largest, and an insufficient current is discharged from the storage battery.   The control unit determines that charging is necessary when the voltage value measured by the voltage sensor is lower than a predetermined first threshold value, and the voltage value measured by the voltage sensor is a predetermined second threshold value. 3. The power supply device according to claim 1, wherein the power supply device determines that the discharge is possible when the height is higher. 4.   When at least one of the power units is stopped and the voltage value measured by the voltage sensor is larger than the first threshold value and smaller than the second threshold value, the control unit operates the number of power supply units. And constant current control of the power supply unit so that the current as the sum of the output current of the power supply unit and the charge / discharge current of the storage battery becomes equal to the current required by the load device. Item 4. The power supply device according to Item 3. The controller is
The power supply apparatus according to claim 1, further comprising a communication unit that controls communication with an external network instead of the control unit, and an external device can be used as the control unit.

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