JP3602103B2 - Power supply parallel connection control method and device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a power supply parallel connection control method and apparatus, and in particular, to prevent a current balance between a 0 system and a 1 system power supply from being disrupted due to a characteristic variation of an OR diode for parallel connection when two power supplies of a 0 system and a 1 system are connected in parallel. And a control method for performing the control.
[0002]
[Prior art]
Conventionally, in a power supply device in which two power supplies of system 0 and system 1 are connected in parallel by an OR diode, the output voltage of each power supply, that is, the input voltage of the OR diode is adjusted to the same voltage, and then the power is supplied to the load by connecting in parallel. Thus, the current between the two power sources is made equal.
[0003]
The purpose of balancing the current between the two power supplies is that if the load current of the power supply becomes unbalanced and the load current is biased to one of the power supplies, heat is relatively concentrated on this power supply and the internal power supply As the temperature rises, the components used deteriorate faster, and the reliability decreases, such as occurrence of a failure or shortening of the service life. For this reason, it is necessary to balance the current between the two power supplies and operate the two power supplies under the same conditions. The purpose of the OR diode is to prevent the output voltages from being applied to and interfere with each other in the output circuit of the other power supply when the outputs are directly connected in parallel.
[0004]
As described above, in order to balance the current between the two power supplies, it is necessary to make the output voltages of the two power supplies uniform, but if the output voltage of one power supply becomes relatively high, the load current increases on the power supply side. And become unbalanced. However, even if the output voltages of the two power supplies are equalized in the initial setting, there is a problem that imbalance occurs when a difference occurs in the output voltage due to a change in environmental conditions or aging.
[0005]
To solve this problem, there is a technique disclosed in Japanese Patent Application Laid-Open No. 62-73315. FIG. 4 is a circuit diagram showing this conventional example. In the figure, in a power supply device in which the output sides of power supply modules 44 and 45 are connected in parallel by diodes 48 and 49 to supply power to a load 50, DC output voltages 46 and 47 are detected, and a difference voltage is generated between the detected voltages. Sometimes, the voltage of one power supply module 45 is controlled, and the difference voltage is minimized to balance the current.
[0006]
Hereinafter, this operation will be described in some detail. A voltage obtained by dividing the DC output voltage 46 by the resistors 52 and 53 and a voltage obtained by dividing the DC output voltage 47 by the resistors 54 and 55 are compared by a differential amplifier 56. When the output voltage 47 is high, the differential amplifier 56 A signal is output to the output to drive the driver circuit unit 57. At this time, when the detection disconnection switch 58 is on, the photocoupler 61 connected from the separate power supply 59 through the resistor 60 operates to supply the detection signal 62 to the power supply module 45. Using the detection signal 62, the DC output voltage 47 of the power supply module 45 can be forcibly reduced. Thereby, the difference between the DC output voltages 46 and 47 is reduced, and the imbalance of the load current is reduced. The resistor 63 is a current limiting resistor.
[0007]
[Problems to be solved by the invention]
As described above, in the conventional example, the output voltage of one power supply is controlled so as not to generate a difference voltage between the output voltages of the two power supplies, so that the current balance is maintained for a time. However, the voltage actually applied to the load is a voltage obtained by subtracting the on-voltages of the OR diodes connected in parallel on the output side.There is no problem if the ON voltages of both OR diodes are the same. There is a problem that current balance is lost due to variations and temperature fluctuations.
[0008]
FIG. 3 is a characteristic diagram showing a temperature characteristic of an on voltage of a general diode. FIG. 3 shows the characteristics when the current is constant, for example, at the rated current. As shown in the figure, the ON voltage causes a difference voltage between the diodes A and B due to temperature fluctuation. That is, at an ambient temperature of 25 ° C., the difference voltage is 0 V, but at + 60 ° C., a difference voltage of 0.1 V is generated.
[0009]
When this diode is used as an OR diode, the current on the diode A side whose ON voltage is lower by 0.1 V increases to correct the voltage difference of 0.1 V, while the current on the diode B side lowers by 0.1 V decreases. The on-voltage operates so that the voltage difference disappears. Therefore, a current imbalance occurs between the two power supplies.
[0010]
More specifically, referring to FIG. 4, it is assumed that the diodes A and B of FIG. First, at an ambient temperature of 25 ° C., the output voltages 48 and 49 are initialized to the same voltage by the output voltage adjusting functions of the power supply modules 44 and 45, respectively. Thereafter, when a difference voltage is generated between the output voltages, the difference voltage is controlled to be minimized as described above. When the ambient temperature reaches + 60 ° C., the output voltages 48 and 49 are stabilized at the same voltage, so that the ON voltages of the diodes 48 and 49 must be the same voltage. However, as shown in FIG. 3, the on-voltages of the diodes 48 and 49 have a difference of 0.1 V under the same condition at + 60 ° C., and the current changes after all to make this difference zero. That is, the current flowing through the diode 48 increases, and the current flowing through the diode 49 decreases. That is, the current of the power supply module 44 increases and the power supply module 45 decreases, and the current balance is lost. Generally, since the operating resistance of a diode is small, the change in the current increases and decreases, and its influence cannot be ignored. Further, the characteristics of the diode have individual differences, and the current balance is lost due to the variation for the same reason as described above.
[0011]
As described above, even if the output voltages of the two power supplies are adjusted to be the same, there is a problem that the current balance is lost due to the characteristics of the OR diode, particularly the temperature fluctuation.
[0012]
[Means for Solving the Problems]
In the power supply parallel connection control method of the present invention, the output sides of the 0-system and 1-system DC power supplies are connected in parallel via an OR diode, and the ambient temperature of the OR diode is detected. The on-voltage of the OR diode with respect to the detected temperature is read from the temperature table, and the value of the read-on voltage is subjected to arithmetic processing, and the DC power is controlled based on the calculation result to control the 0-system and 1-system DC power. The output voltage via the OR diode is made equal .
[0013]
The arithmetic processing may determine a difference between the ON voltages of the two or diodes read from the temperature table, and increase or decrease one of the output voltages of the DC power supply by the difference voltage.
[0014]
Alternatively, in the arithmetic processing, an on-voltage at a temperature point at which the on-voltage of the or-diode is equalized is obtained in advance from the temperature table as a reference on-voltage, and the on-voltage is obtained from the on-voltage of the or-diode read from the temperature table. The reference ON voltage may be subtracted, and the output voltage of the DC power supply corresponding to the difference voltage as a result of the subtraction may be decreased .
[0015]
A specific power supply parallel connection control device according to the present invention includes: a 0-system and a 1-system OR diode in which the outputs of the 0-system and 1-system DC power sources are respectively received on the anode side and the cathode sides are connected in parallel; A temperature sensor for detecting an ambient temperature, a 0-system temperature table and a 1-system temperature table in which a change in ON voltage with respect to a change in the ambient temperature of the OR diode is converted into data, and a temperature sensor corresponding to the detected temperature output from the temperature sensor. The on-voltage of the OR diode is read out from the temperature table at a predetermined cycle, and the ON-voltage data read out is calculated by a predetermined formula to equalize the output voltage of the DC power supply via the OR diode. a calculation control circuit to output system and 1-system control data, respectively, corresponding to the control data to said DC power supply And a 0-system and 1-system power supply regulator for outputting each D / A conversion in that an analog output control signal.
[0016]
The voltage regulator may have a function of manually varying the output control signal and adjusting the output voltage of the corresponding DC power supply.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a first embodiment of the present invention, and FIG. 3 is a characteristic diagram showing characteristics of the diode of FIG. First, in FIG. 1, the 0-system DC power supply 2 and the 1-system DC power supply 3 are in a redundant relationship, and are connected in parallel by the power supply parallel connection control device 1 to supply power to the common load 4.
[0021]
The 0-system and 1-system DC power supplies 2 and 3 are switching power supplies each having a control function of internally setting an output voltage to a predetermined value and automatically stabilizing the set voltage, and a control signal from the outside. It has an external control terminal that receives 101 and 102 and adjusts the output voltage. Normally, the load 4 is operated with a load current of 50% or less of the rated current.
[0022]
The configuration of the power supply connection control device 1 of the present invention will be described. The diodes 11 and 12 of the 0-system and the 1-system which receive the outputs of the 0-system and 1-system DC power supplies 2 and 3 on the anode side and the cathode side are connected in parallel, and a temperature sensor 13 for detecting the ambient temperature of the diodes 11 and 12 , The temperature tables 15 and 16 of the 0-system and the 1-system in which the change in the on-voltage of the diode with respect to the change in the ambient temperature of the diodes 11 and 12 is converted into data, respectively, and the diode 11 corresponding to the detected temperature output from the temperature sensor 13. An operation control circuit 14 which reads out the on-voltages 12 from the temperature tables 15 and 16 at predetermined intervals and performs an arithmetic processing on the on-voltage data read out by a predetermined calculation formula and outputs them as control data 103 and 104 for the 0-system and 1-system, respectively. When the analog control signal 10 of the corresponding control data 104 and 103 in the 0-system and 1-system DC power supply 2 , Constitute a power supply regulator 17, 18 0-system and 1-system to output each D / A conversion to 102.
[0023]
Next, the operation of this device will be described. First, the 0-system and 1-system DC power supplies 2 and 3 are individually set to their respective outputs V ₀ and V ₁ at a predetermined voltage, for example, 48 V, by an internal output voltage adjusting function. The initially set voltage of 48 V is automatically stabilized and fixed by an internal control function with respect to subsequent fluctuations in input, load, temperature, and the like.
[0024]
Next, when the outputs of the 0-system and 1-system DC power supplies 2 and 3 are connected in parallel by diodes 11 and 12 to start supplying power to the load 4, at this time, if the temperature is 25 ° C. shown in FIG. Since the on-voltages Vd ₀ and Vd ₁ are the same voltage, that is, 0.7 V, the load voltage Vc is 47.3 V.
[0025]
Assuming that the ambient temperature changes to + 60 ° C. from this state, if the diodes 11 and 12 are the diodes A and B in FIG. 3, the on-voltages are Vd ₀ = 0.5 V and Vd ₁ = 0.6V. However, in actual operation, the output voltage V0, V1 are both fixed to 48V, _Vd current of the current of the diode 11 is increased diode 12 decreases 0 ₌ Vd 1 ₌ 0.5~0.6V To stabilize. However, since the current balance will be lost if this state is maintained, the control described below is performed in this device.
[0026]
When a temperature of + 60 ° C. is detected by the temperature sensor 13, the arithmetic and control circuit 14 receives this detection signal and outputs the ON voltage Vd of the diodes 11 and 12 at + 60 ° C. to the temperature tables 15 and 16 of the 0 system and the 1 system. ₀ and Vd ₁ are read, and Vd ₀ −Vd ₁ is subtracted internally to calculate the difference voltage.
[0027]
That is, since Vd ₀ = 0.5 V and Vd ₁ = 0.6 V, the difference voltage is −0.1 V. This data is sent to the power supply adjuster 17, where it is D / A converted, converted into a control signal 101 of a predetermined signal format, and applied to the external control terminal of the 1-system DC power supply 3. 1 system DC power supply 3 is controlled to increase the output voltages _{V 1} through the control signal 101 only 0.1V is performed. Therefore, the load voltage Vc is 48 V (V ₀ ) −0.5 V (Vd ₀ ) = 47.5 V or 48.1 V (V ₁ ) −0.6 V (Vd ₁ ) = 47.5 V.
[0028]
On the other hand, when the ambient temperature changes to 0 ° C., the difference voltage becomes +0.1 V, so that V ₁ is controlled to decrease by 0.1 V. In this way, the difference between the ON voltages of the diodes 11 and 12 is compensated by controlling the output voltage of the power supply to maintain the current balance.
[0029]
The above-described arithmetic control method holds only the current balance, but the arithmetic control method described below can also compensate for the absolute value of the load voltage, and the circuit becomes somewhat complicated. However, this method may be used. The arithmetic control circuit 14 obtains a temperature point at which the on-voltages of the diodes 11 and 12 are equal from each other in the temperature tables 15 and 16; The reference ON voltage 0.7V is subtracted from the ON voltages of the OR diodes 11 and 12 read from the temperature tables 15 and 16 at the time of 0 ° C., in this case, 0.5V and 0.6V, and the difference voltage −0. The output voltages V ₀ and V ₁ of the 0-system DC power supply 2 and the 1-system DC power supply 3 corresponding to 2 V and −0.1 V are controlled via power supply adjusters 17 and 18, respectively.
[0030]
Since the power supply adjusters 17 and 18 have a function of manually varying the control signals 101 and 102, the power supply adjusters 17 and 18 perform adjustment at the time of initial setting, for example, when there is an individual difference in the on-voltage of the diodes 11 and 12. Adjustment is possible.
[0031]
That is V0 = 48-0.2 = 47.8V, the V 1 = 48-0.1 = 47.9V. Accordingly, the load voltage VC = 47.8 (V0) -0.5 (Vd0) = 47.3 V or VC = 47.9 (V1) -0.6 (Vd1) = 47.3 V, which is 47.3 V of the initial setting. No change compared.
[0032]
Next, a second embodiment of the present invention will be described with reference to FIG. In this embodiment, the arithmetic control method is simplified as compared with FIG. 2, the power supply parallel connection control device 5 of the present invention detects the ambient temperature of diodes 51 and 52 for connecting the output side of the 0-system DC power supply 2 and the 1-system DC power supply 3 in parallel. The cooling air volume of the fan 55 for the OR diodes 51 and 52 is controlled so as to be constant at a predetermined reference temperature, for example, 25 ° C. shown in FIG. The reference temperature is an ambient temperature of 25 ° C. when the on-voltages of the diodes 51 and 52 are equal, and this temperature is maintained to balance the currents of the power supplies 2 and 3.
[0033]
This device receives the outputs of the 0-system and 1-system DC power supplies 2 and 3 on the anode side, respectively, and detects the 0-system and 1-system diodes 51 and 52 that connect the cathode side in parallel, and the ambient temperature of the diodes 51 and 52. A temperature sensor 53, a fan 55 for cooling the diodes 51 and 52, and a control circuit 54 for inputting the temperature detected by the temperature sensor 53 and controlling the number of revolutions of the fan 55 so that the detected temperature becomes a predetermined reference temperature. It consists of:
[0034]
In the example shown in FIG. 3, the present device cannot be controlled in a temperature range below the ambient temperature + 25 ° C. However, since the ambient temperature of the diode generally becomes higher than the ambient temperature outside the device due to a rise in the temperature inside the device. The control range expands downward by the amount of the temperature rise. That is, if the internal temperature rises by 10 ° C., it is possible to control the temperature up to + 15 ° C., and practicality is hardly impaired.
[0035]
【The invention's effect】
As described above, the power supply parallel connection control device of the present invention compensates for the temperature fluctuation of the ON voltage of the OR diode by adjusting the output voltage of the power supply, or keeps the ambient temperature of the OR diode at a predetermined reference temperature. Therefore, there is an effect that it is possible to reliably prevent the current balance of the power supply from being lost due to the temperature fluctuation of the ON voltage of the OR diode. Further, there is an effect that the fluctuation of the load voltage due to the fluctuation of the ON voltage of the OR diode due to the temperature can be compensated at the same time.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a first embodiment of the present invention.
FIG. 2 is a block diagram showing a second embodiment of the present invention.
FIG. 3 is a characteristic diagram showing temperature characteristics of a diode.
FIG. 4 is a block diagram showing a conventional example.
[Explanation of symbols]
1, 5 power supply parallel connection control device 20 0 system DC power supply 3 1 system DC power supply 4 Load 11, 12, 51, 52 Diode 13, 53 Temperature sensor 14 Operation control circuit 15, 16 Temperature table 17, 18 Power supply regulator 54 Control Circuit 55 fan

Claims (5)

The output sides of the 0-system and 1-system DC power supplies are connected in parallel via an OR diode, the ambient temperature of the OR diode is detected, and the OR diode for each detected temperature is obtained from a temperature table of the OR diode prepared in advance. Is read, and the value of the read ON voltage is subjected to arithmetic processing. The DC power is controlled based on the result of the arithmetic so that the output voltages of the 0-system and 1-system DC power through the OR diode are made equal. And a power supply parallel connection control method. 4. The method according to claim 3, wherein the calculating process calculates a difference between the on-voltages of the two or diodes read from the temperature table, and increases or decreases one of the output voltages of the DC power supply by the difference voltage. 2. The power supply parallel connection control method according to 1. The arithmetic processing is determined in advance from the temperature table as an on-voltage at a temperature point at which the on-voltage of the ore diode is equal to the reference on-voltage, and the on-voltage is obtained from the on-voltage of the ore diode read from the temperature table. 2. The power supply parallel connection control method according to claim 1, wherein the reference ON voltage is subtracted, and the output voltage of the DC power supply corresponding to the difference voltage of the subtraction result is reduced. 0-system and 1-system OR diodes receiving the outputs of the 0-system and 1-system DC power supplies on the anode side and the cathode side connected in parallel, a temperature sensor for detecting the ambient temperature of the OR diode, and the periphery of the OR diode A 0-system temperature table and a 1-system temperature table in which the change of the on-voltage with respect to the temperature change is converted into data, respectively, and the on-voltage of the OR diode corresponding to the detected temperature output from the temperature sensor is obtained at predetermined intervals from the temperature table. An arithmetic and control circuit for arithmetically processing the read on-voltage data according to a predetermined formula to output 0-system and 1-system control data for equalizing the output voltage of the DC power supply via the OR diode, respectively. And D / A converting the control data into an analog output control signal corresponding to the DC power supply. Which supply the parallel connection controller, characterized in that it comprises a 0-system and 1-system power regulator output. The power supply parallel connection control device according to claim 4, wherein the voltage regulator has a function of manually varying the output control signal and adjusting the output voltage of the corresponding DC power supply.

Images