JP2008187850A - Redundant power supply device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To attain a redundant power supply device that controls so that each output current of both the power supply devices, that are connected in parallel becomes equal. <P>SOLUTION: The redundant power supply device supplies power to a load, while power supply devices are connected in parallel. Each power supply device is provided with a current backflow prevention means arranged at the output stage; a first AD conversion means for converting an output voltage into a digital value so as to make it as an output voltage value; a voltage reference value setting means for setting the digital value, equivalent to the output voltage as an output voltage reference value; a control means for controlling a switch element so as to reduce the difference between the output voltage value and the output voltage reference value; a current detection means for detecting voltage value, by converting an output current into the voltage value; a second AD conversion means for converting the voltage value, detected by the current detection means into a digital value so as to make it as an output current value; a data-transmitting/receiving means for transmitting/receiving the output current value between the power supply devices; and a voltage reference value adjusting means for adjusting the output voltage reference value, according to the difference output current value between the power supply devices. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a dual power supply apparatus that connects power supply apparatuses in parallel to supply power to a load, and more particularly to a dual power supply apparatus that controls the output currents of both power supply apparatuses to be equal.

  When power supply devices are connected in parallel, there are redundancy and output capacity addition. In the case of redundancy, for example, 40 W power supply devices are connected in parallel to set the output capacity to 40 W, so that the necessary power can be supplied and free maintenance can be performed even when one power supply device fails. In the case of output capacity addition, for example, 40 W power supply devices are connected in parallel, the output capacity is 40 W + 40 W = 80 W, and by adding the output capacities of both power supply devices, it is possible to supply power that cannot be supplied by one power supply device. To do.

FIG. 2 is a configuration diagram of a conventional dual power supply apparatus.
A state is shown in which power supplies 1a and 1b are connected in parallel to supply power to a load 40.
Diodes are used as the backflow prevention means 11a and 11b, and the power supply devices 1a and 1b are connected in parallel via the butt diodes. The backflow prevention means 11a and 11b prevent the current of the other power supply device from flowing in. The backflow prevention means 11a, 11b may be a switch for controlling the flow of current in addition to the diode. For example, by using an FET, the loss as the backflow prevention means 11a, 11b can be reduced as compared with the diode.

The power supply devices 1a and 1b are power supply devices having the same configuration, and the configuration of the power supply device 1a will be described.
The analog value, which is the voltage on the anode side of the backflow prevention means (diode) 11a, is converted into a digital value by the first AD conversion means 12a to obtain an output voltage value. The latest value of the output voltage value is stored in the register 21a at regular intervals.

A digital value corresponding to an output voltage to be output as the power supply device 1a is set in the voltage reference value setting means 22a as an output voltage reference value. The output voltage reference value stored as a fixed value in the voltage reference value setting means 22a is read out, temporarily stored, and stored in the rewritable register 23a.
The control unit 24a controls on / off of the switch element 31a of the power unit 30a so that the difference between the output voltage value stored in the register 21a and the output voltage reference value stored in the register 23a becomes zero.

  For example, in the case of an insulating switching power supply system as the power unit 30a, a DC voltage applied to the primary side of the transformer is turned on / off by the switch element 31a, and the voltage induced on the secondary side of the transformer is rectified and smoothed by a rectifier diode and a smoothing capacitor. To do. The output voltage is determined by the ratio between the input voltage and the on / off time of the switch element 31a (duty ratio, duty cycle). The output voltage is stabilized by monitoring the output voltage and controlling the duty at the time of switching.

JP-A-5-219733

  When using power supply units connected in parallel, adjust the output voltage of both power supply units so that they match, but the output voltage of both power supply units varies depending on the environmental temperature, internal heat generation, load conditions, etc. End up.

  When the power supply devices are connected in parallel for the purpose of redundancy, the power supply device having a higher output voltage supplies more output current, and the heat generation of both power supply devices is not uniform. In addition, if the power supply with a higher output voltage fails, the power supply that has been waiting in a no-load state will need to supply the full load instantaneously, causing the voltage fluctuation at that moment to increase, In this case, the output specification of the power supply device may be out of range.

  When using power supply units connected in parallel for the purpose of adding output capacity, if the output voltages of both power supply units do not match, the output will be biased. Therefore, the allowable output capacity of the power supply unit with high output voltage will be exceeded. Therefore, there was a problem that it could not be used as output capacity addition.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to realize a dual power supply apparatus that controls the output currents of both power supply apparatuses connected in parallel to be equal.

In order to achieve such a subject, the present invention is configured as follows.
(1) In a dual power supply device that detects an output voltage and supplies power to a load by connecting in parallel power supply devices that feedback control the switch elements based on the detected voltage.
Backflow prevention means arranged in the output stage to prevent backflow of current;
First AD conversion means for converting an output voltage into a digital value to obtain an output voltage value;
Voltage reference value setting means for setting a digital value corresponding to the output voltage as an output voltage reference value;
Control means for controlling on / off of the switch element so that a difference between an output voltage value by the first AD conversion means and an output voltage reference value by the voltage reference value setting means is small;
Current detection means for detecting the output current by converting it into a voltage value;
A second AD converting means for converting the voltage value detected by the current detecting means into a digital value to obtain an output current value;
Data transmission / reception means for transmitting / receiving an output current value by the second AD conversion means between power supply devices;
Voltage reference value adjusting means for adjusting the output voltage reference value by the voltage reference value setting means in accordance with the differential output current value between the output current value by the second AD converting means and the output current value received by the data transmitting / receiving means When,
Each power supply device is provided with a dual power supply device.

(2) The dual power supply apparatus according to (1), wherein the voltage reference value adjusting means adjusts an output voltage reference value by the voltage reference value setting means from the differential output current value according to a conversion table.

(3) An operation mode setting unit that sets an operation mode of whether the data transmission / reception unit transmits an output current value of the second AD conversion unit to the other power supply device or receives from the other power supply device; The duplex power supply apparatus according to (1) or (2), wherein the power supply apparatus whose operation mode setting means is in the reception mode is adjusted to follow the output voltage of the power supply apparatus in the transmission mode.

(4) The data transmission / reception means of the power supply apparatus in which the operation mode setting means is in the reception mode determines that the other power supply apparatus is not mounted when there is no reception data, and performs adjustment by the voltage reference value adjustment means. The redundant power supply apparatus according to (3), which is not performed.

(5) A diagnostic means for diagnosing whether the output current value by the second AD conversion means and the differential output current value are within a specified value range is provided. A redundant power supply device according to claim 1.

(6) The duplex power supply apparatus according to (5), wherein the diagnosis unit shuts down both power supply apparatuses when the differential output current value falls outside a range of a specified value.

(7) The first and second AD conversion means are composed of the same AD converter, wherein the input destination is switched by a switch, and the output destination is designated accordingly (1) to (6) The redundant power supply device according to any one of the above.

The present invention has the following effects.
The output voltage and output current are converted to digital values, and the output voltage of one power supply device is digitally controlled to follow the output voltage of the other power supply device with an adjustment value corresponding to the difference between the output currents of both power supply devices. As a result, the output currents of both power supply devices can be equalized.

Hereinafter, the present invention will be described in detail with reference to the drawings.
FIG. 1 is a block diagram showing an embodiment of the present invention. The same parts as those in the previous figure are given the same reference numerals, and the description of the same parts as those in the prior art is omitted.
An operation for adjusting the output voltage of the power supply device 1a by following the output voltage of the power supply device 1b will be described.
The output currents of the power supply devices 1a and 1b are detected by the current detection means 51a and 51b, and the output currents are converted into voltage values. As the current detection means 51a and 51b, a current detection resistor is generally used.
An analog value, which is a voltage detected by the current detection means 51a, 51b, is converted into a digital value by the second AD conversion means 52a, 52b to obtain an output current value. The latest value of the output current value is stored in the registers 61a and 61b at regular intervals.

  The data transmission / reception means 62a and 62b can transmit / receive output current values to / from the other power supply device connected in parallel, and transmit the output current value to the other power supply device or from the other power supply device. The operation mode for reception is set by the operation mode setting means 63a and 63b. For example, when the setting value of the operation mode setting means 63a, 63b is “0”, the transmission mode is set, and when the setting value is “1”, the reception mode is set.

  When the operation mode setting means 63a of the power supply apparatus 1a is set to the reception mode and the operation mode setting means 63b of the power supply apparatus 1b is set to the transmission mode, the data transmission / reception means 62a is changed from the data transmission / reception means 62b to the current detection means 51b of the power supply apparatus 1b. The output current value detected by the second AD conversion means 52b and converted to a digital value by the second AD conversion means 52b is received at a fixed period, and the latest value is stored in the register 64a. Thereby, the power supply device 1a can acquire the output current value of both power supply devices 1a and 1b.

The voltage reference value adjusting means 65a receives the output current value of its own power supply device 1a and the output current value of the other power supply device 1b from the registers 61a and 64a, respectively, and outputs the output of its own power supply device 1a according to the difference output current value. An offset amount (adjustment value) for adjusting the voltage is calculated. Thereafter, a value obtained by adding the adjustment value calculated by the voltage reference value adjusting unit 65a to the output voltage reference value stored in the voltage reference value setting unit 22a is stored in the register 23a as an adjusted output voltage reference value.
Here, as a calculation method of the adjustment value by the voltage reference value adjustment unit 65a, a method of reading the adjustment value according to the conversion table of the difference output current value and the adjustment value, or an adjustment value from the difference output current value according to a certain conversion formula. A calculation method is conceivable.

The control unit 24a controls on / off of the switch element 31a of the power unit 30a so that the difference between the output voltage value of the register 21a and the adjusted output voltage reference value stored in the register 23a becomes zero.
As a result, the power supply device 1a whose operation mode setting means is in the reception mode is adjusted to follow the output voltage of the power supply device 1b in the transmission mode, and the output currents of the power supply devices 1a and 1b can be equalized. By equalizing the output currents of the power supply devices 1a and 1b, the heat generation of both power supply devices 1a and 1b becomes uniform, and the life of the power supply devices can be made uniform. It can also be used for the purpose of adding output capacity.

When the power supply device 1a that is in the reception mode is removed from the power supply devices 1a and 1b that are connected in parallel, the power supply device 1b that is in the transmission mode bears all the output current that has been equally borne, and the power supply device 1b Continue to work.
Conversely, when the power supply device 1b in the transmission mode is removed from the power supply devices 1a and 1b connected in parallel, the data transmission / reception means 62a of the power supply device 1a in the reception mode has no reception data. It is determined that the power supply device 1b in the transmission mode is not mounted. At this time, the power supply device 1a does not perform adjustment by the voltage reference value adjusting means 65a, but switches to control with the output voltage reference value of its own voltage reference value setting means 22a, and the output current that has been equally shared is in the reception mode. The power supply apparatus 1a bears all, and the power supply apparatus 1a continues to operate as it is.

  The power supply devices 1a and 1b include diagnostic means 66a and 66b for diagnosing whether or not the output current value is normal. The diagnosing means 66a and 66b monitor whether or not the output current values taken from the registers 61a and 61b are within a specified range, and perform appropriate processing on their own power supply devices 1a and 1b. For example, overcurrent protection can be applied by changing the adjustment values of the voltage reference value adjusting means 65a and 65b so that the output voltage becomes smaller when the output current value exceeds a specified value.

  The diagnosis means 66a and 66b monitor whether the differential output current values of both power supply devices 1a and 1b are within a specified range, and perform appropriate processing on the other power supply devices 1b and 1a. For example, in the power supply device 1a, a differential output current value that is a difference between the output current value of the power supply device 1a stored in the register 61a and the output current value of the other power supply device 1b stored in the register 64a. When the power supply is out of the specified range, both power supply devices can be operated to shut down. As another example, when the power supply device 1a is in the reception mode, the diagnosis unit 66a in the reception mode monitors the output current value of the power supply device 1a and the differential output current value of both the power supply devices 1a and 1b, and the relationship between them. The power supply devices 1a and 1b can be controlled separately or simultaneously based on the signal of the diagnostic means 66a in the reception mode based on the above.

Since the power supply devices 1a and 1b shown in FIG. 1 are digitally controlled power supply devices, a portion that handles digital values can be configured as a function of an MPU (Micro Processing Unit). It may be a DSP (Digital Signal Processor), FPGA (Field Programmable Gate Array) or GA (Gate Array).
In addition, by using an MPU with a built-in AD converter, cost reduction by reducing expensive AD converters, high-density mounting, and speeding up of processing by eliminating communication between the MPU and AD converter are achieved. be able to.

In this embodiment, the case where the first and second AD converters are separate AD converters has been described. However, the first and second AD converters are the same AD converter, and the input destination is a multiplexer or the like. The analog switch may be used to switch the data and specify the data storage destination accordingly.
Further, the method of the power supply device is not limited to the switching power supply, and any power supply device that performs feedback control based on the output is applicable.

It is a block diagram which shows one Example of this invention. It is a block diagram of the conventional duplex power supply device.

Explanation of symbols

11a, 11b Backflow prevention means 12a, 12b First AD conversion means 22a, 22b Voltage reference value setting means 24a, 24b Control means 31a, 31b Switch element 40 Load 51a, 51b Current detection means 52a, 52b Second AD conversion means 62a, 62b Data transmission / reception means 63a, 63b Operation mode setting means 65a, 65b Voltage reference value adjustment means 66a, 66b Diagnosis means

Claims (7)

In the dual power supply apparatus that detects the output voltage and supplies power to the load by connecting the power supply apparatus that feedback-controls the switch element based on the detected voltage in parallel.
Backflow prevention means arranged in the output stage to prevent backflow of current;
First AD conversion means for converting an output voltage into a digital value to obtain an output voltage value;
Voltage reference value setting means for setting a digital value corresponding to the output voltage as an output voltage reference value;
Control means for controlling on / off of the switch element so that a difference between an output voltage value by the first AD conversion means and an output voltage reference value by the voltage reference value setting means is small;
Current detection means for detecting the output current by converting it into a voltage value;
A second AD converting means for converting the voltage value detected by the current detecting means into a digital value to obtain an output current value;
Data transmission / reception means for transmitting / receiving an output current value by the second AD conversion means between power supply devices;
Voltage reference value adjusting means for adjusting the output voltage reference value by the voltage reference value setting means in accordance with the differential output current value between the output current value by the second AD converting means and the output current value received by the data transmitting / receiving means When,
Each power supply device is provided with a dual power supply device.   2. The dual power supply apparatus according to claim 1, wherein the voltage reference value adjusting unit adjusts an output voltage reference value by the voltage reference value setting unit according to a conversion table from the differential output current value.   An operation mode setting unit configured to set an operation mode of whether the data transmission / reception unit transmits an output current value of the second AD conversion unit to the other power supply device or receives from the other power supply device; 3. The duplex power supply apparatus according to claim 1, wherein the power supply apparatus whose means is in the reception mode is adjusted so as to follow the output voltage of the power supply apparatus in the transmission mode.   The data transmission / reception means of the power supply apparatus in which the operation mode setting means is in the reception mode determines that the other power supply apparatus is not mounted when there is no reception data, and does not perform adjustment by the voltage reference value adjustment means. The duplex power supply apparatus according to claim 3.   The duplex according to any one of claims 1 to 4, further comprising diagnostic means for diagnosing whether the output current value by the second AD converting means and the differential output current value are within a specified value range. Power supply.   6. The dual power supply apparatus according to claim 5, wherein the diagnosis unit shuts down both power supply apparatuses when the differential output current value is out of a specified value range.   7. The configuration according to claim 1, wherein the first AD converter and the second AD converter are composed of the same AD converter, the input destination is switched by a switch, and the output destination is designated accordingly. The redundant power supply described.

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