Load Sharing Control Device

Abstract

A load sharing control device according to one embodiment of the present invention includes a load sharing control device included in each of a plurality of power supply devices connected in parallel to a load, the load sharing control device including: a first control unit configured to generate a first control signal for controlling the output current of the power supply device using an output current of the power supply device and a current of a load share bus; and a second control unit configured to generate a second control signal for controlling the output voltage of the power supply device using a target voltage of the power supply device, a feedback voltage fed back from the output voltage of the power supply device, and a control voltage based on the first control signal of the first control unit, wherein the first control unit generates the first control signal to make the output current the same as the current of the load share bus and limits the output current to below a critical current.

Description

Technical Field

[0001] The present invention relates to a load sharing control device, and more specifically, to a load sharing control device and a load sharing control circuit capable of power derating.

Background Art

[0002] Generally, a power supply system is configured by connecting a plurality of power supply devices in parallel in order to stably supply power. When using a plurality of power supply devices, there are advantages in terms of heat generation, reliability, redundancy, and modularity compared to using a single power supply device.

[0003] A power supply system using a plurality of power supply devices incorporates a load sharing controller so that the load can be evenly supplied among the power supply devices. At this time, when supplying power using a plurality of power supply devices, it is necessary to design a load sharing controller that can operate stably in various operation modes such as single operation and CC-CV (constant current - constant voltage) operation.

Summary of the Invention

Problems to be Solved by the Invention

[0004] The technical problem to be solved by the present invention is to provide a load sharing control device and a load sharing control circuit capable of power derating.

[0005] The problems of the present invention are not limited to the problems mentioned above, and other problems not mentioned should be clearly understood by those skilled in the art from the following description.

Means for Solving the Problems

[0006] To solve the above technical problem, in a load sharing control device according to an embodiment of the present invention, in each of a plurality of power supply devices connected in parallel to a load, a first control unit that generates a first control signal for controlling the output current of the power supply device by using the output current of the power supply device and the current of the load sharing bus; and a second control unit that generates a second control signal for controlling the output voltage of the power supply device by using the target voltage of the power supply device, the feedback voltage fed back from the output voltage of the power supply device, and a control voltage corresponding to the first control signal of the first control unit. The first control unit generates a first control signal so that the output current becomes the same as the current of the load sharing bus, and limits the output current to be equal to or less than the critical current.

[0007] Further, the first control unit may include a first comparison unit that compares the output current and the current of the load sharing bus; a first calculation unit that calculates the difference between the output current and the current of the load sharing bus; and a current control unit that generates the first control signal based on the output of the first calculation unit.

[0008] Further, the current control unit can generate the first control signal for controlling the magnitude of the feedback voltage input to the second control unit.

[0009] Further, the first control unit may include a second comparison unit that compares the output current and the critical current.

[0010] Further, the second control unit may include a second calculation unit that calculates the difference between the feedback voltage and the control voltage corresponding to the first control signal; a third calculation unit that calculates the difference between the target voltage and the output of the second calculation unit; and a voltage control unit that generates a second control signal for controlling the output voltage of the power supply device based on the output of the third calculation unit.

[0011] Further, at least one of the target voltage or the critical current can be adjusted by the limited power of the power supply device.

[0012] To solve the above technical problem, in a load sharing control circuit according to an embodiment of the present invention, in a load sharing control circuit included in each of a plurality of power supply devices connected in parallel to a load and including a CV circuit or a CC-CV circuit, a maximum current output circuit unit that outputs the larger voltage of an output current sensing voltage obtained by sensing the output current of the power supply device and the voltage of a load sharing bus; a minimum current output circuit unit that outputs the smaller voltage of the output of the maximum current output circuit unit and a voltage corresponding to a critical current; and an amplification unit that amplifies the difference between the output current sensing voltage and the output of the minimum current output circuit unit and applies the amplified voltage to a CV feedback terminal of the CV circuit or the CC-CV circuit.

[0013] Further, the critical current may be a preset value or a value obtained by subtracting a predetermined value from a reference current of the CC-CV circuit.

[0014] Further, the maximum current output circuit unit may include a first comparator that receives the output sensing voltage at a (+) input terminal and receives the voltage of the load sharing bus at a (-) input terminal; and a first diode whose output terminal is connected to an anode and whose cathode is connected to the voltage of the load sharing bus.

[0015] Further, the minimum current output circuit unit may include a second comparator that receives the voltage corresponding to the critical current at a (+) input terminal and receives the output of the maximum current output circuit unit at a (-) input terminal; and a second diode whose output terminal is connected to a cathode and whose anode is connected to the voltage of the load sharing bus.

[0016] Further, the amplification unit may include a transconductance amplifier that amplifies the difference between the output current sensing voltage and the output of the minimum current output circuit unit; a first amplifier that amplifies the output of the transconductance amplifier; and a transistor whose output terminal is connected to a base, whose (-) input terminal is connected to an emitter, and whose collector is connected to the CV feedback terminal.

[0017] Also, the transconductance amplifier can have a predetermined offset voltage.

[0018] Also, it can include a second amplifier that senses and amplifies the output current to output the output current sensing voltage.

[0019] Also, at least one of the reference voltage of the CC-CV circuit, the reference voltage of the CV circuit, or the critical current can be adjusted by the limited power of the power supply device.

[0020] Also, when the load includes a battery, it can be connected to the CC-CV circuit.

Advantages of the Invention

[0021] According to an embodiment of the present invention, while performing load sharing control, single operation and redundancy are possible, and power derating is possible.

[0022] Also, even when a battery load is connected, load sharing is possible in all sections of CC-CV, and even when the output is shorted, the CC control circuit operates to protect the elements.

[0023] The effects according to the invention are not limited to the contents exemplified above, and more various effects are included in this specification.

Brief Description of the Drawings

[0024]

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Best Mode for Carrying Out the Invention

[0025] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0026] However, the technical idea of the present invention is not limited to the partial embodiments described, but can be embodied in various different forms, and within the scope of the technical idea of the present invention, one or more of the constituent elements among the embodiments can be selectively combined or replaced and used.

[0027] Also, the terms (including technical and scientific terms) used in the embodiments of the present invention shall be construed as having the meaning generally understood by those having ordinary knowledge in the technical field to which the present invention pertains, unless specifically defined otherwise, and terms generally used like predefined terms should be able to be construed in consideration of their meaning in the context of the related technology.

[0028] Also, the terms used in the embodiments of the present invention are for the purpose of explaining the embodiments and are not intended to limit the present invention.

[0029] In this specification, the singular form includes the plural form unless otherwise specifically stated in the text, and when described as “at least one (or one or more) of A and (or) B, C”, it can include one or more of all combinations that can be combined with A, B, and C.

[0030] Also, when describing the constituent elements of the embodiments of the present invention, terms such as first, second, A, B, (a), (b), etc. can be used. Such terms are for distinguishing the constituent elements from other constituent elements, and are not limited by the essence, order, or sequence of the corresponding constituent elements by such terms.

[0031] In addition, when it is described that a certain component is "connected", "coupled", or "connected" to another component, that component can include not only the case where it is directly "connected", "coupled", or "connected" to that other component, but also the case where it is "connected", "coupled", or "connected" by yet another component between that component and that other component.

[0032] Also, when it is described that it is formed or arranged "above" or "below" each component, "above" or "below" includes not only the case where two components are in direct contact with each other, but also the case where one or more additional components are formed or arranged between the two components. Further, when expressed as "above" or "below", it can include the meaning not only in the upward direction but also in the downward direction with respect to one component.

[0033] FIG. 1 is a block diagram of a load sharing control device according to an embodiment of the present invention.

[0034] A rolling device according to an embodiment of the present invention is included in each of a plurality of power supply devices connected in parallel to a load, and performs load sharing for controlling the output currents of the plurality of power supply devices to be the same. Here, the power supply device is a PSU (Power Supply Unit), a device that supplies power to a load, and can be a device that supplies power for a server, supplies vehicle DC - DC power, or supplies DC - DC power for a DC distribution system. Naturally, it can also include various other devices that supply power.

[0035] The rolling device included in each power supply device 300 is composed of a first control unit 100 and a second control unit 200. Load sharing is performed using the first control signal 104 generated by the first control unit 100 and the second control signal 203 generated by the second control unit 200, and power supply limitation is possible.

[0036] In order to use the plurality of power supply devices 300 efficiently and stably, it is necessary to perform various functions.

[0037] When multiple power supply devices are used, as shown in Figure 2, the power supply devices are connected in parallel with each other. At this time, for efficient operation, redundancy must be performed. Redundancy means that when a defect or failure occurs in any power supply device, it operates with another power supply device to maintain the system output. Also, depending on the system output load, as shown in the graph of Figure 2, the power supply devices can be driven sequentially to maximize the light load efficiency. As shown in Figure 2, up to 60% of the load, the power supply device 1 (PSU #1) is driven, from 60 to 110%, the power supply device 2 (PSU #2), from 110 to 160%, the power supply device 3 (PSU #3), and above 160%, the power supply device 4 (PSU #4) can be driven to increase the efficiency.

[0038] Also, as shown in Figure 3, it is necessary to perform load sharing. Load sharing means controlling the currents output by each power supply device to be the same. When operating the power supply device 1 (PSU #1) to the power supply device 3 (PSU #3), the system load current I (system load) is I1 + I2 + I3, and load sharing is performed so that I1 = I2 = I3 through load sharing. After that, when driving the power supply device 4 (PSU #4), before driving, I4 is 0, and when load sharing is performed so that I1 = I2 = I3 = I4 through load sharing, the value of each current becomes lower, but the overall system load current is maintained the same. After that, when the system load increases, the value of each current is increased to control the overall system load current to increase.

[0039] All power supply devices include respective output voltage control devices. However, due to deviations in the circuit component characteristics (such as resistance values) of each output voltage control device, as shown in Fig. 4, there may be minute differences in the output target voltages from each other. In such a state, when the outputs of each power supply device are connected in parallel, the system output voltage is controlled by the highest target voltage. Therefore, the power supply device 1 (PSU#1) with the highest target voltage controls the output, and for the remaining power supply devices 2, 3, 4 (PSU #2, #3, #4), since the output voltage is higher than the target voltage of each power supply device, the duty is decreased by each output voltage control device. As a result, the power supply to power supply devices 2, 3, 4 (PSU #2, #3, #4) decreases, the power supply becomes concentrated in power supply device 1 (PSU#1), and a current imbalance occurs. In order to eliminate such an imbalance, load sharing is necessary.

[0040] For load sharing, as shown in Fig. 5, one load share bus line is additionally connected outside the power supply device, and a load share controller is added inside. Here, the highest output current information among the individual output currents of each power supply device is transmitted to the load share bus. However, each load share controller includes a comparator 41 to compare each output current with the current on the load share bus so that the maximum current is transmitted via the load share bus, and may include a diode 42 for transmitting the corresponding output current to the load share bus when the corresponding output current is the maximum current. A voltage sensing each output current is applied to the (+) input terminal of the comparator 41, and a voltage including the maximum current information is applied to the (-) input terminal. When the output current is greater than the maximum current, a high is output to the output of the comparator 42, the diode is turned on, the output current is transmitted to the load share bus, and the output current is transmitted as the maximum current to another power supply device. When the output current is less than the maximum current, the maximum current is maintained as it is.

[0041] If current imbalance occurs and the output current is lower than the maximum current of the load share bus, the output voltage feedback signal is lowered and the duty is increased, thereby increasing the output current. As a result, the output current increases to the same as the maximum current. This state can be called the steady-state. When the target voltage and the output voltage are the same in the steady state where the output current is the same as the maximum current, control of the output voltage with respect to the feedback voltage to the output voltage control device is not executed. However, when the target voltage is lower than the output voltage in the steady state, that is, when the output voltage is 12V in Fig. 4 and the output is controlled by the power supply device 1 (PSU#1), in order to perform load sharing, the feedback voltage of the output voltage to the output voltage control device can be lowered to prevent the duty from decreasing. Thereby, power supply is not concentrated on one of the power supply devices, and load sharing can be achieved.

[0042] Fig. 6 illustrates a CC-CV (constant current-constant voltage) circuit, which serves to prevent the output voltage and current from increasing excessively. When the output voltage (Vout) is lower than the reference voltage (Vref), the output of the comparator 61 goes high, whereby the diode 62 is opened. Also, when the output current (Iout) is lower than the reference current (Iref), the output of the comparator 64 goes high and the diode 63 is opened. That is, VCC is applied to the control signal voltage (Vc) that controls the duty of the power supply device, and it operates to increase the duty of the power supply device. Here, the control signal voltage (Vc) can include a switching operation signal or the like that increases the duty of the power supply device.

[0043] During operation in this way, when the output current (Iout) becomes larger than the reference current (Iref), the output of the comparator 64 goes low, the diode 63 is turned on, whereby the control signal voltage (Vc) becomes low, and thus the duty of the power supply device also becomes low. As a result, it operates so that the output current (Iout) becomes the same as the reference current (Iref), and the mode at this time is called the CC (Constant Current) mode.

[0044] When the output current of the power supply device increases, the output voltage increases, and the output voltage (Vout) becomes greater than the reference voltage (Vref), the output of the comparator 61 goes low, whereby the diode 62 is turned on. As a result, the voltage (Vc) decreases, and thus the duty of the power supply device also decreases. Consequently, it operates so that the output voltage (Vout) becomes the same as the reference voltage (Vref), and this mode is called the CV (Constant Voltage) mode at this time.

[0045] As shown in FIG. 7, when using the output diode and the CC-CV circuit without a load share bus, parallel operation is possible, but load sharing does not occur. For the same reason as in FIG. 4 as the output voltage increases, the duty of the power supply device whose target voltage becomes lower than the output voltage decreases, the current of each power supply device is not maintained, and current imbalance occurs.

[0046] Even in FIG. 8 where a battery is connected to the load, for the same reason, as the battery is charged, the duty of the power supply device whose target voltage becomes lower than the output voltage decreases, the current of each power supply device is not maintained, and current imbalance occurs.

[0047] As described above, the rolling device according to an embodiment of the present invention is configured by a first control unit 100 and a second control unit 200 so that load sharing is performed even when there is a deviation in the target voltage of the power supply device, and load sharing is possible even in the CV mode.

[0048] The first control unit 100 generates a first control signal 104 for controlling the output current 101 of the power supply device 300 by using the output current 101 of the power supply device 300 and the current of the load share bus 400.

[0049] Specifically, for load sharing, the first control unit 100 generates a first control signal 104 so as to follow the maximum current 103 among the output currents of a plurality of power supply devices that receive the output current 101 of the power supply device 300 from the load sharing bus 400. Here, the first control signal 104 can be a control signal that controls the second control unit 200 that controls the output voltage of the power supply device 300. Due to the first control signal 104, the output current 101 comes to operate in the same manner as the maximum current 103. At this time, when the output current 101 of the power supply device 300 is the maximum current among the output currents of other power supply devices, the corresponding output current 101 is transmitted to another power supply device that is the maximum current 103 of the load sharing bus 400.

[0050] The first control unit 100 generates the first control signal 104 so that the output current 101 becomes the same as the maximum current 103 of the load sharing bus 400, but limits the output current 101 to be equal to or less than the critical current 102. If there is no limit value for the output current 101, the output current 101 may continue to increase, which may affect the entire power supply system. Therefore, for power derating of power supply, the output current 101 is limited to be equal to or less than the critical current 102. Here, the critical current 102 can have a preset value, or can be set using the reference current used when the power supply device is under CC (constant current) control. When setting the critical current 102 using the reference current, a predetermined value can be subtracted from the reference current to set the critical current 102. Here, the current value subtracted from the reference current can vary depending on the specifications of the power supply device and the degree of safety requirements. Or, the reference current may be set as the critical current 102.

[0051] The second control unit 200 generates a second control signal 203 for controlling the output voltage of the power supply device 300 by using the target voltage 201 of the power supply device 300, the feedback voltage 202 fed back from the output voltage of the power supply device 300, and a control voltage corresponding to the first control signal 104 of the first control unit 100.

[0052] More specifically, the second control unit 200 controls the power system of the power supply device 300 and generates a second control signal 203 for controlling the output voltage of the power supply device 300 by using the target voltage 201, the feedback voltage 202, and the first control signal 104. The second control signal 203 is generated to control the output voltage of the power supply device 300 such that the voltage obtained by subtracting the control voltage corresponding to the first control signal 104 from the feedback voltage 202 becomes the target voltage 201.

[0053] By using the first control signal 104 of the first control unit 100 that controls the output current 101 to be the same as the maximum current 103 and the second control signal 203 of the second control unit 200 that controls the output voltage of the power supply device 300 such that the voltage obtained by subtracting the control voltage corresponding to the first control signal 104 from the feedback voltage 202 becomes the target voltage 201, load sharing for each power supply device 300 is performed, and the first control unit 100 performs power derating by limiting the output current 101 to be below the critical current 102.

[0054] FIG. 9 is a block diagram of the first control unit of the load sharing control device according to an embodiment of the present invention.

[0055] The first control unit 100 of the load sharing control device according to an embodiment of the present invention can be configured by a first comparison unit 110, a first calculation unit 130, and a current control unit 140, as shown in FIG. 9, and can include a second comparison unit 120. When generating the first control signal, the current is compared or calculated. At this time, when comparing the current, a sensing voltage obtained by measuring a current that is not a current can be used. That is, when comparing currents, a comparison can be made between the sensing voltages obtained by sensing each current.

[0056] The first comparison unit 110 compares the output current 101 with the current of the load share bus 400. The first comparison unit 110 compares the output current 101 with the maximum current 103 to determine which of the output current 101 and the maximum current 103 is larger. When the output current 101 is larger than the maximum current 103, the maximum current of the load share bus 400 is changed to the output current 101.

[0057] The first calculation unit 130 calculates the difference between the output current 101 and the current of the load share bus 400. The first control unit 100 controls the output current 101 to be the same as the maximum current 103. While determining whether the output current 101 and the maximum current 103 are the same, the first calculation unit 130 calculates the difference between the output current 101 and the maximum current 103 in order to generate the first control signal by using the difference.

[0058] The current control unit 140 generates the first control signal based on the output of the first calculation unit 130. That is, the current control unit 140 generates the first control signal so as to reduce the corresponding difference according to the difference between the output current 101 and the maximum current 103 output from the first calculation unit 130. The current control unit 140 can generate the first control signal 104 for controlling the magnitude of the feedback voltage 202 input to the second control unit 200. When the output current 101 is lower than the maximum current 103, it is necessary to control to increase the output current 101, which means increasing the duty of the power supply device 300. That is, the second control unit 200 that controls the duty of the power supply device 300 can lower the feedback voltage of the output voltage used for controlling the duty below the actual feedback voltage, thereby preventing the second control unit 200 from lowering the duty according to the actual feedback voltage.

[0059] Although the output current increases more and more due to the first control signal of the current control unit 140, in order to limit an overly high power supply, the first control unit 100 can include a second comparison unit 120 for limiting the output current to a critical current. The second comparison unit 120 compares the output current 101 with the critical current 102 so that a lower current is applied to the first comparison unit 110. That is, when the output current 101 becomes larger than the critical current 102, the second comparison unit 120 outputs the critical current 102 as an output, the critical current 102 is set to be larger than the maximum current 103, and the critical current 102 is output as the output of the first comparison unit 110. Thereafter, the output current 101 is controlled to be the same as the critical current 102 by the first calculation unit 130 and the current control unit 140, and the output current 101 is limited to the critical current 102. At this time, the critical current can be set to the maximum current value to be controlled by load sharing. Or, it can be set to a current value for limiting the supply power.

[0060] FIG. 10 is a block diagram of a second control unit of a load sharing control device according to an embodiment of the present invention.

[0061] The second control unit 200 of the load sharing control device according to an embodiment of the present invention can be composed of a second calculation unit 210, a third calculation unit 220, and a voltage control unit 230 as shown in FIG. 10.

[0062] The second calculation unit 210 calculates the difference between the feedback voltage 202 and the control voltage by the first control signal 104. As described above, the first control signal 104 is a control signal for lowering or raising the feedback voltage 202 of the output voltage. In order to lower or raise only the control voltage by the first control signal 104 for the feedback voltage 202, the difference between the feedback voltage 202 and the control voltage by the first control signal 104 is calculated.

[0063] The third calculation unit 220 calculates the difference between the target voltage 201 and the output of the second calculation unit 210. The voltage control unit 230 that controls the duty of the power supply device controls so that the output voltage becomes the target voltage 201. For this purpose, the third calculation unit 220 calculates and outputs the difference between the target voltage 201 and the output of the second calculation unit 210.

[0064] The voltage control unit 230 generates a second control signal 203 that controls the output voltage of the power supply device so that the output voltage becomes the target voltage according to the output of the third calculation unit 220. The second control signal 203 is a signal that controls the power supply of the power supply device 300. The voltage control unit 230 can include a pulse width modulation unit (PWM). In order to control the duty for controlling the power supply of the power supply device 300, it can include a pulse width modulation unit that can control the duty of the signal, and thereby the duty of the power supply device can be controlled.

[0065] Separate from the power supply device 300, when it is necessary to limit the supplied power, at least one of the target voltage 201 or the critical current 102 can be adjusted. The supplied power is controlled by the output voltage and the output current, the output voltage is limited to the target voltage 201, and the output current is limited to the critical current 102, but by adjusting at least one of the target voltage 201 or the critical current 102, the supplied power can be limited. That is, thereby power derating, which is supply power limitation, is possible.

[0066] The load sharing control device according to an embodiment of the present invention can be embodied as shown in FIG. 11.

[0067] The comparison of the output current, maximum current, and critical current can be executed by using the sensing voltage and set voltage of each current. The output current sensing voltage 1101 is compared via the comparator 1111 and diode 1112 with the maximum current sensing voltage of the load share bus 1400, and the largest output current among the output currents of each power supply device can be transmitted. The difference between the output current sensing voltage 1101 and the maximum current sensing voltage 1400 is calculated 1130, and based on the corresponding difference, the current control unit 1140 generates a first control signal so that the output current sensing voltage 1101 becomes the same as the maximum current sensing voltage 1400. At this time, the current control unit 1140 can perform control by PI control. As a result, the output current increases, and thereby the output voltage sensing voltage 1101 increases. However, in order to limit the magnitude of the output voltage sensing voltage 1101, a comparison can be made via the critical current voltage 1102 and diode 1120. When the output current sensing voltage 1101 is greater than the critical current voltage 1102, the diode is turned on and the critical current voltage 1102 is input to the (+) terminal input of the comparator 1111. Since the critical current voltage 1102 is greater than the maximum current sensing voltage 1400, the output current sensing voltage 1101 is controlled by the current control unit 1140 to become the same as the critical current voltage 1102, and the output current is limited to the critical current. The configuration that limits the output current to the critical current and operates in the constant current mode to perform load sharing can be referred to as a load sharing controller (CC controller) 1150.

[0068] The control voltage by the control signal of the current control unit 1140 is used to control the feedback voltage of the output voltage 1202. That is, the difference between the feedback voltage of the output voltage 1202 and the control voltage by the control signal of the current control unit 1140 is calculated 1210, and the difference from the target voltage 1201 is calculated 1220 based on the corresponding result. The voltage control unit 1230 generates a second control signal so that the difference between the feedback voltage of the output voltage 1202 and the control voltage by the control signal of the current control unit 1140 becomes the same as the target voltage 1201. At this time, the voltage control unit 1230 can perform control via PI control. The control signal of the voltage control unit 1230 is applied to the pulse width modulation unit (PWM) 1240 to control the duty of the signal applied to the power stage 1300 of the power supply device. The voltage control unit 1230 and the pulse width modulation unit 1240 can be referred to as a CV controller 1250 that limits the voltage to the target voltage and operates in the constant voltage mode.

[0069] As shown in FIG. 11, the load sharing control device implemented as such operates in the CC mode where the output current is stabilized at the maximum current. When the battery voltage as the load is higher than the target voltage, or in the CV mode where the output voltage is stabilized at the target voltage, the battery voltage is controlled by different power supply devices and can operate as shown in FIG. 12. For example, when the battery voltage is 12V and the target voltage is 11V, the output current is in a state of being stabilized at the maximum current, but the output of the calculation unit 1130 is 0, and the control voltage by the control signal output from the current control unit 1140 can be 1V for reducing the feedback voltage of the output voltage, which is 12V, to the target voltage, which is 11V. The difference between the target voltage received by the voltage control unit 1230 and the feedback voltage of the output voltage can control the duty of the power supply device so that 0V is input. That is, by outputting 5V, PWM can output Vg = 24V, Vm = 10V, and duty D = 0.5 to perform load sharing of the power supply device.

[0070] In the CC mode, when the battery voltage is lower than the target voltage, it can operate as shown in FIG. 13. For example, when the battery voltage is 10V and the target voltage is 11V, the output current is stabilized at the maximum current, but the output of the calculation unit 1130 is 0, and the control voltage by the control signal output from the current control unit 1140 based on this can be -1V for increasing the feedback voltage of 10V by the output voltage to the target voltage of 11V. The duty of the power supply device can be controlled so that the difference between the target voltage received by the voltage control unit 1230 and the feedback voltage of the output voltage is 0V input. That is, it can output 4.1V, and the PWM can output Vg = 24V, Vm = 10V, and duty D = 0.5 to perform load sharing of the power supply device.

[0071] The load sharing control circuit according to an embodiment of the present invention is a load sharing control circuit included in each of a plurality of power supply devices including a CV circuit or a CC - CV circuit, connected in parallel to a load. The load sharing control circuit includes a maximum current output circuit unit that outputs the larger voltage of the output current sensing voltage obtained by sensing the output current of the power supply device and the voltage of the load sharing bus, a minimum current output circuit unit that outputs the smaller voltage of the output of the maximum current output circuit unit and the voltage by the critical current, and an amplification unit that amplifies the difference between the output current sensing voltage and the output of the minimum current output circuit unit and applies it to the CV feedback terminal of the CV circuit or the CC - CV circuit.

[0072] FIG. 14 is a circuit diagram of a load sharing control circuit 2150 according to an embodiment of the present invention.

[0073] The load sharing control circuit 2150 according to an embodiment of the present invention is a circuit corresponding to the load sharing control device described with reference to FIGS. 1 to 13. Hereinafter, duplicate descriptions will be omitted. As described with reference to FIG. 13, in order to perform load sharing, it is necessary to apply a (-) value as a control voltage to be subtracted from the feedback voltage of the output voltage. In order to implement this with an analog circuit, as shown in FIG. 14, the load sharing control circuit according to an embodiment of the present invention can be realized.

[0074] The maximum current output circuit section can include a first comparator 2111 that receives the output current sensing voltage 1201 at the (+) input terminal and receives the voltage of the load sharing bus 2400 at the (-) input terminal, and a first diode 2112 whose output terminal and anode are connected and whose cathode is connected to the voltage of the load sharing bus 2400. It can include a second amplifier 2103 that senses and amplifies the output current to output an output current sensing voltage 2101. By sensing and amplifying the output current 2102 with the second amplifier 2103, it is possible to accurately sense the output current. Here, the second amplifier can be a high-precision OP-AMP. Also, the first comparator 2111 can be implemented with an OP-AMP comparator or the like. The first comparator 2111 and the first diode 2112 output the larger voltage of the voltage of the output current 2101 or the voltage of the load sharing bus 2400 as the voltage of the maximum current.

[0075] The minimum current output circuit section can include a second comparator 2122 that receives the voltage due to the critical current 2103 at the (+) input terminal and receives the output of the maximum current output circuit section at the (-) input terminal, and a second diode 2121 whose output terminal is connected to the cathode and whose anode is connected to the voltage of the load share bus 2400. Here, the critical current 2103 can be a preset value or a value (Iref - ΔI) obtained by subtracting a predetermined value (ΔI) from the reference current (Iref) of the CC-CV circuit. Since the cathode-anode direction of the second diode 2121 is opposite to that of the first diode 2112, the smaller voltage among the voltage due to the critical current 2103 and the output of the maximum current output circuit section is output and applied to the amplifier section. That is, the (+) input of the transconductance amplifier 2131 constituting the amplifier section can be limited to the voltage of the critical current.

[0076] The amplifier unit may include a transconductance amplifier 2131 that amplifies the difference between the output current 1201 sensing voltage and the output of the minimum current output circuit unit, a first amplifier 2133 that amplifies the output of the transconductance amplifier 2131, and a transistor 2134 whose output terminal and base are connected to the first amplifier, whose (-) input terminal and emitter are connected to the first amplifier, and whose collector is connected to the CV feedback terminal 2210. A transconductance amplifier is an amplifier that multiplies the difference in voltage input by a gain and outputs it as a current, and outputs the amplified difference between the output current 1201 sensing voltage and the output of the minimum current output circuit unit. The transconductance amplifier 2131 can have a predetermined offset voltage 2132. Thereby, when the difference between the sensing voltage 1201 of the output current and the sensing voltage of the maximum current is equal to or greater than the offset voltage, the current control function can be made to operate. Thereby, errors such as current control due to malfunction of the amplifier can be prevented. Here, the offset voltage may be set in advance and can be set to 25 mV. The output of the transconductance amplifier 2131 is amplified by the first amplifier 2133, and a voltage is applied to the resistor connected to the emitter of the transistor 2134, thereby increasing or decreasing the voltage of the CV feedback terminal 2210 connected to the collector of the transistor 2134. That is, the voltage of the CV feedback terminal 2210 can be controlled to be (+) or (-). Thereby, even in the CV mode where the output voltage 2202 is greater than the reference voltage 2201 which is the target voltage, the power supply device can be operated to enable load sharing.

[0077] As described above, in the implemented load sharing control circuit, at least one of the reference voltage of the CC-CV circuit, the reference voltage of the CV circuit, or the critical current can be adjusted by the limited power of the power supply device. Separately from the power supply device 300, when it is necessary to limit the supplied power, at least one of the reference voltage of the CC-CV circuit corresponding to the target voltage, the reference voltage of the CV circuit, or the critical current can be adjusted. The supplied power is controlled by the output voltage and the output current. The output voltage is limited to the reference voltage, and the output current is limited to the critical current. The supplied power can be limited by adjusting at least one of the reference voltage or the critical current. That is, thereby, power derating, which is a supply power limit, is possible.

[0078] As shown in FIG. 14, the implemented load sharing control circuit according to an embodiment of the present invention can operate in various operation modes.

[0079] When operating stand-alone without being driven in parallel with other power supply devices, as shown in FIG. 15, the load sharing control circuit 2150 is equivalently open, and only the CC-CV circuit operates.

[0080] When driven in parallel with other power supply devices and the output voltage is lower than the target voltage, as shown in FIG. 16, it operates in the CC mode, and the CV circuit and the load sharing control circuit 2150 are equivalently open. The output current 2202 is controlled to operate by being limited to the reference current 2102 by the CC circuit.

[0081] When driven in parallel with other power supply devices and the output voltage is higher than the target voltage, as shown in FIG. 17, it operates in the CV mode, and at the same time, the load sharing control circuit 2150 operates for load sharing. At this time, the CC circuit is equivalently open. At this time, load sharing is performed, but the output current is controlled to operate by being limited to the critical current 2103, which is not the reference current 2102.

[0082] When a battery is connected to a load, as shown in FIG. 14, the load sharing control circuit 2150 is connected to the CC-CV circuit and operates. When a battery is not connected to the load, as shown in FIG. 18, the load sharing control circuit 2150 can be connected to only a CV-circuit that is not a CC-CV circuit and operate. That is, it is included in a power supply device applied to various applications and loads that supply server power, vehicle DC-DC power, or DC-DC power for a DC power distribution system, and can perform load sharing. Naturally, it can also include various devices that supply power.

[0083] As described above, through a load sharing control device or control circuit capable of power derating, stand-alone operation is possible, a redundancy function is performed, and power derating is possible by adjusting the target voltage and critical current. Also, even when a battery is connected to the load, the load sharing operation is possible in all CC-CV sections, and the CC control circuit operates during an output short circuit to protect the elements.

[0084] Naturally, each configuration of the load sharing control device according to an embodiment of the present invention can be implemented by software or by hardware such as a circuit.

[0085] The embodiments of the present invention have been described with reference to the attached drawings above. Those having ordinary knowledge in the technical field to which the present invention pertains should understand that the present invention can be implemented in other specific forms without changing its technical idea or essential features. Therefore, it should be understood that the embodiments described above are exemplary in all aspects and not restrictive.

Claims

1. A first control unit that generates a first control signal for controlling the output current of the power supply device based on information on the current of a load sharing bus to which a voltage indicating information on the output current of the power supply device and the highest output current among the individual output currents of a plurality of power supply devices is applied; and A second control unit that generates a second control signal for controlling the output voltage of the power supply device by using the target voltage of the power supply device, a feedback voltage fed back from the output voltage of the power supply device, and a control voltage corresponding to the first control signal of the first control unit, The first control unit is A load sharing ring control device that generates a first control signal so that the output current becomes the same as the current indicated by the voltage of the load sharing bus, but limits the output current to a critical current or less.

2. The first control unit is A first comparison unit that compares the output current with the current of the load sharing bus; A first calculation unit that calculates the difference between the output current and the current of the load sharing bus; and The load sharing ring control device according to claim 1, comprising a current control unit that generates the first control signal based on the output of the first calculation unit.

3. The current control unit is The load sharing ring control device according to claim 2, which generates the first control signal for controlling the magnitude of the feedback voltage input to the second control unit.

4. The first control unit is The load sharing ring control device according to any one of claims 1 to 3, comprising a second comparison unit that compares the output current with the critical current.

5. The second control unit is A second calculation unit that calculates the difference between the feedback voltage and the control voltage corresponding to the first control signal; A third calculation unit that calculates the difference between the target voltage and the output of the second calculation unit; and The load sharing ring control device according to any one of claims 1 to 4, comprising a voltage control unit that generates a second control signal for controlling the output voltage of the power supply device based on the output of the third calculation unit.

6. The load sharing ring control device according to any one of claims 1 to 5, which adjusts at least one of the target voltage or the critical current according to the limit power of the power supply device.

7. A maximum current output circuit unit that outputs the larger voltage among the output current sensing voltage obtained by sensing the output current of the power supply device and the voltage of the load sharing bus to which a voltage indicating information on the highest output current among the individual output currents of a plurality of power supply devices is applied; A minimum current output circuit section that outputs the smaller voltage among the output of the maximum current output circuit section and the voltage corresponding to the critical current; and A load sharing control circuit including an amplification section that amplifies the difference between the output current sensing voltage and the output of the minimum current output circuit section and applies it to the CV feedback terminal of a CV circuit or a CC-CV circuit.

8. The critical current is The load sharing control circuit according to claim 7, which is a preset value or a value obtained by subtracting a predetermined value from the reference current of the CC-CV circuit.

9. The maximum current output circuit section is A first comparator that receives the output current sensing voltage at the (+) input terminal and receives the voltage of the load sharing bus at the (-) input terminal; and The load sharing control circuit according to claim 7 or 8, including a first diode whose output terminal is connected to the anode and whose cathode is connected to the voltage of the load sharing bus.

10. The minimum current output circuit section is A second comparator that receives the voltage corresponding to the critical current at the (+) input terminal and receives the output of the maximum current output circuit section at the (-) input terminal; and The load sharing control circuit according to any one of claims 7 to 9, including a second diode whose output terminal is connected to the cathode and whose anode is connected to the voltage of the load sharing bus.

11. In a load sharing control method, An operation of generating a first control signal for controlling the output current of the power supply device based on the current information of the load sharing bus to which a voltage indicating the output current of the power supply device and the highest output current among the individual output currents of a plurality of power supply devices is applied, and An operation of generating a second control signal for controlling the output voltage of the power supply device using the target voltage of the power supply device, the feedback voltage fed back from the output voltage of the power supply device, and the control voltage corresponding to the first control signal, The operation of generating the first control signal includes generating the first control signal so that the output current becomes the same as the current indicated by the voltage of the load sharing bus, and an operation of limiting the output current to be below the critical current. A load sharing control method.

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