Power supply system and power supply method

Abstract

The present invention provides a power supply system and a power supply method for reducing the output power of a power supply device having the highest maximum power among a plurality of power supply devices. [Solution] A power supply system 100 is used to supply power to a load 1 and is connected to a load-sharing busbar 2. The power supply system 100 also includes two power supply devices 10 and a control device 20, the two power supply devices 10 are connected in parallel to the load 1, have maximum power and output output power to the load 1, and the control device 20 is electrically connected to the two power supply devices 10, and when the two power supply devices 10 meet a control condition, the one of the two power supply devices 10 with the highest maximum power adjusts its output power based on a control signal from the control device 20 and a shared signal from the load-sharing busbar 2, so that the output powers of the two power supply devices 10 are equal or close to each other.

Description

[Technical field]

[0001] The present invention relates to a power supply system, and more particularly to a power supply system and a power supply method that have at least two power supply devices and supply power. [Background technology]

[0002] Conventionally known power supply systems generally employ at least two power supply devices connected in parallel to provide a backup power source or to increase the total output power of the power supply system. The power supply devices cooperate with each other to supply power, i.e., the power supply devices operate simultaneously, thereby increasing the total output power from the power supply system.

[0003] Regarding the function of increasing the total output power of the power supply system, by electrically connecting the multiple power supply devices to a load-sharing busbar, each of the power supply devices can output output power correspondingly based on a shared signal on the load-sharing busbar, thereby achieving the objective of maintaining a stable supply of power to each of the power supply devices.

[0004] If the maximum power specifications of the plurality of power supply devices are the same, the output powers from the plurality of power supply devices will be the same under the condition of the same shared signal. However, if the maximum power specifications of the plurality of power supply devices are not the same, under the condition of the same shared signal, the plurality of power supply devices will each output an output power at the same percentage based on their respective maximum powers, i.e., among the plurality of power supply devices, the one with the highest maximum power will output a relatively high output power, while the one with the lower maximum power will output a relatively low output power.

[0005] For example, a power supply system includes a first power supply device and a second power supply device, in which the maximum power of the first power supply device is 1200W, and the maximum power of the second power supply device is 2000W.

[0006] If the load requires 320W of power, under the same shared signal condition, the output power of the first power supply will be 120W, which is 10% of the maximum power (1200W), and the output power of the second power supply will be 200W, which is 10% of the maximum power (2000W). Therefore, the total output power will be 320W, which can meet the power consumption needs of the load.

[0007] If the load requires 1600W of power, under the same shared signal conditions, the output power of the first power supply will be 600W, which is 50% of the maximum power (1200W), and the output power of the second power supply will be 1000W, which is 50% of the maximum power (2000W), so the total output power will be 1600W.

[0008] In other words, the output power of the second power supply device is greater than that of the first power supply device, so that long-term use may shorten the service life of the power supply device with the highest maximum power (the second power supply device) and may cause problems in the reliability of the power supply system.

[0009] Also, from the viewpoint of safety regulations, when the input voltage of each power supply falls within the low line, that is, when the input voltage is between AC 90V and AC 120V, the output power of each power supply must not exceed the limit value of the output power of each power supply (e.g., 1000W). In other words, even if the maximum power of a power supply is greater than 1000W, when it falls within the low line, the limited maximum power is 1000W. Therefore, the maximum output power can only be 1000W.

[0010] If the load requires 320W of power, the output power of the first power supply is 120W and the output power of the second power supply is 200W, so the total output power is 320W, which can meet the power consumption needs of the load.

[0011] When the load requires 1600W of power, the output power of the first power supply is 600W and the output power of the second power supply is 1000W, so the total output power is 1600W. At this time, although the output power of the second power supply has reached the upper limit of the safety regulation, it can still meet the power consumption needs of the load.

[0012] However, when the load requires more than 1600W of power, the power supply system cannot supply enough power because the output power of the second power supply has already reached the upper limit of the safety regulation, and therefore it is unable to output any more large total output power when the input voltage falls into the low voltage range, even if the total maximum power of the two power supplies is still greater than 1600W, thereby limiting the total output power of the power supply system. Summary of the Invention [Problem to be solved by the invention]

[0013] In view of this, an object of the present invention is to provide a power supply system and a power supply method capable of reducing the output power of one of a plurality of power supply devices having the highest maximum power. [Means for solving the problem]

[0014] In order to achieve the above object, the present invention provides a power supply system for supplying power to a load and connected to a load-sharing busbar. The power supply system includes at least two power supply devices and a control device, in which the at least two power supply devices are connected in parallel to the load, and each of the power supply devices has a maximum power and outputs an output power to the load that is equal to or less than the maximum power. Each of the power supply devices receives a sharing signal from the load-sharing busbar and adjusts its output power based on the sharing signal. The control device is electrically connected to the at least two power supply devices, and the control device receives each of the maximum powers from each of the power supply devices, and when a control condition is satisfied, the control device outputs a control signal to the at least two power supply devices with the highest maximum power, and adjusts the output power of the at least two power supply devices with the highest maximum power so that the output powers of the at least two power supply devices are equal to or close to each other. In which, the control condition includes a condition that the maximum power of the at least two power supply devices with the highest maximum power is greater than a predetermined maximum power and greater than the maximum power of the other power supply devices.

[0015] The power supply method provided by the present invention is applied to a power supply system. The power supply system includes at least two power supply devices and a control device, the at least two power supply devices being connected in parallel to a load, each of the power supply devices having a maximum power and outputting an output power to the load that is equal to or less than the maximum power. Each of the power supply devices receives a sharing signal from the load sharing busbar and adjusts its output power based on the sharing signal. The power supply method includes a step in which the control device receives each of the maximum powers from each of the power supply devices. When a control condition is satisfied, the control device outputs a control signal to the at least two power supply devices having the highest maximum power. Among these, the control condition includes a condition that the maximum power of the at least two power supply devices having the highest maximum power is greater than a predetermined maximum power and is greater than the maximum power of the other of the power supply devices. The at least two power supply devices having the highest maximum power adjusts its output power based on the control signal so that the output powers of the at least two power supply devices are equal to or close to each other. Effect of the Invention

[0016] The advantage of the present invention is that the power supply system can extend the service life of the power supply device with the highest maximum power by adjusting the output power of the at least two power supply devices so that the output powers of the at least two power supply devices are equal or close to each other, thereby maximizing the total output power of the at least two power supply devices while optimizing the reliability of the power supply system.

[0017] According to the above idea, the at least two power supply devices are electrically connected to an AC power source, and each of the power supply devices transmits input voltage information of the AC power source to the control device correspondingly. The control condition further includes that the input voltage information of the at least two power supply devices having the highest maximum power falls within a low voltage range. Therefore, it is possible to maximize the sum of the output powers of the at least two power supply devices while increasing the total output power of the power supply system under the premise of satisfying safety regulations. [Brief description of the drawings]

[0018] [Figure 1] 1 is a schematic diagram showing a power supply system according to a first preferred embodiment of the present invention; [Diagram 2] 1 is a schematic diagram showing a power supply device according to a first preferred embodiment of the present invention; [Diagram 3] FIG. 2 is a circuit diagram of a selection circuit according to a first preferred embodiment of the present invention. [Figure 4] 2 is a flowchart of a power supply method according to the preferred embodiment of the present invention. [Diagram 5] FIG. 13 is a schematic diagram showing a power supply device according to a third preferred embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] In order to more clearly explain the present invention, preferred embodiments will be described in detail below with reference to the drawings. Figures 1 to 3 show a power supply system 100 according to a first preferred embodiment of the present invention. The power supply system 100 is used to supply power to a load 1 and is connected to a load sharing bus 2. The power supply system 100 includes at least two power supply devices 10 and a control device 20.

[0020] In this embodiment, two power supply devices 10 are described as an example, but the present invention is not limited thereto, and three or more power supply devices 10 may be used. The two power supply devices 10 are a first power supply device 10A and a second power supply device 10B, which are electrically connected to an AC power source 3 and are connected in parallel to the load 1, and convert the AC current of the AC power source 3 into a DC current and supply it to the load 1. The AC power source 3 may be in a high voltage range (high line) or a low voltage range (low line). The high voltage range is, for example, AC 180V to 264V, and the low voltage range is, for example, AC 90V to 120V. Each of the power supply devices 10 has a maximum power and outputs an output power to the load 1. The maximum power is the rated maximum output power of each of the power supply devices 10 itself, and each of the output powers is equal to or less than the maximum power. In this embodiment, a power supply device 10 that outputs a constant voltage is taken as an example. Therefore, the maximum power and the output power are determined by the output current. For example, when the maximum power is 2000W and the constant voltage DC is 54.5V, if the AC power source 3 is in the high voltage range, the maximum output current is about 36.7A. If the AC power source 3 is in the low voltage range, the limited maximum power is 1000W. Therefore, the maximum output current is limited to about 18.34A. Each of the power supply devices 10 obtains a shared signal from the load sharing busbar 2 and adjusts its output power based on the shared signal. In this embodiment, the shared signal is a voltage signal and corresponds to the output power of each of the power supply devices 10, for example, the output current.

[0021] The two power supply devices 10 are electrically connected to the control device 20. In this embodiment, the two power supply devices 10 are electrically connected to the control device 20 and communicate with the control device 20 via a communication interface, such as a power management bus bar 30 (Power Management Bus, PM Bus).

[0022] The two power supply devices 10 have the same configuration, so only one power supply device 10 will be described. The power supply device 10 includes an output circuit 11, a comparison module 12, an output power adjustment module 13, and a signal processing module 14. The output circuit 11 is electrically connected to the load 1, the comparison module 12, and the output power adjustment module 13. The output circuit 11 supplies the output power to the load 1 and outputs a feedback signal. The feedback signal corresponds to the power output by the output circuit 11. In this embodiment, the feedback signal is a voltage signal and corresponds to the output current output by the output circuit 11. The comparison module 12 is electrically connected to the load sharing busbar 2, the output circuit 11, and the output power adjustment module 13. The comparison module 12 receives the feedback signal from the output circuit 11 and the shared signal from the load sharing busbar 2, and outputs an adjustment signal to the output power adjustment module 13 based on the shared signal and the feedback signal. The output power adjustment module 13 adjusts the output power output by the output circuit 11 based on the adjustment signal, i.e., adjusts the output current. The signal processing module 14 is electrically connected to the power management busbar 30 and the comparison module 12, and the signal processing module 14 can selectively output a compensation signal to the comparison module 12 when controlled by the control device 20. The signal processing module 14 detects the input voltage information of the AC power source 3 while detecting the output power of the output circuit 11 in real time. In this embodiment, the input voltage information may be, for example, the voltage value of the AC power source 3.

[0023] In this embodiment, the signal processing module 14 includes a microprocessor 141 and a selection circuit 142 electrically connected to each other, the microprocessor 141 is electrically connected to the power management busbar 30, and the maximum power value of the power supply device 10, the input voltage information, and the instantaneous output power value are stored in the microprocessor 141. The values ​​may be stored in a memory 141A of the signal processing module 14. The memory 141A may be built into the microprocessor 141 or may be independent of the microprocessor 141. The microprocessor 141 controls the selection circuit 142 to generate the compensation signal. The selection circuit 142, for example, includes a voltage adder circuit. FIG. 3 exemplarily shows the selection circuit 142 as a non-inverting voltage adder circuit, which includes an operational amplifier 142A and a plurality of resistors R1 to R4. An output terminal 142A1 of the operational amplifier 142A is electrically connected to the comparison module 12, and resistors R1 and R2 are electrically connected to the microprocessor 141.

[0024] The microprocessor 141 outputs a first voltage to the resistor R1 and / or outputs a second voltage to the resistor R2, and the first voltage and the second voltage are combined with the resistance values ​​of the resistors R1 and R2, so that the operational amplifier 142A converts the first voltage and the second voltage into the compensation signal. In the circuit shown in Fig. 3, the compensation signal is a positive voltage signal, and its voltage value is determined by the first voltage and the second voltage output by the microprocessor 141 and the resistors R1 and R2. When it is not necessary to output the compensation signal, the microprocessor 141 outputs 0V to the resistors R1 and R2. Therefore, the output terminal 142A1 of the operational amplifier 142A becomes 0V, that is, the selection circuit 142 does not output the compensation signal.

[0025] In addition, the comparison module 12 according to this embodiment includes a conversion circuit 121 and a comparison circuit 122 electrically connected to each other, the conversion circuit 121 is electrically connected to the selection circuit 142 and the output circuit 11, and the comparison circuit 122 is electrically connected to the output power adjustment module 13 and the load sharing busbar 2. When the selection circuit 142 does not output the compensation signal, i.e., when it outputs 0V, the conversion circuit 121 outputs the feedback signal to the comparison circuit 122, and the comparison circuit 122 outputs the adjustment signal according to the feedback signal and the shared signal. When the selection circuit 142 outputs the compensation signal, the conversion circuit 121 receives the compensation signal, and outputs a conversion signal to the comparison circuit 122 according to the compensation signal and the feedback signal, and the comparison circuit 122 outputs the adjustment signal according to the conversion signal and the shared signal.

[0026] For example, the conversion circuit 121 may be, for example, a voltage adder circuit, which adds the voltage of the feedback signal and the voltage output by the selection circuit 142 in the signal processing module 14. When the selection circuit 142 outputs 0V, the voltage output by the conversion circuit 121 is equal to the voltage of the feedback signal. Thus, the conversion circuit 121 can output the feedback signal to the comparison circuit 122. The comparison circuit 122 may be, for example, a comparator circuit, which compares the voltage of the feedback signal with the voltage of the shared signal to output the adjustment signal and adjust the output power. When the output power is stable, the voltage of the feedback signal is equal to the voltage of the shared signal.

[0027] When the selection circuit 142 in the signal processing module 14 outputs the compensation signal, the voltage of the conversion signal output by the conversion circuit 121 is the voltage of the feedback signal plus the voltage of the compensation signal, that is, the voltage of the conversion signal is greater than the voltage of the feedback signal. The comparison circuit 122 compares the voltage output by the conversion circuit 121 with the voltage of the shared signal, and outputs the adjustment signal to reduce the output power. When the output power is stable, the voltage of the conversion signal is equal to the voltage of the shared signal.

[0028] The power supply method according to the present embodiment can be executed by the above-described power supply system 100. The power supply method includes the following steps, as shown in FIG.

[0029] In step S11, the control device 20 obtains the maximum power from each of the power supply devices 10.

[0030] In this embodiment, the microprocessor 141 in each of the signal processing modules 14 transmits the stored maximum power value to the control device 20 via the corresponding power management bus bar 30. As a result, the control device 20 can obtain the maximum power of the two power supply devices 10. In addition, each of the signal processing modules 14 is electrically connected to an input detection circuit (not shown) and an output detection circuit (not shown). The input detection circuit is electrically connected to the AC power source 3, and the output detection circuit is electrically connected to the output circuit 11. As a result, each of the signal processing modules 14 detects the input voltage information and the real-time output power value by the input detection circuit and the output detection circuit, respectively, and transmits the input voltage information and the real-time output power value to the control device 20.

[0031] For example, as shown in Table 1 below, if the maximum power of the first power supply device 10A is 1200W and the maximum power of the second power supply device 10B is 2000W, the output powers of the two power supply devices 10 and the corresponding proportions, the voltage of the shared signal, the output power of the first power supply device 10A, and the output power of the second power supply device 10B are shown in Table 1.

[0032] Table 1 exemplarily shows the proportionality corresponding to the output power for each level difference of 10%, but the proportionality corresponding to the output power may actually be a level difference smaller than 10%.

[0033] The first power supply device 10A and the second power supply device 10B each transmit their maximum power value to the control device 20. The comparison module 12 in each power supply device 10 has not yet received the compensation signal. Therefore, each power supply device 10 outputs its output power according to the voltage of the received shared signal and the feedback signal, that is, outputs its output power according to the corresponding proportion to the voltage of the shared signal. When the output power of each power supply device 10 is stable, the voltage of the feedback signal is equal to the voltage of the shared signal. For example, when the shared signal is 4V, the output power of the first power supply device 10A is 600W, the output power of the second power supply device 10B is 1000W, and the feedback signal is also 4V.

[0034] Table 1. Related data of the first power supply device and the second power supply device TIFF0007603868000002.tif96169

[0035] In step S12, when a control condition is met, the control device 20 outputs a control signal to the one of the at least two power supply devices 10 having the highest maximum power. The control condition includes a condition that the maximum power of the one of the at least two power supply devices 10 having the highest maximum power is greater than a predetermined maximum power and is greater than the maximum power of the other power supply device 10. When the two power supply devices 10 do not meet the control condition, for example, when the two power supply devices 10 have the same maximum power, the control device 20 does not output the control signal to any of the power supply devices 10.

[0036] In this embodiment, the predetermined maximum power may be created in advance in the control device 20. The predetermined maximum power may be set, for example, as 1000 W, which is the upper limit of the safety regulations in the low voltage range, but may be set according to needs without being limited thereto. When the control device 20 determines that the maximum power (2000 W) of the second power supply device 10B is greater than the predetermined maximum power (1000 W) and greater than the maximum power (1200 W) of the first power supply device 10A, the control device 20 transmits the control signal to the second power supply device 10B via the corresponding power management bus bar 30. Since the maximum power of the first power supply device 10A is relatively low, the control device 20 does not output the control signal to the first power supply device 10A.

[0037] In this embodiment, the control device 20 stores the data related to the first power supply device 10A and the second power supply device 10B shown in Table 1, and generates a compensation voltage value for adjusting the output power of the second power supply device 10B based on the data shown in Table 1. For example, when the output power of the first power supply device 10A is 600W and the corresponding voltage value is 4V, the control device 20 calculates the difference between the voltage value (2.4V) of the output power (1000W) of the second power supply device 10B and the corresponding voltage value of the output power of the second power supply device 10B of 600W. At this time, the difference between the voltage values ​​is 4V-2.4V=1.6V. Therefore, the control device 20 generates the compensation voltage value correspondingly based on the difference value (1.6V).

[0038] In step S13, the one of the at least two power supply devices 10 with the highest maximum power adjusts its output power based on the control signal, so that the output powers of the at least two power supply devices 10 are equal or close to each other.

[0039] In this embodiment, when the microprocessor 141 of the signal processing module 14 in the second power supply device 10B receives a control signal, it controls the selection circuit 142 to generate the compensation signal according to the control signal, and the selection circuit 142 outputs the compensation signal to the conversion circuit 121 in the comparison module 12. The conversion circuit 121 outputs the conversion signal to the comparison circuit 122 according to the compensation signal and the feedback signal.

[0040] For example, the control signal sent by the control device 20 includes the compensation voltage value (take 1.6V as an example), and the microprocessor 141 controls the selection circuit 142 to generate a compensation signal according to the compensation voltage value in the control signal, and the voltage in the compensation signal is the compensation voltage value. In step S11, since the output power of the second power supply device 10B has been stabilized, the voltage of the feedback signal is equal to the voltage of the shared signal (4V). The conversion circuit 121 obtains the voltage of the conversion signal based on the voltage of the feedback signal and the voltage of the compensation signal to be 5.6V (i.e., 4V+1.6V).

[0041] The comparison circuit 122 compares the voltage (5.6V) output by the conversion circuit 121 with the voltage (4V) of the shared signal, and outputs the corresponding adjustment signal to the output power adjustment module 13. Since the voltage output by the conversion circuit 121 is greater than the voltage of the shared signal, the output power adjustment module 13 adjusts the output power output by the output circuit 11 based on the adjustment signal, and reduces the output power of the second power supply device 10B. That is, the voltage of the feedback signal in the second power supply device 10B is reduced accordingly, and the voltage of the conversion signal output by the conversion circuit 121 is also reduced accordingly. Until the voltage of the conversion signal is equal to the voltage of the shared signal (4V), the comparison circuit 122 stops outputting the voltage adjustment signal, thereby maintaining the output power of the second power supply device 10B stable. At this time, the voltage of the feedback signal is equal to 2.4V, and the output power of the second power supply device 10B is 600W. That is, when the shared signal is 4V, if the first power supply device 10A does not receive a control signal, it outputs the output power (600W) without adjusting its output power. On the other hand, if the second power supply device 10B receives a control signal, it outputs the adjusted output power (600W). This achieves the objective that the output powers of the two power supply devices 10 are equal or close to each other, and also optimizes the reliability of the power supply system 100 by extending the life of the one with the highest maximum power.

[0042] When the load 1 requires a higher power, the voltage of the shared signal increases, and the two power supplies 10 increase their output power together, so that the output powers of both remain equal or close to each other. On the other hand, when the load 1 requires a lower power, the voltage of the shared signal decreases, and the two power supplies 10 decrease their output power together, so that the output powers of both remain equal or close to each other.

[0043] The power supply method according to the first embodiment described above can be applied whether the input voltage of the AC power source 3 to which the two power supply devices 10 are connected is in the high voltage range or the low voltage range.

[0044] For example, in the case of the low voltage range, since the output power of the second power supply device 10B has already been adjusted low, when the adjusted output power of the second power supply device 10B has already reached or is approaching the upper limit of the safety regulation, the sum of the output power of the two power supply devices 10 reaches 1920W (960W+960W), thereby achieving the objective of maximizing the sum of the output power of the power supply system 100. When the second power supply device 10B is not adjusted, the sum of the output power of the two power supply devices 10 becomes 1600W (600W+1000W).

[0045] The power supply system and method according to a second preferred embodiment of the present invention further adjusts the output power of the one of the at least two power supply devices 10 having the highest maximum power when it is in a low voltage range in combination with an AC power source 3. The input voltage of the AC power source 3 to which the two power supply devices 10 are connected is in the low voltage range. The power supply system and method according to this embodiment are almost the same as those of the first embodiment, but differ in that the control conditions are different. In detail, the control conditions include the following first and second conditions. The first condition is that the input voltage information of the power supply device 10 having the highest maximum power falls within a low voltage range. The second condition is that the maximum power of the one of the at least two power supply devices 10 having the highest maximum power is greater than a predetermined maximum power and is also greater than the maximum power of the other power supply device 10.

[0046] Therefore, the power supply method according to the present embodiment can also achieve the objective of maximizing the total output power of the power supply system when the input voltage falls within the low voltage range.

[0047] FIG. 5 shows a power supply 10' according to a third preferred embodiment of the present invention, which has almost the same configuration as the first embodiment, but has the following differences. In this embodiment, the microprocessor 141' in each of the signal processing modules 14' has an analog voltage output means 141B, and the microprocessor 141' outputs voltages with different voltage values ​​to form the compensation signal, or when the microprocessor 141' outputs 0V, it does not output the compensation signal. Therefore, the selection circuit 142 may be omitted for each of the signal processing modules 14'. And the microprocessor 141' is directly electrically connected to the conversion circuit 121. When the microprocessor 141' of the one with the highest maximum power in the at least two power supplies 10' receives the control signal, the microprocessor 141' outputs the compensation signal according to the control signal, which can also achieve the effect that the output powers of the at least two power supplies 10' are equal or close to each other.

[0048] Similarly, the power supply device 10' according to this embodiment may be used in combination with the power supply method according to the second embodiment.

[0049] In the first and second embodiments, when the power supply system includes three or more power supply devices, the second condition of the control condition according to the first embodiment or the control condition according to the second embodiment is a condition that the maximum power of the power supply device having the highest maximum power among the plurality of power supply devices is greater than a predetermined maximum power and is greater than the maximum power of the power supply device having the lowest maximum power. Also, the control signal is output to the power supply device having the highest maximum power among the plurality of power supply devices, and the power supply device having the highest maximum power among the plurality of power supply devices adjusts its output power so that the output power of the power supply device having the highest maximum power is equal to or close to that of the power supply device having the lowest maximum power.

[0050] The above description is merely a preferred embodiment of the present invention, and any equivalent replacement obtained by applying the scope of the patent together with the specification of the present invention should be included in the scope of the patent of the present invention. [Explanation of symbols]

[0051] 100 Power Supply System 10, 10' power supply 10A first power supply device 10B Second power supply device 11 Output circuit 12 Comparison Module 121 Switching Circuit 122 Comparison circuit 13 Output Power Adjustment Module 14, 14' Signal Processing Module 141, 141' Microprocessor 141A Memory 141B Analog voltage output means 142 Selection circuit 142A Operational Amplifier 142A1 Output end 20 Control device 30 Power Management Busbar 1. Load 2 Load Sharing Busbars 3 AC power supply R1, R2, R3, R4 Resistance

Claims

1. 1. A power supply system used to supply power to a load and connected to a load sharing busbar, comprising: The power supply system includes at least two power supply devices and a control device; The at least two power supply devices are connected in parallel to the load, each of the power supply devices has a maximum power and outputs an output power to the load that is less than or equal to each of the maximum powers, each of the power supply devices receives a sharing signal from the load sharing busbar and adjusts its respective output power based on the sharing signal; The control device is electrically connected to the at least two power supply devices, and obtains the maximum power from each of the power supply devices. When a control condition is satisfied, the control device outputs a control signal to the at least two power supply devices having the highest maximum power, and the at least two power supply devices having the highest maximum power adjusts its output power so that the output powers of the at least two power supply devices are equal or close to each other; A power supply system characterized in that the control condition includes a condition that the maximum power of the one of the at least two power supply devices having the highest maximum power is greater than a predetermined maximum power and is also greater than the maximum power of the other of the power supply devices.

2. The at least two power supply devices are electrically connected to an AC power source, and each of the power supply devices transmits input voltage information of the corresponding AC power source to the control device; 2. The power supply system according to claim 1, wherein the control conditions further include a condition that the input voltage information of the power supply device having the highest maximum power among the at least two power supply devices falls within a low voltage range.

3. The power supply device includes an output circuit, a comparison module, an output power adjustment module, and a signal processing module, the output circuit is connected to the load and outputs a feedback signal, the comparison module is electrically connected to the load sharing busbar, the output circuit, and the output power adjustment module, the signal processing module is electrically connected to the control device and the comparison module, and the comparison module outputs an adjustment signal to the output power adjustment module based on the sharing signal and the feedback signal to adjust the output power; 2. The power supply system of claim 1, wherein when the signal processing module of the power supply device having the highest maximum power among the at least two power supply devices receives the control signal, the signal processing module outputs a compensation signal to the comparison module, and the comparison module outputs the adjustment signal to the output power adjustment module based on the shared signal, the feedback signal and the compensation signal.

4. The comparison module in each of the power supply devices includes a conversion circuit and a comparison circuit, the conversion circuit receives the feedback signal and outputs the feedback signal to the comparison circuit, and the comparison circuit outputs the adjustment signal according to the feedback signal and the shared signal; 4. The power supply system of claim 3, wherein when the signal processing module of the at least two power supply devices having the highest maximum power outputs the compensation signal, the corresponding conversion circuit receives the compensation signal and outputs a conversion signal to the comparison circuit based on the compensation signal and the feedback signal, and the comparison circuit outputs the adjustment signal based on the conversion signal and the shared signal.

5. Each of the signal processing modules includes a microprocessor and a selection circuit, the microprocessor is electrically connected to the control device and the selection circuit, and the selection circuit is electrically connected to the conversion circuit; 5. The power supply system of claim 4, wherein when the microprocessor of the power supply device having the highest maximum power receives the control signal, the microprocessor controls the selection circuit to output the compensation signal based on the control signal.

6. Each of the signal processing modules includes a microprocessor electrically connected to the conversion circuit; 5. The power supply system of claim 4, wherein when the microprocessor of the power supply device having the highest maximum power receives the control signal, the microprocessor outputs the compensation signal based on the control signal.

7. A power supply method for a power supply system including at least two power supply devices and a control device, the at least two power supply devices being connected in parallel to a load, each of the power supply devices having a maximum power and outputting an output power to the load that is equal to or less than the maximum power, comprising: Each of the power supply devices receives a shared signal from a load sharing busbar and adjusts its output power based on the shared signal; The power supply method includes: the control device obtaining each of the maximum powers from each of the power supplies; and the control device includes a step of outputting a control signal to a power supply device having the highest maximum power among the at least two power supply devices when a control condition is met; the control condition includes a condition that the maximum power of the one of the at least two power supply devices having the highest maximum power is greater than a predetermined maximum power and is also greater than the maximum power of the other of the power supply devices; A power supply method comprising: adjusting an output power of the at least two power supply devices, the output power of which is the highest among the at least two power supply devices, based on the control signal so that the output powers of the at least two power supply devices are equal or close to each other.

8. The at least two power supply devices are electrically connected to an AC power source; The power supply method includes: each of the power supply devices transmitting input voltage information of the corresponding AC power source to the control device; The power supply method according to claim 7 , wherein the control conditions further include a condition that the input voltage information of the one of the at least two power supply devices having the highest maximum power falls within a low voltage range.

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