Energy storage module, power supply system and control method of energy storage module

Abstract

The application discloses an energy storage module, a power supply system and a control method of the energy storage module. The energy storage module comprises a bidirectional DC / DC converter and an energy storage unit. The first end of the bidirectional DC / DC converter is connected with the energy storage unit. The control method comprises adjusting a reference signal according to a compensation signal, obtaining a current reference signal corresponding to the bidirectional DC / DC converter based on the adjusted reference signal and a current sharing bus signal provided by a power supply module connected to the second end of the bidirectional DC / DC converter, and then controlling the working state of the energy storage module.

Description

Technical Field

[0001] This invention relates to the field of power supply, and in particular to an energy storage module, a power supply system, and a control method for the energy storage module. Background Technology

[0002] In server power supply applications, the common architecture of a power supply unit (PSU) is a two-stage topology: the front stage is a power factor correction circuit (PFC), and the back stage is a DC / DC converter.

[0003] With the development of AI (Artificial Intelligence) and high-performance computing, the power consumption of components such as graphics processing units (GPUs) and central processing units (CPUs) in servers is constantly increasing. As the demands of high-performance computing grow, server power supply systems need to cope with higher power requirements, greater heat dissipation pressure, and more stable voltage control requirements, necessitating more intelligent power management systems to ensure stable operation. Because AI loads often exhibit significant fluctuations, server power output can vary drastically, resulting in inconsistent AC input waveforms and unnecessary noise on the power grid, impacting the quality of the input power grid.

[0004] In existing technologies, energy storage modules such as capacitors are used to compensate for fluctuations in input current, achieving peak shaving and valley filling. When the voltage of an energy storage unit (e.g., a capacitor) in the energy storage module is charged to near its maximum threshold, the usual practice is to limit its charging power, but no additional control is applied to the discharging. The desired outcome at this point is for the energy storage unit to charge less and discharge more. Similarly, when the voltage of an energy storage unit (i.e., the capacitor voltage) is close to its minimum threshold, further discharge is typically limited, but no additional control is applied to the charging. The desired outcome at this point is for the energy storage unit to discharge less and charge more.

[0005] Therefore, how to design an energy storage module, a power supply system, and a control method for the energy storage module, using the energy storage module to compensate for fluctuations in the input current, and simultaneously achieving less charging and more discharging when the energy storage unit is close to the highest threshold, and less discharging and more charging when the voltage of the energy storage unit is close to the lowest threshold, is an important research topic for the inventors. Summary of the Invention

[0006] One objective of this invention is to provide a control method for an energy storage module, thereby solving the problems of the prior art.

[0007] To achieve the aforementioned objectives, the present invention proposes a control method for an energy storage module, wherein the energy storage module includes a bidirectional DC / DC converter and an energy storage unit. A first terminal of the bidirectional DC / DC converter is connected to the energy storage unit. The control method includes adjusting a reference signal based on a compensation signal, and obtaining a current reference signal corresponding to the bidirectional DC / DC converter based on the adjusted reference signal and a current-sharing bus signal provided by a power module connected to the second terminal of the bidirectional DC / DC converter, thereby controlling the operating state of the energy storage module. The compensation signal is determined by the voltage of the energy storage unit.

[0008] In one embodiment, the control method further includes a compensation signal that is positive when the voltage of the energy storage unit is greater than a high voltage threshold and a compensation signal that is negative when the voltage of the energy storage unit is less than a low voltage threshold.

[0009] In one embodiment, the control method further includes subtracting the reference signal from the compensation signal to obtain an adjusted reference signal.

[0010] In one embodiment, the compensation signal is positively correlated with the voltage of the energy storage unit.

[0011] In one embodiment, when the voltage of the energy storage unit is between a low voltage threshold and a high voltage threshold, the compensation signal is zero.

[0012] In one embodiment, when the voltage of the energy storage unit is between a low voltage threshold and a high voltage threshold, the compensation signal is positively correlated with the voltage of the energy storage unit.

[0013] In one embodiment, when the voltage of the energy storage unit is between a low voltage threshold and a high voltage threshold, the rate of change of the compensation signal with the voltage of the energy storage unit is smaller than the rate of change of the compensation signal with the voltage of the energy storage unit when the voltage of the energy storage unit is greater than the high voltage threshold and less than the low voltage threshold.

[0014] In one embodiment, the compensation signal is linearly related to the voltage of the energy storage unit.

[0015] In one embodiment, when the voltage of the energy storage unit exceeds a high voltage threshold and continues to increase to a second high voltage threshold, the adjusted reference signal is set to zero, thereby causing the energy storage unit to exit the charging mode.

[0016] In one embodiment, when the voltage of the energy storage unit is lower than the low voltage threshold and continues to decrease to reach the second low voltage threshold, the adjusted reference signal is made equal to the rated value of the current sharing bus sampling signal, so that the energy storage unit exits the discharge mode. The current sharing bus sampling signal is obtained by sampling the current sharing bus signal, and the rated value of the current sharing bus sampling signal represents the output current when the power module outputs the rated power.

[0017] In one embodiment, the reference signal characterizes the average power of the power module.

[0018] In one embodiment, the reference signal is determined by the current sharing bus signal.

[0019] In one embodiment, the control method further includes generating a control signal for controlling the bidirectional DC / DC converter based on a current reference signal and a sampled signal of the inductor current of the bidirectional DC / DC converter.

[0020] In one embodiment, the control method further includes sampling the current sharing bus signal to obtain a current sharing bus sampling signal; when the current sharing bus sampling signal is greater than the difference between the reference signal and the compensation signal, controlling the energy storage unit to operate in a discharge mode so that the energy storage unit discharges the load of the power module; when the current sharing bus sampling signal is less than the difference between the reference signal and the compensation signal, controlling the energy storage unit to operate in a charging mode so that the power module stores energy in the energy storage unit, thereby compensating for the fluctuation of the input current of the power module.

[0021] Another objective of this invention is to provide an energy storage module that addresses the problems of the prior art.

[0022] To achieve the aforementioned objectives, the energy storage module proposed in this invention includes a bidirectional DC / DC converter and an energy storage unit. A first terminal of the bidirectional DC / DC converter is connected to the energy storage unit, and a second terminal of the bidirectional DC / DC converter is connected to the output terminal of the power module. Each energy storage module also includes a controller configured to employ the aforementioned control method.

[0023] Another objective of this invention is to provide an energy storage module that solves the problems of the prior art.

[0024] To achieve the aforementioned objectives, the power supply system proposed in this invention includes at least one power module and at least one energy storage module. The output terminal of each power module is connected to a load, wherein each power module converts its output current into a voltage signal and transmits it to a current-sharing bus. The output terminal of each energy storage module is connected, and each energy storage module includes a bidirectional DC / DC converter and an energy storage unit. A first terminal of the bidirectional DC / DC converter is connected to the energy storage unit, and a second terminal of the bidirectional DC / DC converter is connected to the output terminal of the power module. Each energy storage module also includes a controller configured to employ the aforementioned control method, wherein the voltage signal on the current-sharing bus is a current-sharing bus signal.

[0025] In one embodiment, the at least one power module is housed in the same housing.

[0026] In one embodiment, the at least one energy storage module is housed in the same housing.

[0027] The present invention has the following features and advantages through the proposed control method for the energy storage module, the energy storage module and the power supply system: the energy storage module charges less and discharges more when it is close to the high voltage threshold, thereby preventing overcharging, and the energy storage module discharges less and charges more when it is close to the low voltage threshold, thereby preventing over-discharging.

[0028] To gain a deeper understanding of the techniques, means, and effects employed by this invention to achieve its intended purpose, please refer to the following detailed description and accompanying drawings. It is believed that the purpose, features, and characteristics of this invention can be understood in a thorough and specific manner from these drawings. However, the drawings are provided for reference and illustration only and are not intended to limit the scope of this invention. Attached Figure Description

[0029] Figure 1 : This is a circuit block diagram of the power supply system of the power module combined with the energy storage module of the present invention;

[0030] Figure 2 : This is a circuit diagram of the energy storage module of the present invention;

[0031] Figure 3 This is a schematic block diagram of the single power supply module and the single energy storage module of the present invention.

[0032] Figure 4 This is a schematic block diagram of multiple power supply modules and multiple energy storage modules of the present invention;

[0033] Figure 5 : This is a block diagram of the control loop of the energy storage module of the present invention;

[0034] Figure 6 This is a schematic diagram illustrating the relationship between the compensation signal and the voltage of the energy storage unit in one embodiment of the present invention.

[0035] Figure 7 This is a schematic diagram illustrating the relationship between the compensation signal and the voltage of the energy storage unit in another embodiment of the present invention.

[0036] Figure 8 : This is a schematic diagram illustrating the principle of the compensation signal setting in this invention;

[0037] Figure 9 : This is a flowchart of the control method for the energy storage module of the present invention;

[0038] Explanation of reference numerals in the attached figures:

[0039] 10: Power supply module;

[0040] 10-1, 10-2: Power supply modules;

[0041] 20: Energy storage module;

[0042] 20-1, 20-2: Energy storage modules;

[0043] 11: Power factor correction circuit;

[0044] 12: DC / DC converter;

[0045] 21: Bidirectional DC / DC converter;

[0046] 22: Energy storage unit;

[0047] L1: Inductance;

[0048] S1: First switching transistor;

[0049] S2: Second switching transistor;

[0050] C1: Capacitor;

[0051] C2: Energy storage capacitor;

[0052] V_ishare: Current sharing bus signal;

[0053] 50: Load;

[0054] Vc: Voltage of the energy storage unit;

[0055] Vsamp: Current sharing bus sampling signal;

[0056] Vref: Reference signal;

[0057] Vref': Adjusted reference signal;

[0058] Vcomp: Compensation signal;

[0059] VH1: High voltage threshold;

[0060] VH2: Second highest voltage threshold;

[0061] VL1: Low voltage threshold;

[0062] VL2: Second low voltage threshold;

[0063] iL: Sampling signal of inductor current;

[0064] Iref: Current reference signal for the energy storage unit;

[0065] Iload: Load current;

[0066] Duty: The duty cycle of the control signal;

[0067] S10~S30: Steps. Detailed Implementation

[0068] The technical content and detailed description of the present invention are explained below with reference to the accompanying drawings.

[0069] Please see Figure 1 The diagram shown is a circuit block diagram of the power supply system of the power module combined with the energy storage module of the present invention. The power supply system includes at least one power supply unit (PSU) 10 and at least one energy storage module (CBU) 20. The power supply module 10 includes, for example but not limited to, a front-end power factor correction circuit (PFC) 11 and a rear-end DC / DC converter 12. The front-end power factor correction circuit (PFC) 11 receives AC power Vac and converts it to DC power, which is then converted to DC power by the rear-end DC / DC converter 12 before being output. The output side of the rear-end DC / DC converter 12 is connected to a load 50 (see [reference]). Figure 3 or Figure 4 ), and to supply power to load 50. In some embodiments, the subsequent DC / DC converter 12 may also be a unipolar AC / DC converter.

[0070] The energy storage module 20 mainly includes a bidirectional DC / DC converter 21 and an energy storage unit 22. There are many architectures for the bidirectional DC / DC converter 21; this invention uses a common bidirectional buck-boost converter as an example, but this is not intended to limit the invention. Similarly, the energy storage unit 22 can be implemented using energy storage elements with energy storage functions; this invention uses an energy storage capacitor C2 (see [reference]). Figure 2 The invention is illustrated using an example, but is not limited thereto. Furthermore, the energy storage capacitor C2 can be, for example, a supercapacitor.

[0071] Specifically, such as Figure 1 As shown, the output of each power module 10 is connected to the load 50, and each power module 10 converts its output current into a voltage signal and transmits it to the current sharing bus. The output of each energy storage module 20 is connected, and each energy storage module 20 includes a bidirectional DC / DC converter 21 and an energy storage unit 22. The first terminal of the bidirectional DC / DC converter 21 is connected to the energy storage unit 22, and the second terminal of the bidirectional DC / DC converter 21 is connected to the output of the power module 10. Each energy storage module 20 also includes a controller configured to execute the control method of the energy storage module 20. The voltage signal on the current sharing bus is the current sharing bus signal.

[0072] Specifically, when the load 50 is too heavy, without the energy storage module 20, the input current of the power module 10 would be too high. However, when the energy storage module 20 is connected, it is controlled to operate in discharge mode, releasing energy from the energy storage unit 22 to the load 50 via the bidirectional DC / DC converter 21, thus working with the power module 10 to supply power to the load 50 and keeping the input current constant. Conversely, when the load 50 is too light, the energy storage module 20 is controlled to operate in charging mode, allowing excess input power to be fed into the energy storage unit 22 via the bidirectional DC / DC converter 21 to charge the energy storage unit 22, thereby keeping the input current constant. Therefore, by providing or receiving current through the energy storage module 20, the output current of the power module 10 does not need to increase or decrease rapidly in a short period of time. This allows the power module 10 to maintain a constant input current and reduce its impact on the power grid.

[0073] Please see Figure 2 The diagram shown is a circuit diagram of the energy storage module of the present invention. As previously described, the bidirectional DC / DC converter 21 of the energy storage module 20 is illustrated using a bidirectional buck-boost converter as an example. Therefore, the bidirectional DC / DC converter 21 includes an inductor L1, a first switch S1, a second switch S2, and a capacitor C1. When the energy storage module 20 operates in discharge mode, the bidirectional DC / DC converter 21 operates in boost mode; when the energy storage module 20 operates in charging mode, the bidirectional DC / DC converter 21 operates in buck mode. Of course, in other embodiments, the opposite may also occur, depending on the configuration of the energy storage unit 22.

[0074] Please see Figure 3The diagram shows a schematic block diagram of the single power supply module and single energy storage module of the present invention. The power supply module 10-1 converts its output current into a voltage signal and connects it to the current sharing bus. This voltage signal on the current sharing bus is called the current sharing bus signal V_ishare. For example, according to the ORV3 (Open Rack Standard V3) specifications, when the power supply module 10-1 outputs 50% of its rated current, the current sharing bus signal V_ishare is 3.5 volts; when the power supply module 10-1 outputs 100% of its rated current, the current sharing bus signal V_ishare is 7 volts. The energy storage module 20-1 can obtain the corresponding load information simply by sampling the current sharing bus signal V_ishare on the current sharing bus. Typically, the current sharing bus signal V_ishare is a signal positively correlated with the output current of the power supply module 10-1, allowing the energy storage module 20-1 to estimate the load condition using the current sharing bus signal V_ishare provided by the power supply module 10-1. For example, a large value of the current sharing bus signal V_ishare indicates that the load 50 requires more power. Conversely, a small value indicates that the load 50 requires less power. A large rate of change in the value of the current sharing bus signal V_ishare indicates that the load 50 is rapidly increasing or decreasing. Therefore, by using the current sharing bus signal V_ishare, there is no need to add additional devices to sample the output current of the power module 10-1 to obtain load information. Furthermore, since the power module 10-1 is typically a pre-packaged unit without a pre-defined location for current sampling, the load information can be cleverly obtained by utilizing the existing information within the power module 10-1.

[0075] Please see Figure 4 As shown, it is a schematic block diagram of multiple power supply modules and multiple energy storage modules of the present invention. Compared to Figure 3 The single power supply module 10-1 and the single energy storage module 20-1 shown are shown. Figure 4This diagram illustrates the parallel operation of multiple (two) power modules 10-1 and 10-2, in conjunction with the coordinated operation of multiple (two) energy storage modules 20-1 and 20-2. In this parallel power module architecture, each power module 10-1 and 10-2 converts its output current into a corresponding voltage signal, and these multiple voltage signals are connected to a shared current-sharing bus. Generally, systems with multiple power modules in parallel require current sharing. Therefore, each power module 10-1 and 10-2 compares its output current with the current-sharing bus signal V_ishare on the shared bus and makes corresponding adjustments to achieve current sharing. For example, if the voltage signal corresponding to the output current of power module 10-1 is lower than the current-sharing bus signal V_ishare, it indicates that power module 10-1 is supplying less current. In this case, the control circuit will control power module 10-1 to output more power to increase its output current, and vice versa. Therefore, the output current of each power module 10-1 and 10-2 tends to be the same, achieving the purpose of load sharing. That is, the current sharing bus signal V_ishare can characterize the average load information of multiple power modules.

[0076] Furthermore, through the coordinated operation of two energy storage modules 20-1 and 20-2 and two power modules 10-1 and 10-2, when the load 50 is too heavy, the energy storage modules 20-1 and 20-2 can be controlled to operate in discharge mode, releasing energy to the load 50; or when the load 50 is too light, the energy storage modules 20-1 and 20-2 can be controlled to operate in charging mode, so that the excess input power charges the energy storage units 22 of the energy storage modules 20-1 and 20-2, thus keeping the input current constant. In addition, although the figure uses two power modules and two energy storage modules as an example, it should be understood that the number of power modules and energy storage modules is not a one-to-one correspondence; the number of parallel modules can be set according to the needs of the load 50. In other embodiments, multiple power modules are connected in parallel and placed in the same housing, and multiple energy storage modules are connected in parallel and placed in the same housing, both placed in power supply racks.

[0077] Please see Figure 9 The diagram shows a flowchart of the control method for the energy storage module of the present invention, and is shown in conjunction with [other diagrams]. Figure 5 The diagram shown is a block diagram of the control loop of the energy storage module of the present invention. The control method of the energy storage module includes, firstly, adjusting a reference signal Vref according to a compensation signal Vcomp (step S10), wherein the compensation signal Vcomp is determined by the voltage Vc of the energy storage unit 22. Specifically, the adjusted reference signal Vref' is obtained by subtracting the compensation signal Vcomp from the reference signal Vref.

[0078] See also Figure 9As shown, after step S10, based on the adjusted reference signal Vref' (i.e., Vref' = Vref - Vcomp) and the current sharing bus signal V_ishare provided by the power module 10, the current reference signal Iref corresponding to the bidirectional DC / DC converter 21 is obtained (step S20), thereby controlling the working state of the energy storage module (step S30).

[0079] Please see Figure 5 The diagram shows a block diagram of the control loop of the energy storage unit of this invention. The adjusted reference signal Vref' is obtained by subtracting the compensation signal Vcomp from the reference signal Vref. The current sharing bus signal V_ishare is sampled to obtain the current sharing bus sampling signal Vsamp. The operating mode of the energy storage module 20 is controlled based on the difference between the adjusted reference signal Vref' and the current sharing bus sampling signal Vsamp. The rated value of the current sharing bus sampling signal Vsamp represents the output current when the power module 10 outputs its rated power. Furthermore, in this invention, the energy storage module 20 is in standby mode, meaning the pre-charging process of the energy storage module 20 has been completed, and the energy storage module 20 is in a state where it can be charged and discharged, ready to compensate for changes in the input current. Therefore, in this invention, the reference signal Vref represents the average power of the power module 10, and the reference signal Vref is obtained by processing the current sharing bus signal V_ishare. It should be understood that there are many ways to obtain the reference signal Vref. For example, the reference signal Vref is the average value of the current sharing bus sampling signal Vsamp over a period of time, or the reference signal Vref is the value obtained by filtering the current sharing bus sampling signal Vsamp. This invention does not limit this.

[0080] Specifically, the difference between the regulated reference signal Vref' and the current sharing bus sampling signal Vsamp is compensated (e.g., but not limited to, a PI controller) to generate a current reference signal Iref corresponding to the bidirectional DC / DC converter 21, and the duty cycle Duty of the control signal controlling the switching transistors in the bidirectional DC / DC converter 21 is generated based on the current reference signal Iref and the sampling signal iL of the inductor current in the bidirectional DC / DC converter 21.

[0081] In some embodiments, the charging mode and discharging mode of the energy storage module 20 can be implemented using the same control loop, i.e. Figure 5 The control loop is shown. When the current reference signal Iref is greater than zero, the sampling signal iL of the inductor current is greater than zero, and the energy storage module 20 enters the charging mode. When the current reference signal Iref is less than zero, the sampling signal iL of the inductor current is also less than zero, and the energy storage module 20 enters the discharging mode. Furthermore, in other embodiments, the charging mode and discharging mode of the energy storage unit 22 can also be implemented using two control loops. The control loop for the charging mode can be as follows: Figure 5 is implemented by the control loop, while the control loop in the discharge mode can swap the positions of the current sharing bus sampling signal Vsamp and the adjusted reference signal Vref', that is, the current sharing bus sampling signal Vsamp minus the adjusted reference signal Vref' is compensated to obtain the current reference signal Iref, so as to ensure that the current reference signal Iref is always greater than zero. No matter which of the above control loops is adopted, when the current sharing bus sampling signal Vsamp is greater than the difference between the reference signal and the compensation signal (that is, Vsamp>Vref-Vcomp), the energy storage module 20 is controlled to operate in the discharge mode, so that the energy storage unit 22 discharges to the load of the power supply module 10. When the current sharing bus sampling signal Vsamp is less than the difference between the reference signal and the compensation signal (that is, Vsamp<Vref-Vcomp), the energy storage module 20 is controlled to operate in the charging mode, so that the power supply module 10 stores energy in the energy storage unit 22, thereby compensating for the fluctuation of the input current of the power supply module 10.

[0082] In the present invention, two main embodiments for determining the compensation signal Vcomp according to the voltage Vc of the energy storage unit 22 are mainly proposed. The first embodiment is as Figure 6 shown, which is a schematic diagram of the relationship between the compensation signal and the voltage of the energy storage unit according to an embodiment of the present invention. Specifically, when the voltage Vc of the energy storage unit 22 is greater than the high voltage threshold VH1, the compensation signal Vcomp is a positive value; on the contrary, when the voltage Vc of the energy storage unit 22 is less than the low voltage threshold VL1, the compensation signal Vcomp is a negative value. Specifically, when the voltage Vc of the energy storage unit 22 is greater than the high voltage threshold VH1, the compensation signal Vcomp is positively correlated with the voltage Vc of the energy storage unit 22, that is, the larger the voltage Vc of the energy storage unit 22 is, the larger the compensation signal Vcomp is. Further, the positive correlation between the compensation signal Vcomp and the voltage Vc of the energy storage unit 22 may be a linear relationship. Similarly, when the voltage Vc of the energy storage unit 22 is less than the low voltage threshold VL1, the compensation signal Vcomp is positively correlated with the voltage Vc of the energy storage unit 22, that is, the smaller the voltage Vc of the energy storage unit 22 is (the larger the negative value is), the smaller the compensation signal Vcomp is (the larger the negative value is). Further, the positive correlation between the compensation signal Vcomp and the voltage Vc of the energy storage unit 22 may be a linear relationship.

[0083] In the following, with reference to Figure 8Let's further explain the setting principle of the compensation signal Vcomp. Taking the example of the voltage Vc of energy storage unit 22 being greater than the high voltage threshold VH1, when the voltage Vc of energy storage unit 22 reaches the high voltage threshold VH1, it indicates that energy storage unit 22 is almost fully charged. If it is in charging mode at this time, energy storage unit 22 is prone to overcharging, meaning its voltage Vc can easily exceed the maximum limit, which is undesirable. If it is in discharging mode, energy storage unit 22 discharges normally, but since it has a lot of energy, it's desirable for it to release more energy. Therefore, when the voltage Vc of energy storage unit 22 reaches the high voltage threshold VH1, the compensation signal Vcomp is used to achieve less charging and more discharging of energy storage unit 22.

[0084] like Figure 8 As shown, the load current Iload changes dynamically. In the first interval, the load suddenly increases, and the energy storage module 20 is in discharge mode. Without the addition of the compensation signal Vcomp, the energy released by the energy storage module 20 is as shown by the area of ​​shaded region 1. After the compensation signal Vcomp is added, since the voltage Vc of the energy storage unit 22 is greater than the high voltage threshold VH1, the compensation signal Vcomp is positive. Therefore, the adjusted reference signal Vref' is obtained by subtracting the compensation signal Vcomp from the reference signal Vref, and the adjusted reference signal Vref' is less than the original reference signal Vref, meaning the adjusted reference signal Vref' is smaller than the original reference signal Vref. Therefore, the energy released by the energy storage module 20 increases the area of ​​shaded region 2, meaning the energy storage module 20 discharges more than before compensation. Furthermore, the larger the voltage Vc of the energy storage unit 22, the larger the compensation signal Vcomp, and the smaller the adjusted reference signal Vref', resulting in more discharge. Correspondingly, in the second interval, the load suddenly decreases, and the energy storage module 20 is in charging mode. Without the addition of the compensation signal Vcomp, the energy stored in the energy storage module 20 is the area of ​​shadow 3 + shadow 4. With the compensation signal Vcomp added, it remains positive. Therefore, subtracting the compensation signal Vcomp from the reference signal Vref yields the adjusted reference signal Vref', which is smaller than the original reference signal Vref. This means the adjusted reference signal Vref' is smaller than the original reference signal Vref. Thus, the energy stored in the energy storage module 20 after compensation is only as shown in shadow 3, reducing the area of ​​shadow 4, meaning the energy storage module 20 charges less than before compensation. Furthermore, the larger the voltage Vc of the energy storage unit 22, the larger the compensation signal Vcomp, resulting in a smaller adjusted reference signal Vref' and less charging. Thus, the setting of the compensation signal Vcomp enables the energy storage unit 22 to discharge more and charge less when its voltage Vc exceeds the high voltage threshold VH1.

[0085] Similarly, when the voltage Vc of energy storage unit 22 drops to the low voltage threshold VL1, it indicates that the voltage of energy storage unit 22 is about to discharge to the minimum voltage state. If it is in discharge mode at this time, energy storage unit 22 is prone to over-discharge, meaning that the voltage Vc of energy storage unit 22 will fall below the minimum limit, which is undesirable. If it is in charging mode at this time, energy storage unit 22 charges normally, but since the energy of energy storage unit 22 is very low at this time, it is desirable for it to store more energy. Therefore, after the voltage Vc of energy storage unit 22 reaches the low voltage threshold VL1, the compensation signal Vcomp is used to achieve less discharge and more charging of energy storage unit 22. Those skilled in the art should understand that the principle is similar to the above, so this invention will not elaborate further.

[0086] Incidentally, when the voltage Vc of energy storage unit 22 is greater than the high voltage threshold VH1, the rate of change of the compensation signal Vcomp with the voltage Vc of energy storage unit 22 is a first rate of change; when the voltage Vc of energy storage unit 22 is less than the low voltage threshold VL1, the rate of change of the compensation signal Vcomp with the voltage Vc of energy storage unit 22 is a second rate of change. The first rate of change and the second rate of change can be the same, or the first rate of change can be greater than the second rate of change, or the first rate of change can be less than the second rate of change.

[0087] Furthermore, in this embodiment, when the voltage Vc of the energy storage unit 22 is between the low voltage threshold VL1 and the high voltage threshold VH1, the compensation signal Vcomp is zero. Therefore, no additional control over the charging and discharging of the energy storage unit 22 is required during this stage.

[0088] Furthermore, in some embodiments, the compensation signal Vcomp increases as the voltage Vc of the energy storage unit 22 increases. When the voltage Vc of the energy storage unit 22 increases from the high voltage threshold VH1 to the second high voltage threshold VH2, the adjusted reference signal is exactly zero, thereby causing the energy storage module 20 to exit the charging mode. Also, since the compensation signal Vcomp gradually increases, the adjusted reference signal gradually decreases to zero, thus causing the energy storage module 20 to slowly exit the charging mode. Similarly, when the voltage Vc of the energy storage unit 22 decreases from the low voltage threshold VL1 to the second low voltage threshold VL2, the adjusted reference signal is exactly equal to the rated value of the current sharing bus sampling signal Vsamp, thereby causing the energy storage module 20 to exit the discharging mode. And, since the compensation signal Vcomp gradually decreases, the adjusted reference signal gradually increases to the rated value of the current sharing bus sampling signal Vsamp, thus causing the energy storage module 20 to slowly exit the discharging mode. The rated value of the current sharing bus sampling signal Vsamp represents the output current when the power module 10 outputs rated power. In summary, the setting of the compensation signal Vcomp can also enable the soft exit of the energy storage module 20.

[0089] Second implementation example Figure 7 The diagram illustrates another embodiment of the relationship between the compensation signal and the voltage of the energy storage unit. When the voltage Vc of the energy storage unit 22 is greater than the high voltage threshold VH1, the compensation signal Vcomp is positive; conversely, when the voltage Vc of the energy storage unit 22 is less than the low voltage threshold VL1, the compensation signal Vcomp is negative. Therefore, when the voltage Vc of the energy storage unit 22 is greater than the high voltage threshold VH1, the compensation signal Vcomp is positively correlated with the voltage Vc of the energy storage unit 22; that is, the larger the voltage Vc of the energy storage unit 22, the larger the compensation signal Vcomp. Similarly, when the voltage Vc of the energy storage unit 22 is less than the low voltage threshold VL1, the compensation signal Vcomp is positively correlated with the voltage Vc of the energy storage unit 22; that is, the smaller the voltage Vc of the energy storage unit 22 (the larger the negative value), the smaller the compensation signal Vcomp (the larger the negative value). Furthermore, the positive correlation between the compensation signal Vcomp and the voltage Vc of the energy storage unit 22 can be a linear relationship.

[0090] Incidentally, when the voltage Vc of energy storage unit 22 is greater than the high voltage threshold VH1, the rate of change of the compensation signal Vcomp with the voltage Vc of energy storage unit 22 is a first rate of change; when the voltage Vc of energy storage unit 22 is less than the low voltage threshold VL1, the rate of change of the compensation signal Vcomp with the voltage Vc of energy storage unit 22 is a second rate of change. The first rate of change and the second rate of change can be the same, or the first rate of change can be greater than the second rate of change, or the first rate of change can be less than the second rate of change.

[0091] The setting method and compensation principle of the compensation signal Vcomp are the same as in the previous embodiment, and therefore will not be repeated. The difference between this embodiment and the previous embodiment is that when the voltage of the energy storage unit 22 is between the low voltage threshold VL1 and the high voltage threshold VH1, the compensation signal Vcomp is also positively correlated with the voltage Vc of the energy storage unit 22. In one embodiment, when the voltage Vc of the energy storage unit 22 is between the low voltage threshold VL1 and the high voltage threshold VH1, the rate of change of the compensation signal Vcomp with the voltage Vc of the energy storage unit 22 is a third rate of change. This third rate of change is less than the first rate of change, and less than the second rate of change.

[0092] like Figure 7 As shown, the magnitude of the first rate of change is Where Vcomp2 and Vcomp1 are positive values, with Vcomp2 greater than Vcomp1, and VH2 and VH1 are positive values, with VH2 greater than VH1; the magnitude of the second rate of change is Where Vcomp2' and Vcomp1' are negative, Vcomp2' is less than Vcomp1', and VL2 and VL1 are positive, VL2 is less than VL1; the magnitude of the third rate of change is Where Vcomp1 is a positive value, Vcomp1' is a negative value, and VH1 and VL1 are positive values, with VH1 being greater than VL1. In summary, S3 is less than S1, S3 is less than S2, and S1 = S2, or S1 is greater than S2, or S1 is less than S2.

[0093] It should be understood that the voltage Vc of energy storage unit 22, falling between the low voltage threshold VL1 and the high voltage threshold VH1, is the most common voltage range for normal operation. The compensation signal Vcomp setting can be applied when multiple energy storage modules 20 are connected in parallel, causing energy storage modules 20 with high capacitor voltages to discharge more and charge less, while causing energy storage modules 20 with low capacitor voltages to charge more and discharge less, thus achieving voltage equalization across the capacitors of multiple energy storage modules 20. When the voltage Vc of energy storage unit 22 is between the low voltage threshold VL1 and the high voltage threshold VH1, rapid adjustment is unnecessary, and rapid adjustment is detrimental to system stability; therefore, the third conversion rate can be set relatively low. However, when the voltage Vc of energy storage unit 22 is less than the low voltage threshold VL1 or greater than the high voltage threshold VH1, it is desirable for the voltage to be rapidly adjusted to prevent it from exceeding the predetermined range.

[0094] Taking the charging of two energy storage modules as an example, when the voltage of the first energy storage module is Vc1 and the voltage of the second energy storage module is Vc2, if Vc2 is greater than Vc1, then the compensation signal Vcomp_c2 of the second energy storage module is greater than the compensation signal Vcomp_c1 of the first energy storage module. Therefore, the adjusted reference signal of the second energy storage module is less than the adjusted reference signal of the first energy storage module. Similarly, according to... Figure 8 Based on this principle, the second energy storage module charges less than the first energy storage module, while the first energy storage module charges more, ultimately achieving capacitor voltage balance between the two energy storage modules.

[0095] In summary, the present invention has the following features and advantages: It prevents overcharging by reducing charging and increasing discharging when the energy storage module approaches a high voltage threshold, and prevents over-discharging by reducing discharging and increasing charging when the energy storage module approaches a low voltage threshold. Furthermore, the present invention can also achieve soft shutdown of the energy storage module and voltage balancing among multiple energy storage units when multiple energy storage modules are connected in parallel.

[0096] The above description is merely a detailed explanation and accompanying drawings of preferred embodiments of the present invention, and the features of the present invention are not limited thereto, nor are they intended to limit the present invention. The entire scope of the present invention should be determined by the following claims. All embodiments that conform to the concept of the claims of the present invention and similar variations thereof should be included in the scope of the present invention. Any variations or modifications that can be easily conceived by those skilled in the art within the field of the present invention can be covered by the following claims of the present invention.

Claims

1. A control method for an energy storage module, wherein the energy storage module includes a bidirectional DC / DC converter and an energy storage unit, wherein a first terminal of the bidirectional DC / DC converter is connected to the energy storage unit, characterized in that, The control method includes: adjusting a reference signal according to a compensation signal, and obtaining a current reference signal corresponding to the bidirectional DC / DC converter based on the adjusted reference signal and a current sharing bus signal provided by a power module connected to the second terminal of the bidirectional DC / DC converter, thereby controlling the operating state of the energy storage module, wherein the compensation signal is determined by the voltage of the energy storage unit.

2. The control method according to claim 1, characterized in that, Also includes: The compensation signal is positive when the voltage of the energy storage unit is greater than a high voltage threshold. When the voltage of the energy storage unit is less than a low voltage threshold, the compensation signal is negative.

3. The control method according to claim 1, characterized in that, Also includes: The adjusted reference signal is obtained by subtracting the compensation signal from the reference signal.

4. The control method according to claim 2, characterized in that, The compensation signal is positively correlated with the voltage of the energy storage unit.

5. The control method according to claim 2, characterized in that, When the voltage of the energy storage unit is between the low voltage threshold and the high voltage threshold, the compensation signal is zero.

6. The control method according to claim 2, characterized in that, When the voltage of the energy storage unit is between the low voltage threshold and the high voltage threshold, the compensation signal is positively correlated with the voltage of the energy storage unit.

7. The control method according to claim 6, characterized in that, When the voltage of the energy storage unit is between the low voltage threshold and the high voltage threshold, the rate of change of the compensation signal with the voltage of the energy storage unit is smaller than the rate of change of the compensation signal with the voltage of the energy storage unit when the voltage of the energy storage unit is greater than the high voltage threshold and less than the low voltage threshold.

8. The control method according to claim 4 or 6, characterized in that, The compensation signal is linearly related to the voltage of the energy storage unit.

9. The control method according to claim 2, characterized in that, When the voltage of the energy storage unit exceeds the high voltage threshold and continues to increase to a second high voltage threshold, the adjusted reference signal becomes zero, thereby causing the energy storage unit to exit the charging mode.

10. The control method according to claim 2, characterized in that, When the voltage of the energy storage unit is lower than the low voltage threshold and continues to decrease to a second low voltage threshold, the adjusted reference signal is made equal to the rated value of a current sharing bus sampling signal, so that the energy storage unit exits the discharge mode. The current sharing bus sampling signal is obtained by sampling the current sharing bus signal, and the rated value of the current sharing bus sampling signal represents the output current when the power module outputs rated power.

11. The control method according to claim 1, characterized in that, The reference signal represents the average power of the power module.

12. The control method according to claim 11, characterized in that, The reference signal is determined by the current sharing bus signal.

13. The control method according to claim 1, characterized in that, Also includes: A control signal for controlling the bidirectional DC / DC converter is generated based on the current reference signal and the sampled signal of the inductor current of the bidirectional DC / DC converter.

14. The control method according to claim 1, characterized in that, Also includes: The current sharing bus signal is sampled to obtain a current sharing bus sampling signal; when the current sharing bus sampling signal is greater than the difference between the reference signal and the compensation signal, the energy storage unit is controlled to operate in discharge mode so that the energy storage unit discharges the load of the power module; when the current sharing bus sampling signal is less than the difference between the reference signal and the compensation signal, the energy storage unit is controlled to operate in charging mode so that the power module stores energy in the energy storage unit, thereby compensating for the fluctuation of the input current of the power module.

15. An energy storage module, characterized in that, include: A bidirectional DC / DC converter and an energy storage unit are provided, wherein a first terminal of the bidirectional DC / DC converter is connected to the energy storage unit, and a second terminal of the bidirectional DC / DC converter is connected to the output terminal of a power module; each energy storage module further includes a controller configured to employ the control method according to any one of claims 1-14.

16. A power supply system, characterized in that, include: At least one power module, the output of each power module is connected to a load, wherein each power module converts its own output current into a voltage signal and transmits it to a current sharing bus; At least one energy storage module, wherein the output terminals of each energy storage module are connected, and each energy storage module includes a bidirectional DC / DC converter and an energy storage unit, wherein a first terminal of the bidirectional DC / DC converter is connected to the energy storage unit, and a second terminal of the bidirectional DC / DC converter is connected to the output terminal of the power module; each energy storage module further includes a controller configured to employ the control method of any one of claims 1-14, wherein the voltage signal on the current sharing bus is the current sharing bus signal.

17. The power supply system according to claim 16, characterized in that, The at least one power module is housed in the same housing.

18. The power supply system according to claim 16, characterized in that, The at least one energy storage module is housed in the same casing.

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