Uninterruptible power supply

Abstract

The application provides an uninterrupted power supply, comprising: a main branch comprising a rectification module and an inversion module; a battery branch comprising a bidirectional power conversion module and a battery; and a controller comprising a charge / discharge controller. The charge / discharge controller is configured to: when an increase in a load amount of the load is greater than a first preset threshold, control the bidirectional power conversion module to perform DC-DC conversion on direct current output by the battery, so that the battery supplies power to the load to meet the increased power requirement of the load, thereby maintaining the output power of the alternating current power supply stable; and when a decrease in the load amount of the load is greater than a second preset threshold, control the bidirectional power conversion module to perform DC-DC conversion on direct current output by the rectification module that exceeds the power requirement of the load, and then charge the battery, thereby maintaining the output power of the alternating current power supply stable.

Description

Technical Field

[0001] This invention relates to the field of power supply, and more specifically to an uninterruptible power supply. Background Technology

[0002] The statements in this section are merely to provide background information in relation to the present invention to aid in understanding the invention, and such background information does not necessarily constitute prior art.

[0003] An uninterruptible power supply (UPS) is an AC power supply that contains batteries and is primarily composed of rectifiers and inverters to stabilize voltage and frequency. UPS mainly utilizes batteries to provide uninterrupted power to computer, server, storage device, network equipment, and other computer, communication network systems, industrial control systems, and industrial equipment requiring continuous operation during power outages. When the mains input is normal, the UPS stabilizes the mains voltage and supplies it to the load while simultaneously charging the battery; when the mains power fails, the UPS provides power from the battery to the load, enabling the load to maintain normal operation and protecting the load's hardware and software from damage.

[0004] UPS systems, due to their reliable uninterrupted power supply capabilities, are widely used in hyperscale data centers worldwide. In recent years, with the rapid application of generative artificial intelligence (AI) in data centers, the power consumption of data center designs has been continuously increasing. When AI algorithms are not running in a data center, most (e.g., 75%) of the GPUs (Graphics Processing Units) are in a sleep state. However, when AI algorithms are running, the power demand of the data center increases with the increase in AI load (e.g., an increase of more than 50%). Therefore, the power demand of the data center can fluctuate significantly in a short period of time as the AI ​​load starts or stops, such as a sudden increase in load from 20% to 50% or a sudden decrease from 50% to 20% within 20ms. This is detrimental to the long-term stable operation of the power grid and may impact the power grid or generators, even causing failures. How to avoid the impact of large or frequent fluctuations in AI loads or other types of loads on the power grid or generators is a pressing problem that needs to be solved. Therefore, it is necessary to improve UPS systems and their control methods to address these issues. Summary of the Invention

[0005] Therefore, the purpose of this invention is to overcome the shortcomings of the prior art and provide an uninterruptible power supply, comprising:

[0006] The input terminal is configured to be electrically connected to an AC power source.

[0007] The output terminal is configured to be electrically connected to the load.

[0008] The main branch includes a rectifier module and an inverter module that are electrically connected sequentially between the input terminal and the output terminal;

[0009] A battery branch, comprising a bidirectional power conversion module and a battery, is configured to be electrically connected to a node between the rectifier module and the inverter module;

[0010] The controller includes a charge / discharge controller, which is configured to:

[0011] When the increase in load exceeds a first preset threshold, the bidirectional power conversion module is controlled to perform DC-DC conversion on the DC power output from the battery, so that the battery supplies power to the load to meet the increased power demand of the load, thereby maintaining the stable output power of the AC power supply; and

[0012] When the decrease in the load amount of the load is greater than the second preset threshold, the bidirectional power conversion module is controlled to convert the DC power output of the rectifier module that exceeds the power demand of the load into DC-DC power to charge the battery, thereby maintaining the stable output power of the AC power supply.

[0013] According to the uninterruptible power supply of the present invention, preferably, the charge / discharge controller is configured as follows:

[0014] Based on the comparison between the DC bus reference voltage and the DC bus sample voltage of the main branch, a first current setpoint is provided;

[0015] When the first current setpoint is greater than the first current preset threshold, the bidirectional power conversion module is controlled based on the comparison between the first current setpoint and the DC bus sampling current so that the battery supplies power to the load to meet the increased power demand of the load, thereby maintaining the stable output power of the AC power supply.

[0016] When the first current setpoint is less than the second current preset threshold, the bidirectional power conversion module is controlled to perform DC-DC conversion on the DC power output of the rectifier module that exceeds the power demand of the load, based on the comparison between the first current setpoint and the DC bus sampling current, to charge the battery, thereby maintaining the stable output power of the AC power supply.

[0017] According to the uninterruptible power supply of the present invention, preferably, the controller is further configured to obtain the average load of the load over a specified time period.

[0018] According to the uninterruptible power supply of the present invention, preferably, the first preset threshold and the second preset threshold are 5%-30% of the average load.

[0019] According to the uninterruptible power supply of the present invention, preferably, the first current preset threshold and the second current preset threshold are proportional to the average current, wherein the average current is the ratio of the average power of the load during the specified time period to the DC bus reference voltage.

[0020] According to the uninterruptible power supply of the present invention, preferably, the controller further includes a rectifier controller and an inverter controller, wherein the rectifier controller is configured to control the rectifier module, and the inverter controller is configured to control the inverter module.

[0021] According to the uninterruptible power supply of the present invention, preferably, the rectifier controller is configured to control the actual voltage of the DC bus of the main branch not to exceed the DC bus voltage limit when the decrease in the load of the load is greater than the second preset threshold and the battery is fully charged.

[0022] According to the uninterruptible power supply of the present invention, preferably, the rectifier controller is further configured to:

[0023] A first current reference value is provided based on the comparison between the DC bus voltage limit and the DC bus sampled voltage;

[0024] A second current reference value is provided, which is the ratio of the average power of the load during the specified time period to the effective value of the AC power input voltage.

[0025] The minimum value between the first current reference value and the second current reference value is taken as the second current setpoint; and

[0026] The rectifier module is controlled based on a comparison between the second current setpoint and the output current of the rectifier module.

[0027] According to the uninterruptible power supply of the present invention, preferably, the bidirectional power conversion module includes two separate DC-DC converters or the bidirectional power conversion module is a bidirectional DC-DC converter.

[0028] According to the uninterruptible power supply of the present invention, preferably, the DC bus voltage limit is proportional to the DC bus reference voltage.

[0029] This invention uses a charge / discharge controller to stabilize the DC bus voltage and fully considers the DC bus voltage control principle of uninterruptible power supplies (UPS) during battery charging and discharging. This achieves stable AC power output even when load fluctuations exceed a preset threshold. In other words, the AC power output will not fluctuate due to large load fluctuations, thus avoiding the impact of large load fluctuations on the AC power grid and its electrical equipment, or the resulting inefficient generator power generation. Furthermore, since the battery will be controlled to supply power when the load increases significantly, it avoids the instantaneous large current in the AC power output that could impact other electrical equipment due to a significant increase in load current. Attached Figure Description

[0030] The embodiments of the present invention will be further described below with reference to the accompanying drawings, wherein:

[0031] Figure 1 This is a circuit diagram of a UPS according to an embodiment of the present invention;

[0032] Figure 2 This is a circuit diagram of a UPS when the increase in the load of the UPS exceeds a first preset threshold Th1, according to an embodiment of the present invention.

[0033] Figure 3 This is a circuit diagram of a UPS when the decrease in the load of the UPS is greater than a second preset threshold Th2, according to an embodiment of the present invention.

[0034] Figure 4 for Figures 1-3 A circuit topology diagram of one embodiment of the charging / discharging module shown in the figure;

[0035] Figure 5 This is a control block diagram of a UPS control method according to an embodiment of the present invention;

[0036] Figure 6 The graph shows the changes in load power and AC power input over time after using a UPS or UPS control method according to an embodiment of the present invention. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that the embodiments given in this invention are for illustrative purposes only and do not limit the scope of protection of this invention.

[0038] A UPS typically includes an AC-DC converter (rectifier), a DC-AC converter (inverter), a battery, a DC-DC converter (charging module) to charge the battery, and a DC-DC converter (discharging module) to convert the battery's output voltage to DC. Generally, when the AC power output is normal, the UPS converts the AC power through the rectifier and inverter and supplies it to the load. Simultaneously, it can charge the battery through the charging module. When the AC power fails, the UPS uses the discharging module to supply the load with the battery's power, ensuring the load continues to operate normally and protecting the load's hardware and software from damage.

[0039] Embodiments of the present invention provide an improved UPS, such as Figure 1 The circuit diagram of the UPS of this embodiment shown is illustrated. The UPS 100 includes an input terminal, an output terminal, a main branch 101, a battery branch 102, a bypass branch 103, and a UPS controller 107. The input terminal of the UPS 100 is configured to be electrically connected to an AC power supply 106, and its output terminal is configured to be electrically connected to a load 104. The main branch 101 includes a rectifier module 1010 and an inverter module 1011 connected sequentially between the input and output terminals of the UPS 100. Preferably, the main branch 101 also includes a main input switch 105, which is connected in series between the input terminal of the UPS 100 and the rectifier module 1010. The battery branch 102 includes a charge / discharge module (also called a power conversion module) 1020 and a battery 1021, and is configured to be electrically connected to the node between the rectifier module 1010 and the inverter module 1011. Bypass branch 103 includes a bypass switch 1031 and is configured to be connected in parallel with main branch 101. UPS controller 107 is configured to control UPS 100. Preferably, UPS controller 107 includes a rectifier controller, an inverter controller, and a charge / discharge controller (not shown). The rectifier controller, inverter controller, and charge / discharge controller can be separate modules implemented in hardware and / or software, or they can be implemented as an integrated module.

[0040] The main input switch 105 is configured to control the connection and disconnection between the AC power supply 106 and the main branch 101. The rectifier module 1010 is configured to convert the input AC power into DC power and supply it to the inverter module 1011; the inverter module 1011 is configured to convert the input DC power into AC power and supply it to the load 104. A bypass switch 1031 is used to control the switching between the main branch 101 and the bypass branch 103; preferably, the bypass switch 1031 is a static switch. The charge / discharge module 1020 is configured to bidirectionally transmit converted DC power. Preferably, the charging / discharging module 1020 includes a charging mode and a power supply mode. When the charging / discharging module 1020 switches to charging mode, it is configured to convert a portion of the DC power output from the rectifier module 1010 into DC power to charge the battery 1021. When the charging / discharging module 1020 switches to power supply mode, it is configured to convert the DC power output from the battery 1021 into DC power and supply it to the inverter module 1011. The inverter module 1011 is configured to convert the input DC power into AC power and supply it to the load 104. The UPS controller 107 is configured to control the UPS 100, wherein the rectifier controller is configured to control the rectifier module 1010, the inverter controller is configured to control the inverter module 1011, and the charging / discharging controller is configured to control the charging / discharging module 1020.

[0041] In one embodiment, the UPS includes controllable switches such as MOSFETs, and the UPS controller is configured to include processing circuitry that drives the on / off switching of each MOSFET. This processing circuitry can be composed of digital electronic circuitry such as arithmetic processing units and storage devices, analog electronic circuitry such as comparators, operational amplifiers, and differential amplifiers, or a combination of digital and analog electronic circuitry.

[0042] In one embodiment of the invention, the AC power source 106 is an AC power grid (e.g., mains power), which supplies power to the data center via a UPS 100. Data centers are the core of modern information technology infrastructure, supporting mission-critical applications such as customer relationship management, enterprise resource planning, and supply chain management systems. Data center components include servers and storage devices, network equipment, cooling and power supply equipment, and monitoring and management systems. The main functions of a data center include data storage, data processing, data networking, data security, data backup, and recovery. When a data center switches its computing scale (e.g., from small-scale to large-scale computing, such as from conventional computing to AI computing, and vice versa), load fluctuations will impact the power grid and other electrical equipment within it, especially when the load fluctuates significantly, potentially causing malfunctions. In this embodiment, the battery 1021 is configured to have a specified charge level between a fully discharged battery and a fully charged battery. This specified charge level is represented, for example, by the battery's state of charge (SOC), which refers to the available state of the remaining charge in the battery, reflecting its remaining capacity. The SOC is 0 when fully discharged and 100% when fully charged. When the increase in load of load 104 exceeds the first preset threshold Th1, such as Figure 2 As shown, the charge / discharge controller controls the charge / discharge module 1020 to convert the DC power output from the battery 1021 into AC power and supply it to the inverter module 1011. The inverter module 1011 then converts the input DC power into AC power and supplies it to the load 104. In this case, the battery 1021 and the AC power supply 106 work together to power the data center. Preferably, the charge / discharge controller controls the battery 1021 to supply power to the load 104 to meet the increased power demand of the load, thereby maintaining the stable output power of the AC power supply. When the decrease in the load of the load 104 is greater than the second preset threshold Th2, such as Figure 3 As shown, the charge / discharge controller controls the charge / discharge module 1020 to convert a portion of the DC power output from the rectifier module 1010 into DC power to charge the battery 1021. Preferably, the charge / discharge controller controls the charge / discharge module 1020 to convert the DC power output from the rectifier module 1010 that exceeds the power demand of the load 104 into DC power to charge the battery 1021, thereby maintaining the stable output power of the AC power supply. In this way, the output power of the AC grid remains stable when the load fluctuates significantly, thus avoiding the impact or other adverse effects of large load fluctuations on the AC grid and its electrical equipment.

[0043] In addition, this embodiment is also applicable to situations where the AC power grid supply capacity is insufficient. For example, during peak electricity consumption periods in summer, when the output power of the AC power grid cannot meet the power demand of the data center, the UPS controller 107 can control the UPS charging / discharging module 1020 to switch to power supply mode, so that the battery 1021 and the AC power supply 106 work together to supply power to the data center and maintain the normal operation of the data center.

[0044] In another embodiment of the present invention, the AC power supply 106 is a generator, and the UPS 100 supplies power to the data center. In this embodiment, when the increase in the load of the load 104 exceeds a first preset threshold Th1, the charge / discharge controller controls the charge / discharge module 1020 to convert the DC power output from the battery 1021 into DC power and supply it to the inverter module 1011. The inverter module 1011 then converts the input DC power into AC power and supplies it to the load 104. In this case, the battery 1021 and the generator work together to supply power to the data center. Preferably, to maintain the stability of the bus voltage of the main branch 101, the charge / discharge controller controls the battery 1021 to supply power to the load 104 to meet the increased power demand of the load. When the decrease in the load of the load 104 exceeds a second preset threshold Th2, the charge / discharge controller controls the charge / discharge module 1020 to convert a portion of the DC power output from the rectifier module 1010 into DC power and charge the battery 1021. Preferably, to maintain a stable bus voltage in the main branch 101, the charge / discharge controller controls the charge / discharge module 1020 to perform DC-DC conversion on the DC power output from the rectifier module 1010 that exceeds the power demand of the load 104, and then uses this DC-DC converter to charge the battery 1021. This avoids the impact and interference caused by large load fluctuations on the generator, and also avoids the potential reduction in generator efficiency that could result from the generator's output power being increased or decreased in real time according to changes in load. Furthermore, this embodiment allows the generator to maintain reliable operation of the data center with a smaller size or volume, without wasting power during low-load periods.

[0045] In an embodiment of the present invention, a large load fluctuation refers to an increase in load amount greater than a first preset threshold Th1 or a decrease in load amount greater than a second preset threshold Th2.

[0046] In embodiments of the present invention, the load quantity refers to the electrical parameters of the load, including voltage, current, and power.

[0047] In an embodiment of the present invention, the battery 1021 is configured to have charging and discharging capacities required to meet energy dispatching under load fluctuations. That is, when power is needed from the battery 1021, it has sufficient charge to supply power to the load added by the load 104, and when it is necessary to transfer electrical energy from the AC power supply 106 that exceeds the power demand of the load 104 to the battery 1021, it has sufficient capacity to receive the aforementioned power.

[0048] In some embodiments of the present invention, the UPS controller 107 is further configured to statistically analyze the average load of the load 104 over a specified time period. This specified time period can be determined according to actual needs, such as 1 minute, 3 hours, or 1 week. A first preset threshold Th1 and a second preset threshold Th2 are proportional to the average load and can be determined according to actual needs (e.g., the tolerance of the AC power grid to shocks caused by load fluctuations). For example, the first preset threshold Th1 and the second preset threshold Th2 can be selected between 5% and 30% of the average load, such as 2%, 3%, 5%, 10%, 15%, 20%, 25% of the average load. In some embodiments of the present invention, the first preset threshold Th1 can be equal to the second preset threshold Th2.

[0049] The working principle of UPS 100 will be explained below, taking AC power supply 106 as an example of AC power grid.

[0050] When the increase in the load of the UPS load is less than or equal to the first preset threshold Th1 or the decrease in the load is less than or equal to the second preset threshold Th2, that is, when the load of the load 104 does not fluctuate significantly, the AC power output from the AC power supply 106 is input to the rectifier module 1010 via the main input switch 105. The rectifier module 1010 converts the input AC power into DC power and outputs it to the inverter module 1011. The inverter module 1011 converts the input DC power into AC power and provides it to the load 104 to supply power to the load 104. At the same time, the charge / discharge controller controls the charge / discharge module 1020 to switch to charging mode. It converts part of the DC power output from the rectifier module 1010 into DC-DC power to charge the battery 1021 to a specified capacity. The specified capacity is preferably 20%-80% of the battery's full charge capacity, that is, the SOC is 20%-80%.

[0051] When the increase in load of load 104 exceeds the first preset threshold Th1, such as Figure 2As shown, the charge / discharge controller controls the charge / discharge module 1020 to convert the DC power output from the battery 1021 into AC power and supply it to the inverter module 1011. The inverter module 1011 then converts the input DC power into AC power and supplies it to the load 104. In this configuration, the battery 1021 and the AC power supply 106 work together to power the data center. Preferably, to maintain the stability of the bus voltage of the main branch 101, the charge / discharge controller controls the battery 1021 to supply power to the load added to the load 104.

[0052] When the decrease in the load of load 104 is greater than the second preset threshold Th2, such as Figure 3 As shown, the charge / discharge controller controls the charge / discharge module 1020 to convert a portion of the DC power output from the rectifier module 1010 into DC power to charge the battery 1021. Preferably, to maintain the stability of the bus voltage of the main branch 101, the charge / discharge controller controls the charge / discharge module 1020 to convert the DC power output from the rectifier module 1010 that exceeds the power demand of the load 104 into DC power to charge the battery 1021.

[0053] In the event of a failure of AC power supply 106, it cannot output electrical energy to power load 104. At this time, the charge / discharge controller controls the charge / discharge module 1020 to switch to power supply mode. It converts the DC power output by battery 1021 into AC power and supplies it to inverter module 1011. Inverter module 1011 converts the input DC power into AC power and supplies it to load 104.

[0054] In the event of a failure in the main branch 101 and battery branch 102 of UPS 100, the bypass switch 1031 closes, and the AC power supply 106 supplies power to the load 104 through the bypass branch 103, and the current no longer flows through the main branch 101 and battery branch 102.

[0055] In some embodiments of the present invention, the charging / discharging module 1020 includes two DC-DC converters, used for charging the battery and discharging the battery, respectively. The circuit topology and operating principle of the DC-DC converters are well known in the art and will not be described in detail here.

[0056] In some embodiments of the present invention, the charge / discharge module 1020 is a bidirectional DC-DC converter. Figure 4 It shows Figures 1-3 The circuit topology of one embodiment of the charging / discharging module 1020 is shown. Figure 4 The bidirectional DC-DC converter shown includes inductors L1 and L2, switching transistors T1, T2, T3, and T4, diodes D1, D2, D3, and D4, switching transistors S1 and S2, and capacitors Cp1 and Cp2. Since the operating principle of the bidirectional DC-DC converter is well-known in the art, it will not be described in detail here. Figure 4The circuit topology of the bidirectional DC-DC converter shown is illustrative and not limiting; any bidirectional DC-DC converter known to those skilled in the art can be applied to this invention.

[0057] In some embodiments of the present invention, the rectifier module 1010 is a bidirectional rectifier module, and the inverter module 1011 is a bidirectional inverter module. The bidirectional rectifier module and bidirectional inverter module used in these embodiments provide flexibility in energy flow control, meeting the complex electricity needs of customers. In one embodiment, the load is a regenerative load. When the regenerative load is unloaded, it can either feed energy back to the battery 1021 to charge it via the inverter module 1011 and the charge / discharge module 1020, or feed energy back to the AC grid via the inverter module 1011 and the rectifier module 1010.

[0058] In some embodiments of the present invention, in order to ensure electrical safety, the charge / discharge controller needs to control the charge / discharge module 1020 to turn off the charging mode before it can switch to the power supply mode, and vice versa.

[0059] Embodiments of the present invention also provide a method for Figures 1-3 The control method for the UPS 100 shown includes the following steps:

[0060] The UPS controller 107 controls the average load power Pav of the load 104 over 48 hours. Based on actual needs, the first preset threshold Th1 = Pav * 20% = 0.2 * Pav is determined, and Th2 = Th1 is selected.

[0061] The UPS controller 107 samples the load power Pt of the load 104. When the load power Pt is within the range of 0.8*Pav to 1.2*Pav, the rectifier module 1010 and inverter module 1011 are controlled to rectify, invert, and regulate the AC power output from the AC power supply 106 and output it to the load 104 to supply power. At the same time, the charging / discharging module 1020 is controlled to switch to charging mode, and a portion of the DC power output from the rectifier module 1010 is converted from DC to DC to charge the battery 1021 to a specified capacity, such as 50%.

[0062] When the increase in load power Pt is greater than 0.2*Pav, the charge / discharge module 1020 converts the DC power output from battery 1021 to AC power and supplies it to inverter module 1011. Inverter module 1011 converts the input DC power to AC power and supplies it to load 104 to power the added load. When the decrease in load power Pt is greater than 0.2*Pav, the charge / discharge module 1020 converts the DC power output from rectifier module 1010 that exceeds the power demand of load 104 to DC-DC power to charge battery 1021.

[0063] In some embodiments of the present invention, such as Figure 5 As shown, the UPS 100's charge / discharge controller includes a battery charge / discharge control module M1.

[0064] The battery charge / discharge control module M1 is configured to selectively control the charging and discharging of the battery 1021 to maintain the stability of the bus voltage of the main branch 101 when the change in the load of the load 104 meets specified conditions. Specifically, when the increase in the load of the load 104 exceeds a first preset threshold Th1, the battery charge / discharge control module M1 outputs a discharge current control signal to control the charge / discharge module 1020 so that the battery 1021 supplies power to the increased load of the load 104; when the decrease in the load of the load 104 exceeds a second preset threshold Th2, the battery charge / discharge control module M1 outputs a charging current control signal to control the charge / discharge module 1020 to convert the DC power output from the rectifier module 1010 that exceeds the power demand of the load 104 into DC-DC power to charge the battery 1021. The battery charge / discharge control module M1 includes a charge / discharge control voltage loop 192, a charging control current loop 194, and a discharging control current loop 193.

[0065] The charge / discharge control voltage loop 192 compares the DC bus reference voltage Uref and the DC bus sampled voltage Ut of the main branch 101 through the first comparison module 160 to calculate the voltage control error. This voltage control error is then adjusted by the first PI control algorithm 161 to obtain the first current setpoint Iset0. When the load of the load 104 fluctuates, it will cause the DC bus sampled voltage Ut to fluctuate, thereby causing the first current setpoint Iset0 to change.

[0066] The first switch module 162 selectively turns on its input port 1 and input port 0 based on a comparison of the first current setpoint Iset0 and the first current preset threshold I1, while the second switch module 163 selectively turns on its input port 1 and input port 0 based on a comparison of the first current setpoint Iset0 and the second current preset threshold I2.

[0067] When the first current setpoint Iset0 is greater than the first current preset threshold I1, the input port 1 of the first switch module 162 is turned on, and the first current setpoint Iset0 is multiplied by 1 by the first multiplier 164 and used as the current setpoint of the discharge control current loop 193. At the same time, the input port 0 of the second switch module 163 is turned on, and the first current setpoint Iset0 is multiplied by 0 by the second multiplier 165 and used as the current setpoint of the charging control current loop 194. In this case, the current setpoint of the discharge control current loop 193 is Iset0, which is compared with the DC bus sampling current It by the second comparison module 166 to calculate the current control error. This current control error is adjusted by the second PI control algorithm 168 and the first transfer function 170 to generate a discharge current control signal. Meanwhile, the current setpoint of the charging control current loop 194 is 0, and no charging control is performed. This causes the battery charging / discharging control module M1 to output a discharge current control signal. This discharge current control signal controls the charging / discharging module 1020 to perform the discharge function so that the battery 1021 supplies power to the load added to the load 104, thereby maintaining the stable output power of the AC power supply.

[0068] Wherein, the first current preset threshold I1 is proportional to the average current Iav, Iav=Pav / Uref, preferably: I1=(1+X1)*Iav, where X1 is the first current limit coefficient, the range of which can be determined according to actual needs, for example, 5%-35%.

[0069] When the first current setpoint Iset0 is less than the second current preset threshold I2, the input port 0 of the first switch module 162 is turned on, and the first current setpoint Iset0 is multiplied by 0 by the first multiplier 164 and used as the current setpoint of the discharge control current loop 193. At the same time, the input port 1 of the second switch module 163 is turned on, and the first current setpoint Iset0 is multiplied by 1 by the second multiplier 165 and used as the current setpoint of the charging control current loop 194. In this case, the current setpoint of the charging control current loop 194 is Iset0, which is compared with the DC bus sampling current It by the third comparison module 167 to calculate the current control error. This current control error is adjusted by the third PI control algorithm 169 and the second transfer function 171 to generate a charging current control signal. Meanwhile, the current setpoint of the discharging control current loop 193 is 0, and no discharging control is performed. This causes the battery charging / discharging control module M1 to output a charging current control signal. This charging current control signal controls the charging / discharging module 1020 to perform the charging function, converting the DC power output from the rectifier module 1010 that exceeds the power demand of the load 104 into DC-DC power to charge the battery 1021, thereby maintaining the stable output power of the AC power supply.

[0070] Wherein, the second current preset threshold I2 is proportional to the average current Iav, Iav=Pav / Uref, preferably: I2=(1-X2)*Iav, where X2 is the second current limit coefficient, the range of which can be determined according to actual needs, for example, 5%-35%.

[0071] When the first current setpoint Iset0 is I2≤Iset0≤I1, the battery charging / discharging control module M1 does not perform its function.

[0072] The rectifier controller of the UPS 100 includes the rectifier control module M2.

[0073] The rectifier control module M2 is configured to maintain the stable output power of the AC power supply 106, and also to control the DC bus sampling voltage Ut to not exceed the DC bus voltage limit Um in extreme cases where the decrease in the load of the load 104 exceeds a second preset threshold Th2, and the battery 1021 can no longer transfer electrical energy from the AC power supply 106 that exceeds the power demand of the load 104 (e.g., the battery is fully charged), thereby preventing overvoltage from causing a fault. The rectifier control module M2 includes a rectifier control voltage loop 190 and a rectifier control current loop 191. In embodiments of the present invention, the DC bus sampling voltage Ut refers to the actual voltage of the DC bus of the main branch 101 obtained by sampling.

[0074] The rectifier control voltage loop 190 compares the DC bus voltage limit Um and the DC bus sampled voltage Ut through the fourth comparison module 150 to calculate the voltage control error. The DC bus voltage limit Um is proportional to the DC bus reference voltage Uref, where Um = (1 + Y) * Uref, and Y is the voltage limit coefficient, the range of which can be determined according to actual needs, such as 2%-50%. This voltage control error is adjusted by the fourth PI control algorithm 151 to obtain the first current reference value Iz. The min module compares the first current reference value Iz with the second current reference value Ix, and takes the minimum of the two as the current setpoint Iset1 of the rectifier control current loop 191. The second current reference value Ix = Pav / Uac, where Uac is the effective value of the AC power supply 106 input voltage. The rectifier control current loop 191 compares the current setpoint Iset1 with the output current It1 of the rectifier module 1010 through the fifth comparison module 152 to calculate the current control error. After the current control error is adjusted by the fifth PI control algorithm 153 and the third transfer function 154, a rectifier control signal is generated to control the output current of the rectifier module 1010 to be stable, preferably maintained at the current setpoint Iset1.

[0075] When the DC bus sampling voltage Ut is less than or equal to the DC bus voltage limit Um, the second current reference value Ix will be less than or equal to the first current reference value Iz. That is, the second current reference value Ix serves as the current setpoint Iset1 for the rectifier control current loop 191. The rectifier control current loop 191 outputs a rectifier control signal to control the rectifier module 1010 based on a comparison between this current setpoint Iset1 and the output current It1 of the rectifier module 1010. In this case, the control function of the rectifier control module M2 is to maintain the stability of the output current of the AC power supply 106.

[0076] In extreme cases, the load on load 104 may drop significantly, while battery 1021, already fully charged, can no longer transfer the electrical energy output from AC power supply 106 that exceeds the power demand of load 104. When the DC bus sampling voltage Ut is greater than the DC bus voltage limit Um, the first current reference value Iz output by rectifier control voltage loop 190 will be less than the second current reference value Ix, i.e., the first current reference value Iz serves as the current setpoint Iset1 for rectifier control current loop 191. Based on the comparison between this current setpoint Iset1 and the output current It1 of rectifier module 1010, rectifier control current loop 191 outputs a rectification control signal to control rectifier module 1010. In this case, the control function of rectifier control module M2 is to control the DC bus sampling voltage Ut to not exceed the DC bus voltage limit Um, thereby preventing overvoltage from causing a fault.

[0077] According to another embodiment of the present invention, the charge / discharge controller of the UPS 100 further includes another battery charge / discharge control module, which is configured to control the AC power supply 106 to charge the battery 1021 to a specified capacity (e.g., SOC of 50%) when the load does not fluctuate significantly, and to control the battery 1021 to supply power to the load 104 in the event of a failure of the AC power supply 106.

[0078] In embodiments of the present invention, the first PI control algorithm to the fifth PI control algorithm can also be any type of control algorithm suitable for use in the present invention, such as the PID control algorithm.

[0079] This invention, through the aforementioned control method, achieves stable power output from the AC power supply when load fluctuations exceed a preset threshold. The output power does not fluctuate due to large load fluctuations, thus avoiding impacts on the AC power grid and its electrical equipment caused by such fluctuations, or resulting in inefficient generator operation. Furthermore, since the battery 1021 is controlled to supply power when the load increases significantly, it prevents the AC power supply 106 from experiencing a sudden surge in output current that could impact other electrical equipment.

[0080] Through the specific embodiments of the present invention described above, the output power of the AC power supply can remain basically stable under large load fluctuations, such as... Figure 6 As shown, curve 1 represents the percentage of AI load power to UPS rated power over time, and curve 2 represents the percentage of AC power input to UPS rated power over time. It can be seen that the output power of AC power does not change with load fluctuations, but remains basically stable over a long period of time, thus solving the problem of load fluctuations impacting the AC power grid and its electrical equipment, or the problem of low generator efficiency caused by this.

[0081] While embodiments of the present invention have been described in the context of data centers or AI workloads, this description is illustrative and not restrictive. The embodiments of the present invention are also applicable to power supply systems in other scenarios, such as hospitals.

[0082] References to "various embodiments," "some embodiments," "one embodiment," or "embodiment," etc., in this specification refer to a specific feature, structure, or property described in connection with the said embodiment, included in at least one embodiment. Therefore, the appearance of the phrases "in various embodiments," "in some embodiments," "in one embodiment," or "in an embodiment," etc., throughout this specification does not necessarily refer to the same embodiment. Furthermore, specific features, structures, or properties can be combined in any suitable manner in one or more embodiments. Therefore, a specific feature, structure, or property shown or described in connection with one embodiment can be combined, in whole or in part, with features, structures, or properties of one or more other embodiments without limitation, provided that the combination is not illogical or inoperable.

[0083] The terms "comprising," "having," and similar expressions used in this specification are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such processes, methods, products, or apparatus. "A" or "an" does not exclude multiple instances. Furthermore, the elements in the accompanying drawings are for illustrative purposes only and are not drawn to scale.

[0084] While the present invention has been described through preferred embodiments, it is not limited to the embodiments described herein, and various changes and modifications are made without departing from the scope of the invention.

Claims

1. An uninterruptible power supply, comprising: The input terminal is configured to be electrically connected to an AC power source. The output terminal is configured to be electrically connected to the load. The main branch includes a rectifier module and an inverter module that are electrically connected sequentially between the input terminal and the output terminal; A battery branch, comprising a bidirectional power conversion module and a battery, is configured to be electrically connected to a node between the rectifier module and the inverter module; The controller includes a charge / discharge controller, which is configured to: When the increase in the load amount of the load exceeds a first preset threshold, the bidirectional power conversion module is controlled to perform DC-DC conversion on the DC power output of the battery so that the battery can supply power to the load to meet the increased power demand of the load, thereby maintaining the stable output power of the AC power supply. as well as When the decrease in the load amount of the load is greater than the second preset threshold, the bidirectional power conversion module is controlled to convert the DC power output of the rectifier module that exceeds the power demand of the load into DC-DC power to charge the battery, thereby maintaining the stable output power of the AC power supply.

2. The uninterruptible power supply according to claim 1, wherein, The charge / discharge controller is configured to: Based on the comparison between the DC bus reference voltage and the DC bus sample voltage of the main branch, a first current setpoint is provided; When the first current setpoint is greater than the first current preset threshold, the bidirectional power conversion module is controlled based on the comparison between the first current setpoint and the DC bus sampling current so that the battery supplies power to the load, thereby maintaining the stable output power of the AC power supply. When the first current setpoint is less than the second current preset threshold, the bidirectional power conversion module is controlled to charge the battery based on the comparison between the first current setpoint and the DC bus sampling current, thereby maintaining the stable output power of the AC power supply.

3. The uninterruptible power supply according to claim 2, wherein the controller is further configured to obtain the average load of the load over a specified time period.

4. The uninterruptible power supply according to claim 3, wherein the first preset threshold and the second preset threshold are 5%-30% of the average load.

5. The uninterruptible power supply according to claim 3, wherein, The first current preset threshold and the second current preset threshold are proportional to the average current value, which is the ratio of the average power of the load during the specified time period to the DC bus reference voltage.

6. The uninterruptible power supply according to any one of claims 2-5, wherein the controller further comprises a rectifier controller and an inverter controller, wherein the rectifier controller is configured to control the rectifier module, and the inverter controller is configured to control the inverter module.

7. The uninterruptible power supply according to claim 6, wherein the rectifier controller is configured to control the actual voltage of the DC bus of the main branch not to exceed the DC bus voltage limit when the decrease in the load of the load is greater than the second preset threshold and the battery is fully charged.

8. The uninterruptible power supply according to claim 7, wherein, The rectifier controller is also configured to: A first current reference value is provided based on the comparison between the DC bus voltage limit and the DC bus sampled voltage; A second current reference value is provided, which is the ratio of the average power of the load during the specified time period to the effective value of the AC power supply input voltage. The minimum value between the first current reference value and the second current reference value is taken as the second current setpoint; as well as The rectifier module is controlled based on a comparison between the second current setpoint and the output current of the rectifier module.

9. The uninterruptible power supply according to any one of claims 1-5, wherein the bidirectional power conversion module comprises two separate DC-DC converters or the bidirectional power conversion module is a bidirectional DC-DC converter.

10. The uninterruptible power supply according to any one of claims 7-8, wherein, The DC bus voltage limit is proportional to the DC bus reference voltage.

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