Energy-saving control method of energy storage power supply, energy storage power supply and storage medium

Abstract

The invention relates to the field of energy storage power supplies, and discloses an energy-saving control method of an energy storage power supply, the energy storage power supply and a storage medium. The energy-saving control method comprises the following steps: sampling alternating current output voltage and alternating current output current, and calculating output apparent power; when the apparent power is greater than or equal to a preset power lower limit threshold value, controlling the inverter to enter a normal mode to work; when the apparent power is smaller than the power lower limit threshold value, the inverter is controlled to enter a first-stage low-power-consumption mode to work, a no-load detection algorithm is executed to judge whether the energy storage power supply is in a no-load state or not, and if yes, the inverter is controlled to be switched to a second-stage low-power-consumption mode to work. According to the method, the light load and the no load can be identified, different low-power-consumption control strategies are adopted in the light load state and the no load state, and the energy loss of the off-grid energy storage power supply in the light load state or the no load state is remarkably reduced.

Description

Technical Field

[0001] The present application relates to the field of energy storage power supplies, and in particular to an energy storage power supply energy-saving control method, an energy storage power supply, and a storage medium. Background Art

[0002] In energy storage applications, DC-DC and DC-AC are often used to form a two-stage power conversion. When off-grid, this two-stage structure of energy storage power supply will cause energy loss due to load changes. How to reduce the energy loss of energy storage power supply when light load or no load has become an urgent problem that needs to be solved.

[0003] The existing technical solution mainly detects the output power of the energy storage power supply. When the output power is less than the set threshold value and lasts for a period of time, the energy storage power supply is judged to be in a no-load state and enters a low-power mode, thereby reducing no-load loss. The defects of this solution are: 1) Limited by the influence of power sampling accuracy, when a small power load is connected, the energy storage power supply cannot distinguish between light load and no-load, and there is a defect of misjudging no-load and shutting down the power output, causing the load to be powered off; 2) In low-power mode, only the control strategy is changed on the DC-DC side, and there is still a lot of energy loss. Summary of the invention

[0004] The embodiments of the present application aim to provide an energy-saving control method for an energy storage power supply, an energy storage power supply and a storage medium, so as to solve the energy loss problem of an off-grid energy storage power supply when lightly loaded or unloaded in the prior art.

[0005] To solve the above technical problems, the present application provides the following technical solutions: According to a first aspect of the present application, there is provided an energy storage power supply energy-saving control method, wherein the energy storage power supply comprises an inverter, wherein the inverter comprises a front-stage DC-DC module and a rear-stage DC-AC module, wherein the front-stage DC-DC module converts a DC input voltage into a DC bus voltage, and the rear-stage DC-AC module converts the DC bus voltage into an expected AC output voltage, wherein the method comprises: Sampling the AC output voltage and AC output current, and calculating the output apparent power; When the apparent power is greater than or equal to a preset power lower limit threshold, controlling the inverter to enter a normal mode of operation; When the apparent power is less than the power lower limit threshold, the inverter is controlled to enter the first-level low power consumption mode, and the no-load detection algorithm is executed to determine whether the energy storage power supply is in a no-load state. If so, the inverter is controlled to enter the second-level low power consumption mode; Among them, in the first-level low power consumption mode, the front-stage DC-DC module works intermittently based on the preset hysteresis response voltage, and the rear-stage DC-AC module adopts a sinusoidal pulse width modulation mode to modulate the inverter waveform. In the second-level low power consumption mode, the front-stage DC-DC module works intermittently based on the hysteresis response voltage, and the rear-stage DC-AC module adopts a trapezoidal pulse width modulation mode to modulate the inverter waveform.

[0006] Optionally, the hysteresis response voltage includes a hysteresis response voltage lower limit and a hysteresis response voltage upper limit, and the front-stage DC-DC module intermittently operates based on a preset hysteresis response voltage as follows: when the DC bus voltage is lower than the hysteresis response voltage lower limit, the front-stage DC-DC module starts pulse driving, until the DC bus voltage reaches the hysteresis response voltage upper limit, the front-stage DC-DC module stops pulse driving.

[0007] Optionally, the no-load detection algorithm includes: When the inverter operates in the first-level low power consumption mode, the DC bus voltage is sampled to detect the first time duration required for the DC bus voltage to drop from a preset first voltage threshold to a preset second voltage threshold. If the first time duration is greater than or equal to a preset discharge time duration threshold, it is determined that the energy storage power supply is in a no-load state.

[0008] Optionally, the discharge time threshold is determined based on a second time required for the DC bus voltage to drop from the first voltage threshold to the second voltage threshold when the energy storage power supply is in a no-load state and the inverter operates in a primary low power consumption mode.

[0009] Optionally, the first voltage threshold is the upper limit of the hysteresis response voltage, and the second voltage threshold is the lower limit of the hysteresis response voltage.

[0010] Optionally, when the inverter operates in a first-level low power consumption mode, the method further includes: Executing the no-load detection algorithm to determine whether the energy storage power supply is in a no-load state; If yes, control the inverter to switch to the secondary low power consumption mode; If not, the AC output voltage and the AC output current are sampled, the output apparent power is calculated, and it is determined whether the apparent power is greater than or equal to the power lower limit threshold. If so, the inverter is controlled to switch to normal mode.

[0011] Optionally, when the inverter operates in the secondary low power consumption mode, the method further includes: Continuously detect the AC output voltage; When it is detected that the absolute value of the difference between the AC output voltage and the corresponding reference voltage amplitude is greater than a preset first voltage difference threshold, controlling the inverter to switch to a normal mode of operation; When the absolute value of the difference between the AC output voltage and the corresponding reference voltage amplitude is detected to be greater than a preset second voltage difference threshold for N consecutive times, the inverter is controlled to switch to a first-level low power consumption mode, the first voltage difference threshold is greater than the second voltage difference threshold, and N is a preset number of times.

[0012] Optionally, when the post-stage DC-AC module adopts a trapezoidal pulse width modulation mode to modulate the inverter waveform, a trapezoidal wave with a triangulation rate of approximately 0.4 is selected for modulation.

[0013] According to a second aspect of the present application, there is provided an energy storage power supply, comprising an inverter, wherein the inverter comprises a front-stage DC-DC module, a rear-stage DC-AC module and a controller, wherein the front-stage DC-DC module converts a DC input voltage into a DC bus voltage, and the rear-stage DC-AC module converts the DC bus voltage into an expected AC output voltage, and the controller is respectively connected to the front-stage DC-DC module and the rear-stage DC-AC module, and the controller comprises: At least one processor and a memory in communication with the at least one processor, the memory storing instructions executable by the at least one processor, the instructions being executed by the at least one processor so that the at least one processor can execute the energy-saving control method for the energy storage power supply described above.

[0014] According to a third aspect of the present application, a computer storage medium is provided, wherein the computer storage medium stores instructions or programs, and when the instructions or programs are executed by at least one processor, the at least one processor executes the energy-saving control method of the energy storage power supply described above.

[0015] The beneficial effect of the embodiment of the present application is: different from the prior art, in the embodiment of the present application, a method for energy-saving control of an energy storage power supply is provided, the energy storage power supply includes an inverter, the inverter includes a front-stage DC-DC module and a rear-stage DC-AC module, when the apparent power is less than the power lower limit threshold, the inverter is first controlled to enter the first-level low-power mode, and then it is identified whether the energy storage power supply is in a no-load state, if so, the inverter is controlled to switch to the second-level low-power mode, wherein in the first-level low-power mode, the front-stage DC-DC module works intermittently based on a preset hysteresis response voltage, and the rear-stage DC-AC module modulates the inverter waveform using a sinusoidal pulse width modulation mode, and in the second-level low-power mode, the front-stage DC-DC module works intermittently based on the hysteresis response voltage, and the rear-stage DC-AC module modulates the inverter waveform using a trapezoidal pulse width modulation mode. The method of the present application can identify light load and no-load, and adopt different low-power control strategies in the light load and no-load states, significantly reducing the energy loss of the off-grid energy storage power supply when light load or no-load. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] One or more embodiments are exemplarily described by pictures in the corresponding drawings, and these exemplified descriptions do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0017] Figure 1 It is a structural schematic diagram of an energy storage power supply provided in an embodiment of the present application; Figure 2 is a schematic diagram of the structure of the controller provided in an embodiment of the present application; Figure 3 It is a flow chart of an energy-saving control method of an energy storage power supply provided in an embodiment of the present application; Figure 4 It is a pulse driving schematic diagram of the front-stage DC-DC module provided in the embodiment of the present application in the normal working mode and the intermittent working mode; Figure 5 It is a schematic diagram of using T-PWM to replace SPWM provided in an embodiment of the present application; Figure 6 It is a schematic diagram of a curve showing the relationship between the triangulation rate of a trapezoidal wave, the waveform distortion rate, and the DC voltage utilization rate provided in an embodiment of the present application; Figure 7 It is a flowchart of a no-load detection algorithm provided in an embodiment of the present application; Figure 8 is a schematic diagram of a flow chart for determining a discharge duration threshold provided in an embodiment of the present application; Fig. 9 It is a flow chart of another energy-saving control method of an energy storage power supply provided in an embodiment of the present application. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0019] In addition, the technical features involved in each embodiment of the present application described below can be combined with each other as long as they do not conflict with each other.

[0020] It should be noted that the steps shown in the flowcharts of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and that, although a logical order is shown in the flowcharts, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0021] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of an energy storage power supply provided in an embodiment of the present application. Figure 1 As shown, the energy storage power supply 100 includes a DC source 10 and an inverter 20, wherein the inverter 20 includes a front-stage DC-DC module 21, a rear-stage DC-AC module 22 and a controller 23. The front-stage DC-DC module 21 converts the DC input voltage from the DC source 10 into a DC bus voltage, and the rear-stage DC-AC module 22 converts the DC bus voltage into a desired AC output voltage. The controller 23 is respectively connected to the front-stage DC-DC module 21 and the rear-stage DC-AC module 22, and is used for driving control of the front-stage DC-DC module 21 and inverter conversion control of the rear-stage DC-AC module 22.

[0022] In some embodiments, the controller 23 further includes a sampling circuit for sampling the AC output voltage and the AC output current. The controller 23 may be a microcontroller unit (MCU) or a digital signal processing (DSP) controller.

[0023] In some embodiments, the energy storage power supply 100 further includes an AC output filter circuit, which is composed of an inductor L and a filter capacitor C2. When a load is connected, the load is connected in parallel with the filter capacitor C2.

[0024] The energy storage power supply 100 can be connected to the power grid or to a local load. The energy storage power supply energy saving control method provided in this application is a solution to the energy loss problem of the off-grid energy storage power supply 100 in a light load or no-load state.

[0025] Please refer to Figure 2 , Figure 2 A structure of the controller 23 is shown as an example. Figure 2 As shown, the controller 23 includes at least one processor 231 and a memory 232, wherein the memory 232 may be built in the controller 23 or externally located outside the controller 23, and the memory 232 may also be a remotely located memory connected to the controller 23 via a network.

[0026] The memory 232, as a non-volatile computer-readable storage medium, can be used to store non-volatile software programs, non-volatile computer executable programs and modules. The memory 232 may include a program storage area and a data storage area, wherein the program storage area may store an operating system, at least one application required for a function; the data storage area may store data created according to the use of the terminal, etc. In addition, the memory 232 may include a high-speed random access memory, and may also include a non-volatile memory, such as at least one disk storage device, a flash memory device, or other non-volatile solid-state storage device. In some embodiments, the memory 232 may optionally include a memory remotely arranged relative to the processor 231, and these remote memories may be connected to the terminal via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0027] The processor 231 performs various functions of the terminal and processes data by running or executing software programs and / or modules stored in the memory 232, and calling data stored in the memory 232, thereby monitoring the terminal as a whole, for example, implementing the energy-saving control method of the energy storage power supply provided in any embodiment of the present application.

[0028] The processor 231 may be one or more, Figure 2 A processor 231 is taken as an example. The processor 231 and the memory 232 may be connected via a bus or other means. The processor 231 may include a central processing unit (CPU), a digital signal processor (DSP), an application specific integrated circuit (ASIC), a controller, a field programmable gate array (FPGA) device, etc. The processor 231 may also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors combined with a DSP core, or any other such configuration.

[0029] Please refer to Figure 3 , Figure 3 A flow chart of an energy storage power supply energy-saving control method provided in an embodiment of the present application. The energy storage power supply includes an inverter, and the inverter includes a front-stage DC-DC module, a rear-stage DC-AC module and a controller, wherein the front-stage DC-DC module converts the DC input voltage into a DC bus voltage, and the rear-stage DC-AC module converts the DC bus voltage into the expected AC output voltage. The controller is respectively connected to the front-stage DC-DC module and the rear-stage DC-AC module, and is used for driving control of the front-stage DC-DC module and inverter conversion control of the rear-stage DC-AC module. In some embodiments, the energy storage power supply here can be provided by, for example, Figure 1-Figure 2 The structural implementation shown and the specific implementation process have been described in detail in the above embodiments and will not be repeated here.

[0030] like Figure 3 As shown, the energy-saving control method of the energy storage power supply includes: Step S301, sampling the AC output voltage and the AC output current, and calculating the output apparent power.

[0031] AC output voltage of the inverter and AC output current Sampling is performed to calculate the apparent power of the output , the calculation formula is as follows:

[0032] in, is the total number of sampling points in one sine cycle, For the sampling points.

[0033] Step S302: When the apparent power is greater than or equal to a preset power lower limit threshold, the inverter is controlled to enter a normal mode.

[0034] In one embodiment, a power lower limit threshold of the apparent power is preset (for example, 5% of the rated apparent power), and when the apparent power is greater than or equal to the power lower limit threshold, the inverter enters the normal mode. In the normal mode, the front-stage DC-DC module and the rear-stage DC-AC module of the inverter work normally according to the existing control strategy. Specifically, the front-stage DC-DC module is in a continuous periodic pulse drive mode, and the rear-stage DC-AC module uses a sinusoidal pulse width modulation mode to modulate the inverter waveform.

[0035] Step S303, when the apparent power is less than the power lower limit threshold, the inverter is controlled to enter the first-level low power consumption mode, and the no-load detection algorithm is executed to determine whether the energy storage power supply is in a no-load state. If so, the inverter is controlled to switch to the second-level low power consumption mode.

[0036] When the apparent power is less than the power lower limit threshold, the inverter enters the first-level low-power mode, and executes the no-load detection algorithm in the first-level low-power mode to determine whether the energy storage power supply is in a no-load state. If so, the inverter is controlled to switch to the second-level low-power mode. In the first-level low-power mode, the front-stage DC-DC module enters the intermittent working mode, and works intermittently based on the preset hysteresis response voltage. The rear-stage DC-AC module works normally and uses the sinusoidal pulse width modulation mode to modulate the inverter waveform; in the second-level low-power mode, the front-stage DC-DC module enters the intermittent working mode, and the inverter waveform modulation mode of the rear-stage DC-AC module is switched from sinusoidal pulse width modulation to trapezoidal pulse width modulation.

[0037] When the energy storage power supply is in light load / no load state, the main loss is switching loss. Therefore, when the inverter works in low power mode, the front-stage DC-DC module switches from the normal continuous working mode to the intermittent working mode. Figure 4 As shown, in the intermittent working mode, the driving pulse of the front-stage DC-DC module is intermittently turned off to reduce the driving loss of the front-stage DC-DC module.

[0038] In the intermittent working mode, a hysteresis response voltage is set, and the hysteresis response voltage includes a hysteresis response voltage lower limit and a hysteresis response voltage upper limit. After the front-stage DC-DC module enters the intermittent working mode, the DC bus voltage is sampled. When it is detected that the DC bus voltage is lower than the hysteresis response voltage lower limit, the front-stage DC-DC module is controlled to start pulse driving, and the DC bus voltage continues to increase under the action of the pulse driving. When it is detected that the DC bus voltage reaches the hysteresis response voltage upper limit, the front-stage DC-DC module is controlled to stop pulse driving.

[0039] In one embodiment, the lower limit of the hysteresis response voltage is the minimum voltage value that enables the subsequent DC-AC module to work normally. Assume that the rated peak voltage of the energy storage power supply on the inverter side is U ac The inverter efficiency is 95%, that is, the DC bus voltage is at least 1.05 x U ac Considering the influence of hysteresis response delay, the lower limit of hysteresis response voltage can be selected as 1.1ⅹU ac The upper limit of the hysteresis response voltage is the maximum value within the hardware allowed range.

[0040] When the energy storage power supply is in the no-load state, in order to improve the utilization rate of the DC bus voltage and further reduce the no-load loss, the subsequent DC-AC module adopts the trapezoidal pulse width modulation (T-PWM) mode to replace the original sinusoidal pulse width modulation (SPWM) mode to modulate the inverter waveform.

[0041] Please refer to Figure 5 and Figure 6 , Figure 5 is a schematic diagram of using T-PWM to replace SPWM provided in an embodiment of the present application, Figure 6 : is a diagram showing the relationship between the triangulation rate of the trapezoidal wave, the waveform distortion rate, and the DC voltage utilization rate provided in the embodiment of the present application. Figure 6 In the figure, the horizontal axis is the triangulation rate. , the solid line curve is the waveform distortion rate, and the dotted line curve is the DC voltage utilization rate. Figure 5 It can be seen that for the same amplitude modulation signal, the enclosed area of ​​the trapezoidal wave is significantly larger than that of the sine wave, so that the amplitude of the basic component of the trapezoidal wave is larger than that of the sine wave, and the utilization rate of the DC bus voltage is improved. Figure 6 It can be seen that the triangulation rate When the waveform distortion rate is around 0.4 to 0.8, the DC voltage utilization rate is very low, while the DC voltage utilization rate is higher around 0.4. Preferably, when the post-stage DC-AC module modulates the inverter waveform using a trapezoidal pulse width modulation mode, a trapezoidal wave with a triangular rate of around 0.4 is selected for modulation.

[0042] The no-load detection algorithm in this application is executed when the inverter works in the first-level low-power mode. In one embodiment, the no-load detection algorithm includes: when the inverter works in the first-level low-power mode, the DC bus voltage is sampled, and the first time required for the DC bus voltage to drop from a preset first voltage threshold to a preset second voltage threshold is detected. If the first time is greater than or equal to the preset discharge time threshold, the energy storage power supply is judged to be in a no-load state. Among them, the first voltage threshold is greater than the second voltage threshold. In one embodiment, the first voltage threshold is the upper limit of the hysteresis response voltage, and the second voltage threshold is the lower limit of the hysteresis response voltage. The discharge time threshold is the maximum time required for the DC bus voltage to drop from the first voltage threshold to the second voltage threshold when the inverter works in the first-level low-power mode, that is, the time required when the energy storage power supply is in a no-load state. If the energy storage power supply is connected to a load, the DC bus voltage drops faster and takes less time. Therefore, when the first time is greater than or equal to the discharge time threshold, the energy storage power supply can be judged to be in a no-load state.

[0043] Please refer to Figure 7 and Figure 8 , Figure 7 is a flowchart of a no-load detection algorithm provided in an embodiment of the present application, Figure 8 is a flow chart of determining a discharge duration threshold provided by an embodiment of the present application. Figure 7 As shown, the process of the no-load detection algorithm includes: Step S701, sampling the DC bus voltage.

[0044] Step S702, determining whether the DC bus voltage is less than the hysteresis response voltage lower limit, if so, proceeding to step S703, if not, proceeding to step S701.

[0045] Step S703, turning on the driving pulse of the front-stage DC-DC module to increase the DC bus voltage.

[0046] Step S704: sampling the DC bus voltage.

[0047] Step S705, determining whether the DC bus voltage rises to the upper limit of the hysteresis response voltage, if so, proceeding to step S706, if not, proceeding to step S704.

[0048] Step S706, turning off the pulse drive of the front-stage DC-DC module and starting the timer.

[0049] Step S707, sampling the DC bus voltage.

[0050] Step S708, determining whether the DC bus voltage drops to the lower limit of the hysteresis response voltage, if so, proceeding to step S709, if not, proceeding to step S707.

[0051] Step S709, stop the timer and record the timing duration as the first duration.

[0052] Step S710, determining whether the first time duration is greater than or equal to a preset discharge time duration threshold, if so, proceeding to step S711, if not, proceeding to step S712.

[0053] Step S711, determining whether the energy storage power supply is in a no-load state.

[0054] Step S712, determining whether the energy storage power source is in a light load state.

[0055] like Figure 8 As shown, the process of determining the discharge duration threshold includes: Step S801, disconnecting the load connected to the energy storage power supply, and then controlling the energy storage power supply to start up.

[0056] Step S802, sampling the AC output voltage and the AC output current, and calculating the output apparent power.

[0057] Step S803, determine whether the apparent power is less than the power lower limit threshold, if so, proceed to step S804, if not, proceed to step S802.

[0058] Step S804: sampling the DC bus voltage.

[0059] Step S805, determining whether the DC bus voltage is less than the hysteresis response voltage lower limit, if so, proceeding to step S806, if not, proceeding to step S804.

[0060] Step S806, turning on the driving pulse of the front-stage DC-DC module to increase the DC bus voltage.

[0061] Step S807, sampling the DC bus voltage.

[0062] Step S808, determining whether the DC bus voltage rises to the upper limit of the hysteresis response voltage, if so, proceeding to step S809, if not, proceeding to step S807.

[0063] Step S809, turning off the pulse drive of the front-stage DC-DC module and starting the timer.

[0064] Step S810, sampling the DC bus voltage.

[0065] Step S811, determine whether the DC bus voltage drops to the lower limit of the hysteresis response voltage, if so, go to step S812, if not, go to step S810.

[0066] Step S812, stop the timer and record the timing duration as the second duration.

[0067] Step S813, determining a discharge duration threshold according to the second duration.

[0068] In one embodiment, the discharge time threshold is the same as the second time. After the discharge time threshold is determined, the discharge time threshold is stored in a memory of the inverter.

[0069] It should be noted that Figure 7 The no-load detection algorithm is executed based on the first voltage threshold being the upper limit of the hysteresis response voltage and the second voltage threshold being the lower limit of the hysteresis response voltage. In other embodiments, the first voltage threshold and the second voltage threshold may also be other values ​​that satisfy the following relationship: the upper limit of the hysteresis response voltage ≥ the first voltage threshold > the second voltage threshold ≥ the lower limit of the hysteresis response voltage. When the first voltage threshold is not the upper limit of the hysteresis response voltage and the second voltage threshold is not the lower limit of the hysteresis response voltage, it is only necessary to Figure 7 Steps S706 to S709 can be modified to the following steps: Step S706 ′, turning off the pulse drive of the front-stage DC-DC module.

[0070] Step S707 ′, sampling the DC bus voltage, and starting a timer when detecting that the DC bus voltage drops to a first voltage threshold.

[0071] Step S708', sampling the DC bus voltage, and stopping the timer when it is detected that the DC bus voltage drops to a second voltage threshold.

[0072] Step S709', recording the measured duration as the first duration.

[0073] It is understandable that when the first voltage threshold is not the upper limit of the hysteresis response voltage and the second voltage threshold is not the lower limit of the hysteresis response voltage, the process of determining the discharge duration threshold also needs to be modified accordingly with reference to the above process.

[0074] based on Figures 3 to 8 The energy-saving control method of the energy storage power supply can determine the working mode of the inverter in the initial state, and the subsequent working mode of the inverter can be determined based on the current working mode of the inverter and the current detection data.

[0075] Specifically, when the inverter operates in the first-level low-power mode, the energy-saving control method also includes: executing a no-load detection algorithm to determine whether the energy storage power supply is in a no-load state; if so, controlling the inverter to switch to the second-level low-power mode; if not, sampling the AC output voltage and the AC output current, calculating the output apparent power, and determining whether the apparent power is greater than or equal to the power lower limit threshold; if so, controlling the inverter to switch to normal mode.

[0076] When the inverter is working in the secondary low power consumption mode, the energy-saving control method further includes: continuously detecting the AC output voltage, and when it is detected that the absolute value of the difference between the AC output voltage and the corresponding reference voltage amplitude is greater than the preset first voltage difference threshold (i.e., the energy storage power supply is connected to a heavy load), controlling the inverter to switch to the normal mode; when it is detected that the absolute value of the difference between the AC output voltage and the corresponding reference voltage amplitude is greater than the preset second voltage difference threshold for N consecutive times (i.e., the energy storage power supply is connected to a light load), controlling the inverter to switch to the primary low power consumption mode, wherein the first voltage difference threshold is greater than the second voltage difference threshold (for example, the first voltage difference threshold is 120V, and the second voltage difference threshold is 80V), and N is the preset number of times. In one embodiment, N=0.0015ⅹf, where f is the main control interruption frequency of the inverter, that is, within one cycle (taking the AC voltage with a frequency of 50Hz as an example, the duration of one cycle is 20ms), the voltage deviation that meets the above conditions is maintained for a duration of 1.5ms, which means that the energy storage power supply is connected to a light load.

[0077] Please refer to Fig. 9 , Fig. 9 It is a complete process of energy-saving control method of energy storage power supply, including: Step S901, sampling the AC output voltage and the AC output current, and calculating the output apparent power.

[0078] Step S902, determine whether the apparent power is less than the power lower limit threshold, if so, go to step S903, if not, go to step S908.

[0079] Step S903, controlling the inverter to enter the first level low power consumption mode.

[0080] Step S904, execute the no-load detection algorithm to determine whether the energy storage power supply is in a no-load state, if so, proceed to step S905, if not, proceed to step S901.

[0081] Step S905, controlling the inverter to enter the secondary low power consumption mode.

[0082] Step S906, determine whether the energy storage power supply is connected to the load, if so, go to step S907, if not, go to step S905.

[0083] Specifically, the AC output voltage is continuously detected by the voltage sensor, and when the absolute value of the difference between the AC output voltage and the corresponding reference voltage amplitude is detected to be greater than the first voltage difference threshold, or when the absolute value of the difference between the AC output voltage and the corresponding reference voltage amplitude is detected to be greater than the second voltage difference threshold for N consecutive times, it is determined that the energy storage power supply is connected to the load. The meanings of the first voltage difference threshold, the second voltage difference threshold and N are described in detail above.

[0084] Step S907, determine whether the energy storage power supply is connected to the heavy load, if so, go to step S908, if not, go to step S903.

[0085] Specifically, when it is detected that the absolute value of the difference between the AC output voltage and the corresponding reference voltage amplitude is greater than the first voltage difference threshold, it is determined that the energy storage power supply is connected to a heavy load.

[0086] Step S908, controlling the inverter to enter normal mode.

[0087] The energy-saving control method of the energy storage power supply provided by the present application, the energy storage power supply includes an inverter, the inverter includes a front-stage DC-DC module and a rear-stage DC-AC module, when the apparent power is less than the power lower limit threshold, the inverter is first controlled to enter the first-level low-power mode, and then it is identified whether the energy storage power supply is in a no-load state, if so, the inverter is controlled to switch to the second-level low-power mode, wherein in the first-level low-power mode, the front-stage DC-DC module works intermittently based on a preset hysteresis response voltage, and the rear-stage DC-AC module modulates the inverter waveform using a sinusoidal pulse width modulation mode, and in the second-level low-power mode, the front-stage DC-DC module works intermittently based on the hysteresis response voltage, and the rear-stage DC-AC module modulates the inverter waveform using a trapezoidal pulse width modulation mode. The method of the present application can identify light load and no-load, and adopt different low-power control strategies in the light load and no-load states, significantly reducing the energy loss of the off-grid energy storage power supply when light load or no-load.

[0088] According to an embodiment of the present application, a computer-readable storage medium is provided, the type of which is as described above, the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the processor executes the steps of the energy-saving control method of the energy storage power supply described above.

[0089] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a general hardware platform, and of course, by hardware. Based on this understanding, the above technical solution, in essence or in other words, the part that contributes to the relevant technology, can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiment.

[0090] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application. Therefore, any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A method for energy-saving control of an energy storage power supply, characterized in that: The energy storage power supply includes an inverter, the inverter includes a front-stage DC-DC module and a rear-stage DC-AC module, the front-stage DC-DC module converts a DC input voltage into a DC bus voltage, and the rear-stage DC-AC module converts the DC bus voltage into an expected AC output voltage. The method includes: Sampling the AC output voltage and AC output current, and calculating the output apparent power; When the apparent power is greater than or equal to a preset power lower limit threshold, controlling the inverter to enter a normal mode of operation; When the apparent power is less than the power lower limit threshold, the inverter is controlled to enter the first-level low power consumption mode, and the no-load detection algorithm is executed to determine whether the energy storage power supply is in a no-load state. If so, the inverter is controlled to switch to the second-level low power consumption mode; Among them, in the first-level low power consumption mode, the front-stage DC-DC module works intermittently based on the preset hysteresis response voltage, and the rear-stage DC-AC module adopts a sinusoidal pulse width modulation mode to modulate the inverter waveform. In the second-level low power consumption mode, the front-stage DC-DC module works intermittently based on the hysteresis response voltage, and the rear-stage DC-AC module adopts a trapezoidal pulse width modulation mode to modulate the inverter waveform.

2. The method according to claim 1, characterized in that The hysteresis response voltage includes a hysteresis response voltage lower limit and a hysteresis response voltage upper limit. The front-stage DC-DC module works intermittently based on the preset hysteresis response voltage: when the DC bus voltage is lower than the hysteresis response voltage lower limit, the front-stage DC-DC module starts pulse driving until the DC bus voltage reaches the hysteresis response voltage upper limit, and the front-stage DC-DC module stops pulse driving.

3. The method according to claim 2, characterized in that The no-load detection algorithm includes: When the inverter operates in the first-level low power consumption mode, the DC bus voltage is sampled to detect the first time duration required for the DC bus voltage to drop from a preset first voltage threshold to a preset second voltage threshold. If the first time duration is greater than or equal to a preset discharge time duration threshold, it is determined that the energy storage power supply is in a no-load state.

4. The method according to claim 3, characterized in that The discharge time threshold is determined based on a second time required for the DC bus voltage to drop from the first voltage threshold to the second voltage threshold when the energy storage power supply is in a no-load state and the inverter operates in a primary low power consumption mode.

5. The method according to claim 3, characterized in that: The first voltage threshold is the upper limit of the hysteresis response voltage, and the second voltage threshold is the lower limit of the hysteresis response voltage.

6. The method according to any one of claims 1 to 5, characterized in that: When the inverter operates in the first-level low power consumption mode, the method further includes: Executing the no-load detection algorithm to determine whether the energy storage power supply is in a no-load state; If yes, control the inverter to switch to the secondary low power consumption mode; If not, the AC output voltage and the AC output current are sampled, the output apparent power is calculated, and it is determined whether the apparent power is greater than or equal to the power lower limit threshold. If so, the inverter is controlled to switch to normal mode.

7. The method according to any one of claims 1 to 5, characterized in that: When the inverter operates in the secondary low power consumption mode, the method further includes: Continuously detect the AC output voltage; When it is detected that the absolute value of the difference between the AC output voltage and the corresponding reference voltage amplitude is greater than a preset first voltage difference threshold, controlling the inverter to switch to a normal mode of operation; When the absolute value of the difference between the AC output voltage and the corresponding reference voltage amplitude is detected to be greater than a preset second voltage difference threshold for N consecutive times, the inverter is controlled to switch to a first-level low power consumption mode, the first voltage difference threshold is greater than the second voltage difference threshold, and N is a preset number of times.

8. The method according to any one of claims 1 to 5, characterized in that: When the latter DC-AC module adopts the trapezoidal pulse width modulation mode to modulate the inverter waveform, a trapezoidal wave with a triangular ratio of about 0.4 is selected for modulation.

9. An energy storage power supply, characterized in that: The inverter includes a front-stage DC-DC module, a rear-stage DC-AC module and a controller. The front-stage DC-DC module converts a DC input voltage into a DC bus voltage. The rear-stage DC-AC module converts the DC bus voltage into an expected AC output voltage. The controller is connected to the front-stage DC-DC module and the rear-stage DC-AC module respectively. The controller includes: At least one processor and a memory communicatively connected to the at least one processor, the memory storing instructions executable by the at least one processor, the instructions being executed by the at least one processor so that the at least one processor can execute the energy-saving control method for the energy storage power supply as described in any one of claims 1 to 8.

10. A computer storage medium, characterized in that: The computer storage medium stores instructions or programs, and when the instructions or programs are executed by at least one processor, the at least one processor executes the energy-saving control method for the energy storage power supply according to any one of claims 1 to 8.

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