Inverter off-grid idle low-power consumption control method and related device

Abstract

The application provides an inverter off-grid no-load low-power consumption control method and related device. The inverter off-grid no-load low-power consumption control method comprises the following steps: detecting the current parameter of the off-grid AC output end of the inverter, and when the current parameter meets the preset no-load condition, controlling the inverter to enter the no-load low-power consumption mode; in the no-load low-power consumption mode, controlling the AC output end of the DC / AC unit to perform intermittent AC voltage output at a preset time interval; and during each intermittent AC voltage output, judging whether there is a load connected according to the current parameter; in the no-load low-power consumption mode, when the voltage of the DC bus decreases to a first threshold value, starting the DC / DC unit to charge the DC bus; when the voltage of the DC bus increases to a second threshold value, closing the DC / DC unit; and in the process that the voltage of the DC bus naturally decreases from the second threshold value to the first threshold value, keeping the DC / DC unit in the closed state. The application reduces the switching loss of the DC / AC unit and the DC / DC unit in the off-grid no-load scene.

Description

Technical Field

[0001] This invention relates to the field of energy storage equipment technology, and more specifically, to a method and related apparatus for controlling the low power consumption of an inverter when it is off-grid and under no-load conditions. Background Technology

[0002] In the application scenarios of energy storage inverters and energy storage power supplies, the main sources of power for energy storage batteries are solar photovoltaic panels, mains power, and diesel power. During actual product use, the energy from solar photovoltaic panels is affected by factors such as sunshine duration and intensity, and weather conditions, while the energy from mains power is affected by factors such as mains power prices. Therefore, while meeting normal output requirements, the inverter needs to minimize its own power consumption to allow the battery to maintain a longer discharge time. For off-grid, no-load scenarios where the inverter is disconnected from the mains power supply and the AC port has no load, existing no-load control schemes for energy storage inverters require the DC / AC (Direct Current to Alternating Current) unit to continuously output a complete sine wave, and the DC / DC (Direct Current to Direct Current) unit to dynamically adjust the voltage. However, under these conditions, the long-term operation of the switching transistors in the DC / AC and DC / DC units results in significant switching losses, leading to substantial ineffective power consumption by the battery. Summary of the Invention

[0003] The present invention aims to solve the technical problems existing in the prior art or related technologies.

[0004] Therefore, the first aspect of the present invention proposes a method for controlling low power consumption of an inverter when it is off-grid and under no-load conditions.

[0005] A second aspect of the present invention proposes an inverter off-grid, no-load, low-power control system.

[0006] A third aspect of the present invention provides an inverter.

[0007] A fourth aspect of the present invention provides a storage medium.

[0008] In view of this, according to a first aspect of the present invention, an off-grid no-load low-power control method for an inverter is proposed, wherein the off-grid no-load low-power control method includes: detecting the current parameter of the off-grid AC output terminal of the inverter; when the current parameter meets a preset no-load condition, controlling the inverter to enter a no-load low-power mode; the inverter includes a DC / AC unit, a DC / DC unit, and a DC bus, the DC bus being used to connect the DC / AC unit and the DC / DC unit; in the no-load low-power mode, controlling the AC output terminal of the DC / AC unit to intermittently output AC voltage at preset time intervals, the duration of each output being a preset short-time period; within the preset time interval, controlling the DC / AC unit to... The C unit is turned off; and during each intermittent AC voltage output, the current parameter at the off-grid AC output terminal is detected, and the current parameter is used to determine whether a load is connected; if a load is connected, the inverter is controlled to exit the no-load low-power mode; if no load is connected, the no-load low-power mode is maintained; in the no-load low-power mode, when the DC bus voltage drops to the first threshold, the DC / DC unit is started to charge the DC bus to raise the DC bus voltage; when the DC bus voltage rises to the second threshold, the DC / DC unit is turned off; during the process of the DC bus voltage naturally dropping from the second threshold to the first threshold, the DC / DC unit is kept in the off state; wherein, the first threshold is less than the second threshold.

[0009] The inverter off-grid no-load low-power control method provided by this invention mainly includes: firstly, collecting the current parameters of the off-grid AC output terminal of the inverter during operation, wherein the AC output terminal is the socket terminal for external power supply of the inverter, and the current parameter is the sampled value of the AC output current. Then, the current parameter is compared with a preset no-load condition; if the condition is met, the inverter enters the no-load low-power mode. The preset no-load condition is a no-load judgment current rule pre-written into the controller. For example, the preset no-load condition can be less than a preset no-load current threshold. That is, when the current parameter is less than the preset no-load current threshold, the inverter is controlled to enter the no-load low-power mode; when the current parameter is not less than the preset no-load current threshold, the inverter is not controlled to enter the no-load low-power mode. The no-load low-power mode is an energy-saving operating condition in which most power devices are in sleep mode. The inverter is composed of a DC / DC unit, a DC bus, and a DC / AC unit connected sequentially. The DC / DC unit is a DC-DC boost converter, the DC / AC unit is a DC-to-AC inverter unit, and the DC bus is a high-voltage energy storage line connecting the two conversion stages. In the no-load low-power mode, the DC / AC unit's AC output terminal is controlled to intermittently output AC voltage at preset time intervals. The duration of each output is a preset short period, where the preset time interval is the interval between two inspection pulses, and intermittent AC voltage output refers to only short-term output of detection pulses rather than continuous power supply. The preset short period is the duration of a single pulse output. In other words, in the no-load low-power mode, the DC / AC unit is controlled to intermittently output short-term AC detection pulses at preset time intervals, and the DC / AC unit is turned off during the intervals. Simultaneously, the current parameters of the off-grid AC output terminal are synchronously collected during each output pulse. Based on the current parameters, it is determined whether a load is connected. If a load is present, the no-load low-power mode is exited; otherwise, the current mode is maintained. In the no-load low-power mode, the DC bus voltage also needs to be monitored in real time. When the bus voltage drops to a first threshold, the DC / DC unit is activated to charge the bus capacitor to increase the DC bus voltage. The first threshold is the lower limit of the bus charge / discharge hysteresis. When the bus voltage rises to the second threshold, the DC / DC unit is shut down. The second threshold is the upper limit of the bus charge / discharge hysteresis, and the first threshold is less than the second threshold. When the bus voltage naturally falls back from the second threshold to the first threshold, the DC / DC unit remains off throughout the entire process. This invention, by controlling the DC / DC unit and DC / AC unit to operate only intermittently for short periods in no-load low-power mode, and blocking their drives during the rest of the time, can eliminate high-frequency switching losses, significantly reduce off-grid no-load energy consumption, reduce ineffective power consumption of energy storage batteries, and effectively extend the standby life of the equipment.

[0010] In some technical solutions, the preset short-time period can optionally be one-quarter or one-half of the power frequency period.

[0011] In some technical solutions, optionally, when the voltage of the DC bus drops to a first threshold, the step of starting the DC / DC unit to charge the DC bus includes: after the DC / DC unit is turned on, controlling the power transistor in the DC / DC unit to charge the DC bus at a maximum preset duty cycle and a fixed preset operating frequency.

[0012] In some technical solutions, optionally, the step of determining whether a load is connected based on the current parameters includes: when the current parameters meet the preset no-load conditions, determining that no load is connected; when the current parameters do not meet the preset no-load conditions, determining that a load is connected.

[0013] In some technical solutions, optionally, the preset no-load condition is that the average value of the current parameters within a preset time period is less than or equal to a preset no-load current threshold.

[0014] In some technical solutions, optionally, when the DC / AC unit is intermittently outputting AC voltage at its AC output terminal, the DC / AC unit is controlled to perform a zero-phase soft-start operation.

[0015] In some technical solutions, optionally, if a load is connected, the step of controlling the inverter to exit the no-load low-power mode includes: when a load is connected, controlling the DC / AC unit to maintain the output AC voltage and controlling the DC / DC unit to start, so that the inverter exits the no-load low-power mode.

[0016] According to a second aspect of the present invention, an off-grid no-load low-power control system for an inverter is provided, wherein the off-grid no-load low-power control system comprises: a first processing module, which is used to detect the current parameter of the off-grid AC output terminal of the inverter, and when the current parameter meets a preset no-load condition, controls the inverter to enter a no-load low-power mode; the inverter includes a DC / AC unit, a DC / DC unit, and a DC bus, the DC bus being used to connect the DC / AC unit and the DC / DC unit; a second processing module, which is used to control the AC output terminal of the DC / AC unit to intermittently output AC voltage at a preset time interval in the no-load low-power mode, the duration of each output being a preset short-time period; within the preset time interval, the control... The DC / AC unit is shut down; and during each intermittent AC voltage output, the current parameter at the off-grid AC output terminal is detected, and the current parameter is used to determine whether a load is connected; if a load is connected, the inverter is controlled to exit the no-load low-power mode; if no load is connected, the no-load low-power mode is maintained; the third processing module is used to start the DC / DC unit to charge the DC bus to raise the DC bus voltage when the DC bus voltage drops to the first threshold in the no-load low-power mode; when the DC bus voltage rises to the second threshold, the DC / DC unit is shut down; and the DC / DC unit is kept in the off state during the process of the DC bus voltage naturally dropping from the second threshold to the first threshold; wherein, the first threshold is less than the second threshold.

[0017] The inverter off-grid no-load low-power control system provided by this invention mainly includes: a first processing module, a second processing module, and a third processing module. During operation, the first processing module first collects the current parameters of the inverter's off-grid AC output terminal, where the AC output terminal is the socket terminal for external power supply, and the current parameters are sampled values ​​of the AC output current. Then, the current parameters are compared with preset no-load conditions. If the conditions are met, the inverter enters the no-load low-power mode. The preset no-load conditions are no-load judgment current rules pre-written into the controller. For example, the preset no-load conditions can be less than a preset no-load current threshold. That is, when the current parameter is less than the preset no-load current threshold, the inverter is controlled to enter the no-load low-power mode; when the current parameter is not less than the preset no-load current threshold, the inverter is not controlled to enter the no-load low-power mode. The no-load low-power mode is an energy-saving operating condition in which most power devices are in sleep mode. The inverter is composed of a DC / DC unit, a DC bus, and a DC / AC unit connected sequentially. The DC / DC unit is a DC-DC boost converter, the DC / AC unit is a DC-to-AC inverter, and the DC bus is a high-voltage energy storage line connecting the two conversion stages. In the no-load low-power mode, the second processing module controls the AC output terminal of the DC / AC unit to output intermittent AC voltage at preset time intervals. The duration of each output is a preset short period. The preset time interval is the interval between two inspection pulses. Intermittent AC voltage output means that only a short-term detection pulse is output instead of continuous power supply. The preset short period is the duration of a single pulse output. That is to say, in the no-load low-power mode, the DC / AC unit is controlled to intermittently output short-term AC detection pulses at preset time intervals, and the DC / AC unit is turned off during the interval. At the same time, the current parameters of the off-grid AC output terminal are synchronously collected during each output pulse. The current parameters are used to determine whether there is a load connected. If there is a load, the no-load low-power mode is exited; otherwise, the current mode is maintained. In the no-load low-power mode, the third processing module needs to monitor the DC bus voltage in real time. When the bus voltage drops to a first threshold, the DC / DC unit is activated to charge the bus capacitor to increase the DC bus voltage. The first threshold is the lower limit of the bus charge / discharge hysteresis. When the bus voltage rises to a second threshold, the DC / DC unit is shut down. The second threshold is the upper limit of the bus charge / discharge hysteresis, and the first threshold is less than the second threshold. When the bus voltage naturally falls back from the second threshold to the first threshold, the DC / DC unit remains off throughout the process. This invention, by controlling the DC / DC unit and DC / AC unit to operate only intermittently for short periods in the no-load low-power mode, and blocking their drives during the rest of the time, can eliminate high-frequency switching losses, significantly reduce off-grid no-load energy consumption, reduce ineffective power consumption of energy storage batteries, and effectively extend the standby life of the equipment.

[0018] According to a third aspect of the present invention, an inverter is proposed, comprising an inverter off-grid, no-load, low-power control system as described in any of the above technical solutions.

[0019] The inverter provided by this invention mainly includes an off-grid, no-load, low-power control system for inverters as described in any of the above technical solutions, which can achieve the technical effects of any of the above technical solutions, and will not be elaborated further here.

[0020] According to a fourth aspect of the invention, a storage medium is provided on which a computer program is stored, which, when executed by a processor, implements the steps of the inverter off-grid no-load low-power control method as described in any of the preceding claims.

[0021] The storage medium provided by this invention enables the computer program to implement the steps of the above-mentioned inverter off-grid no-load low-power control method when executed by a processor, and can achieve the technical effects of any of the above technical solutions, which will not be elaborated here.

[0022] Additional aspects and advantages of the invention will become apparent in the following description or may be learned by practice of the invention. Attached Figure Description

[0023] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0024] Figure 1 One of the flowcharts of an inverter off-grid no-load low power consumption control method according to an embodiment of the present invention is shown;

[0025] Figure 2 The following is a timing diagram of the off-grid no-load output logic of an inverter according to an embodiment of the present invention;

[0026] Figure 3 The second schematic flowchart illustrates an embodiment of the inverter off-grid no-load low power consumption control method of the present invention.

[0027] Figure 4 The third schematic flowchart illustrates an embodiment of the inverter off-grid no-load low power consumption control method of the present invention;

[0028] Figure 5 A structural block diagram of an inverter according to an embodiment of the present invention is shown;

[0029] Figure 6 One of the schematic diagrams of the DC / DC unit in an inverter according to an embodiment of the present invention is shown;

[0030] Figure 7 A second schematic diagram of the structure of the DC / DC unit in an inverter according to an embodiment of the present invention is shown.

[0031] Figure 8 One of the schematic diagrams of the DC / AC unit in an inverter according to an embodiment of the present invention is shown;

[0032] Figure 9 A second schematic diagram of the structure of the DC / AC unit in an inverter according to an embodiment of the present invention is shown.

[0033] Figure 10 A block diagram of an inverter off-grid no-load low-power control system according to an embodiment of the present invention is shown.

[0034] in, Figures 5 to 9 The correspondence between the reference numerals and component names in the attached drawings is as follows:

[0035] 10 Inverter, 102 DC / DC Unit, 104 Bus Capacitor, 106 DC / AC Unit, 108 DC / DC Low-Voltage Side, 110 DC / DC High-Voltage Side, 112 Inverter Bridge Arm, 114 Output Relay, 116 AC Output Port, C1 First Capacitor, C2 Second Capacitor, Q1 First Switch, Q2 Second Switch, Q3 Third Switch, Q4 Fourth Switch, Q5 Fifth Switch, Q6 Sixth Switch, Q7 Seventh Switch, Q8 Eighth Switch, L1 First Inductor, C3 Third Capacitor, Q9 Ninth Inductor Switching transistors: Q10 (10th switch), Q11 (11th switch), Q12 (12th switch), Q13 (13th switch), Q14 (14th switch), Q15 (15th switch), Q16 (16th switch), L2 (2nd inductor), L3 (3rd inductor), C4 (4th capacitor), C5 (5th capacitor), C6 (6th capacitor), Q17 (17th switch), Q18 (18th switch), Q19 (19th switch), Q20 (20th switch), L4 (4th inductor), L5 (5th inductor), C7 (7th capacitor), C8 (8th capacitor), C9 (9th capacitor). Detailed Implementation

[0036] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other.

[0037] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0038] Figure 1 This diagram illustrates one embodiment of an inverter off-grid no-load low-power control method according to the present invention. The inverter off-grid no-load low-power control method includes:

[0039] Step 102: Detect the current parameters of the off-grid AC output terminal of the inverter. When the current parameters meet the preset no-load conditions, control the inverter to enter the no-load low-power mode. The inverter includes a DC / AC unit, a DC / DC unit, and a DC bus. The DC bus is used to connect the DC / AC unit and the DC / DC unit.

[0040] Step 104: In the no-load low-power mode, control the AC output terminal of the DC / AC unit to intermittently output AC voltage at preset time intervals, with the duration of each output being a preset short period; within the preset time interval, control the DC / AC unit to turn off; and during each intermittent AC voltage output, detect the current parameter of the off-grid AC output terminal, and determine whether a load is connected based on the current parameter; if a load is connected, control the inverter to exit the no-load low-power mode; if no load is connected, maintain the no-load low-power mode.

[0041] Step 106: In no-load low-power mode, when the voltage of the DC bus drops to the first threshold, the DC / DC unit is started to charge the DC bus to raise the voltage of the DC bus; when the voltage of the DC bus rises to the second threshold, the DC / DC unit is turned off; during the process of the DC bus voltage naturally dropping from the second threshold to the first threshold, the DC / DC unit is kept in the off state; wherein, the first threshold is less than the second threshold.

[0042] The inverter off-grid no-load low-power control method provided by this invention mainly includes: firstly, collecting the current parameters of the off-grid AC output terminal of the inverter during operation, wherein the AC output terminal is the socket terminal for external power supply of the inverter, and the current parameter is the sampled value of the AC output current. Then, the current parameter is compared with a preset no-load condition; if the condition is met, the inverter enters the no-load low-power mode. The preset no-load condition is a no-load judgment current rule pre-written into the controller. For example, the preset no-load condition can be less than a preset no-load current threshold. That is, when the current parameter is less than the preset no-load current threshold, the inverter is controlled to enter the no-load low-power mode; when the current parameter is not less than the preset no-load current threshold, the inverter is not controlled to enter the no-load low-power mode. The no-load low-power mode is an energy-saving operating condition in which most power devices are in sleep mode. The inverter is composed of a DC / DC unit, a DC bus, and a DC / AC unit connected sequentially. The DC / DC unit is a DC-DC boost converter, the DC / AC unit is a DC-to-AC inverter unit, and the DC bus is a high-voltage energy storage line connecting the two conversion stages. In the no-load low-power mode, the DC / AC unit's AC output terminal is controlled to intermittently output AC voltage at preset time intervals. The duration of each output is a preset short period, where the preset time interval is the interval between two inspection pulses, and intermittent AC voltage output refers to only short-term output of detection pulses rather than continuous power supply. The preset short period is the duration of a single pulse output. In other words, in the no-load low-power mode, the DC / AC unit is controlled to intermittently output short-term AC detection pulses at preset time intervals, and the DC / AC unit is turned off during the intervals. Simultaneously, the current parameters of the off-grid AC output terminal are synchronously collected during each output pulse. Based on the current parameters, it is determined whether a load is connected. If a load is present, the no-load low-power mode is exited; otherwise, the current mode is maintained. In the no-load low-power mode, the DC bus voltage also needs to be monitored in real time. When the bus voltage drops to a first threshold, the DC / DC unit is activated to charge the bus capacitor to increase the DC bus voltage. The first threshold is the lower limit of the bus charge / discharge hysteresis. When the bus voltage rises to the second threshold, the DC / DC unit is shut down. The second threshold is the upper limit of the bus charge / discharge hysteresis, and the first threshold is less than the second threshold. When the bus voltage naturally falls back from the second threshold to the first threshold, the DC / DC unit remains off throughout the entire process. This invention, by controlling the DC / DC unit and DC / AC unit to operate only intermittently for short periods in no-load low-power mode, and blocking their drives during the rest of the time, can eliminate high-frequency switching losses, significantly reduce off-grid no-load energy consumption, reduce ineffective power consumption of energy storage batteries, and effectively extend the standby life of the equipment.

[0043] In some embodiments, the preset short-time period may optionally be one-quarter of the power frequency period or one-half of the power frequency period.

[0044] In this embodiment, the preset short-time period for the intermittent output of the DC / AC unit can be selected as either a quarter-cycle or a half-cycle of the power frequency. The power frequency period is 20ms, corresponding to a complete sine wave of 50Hz mains power; the quarter-cycle period is 5ms; and the half-cycle period is 10ms. The two duration parameters can be switched according to the usage scenario. Once the pulse reaches the set duration, the inverter drive is immediately blocked, awaiting the next round of timed inspection. This invention, by setting two selectable pulse durations, balances low-power performance under no-load conditions with load identification accuracy. Using a quarter-cycle reduces the inverter's operating time to decrease power loss, while using a half-cycle extends the current sampling window, making it easier to capture small load currents and adapting to low-power load identification scenarios. Simultaneously, it strictly limits the maximum pulse output duration to avoid excessive battery consumption caused by prolonged continuous inverter output.

[0045] In some embodiments, optionally, when the voltage of the DC bus drops to a first threshold, the step of starting the DC / DC unit to charge the DC bus includes: after the DC / DC unit is turned on, controlling the power transistor in the DC / DC unit to charge the DC bus at a maximum preset duty cycle and a fixed preset operating frequency.

[0046] In this embodiment, the step of starting the DC / DC unit to charge the DC bus when the DC bus voltage drops to a first threshold includes: after the bus voltage drops to the first threshold (which serves as the lower limit of the hysteresis loop) and the DC / DC unit is started, the controller outputs a drive waveform with a fixed maximum preset duty cycle and a fixed preset operating frequency to control the internal power transistor of the DC / DC unit to continuously boost the voltage of the bus capacitor. Throughout the boost process, the PWM parameters are not dynamically adjusted; only the bus voltage is sampled in real time to determine whether a second threshold (which serves as the upper limit of the hysteresis loop) has been reached. Here, the maximum preset duty cycle is the upper limit value of the DC / DC power transistor's on-state duty cycle, used to maximize the bus charging speed. The fixed preset operating frequency refers to the constant switching frequency of the DC / DC switching transistor. This invention relies on a constant maximum duty cycle boost to quickly raise the bus voltage, shorten the overall operating time of the DC / DC unit, reduce switching losses, and simultaneously eliminate the need for dynamic voltage regulation closed-loop calculations, simplifying the control algorithm, reducing the real-time computational overhead of the main control chip, and improving program stability.

[0047] In some embodiments, the step of determining whether a load is connected based on the current parameters may include: determining that no load is connected when the current parameters meet a preset no-load condition; and determining that a load is connected when the current parameters do not meet the preset no-load condition.

[0048] In this embodiment, the step of determining whether a load is connected based on the current parameter includes: after continuously collecting the current parameter of the AC output terminal during the pulse period, comparing the current parameter with a pre-written preset no-load condition; if the current parameter meets the preset no-load condition, it is determined that no load is connected; if the current parameter does not meet the preset no-load condition, it is determined that a load is connected. This invention has a simple and clear determination logic and well-defined operating condition boundaries, classifying only two operating states: with load and without load. This avoids program fluctuations caused by complex multi-range determination logic and effectively reduces the probability of misjudgment in load identification.

[0049] In some embodiments, optionally, the preset no-load condition is that the average value of the current parameters within a preset time period is less than or equal to a preset no-load current threshold.

[0050] In this embodiment, multiple sets of current sampling points are collected within a preset duration corresponding to a single inspection pulse, and the average value is calculated. The average value is compared with a preset no-load current threshold. If the average value is less than or equal to the preset no-load current threshold, the no-load condition is determined to be met. Here, the preset duration is the complete duration of a single AC detection pulse, and the preset no-load current threshold is a pre-calibrated critical current value used to distinguish between no-load and loaded conditions. This invention uses the average current over a period of time to replace the instantaneous current at a single point to complete the condition determination. This can filter out noise interference from the sampling circuit, significantly improve the anti-interference capability and determination accuracy of load identification, and avoid misjudgment of no-load due to instantaneous current noise.

[0051] In some embodiments, optionally, when intermittent AC voltage output is performed at the AC output terminal of the control DC / AC unit, the control DC / AC unit performs a zero-phase soft-start operation.

[0052] In this embodiment, when controlling the DC / AC unit to output intermittent AC voltage, the DC / AC unit is simultaneously controlled to perform a zero-phase soft-start operation. The 0° zero-crossing point of the sine wave is locked as the starting phase of the voltage output. The PWM modulation duty cycle is linearly and slowly increased to gradually raise the output voltage. The complete soft-start process covers the entire duration of the short pulse. After the pulse ends, the duty cycle is gradually reduced and the inverter drive is blocked. The zero-phase soft-start is an inverter start-up control method that uses the zero-crossing point of the AC sine wave as the output starting point and slowly raises the output amplitude. This invention can eliminate the inrush current and bus voltage spikes generated during inverter start-up, reduce the instantaneous electrical stress on power semiconductor devices, and reduce the risk of device aging and breakdown damage. Simultaneously, the stable and shock-free sampling current waveform can avoid load identification misjudgment caused by inrush noise.

[0053] In some embodiments, optionally, the step of controlling the inverter to exit the no-load low-power mode when a load is connected includes: when a load is connected, controlling the DC / AC unit to maintain the output AC voltage and controlling the DC / DC unit to start, so that the inverter exits the no-load low-power mode.

[0054] In this embodiment, the step of controlling the inverter to exit the no-load low-power mode when a load is connected includes: when an external load is detected, controlling the DC / AC unit to continuously output complete power frequency AC power, while continuously enabling the DC / DC unit to perform dynamic voltage regulation, and the entire unit directly exits the no-load low-power cycle and switches to the normal load-carrying operating mode. This invention achieves seamless and stable power supply after a load is connected by synchronously and continuously enabling the two-stage power conversion units, avoiding AC output interruption and bus voltage drop issues. The DC / DC unit's dynamic voltage regulation continuously provides stable DC bus support to the inverter unit, ensuring stable output AC voltage amplitude.

[0055] For example, such as Figure 2 As shown, Figure 2 The diagram illustrates the off-grid no-load output logic timing of an inverter according to an embodiment of the present invention. The maximum bus voltage is set to 480V, the preset bus voltage to 420V, and the minimum bus voltage to 320V. When the inverter output current sampling detects that the average output current is less than a set threshold, the inverter enters a no-load low-power mode. In low-power mode, all drives in the DC / AC unit and the DC / DC unit are turned off. The inverter continuously monitors the bus voltage. When the detected bus voltage is lower than the minimum bus voltage of 320V, the DC / DC unit drives begin operating, and the bus voltage increases. When the bus voltage rises to the preset bus voltage of 420V, the DC / DC unit drives stop operating. The DC / AC unit outputs intermittent AC voltage at preset time intervals, with each output lasting for a preset short period, which can be 5ms. During the preset time interval, the DC / AC unit is turned off. The output current is detected during each intermittent AC voltage output. When the current is less than the current setting value for half a power frequency cycle, it indicates that the inverter is not connected to the load at this time. Therefore, the system continues to maintain the no-load low-power mode.

[0056] When entering the no-load low-power mode, the power transistor drive of the DC / AC unit is first turned off. Then, the DC / DC unit drive is turned off when the bus voltage rises to the highest bus voltage. During this period, the bus voltage gradually decreases until it drops to the lowest bus voltage of 320V. The time it takes for the bus voltage to drop is related to the power of the auxiliary power supply during standby. During the charging process of the bus capacitor by the DC / DC unit, it always operates at its maximum duty cycle and typical operating frequency. The interval between output detection pulses by the DC / AC unit can be determined based on usage habits, experience, and actual needs. The longer the interval, the lower the off-grid no-load power consumption and the higher the battery energy utilization rate.

[0057] Figure 3 This is a second schematic flowchart illustrating an embodiment of the inverter off-grid no-load low-power control method of the present invention; wherein the inverter off-grid no-load low-power control method includes:

[0058] Step 302: Detect the off-grid output current;

[0059] Step 304: Determine whether the current is less than the set current threshold. If the result is yes, proceed to step 306. If the result is no, proceed to step 302.

[0060] Step 306: Enter off-grid low power mode.

[0061] In this embodiment, the inverter off-grid no-load low-power control method includes: comparing the average value of the off-grid AC output current over a period of time with a set current threshold to determine whether to enter the off-grid low-power mode. If the current value is greater than or equal to the predetermined current threshold, the off-grid low-power mode is not entered; if the current value is less than the predetermined current threshold, the off-grid low-power mode is entered.

[0062] Figure 4 The third schematic flowchart illustrates an embodiment of the inverter off-grid no-load low-power control method of the present invention; wherein the inverter off-grid no-load low-power control method includes:

[0063] Step 402: The DC / DC unit begins operation;

[0064] Step 404: Check whether the bus voltage reaches the threshold and the interval is greater than 15ms. If the result is yes, proceed to step 406; if the result is no, proceed to step 402.

[0065] Step 406: DC / AC unit starts outputting for 5ms;

[0066] Step 408: Turn off the DC / AC unit output;

[0067] Step 410: Check whether the bus voltage has reached the maximum bus voltage. If the result is yes, proceed to step 412; if the result is no, proceed to step 402.

[0068] Step 412: Turn off the DC / DC unit;

[0069] Step 414: Check if the bus voltage is lower than the maximum bus voltage. If the result is yes, proceed to step 416; if the result is no, proceed to step 402.

[0070] Step 416: Start the DC / DC unit.

[0071] In this embodiment, the inverter off-grid no-load low-power control method includes: first, controlling the DC / DC unit to run and boost voltage, and simultaneously checking whether the bus voltage reaches a set threshold and whether the inspection interval exceeds 15ms. Only when both conditions are met simultaneously will the DC / AC unit start outputting an AC detection pulse with a duration of 5ms. If the conditions are not met, the DC / DC unit continues to operate. After the DC / AC unit completes the 5ms pulse output, it immediately shuts down. Then, it determines whether the bus voltage has risen to the maximum bus voltage. If the maximum bus voltage has been reached, the DC / DC unit is shut down. If the maximum bus voltage has not been reached, the DC / DC unit continues to run and boost voltage. After the DC / DC unit is shut down, the bus voltage is continuously monitored. Once the bus voltage is lower than the maximum bus voltage, the DC / DC unit is restarted to continue boosting voltage. If the bus voltage does not rise below the maximum bus voltage, the original loop judgment logic is maintained.

[0072] In this invention, once the low-power mode is entered, the DC / AC unit's AC output voltage is output intermittently, with the specific interval duration set according to actual needs. Each intermittent output determines whether the off-grid output has started a load. The off-grid output current or its average value is detected to determine whether the no-load low-power mode should be exited. Once the inverter system enters the off-grid no-load low-power mode, during the intermittent output from the off-grid output, the DC / AC unit's switching transistors are off, but the off-grid output relay remains closed. The DC / DC unit's switching transistors only operate for a short period during the process of the bus voltage rising from the set minimum voltage to the maximum voltage. Because the overall system power consumption is relatively low at this time, the bus capacitor value is relatively large, so the bus voltage drop rate is very slow. For a long period, the power switching transistors of both the DC / DC unit and the DC / AC unit are not operating, and the only loss in the entire system is the loss generated by the auxiliary power supply. This invention maintains the lowest no-load power consumption and a relatively short operating time across the entire battery voltage operating range. It adapts to different battery voltages within the same bus voltage range and output. Theoretically, the lowest bus voltage can be set at the lowest steady-state operating voltage of the auxiliary power supply.

[0073] Compared to related technical solutions, this invention actively searches for a load on the port in a short time, avoiding most of the unnecessary time spent idling and waiting to receive a load, thus saving valuable battery energy. Simultaneously, it maintains a minimum power consumption mode during load detection. During port load detection, the voltage at the off-grid output port only lasts for half or a quarter of a power frequency cycle. The load status is determined by monitoring the output current throughout the process. When the port initiates a load, the current changes normally with the voltage when issuing a no-load detection output voltage. The output voltage detection also features a soft-start function, preventing current surges and oscillations. During no-load operation, the DC / DC unit maintains its maximum duty cycle, and the bus voltage remains at the set value, preventing any momentary drops in bus voltage.

[0074] In this invention, the actual inverter voltage interval output duration can be set independently based on time period, electricity usage habits, lifestyle, and user experience, with energy saving and practicality as the goals. Simultaneously, the off-grid voltage output has a soft-start function; the phase angle of the output voltage starts from 0°, and the output voltage value increases slowly, with the current also increasing at a slow rate, preventing surges, oscillations, and triggering overcurrent protection.

[0075] For example, such as Figure 5 As shown, the inverter 10 of the present invention mainly includes: a DC / DC unit 102, a bus capacitor 104, and a DC / AC unit 106 connected in sequence. The DC / DC unit 102 includes a DC / DC low-voltage side 108 and a DC / DC high-voltage side 110 connected in series. The DC / DC low-voltage side 108 is responsible for connecting to an external low-voltage DC power source, which is boosted by an internal power conversion circuit and output as high-voltage DC power from the DC / DC high-voltage side 110. The bus capacitor 104 serves as a high-voltage energy storage buffer element, storing the high-voltage DC power output from the DC / DC high-voltage side 110, stabilizing the DC bus voltage, and buffering power fluctuations between the preceding and following stages. The DC / AC unit 106 has a three-stage internal structure connected in series: inverter bridge arm 112, output relay 114, and AC output port 116. The high-voltage DC output from the bus capacitor 104 is fed into the inverter bridge arm 112, which inverts the DC into power frequency AC. After the AC is controlled by the on / off state of the output relay 114, the AC power is finally output from the AC output port 116.

[0076] like Figure 6 and Figure 7As shown, the DC / DC unit 102 specifically consists of three parts: a primary-side full-bridge inverter circuit, a resonant network, and a secondary-side full-bridge inverter circuit. The first capacitor C1 is connected in parallel across the primary-side input bus, forming an input voltage regulator buffer capacitor. The first switch Q1 and the second switch Q2 form the left half-bridge arm, and the third switch Q3 and the fourth switch Q4 form the right half-bridge arm, together constituting the primary-side full-bridge inverter circuit. The first switch Q1 and the second switch Q2 are connected in series (upper and lower pairs), and the third switch Q3 and the fourth switch Q4 are connected in series (upper and lower pairs). These two sets of series-connected bridge arms are then connected in parallel across the first capacitor C1. The center taps of both sets of bridge arms are led out and connected to both ends of the resonant network. Figure 6 As shown, the resonant network can be composed of a first inductor L1, such as... Figure 7 As shown, the resonant network can also be composed of a first inductor L1 and a third capacitor C3 connected in series. The first inductor L1 and the third capacitor C3 are connected end to end, and the whole network is connected across the two output midpoints of the primary full-bridge inverter circuit and the two input midpoints of the secondary full-bridge inverter circuit. The resonant network serves as a resonant isolation conversion channel for bidirectional energy transmission, and relies on resonant soft switching to achieve zero-voltage turn-on of the switching transistors, reducing switching losses. The second capacitor C2 is connected in parallel across the two ends of the secondary output bus, serving as an output filter energy storage capacitor. The fifth switch Q5 and the sixth switch Q6 form the left secondary bridge arm, and the seventh switch Q7 and the eighth switch Q8 form the right secondary bridge arm, forming the secondary full-bridge inverter circuit. The fifth switch Q5 and the sixth switch Q6 are connected in series, and the seventh switch Q7 and the eighth switch Q8 are connected in series. The two sets of series bridge arms are connected in parallel across the two ends of the second capacitor C2, and the midpoints of the two sets of bridge arms are respectively connected to the two ends of the resonant network.

[0077] like Figure 8As shown, the DC / AC unit 106 includes: a DC input side, a buffer clamping branch, an inverter full-bridge arm, an output LC filter network, and an AC output terminal. On the DC input side, the fourth capacitor C4 and the fifth capacitor C5 are connected in series to form a high-voltage DC bus, with the midpoint of the bus at DC zero potential. The buffer clamping branch consists of the ninth switch Q9, the tenth switch Q10, the eleventh switch Q11, and the twelfth switch Q12 connected in reverse parallel, bridging the upper and lower ends of the DC bus and the midpoint of the full bridge. It is used to absorb voltage spikes, clamp the bus voltage, and protect the power switching devices. The upper right bridge arm of the inverter full-bridge arm consists of the thirteenth switch Q13 and the fourteenth switch Q14 connected in series, and the lower right bridge arm consists of the fifteenth switch Q15 and the sixteenth switch Q16 connected in series. The two sets of bridge arms are connected in parallel on the DC bus formed by the fourth capacitor C4 and the fifth capacitor C5. The midpoints of the two sets of bridge arms are led out as the inverter AC output terminals. The two midpoints of the output LC filter network are connected to the second inductor L2 and the third inductor L3, respectively. The sixth capacitor C6 and the seventh capacitor C7 are connected across the two inductors to form a dual-channel LC filter. At the AC output terminal, the L-phase line and N-neutral line are led out from the rear of the second inductor L2 and the third inductor L3 as the external AC power supply interface.

[0078] like Figure 9 As shown, the DC / AC unit 106 includes: a DC input side, an inverter full-bridge arm, an output LC filter, and an output interface. The DC input side retains only a single supporting capacitor, the eighth capacitor C8, as the DC bus capacitor. The inverter full-bridge arm consists of the seventeenth switch Q17, the eighteenth switch Q18, the nineteenth switch Q19, and the twentieth switch Q20. The midpoints of the two sets of bridge arms are connected to the fourth inductor L4 and the fifth inductor L5, respectively. The ninth capacitor C9 is connected across the rear ends of the two inductors, forming a single-path LC filter. At the AC output end, the L-phase line and N-neutral line are led out from the rear ends of the fourth inductor L4 and the fifth inductor L5, serving as the external AC power supply interface.

[0079] Figure 10 A structural block diagram of an inverter off-grid no-load low-power control system according to an embodiment of the present invention is shown; wherein, the inverter off-grid no-load low-power control system 100 includes:

[0080] The first processing module 1002 is used to detect the current parameters of the off-grid AC output terminal of the inverter. When the current parameters meet the preset no-load conditions, the inverter is controlled to enter the no-load low-power mode. The inverter includes a DC / AC unit, a DC / DC unit and a DC bus. The DC bus is used to connect the DC / AC unit and the DC / DC unit.

[0081] The second processing module 1004 is used to control the AC output terminal of the DC / AC unit to intermittently output AC voltage at preset time intervals in the no-load low-power mode, with the duration of each output being a preset short period; control the DC / AC unit to turn off within the preset time interval; and during each intermittent AC voltage output, detect the current parameter of the off-grid AC output terminal and determine whether a load is connected based on the current parameter; if a load is connected, control the inverter to exit the no-load low-power mode; if no load is connected, maintain the no-load low-power mode.

[0082] The third processing module 1006 is used to, in no-load low-power mode, when the voltage of the DC bus drops to a first threshold, start the DC / DC unit to charge the DC bus to raise the voltage of the DC bus; when the voltage of the DC bus rises to a second threshold, turn off the DC / DC unit; and keep the DC / DC unit in a turned-off state during the process of the DC bus voltage naturally dropping from the second threshold to the first threshold; wherein the first threshold is less than the second threshold.

[0083] The inverter off-grid no-load low-power control system 100 provided by this invention mainly includes: a first processing module 1002, a second processing module 1004, and a third processing module 1006. During operation, the first processing module 1002 first collects the current parameters of the inverter's off-grid AC output terminal. The AC output terminal is the socket terminal through which the inverter supplies power, and the current parameters are sampled values ​​of the AC output current. Then, the current parameters are compared with preset no-load conditions. If the conditions are met, the inverter enters the no-load low-power mode. The preset no-load conditions are no-load current rules pre-written into the controller. For example, the preset no-load conditions can be less than a preset no-load current threshold. That is, when the current parameter is less than the preset no-load current threshold, the inverter is controlled to enter the no-load low-power mode; when the current parameter is not less than the preset no-load current threshold, the inverter is not controlled to enter the no-load low-power mode. The no-load low-power mode is an energy-saving operating condition in which most power devices are in sleep mode. The inverter is composed of a DC / DC unit, a DC bus, and a DC / AC unit connected sequentially. The DC / DC unit is a DC-DC boost converter, the DC / AC unit is a DC-to-AC inverter, and the DC bus is a high-voltage energy storage line connecting the two conversion stages. In the no-load low-power mode, the second processing module 1004 controls the AC output terminal of the DC / AC unit to output intermittent AC voltage at preset time intervals. The duration of each output is a preset short period. The preset time interval is the interval between two inspection pulses. Intermittent AC voltage output refers to outputting detection pulses only for a short time instead of continuous power supply. The preset short period is the duration of a single pulse output. In other words, in the no-load low-power mode, the DC / AC unit is controlled to output short-time AC detection pulses intermittently at preset time intervals, and the DC / AC unit is turned off during the interval. At the same time, the current parameters of the off-grid AC output terminal are synchronously collected during each output pulse. The current parameters are used to determine whether there is a load connected. If there is a load, the no-load low-power mode is exited; otherwise, the current mode is maintained. In the no-load low-power mode, the third processing module 1006 needs to monitor the DC bus voltage in real time. When the bus voltage drops to a first threshold, the DC / DC unit is activated to charge the bus capacitor to increase the DC bus voltage. The first threshold is the lower limit of the bus charge / discharge hysteresis. When the bus voltage rises to a second threshold, the DC / DC unit is shut down. The second threshold is the upper limit of the bus charge / discharge hysteresis, and the first threshold is less than the second threshold. When the bus voltage naturally falls back from the second threshold to the first threshold, the DC / DC unit remains off throughout the process. This invention, by controlling the DC / DC unit and DC / AC unit to operate only intermittently for short periods in the no-load low-power mode, and blocking the drive during the rest of the time, can eliminate high-frequency switching losses, significantly reduce off-grid no-load energy consumption, reduce ineffective power consumption of energy storage batteries, and effectively extend the standby life of the equipment.

[0084] In some embodiments, the preset short-time period may optionally be one-quarter of the power frequency period or one-half of the power frequency period.

[0085] In this embodiment, the preset short-time period for the intermittent output of the DC / AC unit can be selected as either a quarter-cycle or a half-cycle of the power frequency. The power frequency period is 20ms, corresponding to a complete sine wave of 50Hz mains power; the quarter-cycle period is 5ms; and the half-cycle period is 10ms. The two duration parameters can be switched according to the usage scenario. Once the pulse reaches the set duration, the inverter drive is immediately blocked, awaiting the next round of timed inspection. This invention, by setting two selectable pulse durations, balances low-power performance under no-load conditions with load identification accuracy. Using a quarter-cycle reduces the inverter's operating time to decrease power loss, while using a half-cycle extends the current sampling window, making it easier to capture small load currents and adapting to low-power load identification scenarios. Simultaneously, it strictly limits the maximum pulse output duration to avoid excessive battery consumption caused by prolonged continuous inverter output.

[0086] In some embodiments, the third processing module 1006 is optionally configured to control the power transistor in the DC / DC unit to charge the DC bus at a maximum preset duty cycle and a fixed preset operating frequency after the DC / DC unit is turned on.

[0087] In this embodiment, the third processing module 1006 is specifically used to, when the bus voltage drops to the first threshold (which serves as the lower limit of the hysteresis loop) and the DC / DC unit is activated, output a drive waveform with a fixed maximum preset duty cycle and a fixed preset operating frequency. This waveform controls the internal power transistor of the DC / DC converter to continuously boost the bus capacitor. Throughout the boost process, the PWM parameters are not dynamically adjusted; only the bus voltage is sampled in real-time to determine whether the second threshold (which serves as the upper limit of the hysteresis loop) has been reached. The maximum preset duty cycle is the upper limit of the DC / DC power transistor's on-state duty cycle, used to maximize the bus charging speed. The fixed preset operating frequency refers to the constant switching frequency of the DC / DC switching transistor. This invention relies on a constant maximum duty cycle boost to quickly raise the bus voltage, shorten the overall operating time of the DC / DC unit, reduce switching losses, eliminate the need for dynamic voltage regulation closed-loop calculations, simplify the control algorithm, reduce the real-time computational overhead of the main control chip, and improve program stability.

[0088] In some embodiments, optionally, the second processing module 1004 is specifically used to determine that no load is connected when the current parameter meets the preset no-load condition; and to determine that a load is connected when the current parameter does not meet the preset no-load condition.

[0089] In this embodiment, the second processing module 1004 is specifically used to compare the current parameters of the AC output terminal, which are continuously collected during the detection pulse, with pre-written preset no-load conditions. If the current parameters meet the preset no-load conditions, it is determined that no load is connected; if the current parameters do not meet the preset no-load conditions, it is determined that a load is connected. The determination logic of this invention is simple and clear, and the working condition distinction boundary is well-defined. It only divides the operating state into two categories: with load and without load, avoiding program operation fluctuations caused by complex determination logic in multiple intervals, and effectively reducing the probability of misjudgment in load identification.

[0090] In some embodiments, optionally, the preset no-load condition is that the average value of the current parameters within a preset time period is less than or equal to a preset no-load current threshold.

[0091] In this embodiment, multiple sets of current sampling points are collected within a preset duration corresponding to a single inspection pulse, and the average value is calculated. The average value is compared with a preset no-load current threshold. If the average value is less than or equal to the preset no-load current threshold, the no-load condition is determined to be met. Here, the preset duration is the complete duration of a single AC detection pulse, and the preset no-load current threshold is a pre-calibrated critical current value used to distinguish between no-load and loaded conditions. This invention uses the average current over a period of time to replace the instantaneous current at a single point to complete the condition determination. This can filter out noise interference from the sampling circuit, significantly improve the anti-interference capability and determination accuracy of load identification, and avoid misjudgment of no-load due to instantaneous current noise.

[0092] In some embodiments, optionally, when intermittent AC voltage output is performed at the AC output terminal of the control DC / AC unit, the control DC / AC unit performs a zero-phase soft-start operation.

[0093] In this embodiment, when controlling the DC / AC unit to output intermittent AC voltage, the DC / AC unit is simultaneously controlled to perform a zero-phase soft-start operation. The 0° zero-crossing point of the sine wave is locked as the starting phase of the voltage output. The PWM modulation duty cycle is linearly and slowly increased to gradually raise the output voltage. The complete soft-start process covers the entire duration of the short pulse. After the pulse ends, the duty cycle is gradually reduced and the inverter drive is blocked. The zero-phase soft-start is an inverter start-up control method that uses the zero-crossing point of the AC sine wave as the output starting point and slowly raises the output amplitude. This invention can eliminate the inrush current and bus voltage spikes generated during inverter start-up, reduce the instantaneous electrical stress on power semiconductor devices, and reduce the risk of device aging and breakdown damage. Simultaneously, the stable and shock-free sampling current waveform can avoid load identification misjudgment caused by inrush noise.

[0094] In some embodiments, optionally, the second processing module 1004 is specifically configured to control the DC / AC unit to maintain the output AC voltage and control the DC / DC unit to start when a load is connected, so that the inverter exits the no-load low-power mode.

[0095] In this embodiment, the second processing module 1004 is specifically used to control the DC / AC unit to continuously maintain the output of complete power frequency AC when an external load is detected, while simultaneously keeping the DC / DC unit running dynamically with voltage regulation. The entire unit directly exits the no-load low-power cycle and switches to the conventional load-carrying operating mode. This invention achieves seamless and stable power supply after the load is connected by synchronously and continuously keeping the two power conversion units running, without the problems of AC output interruption or bus voltage drop. Relying on the dynamic voltage regulation of the DC / DC unit to continuously provide stable DC bus support for the inverter unit, it ensures the stability of the output AC voltage amplitude.

[0096] An inverter according to one embodiment of the present invention includes an inverter off-grid no-load low-power control system as described in any of the above claims.

[0097] The inverter provided by the present invention mainly includes an inverter off-grid no-load low-power control system as described in any one of the above embodiments, which can achieve the technical effects of any of the above embodiments, and will not be described in detail here.

[0098] One embodiment of the present invention provides a storage medium storing a computer program thereon, which, when executed by a processor, implements the steps of the inverter off-grid no-load low-power control method as described above.

[0099] The storage medium provided by this invention enables the computer program to implement the steps of the above-described inverter off-grid no-load low-power control method when executed by a processor, and can achieve the technical effects of any of the above embodiments, which will not be elaborated further.

[0100] In the description of this specification, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance, unless otherwise expressly specified and limited. The terms "connection," "installation," and "fixing," etc., should be interpreted broadly. For example, "connection" can mean a fixed connection, a detachable connection, or an integral connection; it can mean a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0101] In the description of this specification, the terms "one embodiment," "some embodiments," "specific embodiment," etc., refer to specific features, structures, materials, or characteristics described in connection with an embodiment or example that are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0102] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for controlling low power consumption of an inverter under off-grid no-load conditions, characterized in that, The inverter off-grid no-load low power consumption control method includes: The current parameter of the off-grid AC output terminal of the inverter is detected. When the current parameter meets the preset no-load condition, the inverter is controlled to enter the no-load low-power mode. The inverter includes a DC / AC unit, a DC / DC unit and a DC bus. The DC bus is used to connect the DC / AC unit and the DC / DC unit. In the no-load low-power mode, the AC output terminal of the DC / AC unit is controlled to intermittently output AC voltage at preset time intervals, with each output lasting for a preset short period. During the preset time interval, the DC / AC unit is controlled to shut down. During each intermittent AC voltage output, the current parameter of the off-grid AC output terminal is detected, and the presence of a load is determined based on the current parameter. If a load is connected, the inverter is controlled to exit the no-load low-power mode; if no load is connected, the no-load low-power mode is maintained. In the no-load low-power mode, when the voltage of the DC bus drops to a first threshold, the DC / DC unit is activated to charge the DC bus to raise its voltage; when the voltage of the DC bus rises to a second threshold, the DC / DC unit is turned off; during the process of the DC bus voltage naturally dropping from the second threshold to the first threshold, the DC / DC unit remains in the off state; wherein the first threshold is less than the second threshold.

2. The inverter off-grid no-load low-power control method according to claim 1, characterized in that, The preset short-time period is one-quarter of the power frequency period or one-half of the power frequency period.

3. The inverter off-grid no-load low-power control method according to claim 1, characterized in that, The step of activating the DC / DC unit to charge the DC bus when the voltage of the DC bus drops to a first threshold includes: After the DC / DC unit is turned on, the power transistors in the DC / DC unit are controlled to charge the DC bus at the maximum preset duty cycle and a fixed preset operating frequency.

4. The inverter off-grid no-load low power consumption control method according to claim 1, characterized in that, The step of determining whether a load is connected based on the current parameter includes: When the current parameter meets the preset no-load condition, it is determined that no load is connected; When the current parameter does not meet the preset no-load condition, it is determined that the load is connected.

5. The inverter off-grid no-load low-power control method according to claim 4, characterized in that, The preset no-load condition is that the average value of the current parameters within a preset time period is less than or equal to a preset no-load current threshold.

6. The inverter off-grid no-load low power consumption control method according to any one of claims 1 to 5, characterized in that, When controlling the intermittent AC voltage output at the AC output terminal of the DC / AC unit, the DC / AC unit is controlled to perform a zero-phase soft-start operation.

7. The inverter off-grid no-load low-power control method according to any one of claims 1 to 5, characterized in that, The step of controlling the inverter to exit the no-load low-power mode if a load is connected includes: When the load is connected, the DC / AC unit is controlled to maintain the output AC voltage, and the DC / DC unit is controlled to start, so that the inverter exits the no-load low-power mode.

8. An off-grid, no-load, low-power control system for an inverter, characterized in that, The inverter off-grid, no-load, low-power control system includes: The first processing module is used to detect the current parameter of the off-grid AC output terminal of the inverter. When the current parameter meets the preset no-load conditions, the inverter is controlled to enter the no-load low-power mode. The inverter includes a DC / AC unit, a DC / DC unit and a DC bus. The DC bus is used to connect the DC / AC unit and the DC / DC unit. The second processing module is used to control the AC output terminal of the DC / AC unit to intermittently output AC voltage at preset time intervals in the no-load low-power mode, with the duration of each output being a preset short period; control the DC / AC unit to shut down during the preset time interval; and during each intermittent AC voltage output, detect the current parameter of the off-grid AC output terminal and determine whether a load is connected based on the current parameter; if a load is connected, control the inverter to exit the no-load low-power mode; if no load is connected, maintain the no-load low-power mode. The third processing module is configured to, in the no-load low-power mode, activate the DC / DC unit to charge the DC bus to raise its voltage when the DC bus voltage drops to a first threshold; and shut down the DC / DC unit when the DC bus voltage rises to a second threshold; and keep the DC / DC unit in a shut-off state during the process of the DC bus voltage naturally dropping from the second threshold to the first threshold; wherein the first threshold is less than the second threshold.

9. An inverter, characterized in that, include: The inverter off-grid no-load low-power control system as described in claim 8.

10. A storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the inverter off-grid no-load low-power control method as described in any one of claims 1 to 7.

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