Abstract: The present disclosure discloses a method for producing raw cotton of machine-harvested long-staple cotton with a modal length of greater than or equal to 35 mm, including the steps: planting sea-island long-staple cotton and machining seed cotton, wherein planting the sea-island long-staple cotton includes preparation before machine harvesting, defoliation and ripening, choosing a cotton variety, etc.; and machining the seed cotton includes preparation before seed cotton ginning, mechanical separation of cotton seeds and raw cotton, and finishing the separated raw cotton. Raw cotton fibers obtained by the method of the present disclosure have main quality indexes that: a fiber length is 36.5-38.4 mm, a specific strength is 42.3-46.1 cN/tex, a uniformity is 86.2-87.0%, a foreign-fiber content is 0.2-0.4 g/t, and an impurity content is 2.6-3.4%.

Abstract: This application discloses a photovoltaic device, a photovoltaic inverter, a system, and a power limit control method. The device includes a DC-DC converter circuit, an inverter circuit, and a controller. An input end of the DC-DC converter circuit is connected to a photovoltaic array, and an output end of the DC-DC converter circuit is connected to an input end of the inverter circuit. The controller is configured to: receive a power scheduling instruction, where the power scheduling instruction carries a power reference value; and when the power reference value is less than a power at a maximum power point, reduce an input current of the DC-DC converter circuit; or when an input voltage of the DC-DC converter circuit is greater than or equal to a preset voltage, increase an input current of the DC-DC converter circuit until an output power of an inverter becomes consistent with the power reference value.

Abstract: A method and an apparatus for detecting a short circuit of an inverter, and an inverter are provided. A voltage of a common bus is increased when a plurality of boost circuits in the inverter are all in a non-working state, and after circuit parameters of input sides of all the plurality of boost circuits are detected, a boost circuit in which a diode is short-circuited in the plurality of boost circuits is further determined based on the circuit parameters of the input sides of the boost circuits. According to the method and the apparatus for detecting a short circuit of an inverter, and the inverter, circuit complexity of the inverter can be reduced, and circuit complexity of a photovoltaic power generation system including the inverter is reduced.

Abstract: A photovoltaic system includes at least one DC/DC converter and the inverter. An input terminal of the at least one DC/DC converter is configured to connect to a photovoltaic module, an output terminal is configured to connect to an input terminal of the inverter by using a direct current bus, and an output terminal of the inverter is connected to an alternating current grid. When the inverter is switched from a non-power-limited working state to a power-limited working state, the inverter adjusts a bus voltage of the inverter to rise from a first voltage to a second voltage. After running in the power-limited working state for a time interval, the inverter adjusts the bus voltage to drop from the second voltage to a third voltage, where the third voltage is less than or equal to the first voltage.

Abstract: This application relates to a converter in a photovoltaic power generation system and a converter control method. An input end of the converter is connected to at least one photovoltaic module, and an output end is connected to an inverter. The control method includes: determining an output power-voltage (PV) curve of a converter based on an output PV curve of the photovoltaic module; and controlling a voltage output of the converter based on the output PV curve of the converter. The output PV curve includes at least a simulated voltage limiting section and a constant power section that are connected. In this application, an existing MPPT control policy of the inverter can be adapted when a voltage-limited output is implemented, to avoid a case in which a power of a photovoltaic string drops to zero.

Abstract: A converter system includes a plurality of converters, a sampling circuit, and a control circuit. The plurality of converters are connected in parallel. Each converter includes a detection circuit which includes a first switch and at least two resistors. The first switch is connected in parallel with one of the at least two resistors. The control circuit control the sampling circuit to collect a first voltage and a second voltage, where the first voltage is a voltage that is between a second bus and a ground cable and that is collected by the sampling circuit when first switches in detection circuits of a first quantity are in a turn-on state, the second voltage is a voltage that is between the second bus and the ground cable and that is collected by the sampling circuit when first switches in detection circuits of a second quantity are in a turn-on state.

Abstract: This application provides a photovoltaic energy storage control module and a photovoltaic energy storage control method. A control component included in the photovoltaic energy storage control module can set reference values of bus voltages of a first direct-current converter, a second direct-current converter, and an inverter. Further, the first direct-current converter, the second direct-current converter, and the inverter can automatically adjust a power supply relationship among the first direct-current converter, the second direct-current converter, and the inverter based on a value relationship among the reference values of the bus voltages of the first direct-current converter, the second direct-current converter, and the inverter. In this way, flexibility of the photovoltaic energy storage control module is improved.

Abstract: A photovoltaic power generation system includes a single-stage inverter, an anti-backflow circuit, a photovoltaic string, and a coupling capacitor. The anti-backflow circuit is connected to one input end of the single-stage inverter, one output end of the photovoltaic string is connected to the other input end of the single-stage inverter, and the other output end of the photovoltaic string is connected to the anti-backflow circuit. The photovoltaic string includes a buck optimizer and a photovoltaic panel. The anti-backflow circuit is configured to prevent a backflow current from flowing back to the photovoltaic string. The coupling capacitor is connected in parallel to two ends of the anti-backflow circuit and is configured to transmit a signal between each buck optimizer in the photovoltaic string and the single-stage inverter, to control backflow of the backflow current when the anti-backflow circuit fails.

Abstract: A three-level converter includes a high-voltage side unit, a low-voltage side unit, a flying capacitor, a first switch to a fourth switch, and a control unit. When a voltage of the flying capacitor falls outside a safe target voltage range, the control unit may control the third switch and the fourth switch to be normally open, and control, based on the voltage of the flying capacitor and a voltage of the low-voltage side unit, each of the first switch and the second switch to be turned on or off, so that the voltage of the flying capacitor falls within the target voltage range. Alternatively, the control unit may control the first switch and the second switch to be normally open, and control, based on the voltage of the flying capacitor and a voltage of the low-voltage side unit.

Abstract: A power system includes N direct current coupling units, N direct current buses, and a main controller. The main controller is configured to: obtain a total network input demand power (a network input power required by the power grid); obtain first amplitude limiting values (indicate a maximum discharging power that can be supplied by each energy unit to the power grid); and determine first network input power values (a power value allocated to each energy unit and that is input to the power grid, and at least one direct current coupling unit is in a first amplitude limiting state) based on the total network input demand power and the first amplitude limiting values, and the first amplitude limiting state is that a first network input power value of direct current coupling unit is equal to a first amplitude limiting value corresponding to the direct current coupling unit.

Abstract: The present disclosure discloses a method for producing raw cotton of machine-harvested long-staple cotton with a modal length of greater than or equal to 35 mm, including the steps: planting sea-island long-staple cotton and machining seed cotton, wherein planting the sea-island long-staple cotton includes preparation before machine harvesting, defoliation and ripening, choosing a cotton variety, etc.; and machining the seed cotton includes preparation before seed cotton ginning, mechanical separation of cotton seeds and raw cotton, and finishing the separated raw cotton. Raw cotton fibers obtained by the method of the present disclosure have main quality indexes that: a fiber length is 36.5-38.4 mm, a specific strength is 42.3-46.1 cN/tex, a uniformity is 86.2-87.0%, a foreign-fiber content is 0.2-0.4 g/t, and an impurity content is 2.6-3.4%.

Abstract: A battery charging and discharging system includes: the battery charging and discharging circuit and a control circuit. The control circuit includes a processor. The processor is configured to: determine a first target current value corresponding to each of at least two feedback controls based on sampled data corresponding to the at least two feedback controls; determine a second target current value based on the first target current value corresponding to each of the at least two feedback controls; and comprehensively balance a first target current value of each feedback control, to adaptively determine a second target current value. A drive signal is generated based on the second target current value, and the drive signal is output to the DC/DC converter.

Abstract: A photovoltaic power generation system includes a plurality of photovoltaic batteries, a DC/DC module, a direct current bus capacitor, an energy storage component, and a power control apparatus, where an input side of the DC/DC module is coupled to the plurality of photovoltaic batteries, an output side of the DC/DC module is coupled to the direct current bus capacitor, and output electric energy provided by the photovoltaic batteries to the direct current bus capacitor; the energy storage component is coupled to the direct current bus capacitor, the power control apparatus is separately coupled to the direct current bus capacitor and the energy storage component, and is configured to: detect a first voltage of the direct current bus capacitor, and when the first voltage meets a preset compensation condition, control the energy storage component to charge the direct current bus capacitor.

Abstract: A voltage source inverter includes a bus capacitor, a bidirectional power tube, a filter inductor, and a filter capacitor. A voltage control method includes: respectively obtaining a first feedback current and a first feedback voltage from an output end of the filter inductor and an output end of the filter capacitor; obtaining a first duty cycle and a second duty cycle based on the first feedback current, a maximum current reference value, and a minimum current reference value in a current loop; obtaining a third duty cycle based on the first feedback voltage and a voltage reference value in a voltage loop; and selecting one of the first duty cycle, the second duty cycle, and the third duty cycle, and controlling the bidirectional power tube, so that a duty cycle of the bidirectional power tube is between the first duty cycle and the second duty cycle.

Abstract: A power supply system and an IV curve scanning method for a power supply system. The power supply system includes at least a first inverter and a second inverter. The first inverter starts, at an IV curve scanning start time of the first inverter, to perform IV curve scanning on a string connected to the first inverter, and the second inverter starts, at an IV curve scanning start time of the second inverter, to perform IV curve scanning on a string connected to the second inverter. Their IV curve scanning start time is different. In addition, a time interval between the IV curve scanning their start time is less than a preset IV curve scanning period. In the embodiments, fluctuation of an output power of the power supply system during IV curve scanning can be reduced, thereby improving system stability of the power supply system.

Abstract: An energy system mainly includes a charging and discharging control apparatus and an energy storage battery. When a battery level is not greater than a discharging level threshold and a charging current of the energy storage battery is less than a charging current threshold, the charging and discharging control apparatus may control the energy storage battery to stop charging and discharging. When the battery level is not less than a charging level threshold and a discharging current of the energy storage battery is less than a discharging current threshold, the charging and discharging control apparatus may also control the energy storage battery to stop charging and discharging.

Abstract: A power conversion module includes a power transistor and a sampling control unit. The sampling control unit determines a given duty cycle of the power conversion module based on the bus reference duty cycle, the power supply reference duty cycle, and the current limiting reference duty cycle, and controls, based on the given duty cycle, the power transistor to work, to control the direct current bus to have a target bus voltage and enable the power conversion module to run at the maximum power point. In this application, the direct current bus can be stabilized and the power conversion module can be controlled to run at the maximum power point.

Abstract: This application provides a photovoltaic system and a power supply current control method thereof. The photovoltaic system includes a direct current bus and at least two power supply units connected in parallel to the direct current bus. The power supply current control method of a photovoltaic system includes: obtaining a current power supply state parameter of each of the at least two power supply units, determining a reference power supply current value of each power supply unit based on the current power supply state parameter of each power supply unit, and adjusting a current supply power of each power supply unit based on the reference power supply current value of each power supply unit. According to this application, appropriate load distribution between power supply units can be ensured, and applicability is high.

Abstract: Embodiments of this application relate to the field of control technologies, and provide a control method and a distributed power system. The method includes: controlling an inverter to work in a current source mode, where the current source mode means that the inverter serves as a current source to convert a direct current generated by a power supply device into an alternating current and output the alternating current to the alternating current grid; and controlling the inverter to switch from the current source mode to a voltage source mode when it is detected that a voltage at a first target port jumps. In this way, an output voltage of the inverter may be controlled within a safety range, so that a local load can be protected before a cause of an abnormal voltage is detected, and comparatively, power may be continuously supplied to the local load.

Abstract: A detection method and a related apparatus. Whether a first converter and a second converter are connected to a same combiner device is determined by determining an output port voltage signal of the first converter and an output port voltage signal of the second converter, so that first information or second information is generated and notified to staff. Generally, if a first converter and a second converter in a combiner system are not connected to a same combiner device, it may be considered as that a wire connection of the first converter or the second converter is incorrect. In the detection method and the related apparatus, whether there is a wiring error in the combiner system of the converters can be quickly and accurately determined in an application scenario in which voltage information at a combiner point cannot be obtained.