Abstract: A method and device for modulating a five-level inverter, and a photovoltaic system are provided. The method includes: acquiring a voltage command value Vcmd of a phase bridge; controlling a first and a fourth switching devices to be switched on alternately when Vcmd?V1Pos+Vthrs1; controlling the first and a third switching devices to be switched on alternately when V1Pos?Vthrs2?Vcmd<V1Pos+Vthrs1; controlling the fourth and the third switching devices to be switched on alternately when 0?Vcmd<V1Pos?Vthrs2; controlling the third and a fifth switching devices to be switched on alternately when ?V1Neg+Vthrs3?Vcmd<0; controlling the third and a second switching devices to be switched on alternately when ?V1Neg?Vthrs4?Vcmd<?V1Neg+Vthrs3; controlling the fifth and the second switching devices to be switched on alternately when Vcmd<?V1Neg?Vthrs4.

Abstract: A control method and apparatus for photovoltaic inverters connected in parallel at an AC side are provided and the method includes the following steps: detecting a first direct voltage of the first inverter and a second direct voltage of the second inverter; obtaining a difference between the first direct voltage and the second direct voltage; and adjusting the direct voltages of the inverters to control the difference to be within a predetermined range and control a common-mode voltage in the common-mode loop to be within a predetermined common-mode voltage range.

Abstract: A method and device for monitoring and suppressing a resonance are provided, which are applied to a grid-connected generation system. A current sample voltage of a preset sample point of the grid-connected generation system is monitored in a real time manner; amplitudes of harmonics of the current sample voltage are acquired using a preset algorithm; it is verified whether a resonance occurs in the grid-connected generation system currently based on the acquired amplitudes of the harmonics; in a case that the resonance occurs in the grid-connected generation system, current corrections of parameters of inverters in the grid-connected generation system are acquired according to a preset rule and the parameters of the inverters are adjusted using the current corrections and a selected resonance suppressing algorithm.

Abstract: A charging and discharging system, a charging and discharging method, and a photovoltaic power generation system are provided. The charging and discharging system includes: a unidirectional converter, a unidirectional switch, an energy storage device and a controller; where an input terminal of the unidirectional converter is connected to an output terminal of a photovoltaic device of a photovoltaic power generation system to which the charging and discharging system is applied, and an output terminal of the unidirectional converter is connected to an input terminal of the energy storage device; the unidirectional switch is connected between an output terminal of the energy storage device and an input terminal of a bidirectional inverter of the photovoltaic power generation system to which the charging and discharging system is applied; the controller is connected to the unidirectional converter, the unidirectional switch, the energy storage device and the bidirectional inverter.

Abstract: A heart-shaped self-locking button includes one housing and one push rod. The push rod is slidably arranged within the housing. A heart-shaped structure is formed on the push rod. The button includes one pin and one flexible element. One end of the pin is fixed on the housing, while the other end is fitted with the heart-shaped structure. The flexible element is arranged between the housing and the push rod and presses the pin towards the heart-shaped structure to allow the pin to be in constant contact with the heart-shaped structure. The heart-shaped structure is arranged on the push rod. Also, the flexible element between the housing and the push rod is utilized to press the pin towards the heart-shaped structure on the push rod to allow the pin to be in constant contact with the heart-shaped structure when moving.

Abstract: The present invention discloses a hypericin albumin nanoparticle-Escherichia coli serum antibody complex, which is obtained through adding mixed hypericin albumin nanoparticles and rabbit anti-Escherichia colis into ethanediol, irradiating them with carbon ion, setting them at a low temperature for 2 hours after irradiation, centrifuging them at a low temperature, and freezing and drying the precipitates. Its preparation method and application are also provided.

Abstract: Systems and methods for generating a three-dimensional gas map includes a remote vehicle including reflective material. A positioning stage including multidimensional movement to track the remote vehicle. A light head to reflect light off of the remote vehicle. A controller to analyze received light to determine gas content and generate a three-dimensional gas map.

Abstract: Disclosed are a medium and high voltage grid-connected power generation system, a medium and high voltage grid-connected system, and a control circuitry thereof. The voltage of the medium and high voltage power grid is collected through the control circuitry. A power grid amplitude and a power grid phase synchronization signal are obtained, and then sent to an inverter unit through a communication line.

Abstract: A method and device for switching an operation mode of a five-level inverter are provided. The method includes: determining a first three-level operation mode as a three-level operation mode to be switched to from a five-level operation mode in a case that a PV input voltage is higher than a bridge line-line voltage command value; switching, after the operation mode is switched to the first three-level operation mode, the operation mode from the first three-level operation mode to a second three-level operation mode, in a case that a junction temperature of a switching device operating in the first three-level operation mode exceeds a first preset value; and switching the operation mode from the second three-level operation mode to the first three-level operation mode in a case that the junction temperature of a switching device operating in the second three-level operation mode exceeds a second preset value.

Abstract: The invention relates to an evaporative humidifier including a water reservoir, a wick unit and a fan unit. The wick unit is configured to absorb water from the water reservoir. The fan unit is arranged within a fan housing and configured to force an air flow to flow through the wick unit. The fan housing comprises a top cover unit defining at least one annular air outlet at an outer part adjacent a circumference of the top cover unit. One of the main advantages of this invention is that the evaporative humidifier has an optimal air flow path and can operate in a low noise. The invention also relates to an indoor climate controlling system using such an evaporative humidifier.

Abstract: Provided are a parallel inverter system, and a shutdown control method and a shutdown control device for the parallel inverter system. A shutdown instruction is determined and responded according to a level of the shutdown instruction. The shutdown instruction is determined to be an emergency shutdown instruction under certain emergency shutdown conditions, and a driving signal for the power switch devices of the inverter apparatus is needed to be instantly locked out. The shutdown instruction is determined to be a normal shutdown instruction under non-emergency shutdown conditions, a switch-off signal is transmitted to alternating-current switches connected to the inverter apparatus to be shut down, states of the alternating-current switches connected to the inverter apparatus to be shut down are detected, the driving signal for the power switch devices of the inverter apparatus to be shut down is instantly locked out in a case that the alternating-current switches are switched off.

Abstract: A method for preparing a chitosan complex film comprises: (1) reacting polyvinyl alcohol-124 with butanedioic anhydride to obtain a modified polyvinyl alcohol; (2) formulating the modified polyvinyl alcohol-124 into a 0.4 wt % aqueous solution, then adding the aqueous solution containing 0.4 wt % of modified polyvinyl alcohol-124 dropwise into an acetic acid solution at a concentration of 0.4 wt % chitosan to obtain a mixed solution; (3) adjusting the pH value of the mixed solution with a 0.01 wt % NaOH solution to pH 5.5, and removing surface bubbles after standing for one hour to obtain a casting solution; (4) pouring the casting solution into a culture dish, placing the culture dish into an oven at 60° C. and drying to a constant weight to obtain the chitosan complex film. The materials used in the method are inexpensive, and the reaction is not complicated, so the cost of the product is not high.

Abstract: Systems and methods for generating a three-dimensional gas map includes a remote vehicle including reflective material. A positioning stage including multidimensional movement to track the remote vehicle. A light head to reflect light off of the remote vehicle. A controller to analyze received light to determine gas content and generate a three-dimensional gas map.

Abstract: The present invention discloses a hypericin albumin nanoparticle-Escherichia coli serum antibody complex, which is obtained through adding mixed hypericin albumin nanoparticles and rabbit anti-Escherichia colis into ethanediol, irradiating them with carbon ion, setting them at a low temperature for 2 hours after irradiation, centrifuging them at a low temperature, and freezing and drying the precipitates. Its preparation method and application are also provided.

Abstract: A control method and apparatus for photovoltaic inverters connected in parallel at an AC side are provided and the method includes the following steps: detecting a first direct voltage of the first inverter and a second direct voltage of the second inverter; obtaining a difference between the first direct voltage and the second direct voltage; and adjusting the direct voltages of the inverters to control the difference to be within a predetermined range and control a common-mode voltage in the common-mode loop to be within a predetermined common-mode voltage range.

Abstract: A method and device for switching an operation mode of a five-level inverter are provided. The method includes: determining a first three-level operation mode as a three-level operation mode to be switched to from a five-level operation mode in a case that a PV input voltage is higher than a bridge line-line voltage command value; switching, after the operation mode is switched to the first three-level operation mode, the operation mode from the first three-level operation mode to a second three-level operation mode, in a case that a junction temperature of a switching device operating in the first three-level operation mode exceeds a first preset value; and switching the operation mode from the second three-level operation mode to the first three-level operation mode in a case that the junction temperature of a switching device operating in the second three-level operation mode exceeds a second preset value.

Abstract: A method and device for modulating a five-level inverter, and a photovoltaic system are provided. The method includes: acquiring a voltage command value Vcmd of a phase bridge; controlling a first and a fourth switching devices to be switched on alternately when Vcmd?V1Pos+Vthrs1; controlling the first and a third switching devices to be switched on alternately when V1Pos?Vthrs2?Vcmd<V1Pos+Vthrs1; controlling the fourth and the third switching devices to be switched on alternately when 0?Vcmd<V1Pos?Vthrs2; controlling the third and a fifth switching devices to be switched on alternately when ?V1Neg+Vthrs3?Vcmd<0; controlling the third and a second switching devices to be switched on alternately when ?V1Neg?Vthrs4?Vcmd<?V1Neg+Vthrs3; controlling the fifth and the second switching devices to be switched on alternately when Vcmd<?V1Neg?Vthrs4.

Abstract: Provided are a parallel inverter system, and a shutdown control method and a shutdown control device for the parallel inverter system. A shutdown instruction is determined and responded according to a level of the shutdown instruction. The shutdown instruction is determined to be an emergency shutdown instruction under certain emergency shutdown conditions, and a driving signal for the power switch devices of the inverter apparatus is needed to be instantly locked out. The shutdown instruction is determined to be a normal shutdown instruction under non-emergency shutdown conditions, a switch-off signal is transmitted to alternating-current switches connected to the inverter apparatus to be shut down, states of the alternating-current switches connected to the inverter apparatus to be shut down are detected, the driving signal for the power switch devices of the inverter apparatus to be shut down is instantly locked out in a case that the alternating-current switches are switched off.

Abstract: A heart-shaped self-locking button includes one housing and one push rod. The push rod is slidably arranged within the housing. A heart-shaped structure is formed on the push rod. The button includes one pin and one flexible element. One end of the pin is fixed on the housing, while the other end is fitted with the heart-shaped structure. The flexible element is arranged between the housing and the push rod and presses the pin towards the heart-shaped structure to allow the pin to be in constant contact with the heart-shaped structure. The heart-shaped structure is arranged on the push rod. Also, the flexible element between the housing and the push rod is utilized to press the pin towards the heart-shaped structure on the push rod to allow the pin to be in constant contact with the heart-shaped structure when moving.

Abstract: A method and device for monitoring and suppressing a resonance are provided, which are applied to a grid-connected generation system. A current sample voltage of a preset sample point of the grid-connected generation system is monitored in a real time manner; amplitudes of harmonics of the current sample voltage are acquired using a preset algorithm; it is verified whether a resonance occurs in the grid-connected generation system currently based on the acquired amplitudes of the harmonics; in a case that the resonance occurs in the grid-connected generation system, current corrections of parameters of inverters in the grid-connected generation system are acquired according to a preset rule and the parameters of the inverters are adjusted using the current corrections and a selected resonance suppressing algorithm.