Abstract: The present disclosure provides a method for experimentally determining a critical sand-carrying gas velocity of a shale gas well. The method includes: collecting well structure and production data, calculating parameter ranges of a gas flow velocity and a liquid flow velocity; carrying out a physical simulation experiment of sand carrying in the shale gas well to obtain the sand holding capacity of the wellbore under different experimental conditions, and calculating a sand holding rate; by observing a change curve of the sand holding rate of the wellbore vs. the gas flow velocity, defining a turning point, and sensitively analyzing the influence of other experimental variables on the turning point, to calculate the critical sand-carrying production of the shale gas well under different conditions. Therefore, this calculation method is simple and applicable, and provides a theoretical basis for the optimization design of water drainage and gas production process.

Abstract: Approximately one-half of the loss of delivered power from a solar panel having photovoltaic (PV) cells connected in series to form sub-panels due to shading is recovered at low hardware cost by connecting sub-panels in series and providing maximum power point tracking control in common for the series connected sub-panels such that the respective sub-panels produce equal voltages even in the presence of shading of a portion of one or more sub-panels. By doing so, the input voltage of respective power converters which control the voltage at which each sub-panel is operated can be placed close to the maximum power point of each sub-panel regardless of shading and maximum total power harvested even though the respective sub-panels are not operated at optimum voltages.

Abstract: A multi-path constant current driving circuit. In the multi-path constant current driving circuit, a current sharing transformer (T31, T32, T33, T3(n?1)) is provided in power supply circuits which are provided with adjacent rectifier and filter units (Z31, Z32, Z33, Z3n). A first winding of the current sharing transformer (T31, T32, T33, T3(n?1)) is connected between a first terminal of a secondary winding of a first power supply circuit and the rectifier and filter unit (Z31, Z32, Z33, Z3n) of the first power supply circuit. A second winding of the current sharing transformer (T31, T32, T33, T3(n?1)) is connected between a first terminal of a secondary winding of a second power supply circuit and the rectifier and filter unit (Z31, Z32, Z33, Z3n) of the second power supply circuit. In-phase current flows through the dotted terminal of the first winding and the synonym terminal of the second winding of the current sharing transformer (T31, T32, T33, T3(n?1)).

Abstract: A drive circuit for realizing accurate constant current of multiple LEDs is disclosed. The drive circuit comprises a high-frequency impulse Alternating Current (AC) power carrying N circuit units with same structure. Each of the circuit unit comprises a rectifier filter circuit, a blocking capacitor C1 and two LED loads. The rectifier filter circuit comprises two independent half-wave rectifier circuits, and two filter capacitors. Each of the two half-wave rectifier circuits comprises two diodes connected in series to supply power for the corresponding LED load. The filter capacitor is connected in parallel with the two ends of an LED load respectively, and the blocking capacitor C1 is connected in series with the input end of the rectifier filter circuit. The circuit also comprises N?1 equalizing transformers, each of which connects in series between two adjacent circuit units.

Abstract: Approximately one-half of the loss of delivered power from a solar panel having photovoltaic (PV) cells connected in series to form sub-panels due to shading is recovered at low hardware cost by connecting sub-panels in series and providing maximum power point tracking control in common for the series connected sub-panels such that the respective sub-panels produce equal voltages even in the presence of shading of a portion of one or more sub-panels. By doing so, the input voltage of respective power converters which control the voltage at which each sub-panel is operated can be placed close to the maximum power point of each sub-panel regardless of shading and maximum total power harvested even though the respective sub-panels are not operated at optimum voltages.

Abstract: A constant current control circuit with multiple outputs for a LED driver, the circuit including a single-output constant current power supply, and multiple output circuits, each output circuit comprising a current sharing circuit, a current sharing control circuit and a LED load. The LED load and the current sharing circuit are in series and form a series loop with a first terminal and a second terminal of the series loop connected to a first output terminal and a second output terminal of the constant current power supply.

Abstract: A multi-path constant current drive circuit includes a DC/AC converter, a main transformer and at least two rectifying and filtering units. The main transformer includes at least one assistant side winding with a tap; together with the assistant side winding of the main transformer, each of the at least two rectifying and filtering units respectively forms a power supply loop; each power supply loop includes a first rectifying loop and a second rectifying loop, which are relatively used for the rectification of the positive and the negative half-cycle alternating voltage; a current-equalizing transformer is arranged between the adjacent first power supply loop and second power supply loop, the windings of the current-equalizing transformer are respectively in the rectifying loops contained in the first power supply loop and the second power supply loop, thus realizing the current equalization between the different rectifying loops in which the adjacent rectifying and filtering units are contained.

Abstract: A LED drive circuit for SCR dimming including an external controller configured to receive AC voltage from a power network to convert the AC voltage to an AC voltage with a lacked phase by phase controlling the voltage through a thyristor, and a LED driver that includes a bridge rectifier configured to shape the AC voltage with the lacked phase output into a unidirectional pulse DC voltage, and a phase angle detecting circuit configured to shape the AC voltage signal output with lacked phase from the external controller into a saw-tooth wave pulse signal.

Abstract: The invention discloses a hollow, liquid cooling and strip-shaped LED lamp, comprising an LED driver, an LED light source, and LED substrate, a light distributing lampshade, electrical connectors at two ends and a lamp socket. The invention is characterized in that a hollow inner container is set in the light distributing lampshade. The hollow chamber between the hollow inner container and the light distributing lampshade is filled with heat conducting liquid. The LED substrate is immersed in the heat conducting liquid. The invention conducts heat by conduction and convection of the heat conducting liquid, which can obtain good heat radiating effect. Meanwhile, the inner container and the light distributing lampshade form a hollow radiating shell filled with high performance heat conducting liquid, and the hollow radiating shell can be made of light weight materials. Therefore, the radiating shell is light in weight, environmental friendly, durable and low cost.

Abstract: A current-driven synchronous rectifying drive circuit designed for a T-type voltage doubler rectifier with an energy feedback circuit including a clamp and energy feedback circuit, a high frequency transformer, a current transducer, an energy storage capacitor, an output capacitor, a first and a second synchronous rectifier, and a first drive circuit connected to the first synchronous rectifier and a second drive circuit connected to the second synchronous rectifier.

Abstract: A drive circuit for realizing accurate constant current of multiple LEDs is disclosed. The drive circuit comprises a high-frequency impulse Alternating Current (AC) power carrying N circuit units with same structure. Each of the circuit unit comprises a rectifier filter circuit, a blocking capacitor C1 and two LED loads. The rectifier filter circuit comprises two independent half-wave rectifier circuits, and two filter capacitors. Each of the two half-wave rectifier circuits comprises two diodes connected in series to supply power for the corresponding LED load. The filter capacitor is connected in parallel with the two ends of an LED load respectively, and the blocking capacitor C1 is connected in series with the input end of the rectifier filter circuit. The circuit also comprises N?1 equalizing transformers, each of which connects in series between two adjacent circuit units.

Abstract: A multi-path constant current drive circuit includes a DC/AC converter, a main transformer and at least two rectifying and filtering units. The main transformer includes at least one assistant side winding with a tap; together with the assistant side winding of the main transformer, each of the at least two rectifying and filtering units respectively forms a power supply loop; each power supply loop includes a first rectifying loop and a second rectifying loop, which are relatively used for the rectification of the positive and the negative half-cycle alternating voltage; a current-equalizing transformer is arranged between the adjacent first power supply loop and second power supply loop, the windings of the current-equalizing transformer are respectively in the rectifying loops contained in the first power supply loop and the second power supply loop, thus realizing the current equalization between the different rectifying loops in which the adjacent rectifying and filtering units are contained.

Abstract: A multi-path constant current driving circuit. In the multi-path constant current driving circuit, a current sharing transformer (T31, T32, T33, T3(n?1)) is provided in power supply circuits which are provided with adjacent rectifier and filter units (Z31, Z32, Z33, Z3n). A first winding of the current sharing transformer (T31, T32, T33, T3(n?1)) is connected between a first terminal of a secondary winding of a first power supply circuit and the rectifier and filter unit (Z31, Z32, Z33, Z3n) of the first power supply circuit. A second winding of the current sharing transformer (T31, T32, T33, T3(n?1)) is connected between a first terminal of a secondary winding of a second power supply circuit and the rectifier and filter unit (Z31, Z32, Z33, Z3n) of the second power supply circuit. In-phase current flows through the dotted terminal of the first winding and the synonym terminal of the second winding of the current sharing transformer (T31, T32, T33, T3(n?1)).

Abstract: The invention discloses a hollow, liquid cooling and strip-shaped LED lamp, comprising an LED driver, an LED light source, and LED substrate, a light distributing lampshade, electrical connectors at two ends and a lamp socket. The invention is characterized in that a hollow inner container is set in the light distributing lampshade. The hollow chamber between the hollow inner container and the light distributing lampshade is filled with heat conducting liquid. The LED substrate is immersed in the heat conducting liquid. The invention conducts heat by conduction and convection of the heat conducting liquid, which can obtain good heat radiating effect. Meanwhile, the inner container and the light distributing lampshade form a hollow radiating shell filled with high performance heat conducting liquid, and the hollow radiating shell can be made of light weight materials. Therefore, the radiating shell is light in weight, environmental friendly, durable and low cost.

Abstract: A constant current control circuit with multiple outputs for a LED driver, the circuit including a single-output constant current power supply, and multiple output circuits, each output circuit comprising a current sharing circuit, a current sharing control circuit and a LED load. The LED load and the current sharing circuit are in series and form a series loop with a first terminal and a second terminal of the series loop connected to a first output terminal and a second output terminal of the constant current power supply.

Abstract: A LED drive circuit for SCR dimming including an external controller configured to receive AC voltage from a power network to convert the AC voltage to an AC voltage with a lacked phase by phase controlling the voltage through a thyristor, and a LED driver that includes a bridge rectifier configured to shape the AC voltage with the lacked phase output into a unidirectional pulse DC voltage, and a phase angle detecting circuit configured to shape the AC voltage signal output with lacked phase from the external controller into a saw-tooth wave pulse signal.

Abstract: A current-driven synchronous rectifying drive circuit designed for a T-type voltage doubler rectifier with an energy feedback circuit including a clamp and energy feedback circuit, a high frequency transformer, a current transducer, an energy storage capacitor, an output capacitor, a first and a second synchronous rectifier, and a first drive circuit connected to the first synchronous rectifier and a second drive circuit connected to the second synchronous rectifier.

Abstract: A pulse current transducer including at least one open core, an armature, together with the at least one open core form a closed magnetic circuit, a winding wound around the at least one open core, at least one signal output pin connected to the at least one open core, and a conducting strip between the armature and the at least one open core.