An enhanced control mechanism for an LED light string system is provided for switching between one of two DC output phases or polarities so as to actuate one or the other of two LEDs within the bulbs on the light string. The control mechanism is further configured to allow switching so as to pass through the input power provided by a high-to-low voltage converter that is plugged into its electrical power feeding end. The control mechanism may then provide rectified AC voltage, or DC voltage, of various switched values to the LED string according to the particular needs of the LED bulbs.

Apparatus and method for controlling LED light strings

Four-switch buck-boost (FSBB) converter is widely used in battery applications due to the simple structure and the excellent performance of both voltage step-up and step-down. With the quadrangle control method, FSBB converter can realize zero voltage switching (ZVS) of all power switches, and thus can adapt to the high-frequency trends. However, the conventional quadrangle control method has two problems: 1) the efficiency degradation caused by the large root mean square (RMS) current of the inductor, and 2) the instability caused by the coupling relationship between multiple control variables. In this article, an improved quadrangle control method is proposed to solve the two problems, making FSBB converter a good candidate for high-frequency battery applications. First, the loss analysis is built to determine the relationship between loss and the control variables. Then, the conditions to achieve the minimum loss are obtained. Second, the decoupling compensation strategy is applied to free the coupling relationship to improve the stability. The proposed strategy can achieve three control goals: 1) ZVS of all power switches; 2) minimize the total loss; and 3) stable closed-loop system. Finally, a 1MHz 280W FSBB prototype is built to verify the proposed control method. The prototype achieves all control goals and 98.1% peak efficiency.

An Improved Quadrangle Control Method for Four-Switch Buck-Boost Converter With Reduced Loss and Decoupling Strategy

The present disclosure is directed at an apparatus, method and plant for desalinating saltwater and contaminated saltwater. The apparatus comprises a stack and a manifolding assembly. The stack comprises a product chamber, a first and second concentrate chamber, an anion exchange membrane forming a boundary between the first concentrate chamber and the product chamber and a cation exchange membrane forming a boundary between the second concentrate chamber and the product chamber. The manifolding assembly comprises product and concentrate manifolding fluidly coupled to the product and concentrate chambers respectively, to convey a saltwater being desalinated to and away from the product chamber, and a concentrate to and away from the concentrate chambers. The stack may include a diluent chamber and adjacent anion or cation exchange membranes between the product chamber, diluent chamber and concentrate chamber to respectively convey anions or cations across multiple chambers. The stack may also contain a rinse chamber bounded by an anion exchange membrane to guard the stack electrodes from scaling cations. A cleaning system for cleaning the stack is also disclosed.

Method, apparatus and system for desalinating saltwater

A method of operating a wind park having a plurality of wind turbines is provided. The method includes determining a grid condition indicator indicative of the condition of a grid into which the wind park feeds; determining a first maximum power value of the wind park on the basis of the grid condition indicator; determining an operating margin on the basis of the grid condition indicator, for a grid condition indicator indicative of a weak grid; determining a second maximum power value on the basis of the operating margin; and curtailing the active power output of the wind park according to a maximum power value. A computer program product for carrying out the steps of such a method; an active power controller adapted for use in operating a wind turbine of a wind park; a wind turbine; and a wind park are also provided.

Method of operating a wind park

A power converter includes a plurality of first converter cells, a plurality of second converter cells, and a plurality of DC link capacitors. Each DC link capacitor links one of the plurality of first converter cells and one of the plurality of second converter cells. A failure management unit is configured to detect a faulty converter cell, and to deactivate the faulty converter cell while maintaining a power conversion operation of the power converter.

Multi-cell power conversion method with failure detection and multi-cell power converter

A system for power conversion includes a power converter having switching elements, a detector, and a controller is provided. The detector detects a parameter and provides electrical signals indicative of the parameter. The controller receives the electrical signals transmitted from the detector, and sends commands to instruct the power converter to perform power conversion by operating the switching elements in accordance with switching signals at a different frequency in response to a detection of the system condition. A method for operating the system is also provided.

System and method for converter switching frequency control

A system includes a plurality of stacks and a plurality of converters. Each of the plurality of converters is operable to charge a corresponding stack for adsorbing ions in the liquid. When one of the plurality of stacks is charged or discharged at a first state, one of the plurality of conveners associating with the stack operates in a first mode, and is configured to indirectly convert a first voltage to a second voltage at least by an intermediate stage. When one of the plurality of stacks is charged or discharged at a second state, one of the plurality of converters associating with the stack operates in a second mode, and is configured to directly convert the first voltage to the second voltage.

System and method for power charging or discharging

A power generation system comprises a power source, a transformer module for converting a low voltage from the power source into a higher voltage, and a voltage-multiplier module for amplifying higher voltage from the transformer module. The transformer module comprises a number N of transformer units. Each transformer unit comprises at least one transformer, and each transformer comprises a magnetic core, a primary winding, and a secondary winding. Primary windings of the transformers in the transformer module are electrically coupled in parallel to the power source, secondary windings of the transformers of each transformer unit comprise a pair of output terminal, and N is equal to or greater than two. The voltage-multiplier module comprises the number N of multipliers. Each multiplier module comprises a positive and a negative input terminal, and a positive and a negative output terminal. Positive and negative terminals of each multiplier are electrically coupled to the positive and negative output terminals of a corresponding transformer unit, and positive and negative output terminals of the multipliers are connected in series.

High-voltage power generation system and package

A device includes a first electrode and a second electrode spaced from the first electrode to define a volume. An anion exchange membrane and a cation exchange membrane are disposed within the volume. A controller controls a supply of electrical current from an electrical source to the first electrode and to the second electrode. The electrical current supply is controlled to switch from a first mode of operation to a second mode of operation providing electrical current having a reverse polarity during each cycle. The electrical current is supplied at a controlled cycle rate and for a controlled duration. The cycle rate is greater than about 100 hertz and less than about 10 kilohertz.

Electrodialysis device and process

A system having an alternating current (AC) driven LED unit, an AC voltage regulator, and a controller is provided. The AC driven LED unit includes a first LED and a second LED coupled in reverse parallel. The AC voltage regulator is operable to receive AC voltage originating from an AC voltage source, regulate the AC voltage according to control signals from the controller, and apply regulated AC voltage to the AC driven LED unit, so as to enable the first LED and the second LED to emit light according to the regulated AC voltage. In addition, a method is provided for driving the LED by regulating the AC voltage. By regulating the AC voltage using the AC voltage regulator, benefits of restraining voltage fluctuations, reducing THD, improving power factor, providing dimming control, and mitigating flicker phenomenon can be achieved.

System and method for driving light emitting diodes

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