11 results about "Constant voltage" patented technology

According to one embodiment, a digital protection relay includes an auxiliary transformer (2) which decreases a voltage of an electrical signal from a main circuit transformer (1) to a predetermined voltage; a detection resistance circuit (20) including a Π-type or T-type circuit including an input connected to an output of the auxiliary transformer (2); an analog detection circuit (3) which is connected to an output of the detection resistance circuit (20) and detects a quantity of electricity of an electrical signal from the auxiliary transformer (2); an A/D conversion circuit (4) connected to the analog detection circuit (3); a central processing device 5 which is connected to the A/D conversion circuit (5) and performs a protection operation; and a trip output contact (9) which is closed by processing of the central processing device (5) and operates an external breaker (21). In the digital protection relay, an input contact terminal 11 for inputting a test signal with a constant voltage from an external test device (13) to the analog detection circuit (3) as a signal corresponding to an output of the auxiliary transformer (2) is provided between the detection resistance circuit (20) and the analog detection circuit (3).

The invention relates to a novel LED (light emitting diode) lighting driving power supply, wherein the input end of the driving power supply is connected with the output end of the driving power supply via a feedback circuit; the feedback circuit comprises a voltage control loop, a current control loop and a PWM (pulse width modulation) regulating circuit; the feedback signals of the voltage control loop and the current control loop are input to the PWM regulating circuit by an optical coupler; the PWM regulating circuit is connected with a transformer circuit so as to control the output voltage; and in the current control loop, a triode is adopted to be matched with a sampling resistor so as to regulate the input duty ratio of the PWM chip, thereby regulating the output current and keeping constant current. The driving power supply combines the triode, a constant voltage source and the optical coupler to control a load end and the PWM controller of the whole circuit so as to output the constant current and constant voltage, thereby driving the LED. The novel LED lighting driving power supply needs few required apparatuses and is high in reliability.

The invention provides a method for preparing flowerlike nanometer cobalt by using electro-conductive glass FTO, an anodised aluminum template (AAO) and an aqueous high-molecular adhesive as a combined electrode. The method comprises the following steps: (1) preparation of a working electrode: a step of coating the electro-conductive glass with a solution of the aqueous high-molecular adhesive--polyvinyl alcohol (PVA) through spin coating and bonding the anodised aluminum template so as to obtain the FTO/PVA/AAO combined electrode; (2) preparation of an electrolyte: separately preparing cobaltous sulfate and a boric acid solution and mixing the cobaltous sulfate with the boric acid solution; (3) electrodeposition reaction: a step of carrying out constant-voltage electrodeposition on the combined working electrode; and (4) post-treatment: a step of soaking the working electrode having undergone electrodeposition in sodium hydroxide to remove the anodised aluminum template. According to the invention, FTO/PVA/AAO is used as the combined working electrode and constant-voltage electrodeposition is carried out so as to prepare the novel flowerlike nanostructured cobalt; and the method is simple and fast and has the advantages of mild reaction conditions, short time, high efficiency and no need for high temperature and high pressure conditions compared with conventional methods.

The invention relates to a weak-magnetic control method and device of a high-speed permanent-magnet generator. When the speed of turbulent-flow wind is suddenly increased, the voltage of a port at the side of an instantaneous ultra-speed machine of the high-speed permanent-magnet generator is increased sharply, and when the voltage of the port of a motor is higher than an allowable voltage of a port of a current transformer at the side of the motor, a constant-voltage control strategy is adopted so as to guarantee safety of the current transformer of the unit. The weak-magnetic control method and device have the advantages that safe operation of the high-speed permanent-magnet full-power unit under the ultra-speed working condition is realized.

The invention provides a method for keeping constant-power output of multiple power supply modules. The method comprises the following steps: acquiring output current of each power supply module in multiple power supply modules; judging the relationship between the output current of the current power supply module and rated current; when the output current is not greater than the rated current, making the current power supply module output at a constant voltage; and when the output current is greater than the rated current, reducing the output voltage of the current power supply module, and increasing the output current of the current power supply module to make the current power supply module output at constant power, so that constant power output can be realized when multiple power supply modules are output in parallel. According to the method provided by the invention, the complexity of the power supply module is not increased, and passive current sharing can be realized by only changing the output characteristics of the power supply module, so that the load regulation rate index of passive current sharing is improved, the internal control loop bandwidth of the power supply module is shared during parallel application, and the dynamic response capability during a periodic pulse load period is improved.

The invention belongs to a method for designing an internal-rotation constant pressure pump structured as an external rotator, characterized in that: the inner surface of a pump body (1) is provided with a spiral groove with a rectangular normal section, a hollow cavity spiral groove body (2) is sleeved between the pump body (1) and an eccentric shaft (5), the outer surface of the hollow cavity spiral groove body is provided with the spiral groove which is identical in shape to and fits in size with the spiral groove at the inner surface of the pump body (1), the inner spiral groove is engaged with the outer spiral groove, the inner surface of the spiral groove body (2) is in sliding connection with the outer surface of the eccentric shaft (5) in a manner of arc fitting; the eccentric shaft (5) is connected with an end cap body of the pump body (1) via a bearing (7), the pump body (1) structured as the external rotator rotates while the eccentric shaft (5) is fixed, and two ends of the eccentric shaft (5) are respectively provided with channel ports for a liquid inlet or a liquid outlet. The internal-rotation constant pressure pump has the advantages of high output pressure, being capable of constant voltage change flow and mixed conveyance of liquid/gas, good interior sealing effect, small volume, low noise, low energy consumption and wide application range.