43 results about "Modulation transformer" patented technology

A modulated transformer-coupled gate control signaling method and apparatus provides reduction of circuit complexity and robust design characteristics in switching power circuits having a transformer-coupled gate drive. A modulated control signal at a rate substantially higher than the switching circuit gate control rate is provided from the controller circuit to a demodulator via transformer coupling. Power for the demodulator can be obtained by rectifying the modulated control signal at the demodulator, or from another transformer winding. The modulation scheme is chosen to have a DC average value of zero, eliminating any magnetization current management requirements. The modulated control signal may carry redundant control information and/or may encode additional information to provide a more sophisticated gate drive control, such as oversampled gate control information.

A simplified electronic ballast for a discharge lamp which provides dimming by control of inverter frequency through modulation of magnetizing current in a transformer such that the switching frequency is made substantially independent of the load presented. The principle of frequency control in a manner independent of the load is extendable to other types of loads and power supplies and converters to regulate power coupled to the load. Clamping capacitors are used to replace other clamping circuits in order to allow current injection to be controlled by a simple variable voltage while frequency control by current injection provides enhanced circuit performance.

The invention is an energy quality controller for a traction power substation, composed of a three-phase converter and a Scott transformer, two orthogonal single-phase output power supplies are connected with two single-phase output ends of the Scott transformer, respectively, the three-phase converter connects in series with a three-phase output end of the Scott transformer, where the three-phase converter is an inverter with capacitor in parallel with the DC bus. It controls two power supply arms of the traction transformer at the same time and can effectively compensate harmonics in drawing electric network, reactive power and negative sequence current.

The invention provides an alternating-current ultrahigh voltage main transformer and regulation transformer combined partial discharge testing system which comprises a variable frequency power source, a testing transformer, a compensation reactor, a capacitive voltage divider, partial discharge detection systems, a regulation compensation transformer and an alternating-current ultrahigh voltage main transformer. The output end of the variable frequency power source is connected with the low voltage side of the testing transformer. The high voltage side of the testing transformer is connected with the low voltage side of the regulation compensation transformer. The high voltage side of the regulation compensation transformer is connected with the low voltage side of the alternating-current ultrahigh voltage main transformer. The compensation reactor and the capacitive voltage divider are connected between the testing transformer and the regulation compensation transformer in parallel. The alternating-current ultrahigh voltage main transformer and the regulation compensation transformer are each provided with one partial discharge detection system. Alternating-current ultrahigh voltage main transformer and regulation transformer on-site partial discharge testing can be completed at a time, so that the testing procedures are greatly simplified; during testing, electrical connecting wires of the alternating-current ultrahigh voltage main transformer and the regulation compensation transformer do not need to be disassembled, on-site workloads are lowered, and the working efficiency is improved.

An amplitude modulated pulse transmitter designed to operate across a multi MHz range of modulation frequencies. A wire wound rare earth magnet is to be utilized instead of the typical modulation transformer. Additionally, a plurality of electrolytic capacitors are also employed in the transmitter.

The invention relates to a transmitting device for transmission through space, using electromagnetic waves of the infrared and/or visible and/or ultraviolet bands produced by one or several diodes producing electroluminescent light.

The device is connected by its input terminals (1) to an a.c. energy distribution system. A mains filter (2) reduces the conducted electromagnetic disturbances produced by the power circuits comprising a rectifier (3), a power-factor-correction circuit (4), an auxiliary power supply (5) and a DC-to-DC converter (8). The output of the DC-to-DC converter (8) is connected to several high power light-emitting diodes connected in series (9). A receiving set for transmission via power distribution lines (6) delivers demodulated signals applied to the control circuitry (7) which provides the current command of the DC-to-DC converter (8) and the modulated current applied to the light-emitting diodes (9) through the modulation transformer (10), as a function of the demodulated signals and of the temperature which is measured by a temperature sensor (11). The produced light is modulated as a function of the demodulated signals.

The invention relates to a power system with an electric circuit connected between a power grid and a power source. The electric circuit includes a main power converter having main input terminals connected to the power source 16 by a DC link and output terminals. The main power converter is controlled by a controller. The electric circuit includes a main transformer having a primary winding 8a and a secondary winding, the primary winding being connected to the output terminals of the main power converter. Main switchgear is connected between the secondary winding of the main transformer and the power grid. An auxiliary transformer has a primary winding connected to the power grid in parallel with the main switchgear and a secondary winding connected to the controller. A pre-charge circuit is connected between the auxiliary transformer and the DC link.

The invention discloses a main transformer and high voltage side cable zero-sequence differential protection polarity test circuit and method. According to the test circuit, a maintenance power supply is connected when a main transformer and a high voltage side bus are in the stop state, a single-phase voltage regulator is regulated and current is outputted to the appropriate value so that a current loop composed of the maintenance power supply-single-phase voltage regulator TT-isolation transformer TI-ammeter-main transformer high voltage side Y-shaped three-phase windings-main transformer high voltage side cable-main transformer high voltage side line knife Q9-GIS circuit breaker Q0-primary female knife Q1 (or secondary female knife Q2)-primary female grounding knife QG1 (or secondary female grounding knife)-grounding network-ground is formed. The current flows through the primary side of the first zero-sequence current mutual inductor ZCT1 and the second zero-sequence current mutual inductor ZCT2 of a zero-sequence differential protection device 87GMC so that simulation of zero-sequence current of the primary system in case of external grounding fault can be realized, and the polarity of the main transformer and the high voltage side cable zero-sequence differential protection device can be tested and inspected by the loop current.

The invention discloses a test method of a main transformer CT (Current Transformer). The test method comprises the steps of: in the case that the current transformers have all secondary loop current, leads are used for respectively connecting the high-voltage side, the middle-voltage side and the low-voltage side of the main transformer, and stride over the transformer; an isolation switch at one side and a breaker and an earthing isolation switch at the other two sides are closed; three-phase current is applied to the current transformer side of the side with the unclosed breaker and earthing isolation switch, so that the current flows through the current transformers at three sides of the transformer so as to simulate load current states at the three sides when the transformer operates normally; the current value, phase and differential current of each side are detected at the differential protection device for the main transformer, if the differential current is equal to 0, the ratio of transformation, the polarity and the wiring of the differential loop of each current transformer are correct. According to the test method of the main transformer CT, the correctness of the current value, phase and differential current of each main transformer CT can be simultaneously tested, so that the work efficiency and test quality are improved, and the electrical device is ensured to operate reliably.

A direct current metering device belongs to current metering equipment in the electrotechnology, solves the problems of insufficient precision and stability of the existing current sensing device used for industrial gauging, and is used for the standard gauging in the strong direct current industrial field with the reliable and stably operated structure. The direct current metering device comprises a sensing head, an exciting transformer, a modulation transformer, a low pass filter, a phase sensitive demodulator, a synthesis modulator and a power amplifier; the sensing head is annular and comprises a first annular detection iron core, a second annular detection iron core and an annular magnetic shield iron core; the first and second annular detection iron cores, respectively wound by two sets of detection windings, are overlapped to be wholly placed in the annular hollow cavity of the annular magnetic shield iron core; and a feedback winding surrounds the annular magnetic shield iron core. The direct current metering device can realize the accurate gauging of the industrial strong direct current with ten thousands of amperes, realizes full automation traction in the whole process without unbalance, and is high in stability and reliability and suitable for industrial application, and the proportion precision achieves more than 0.02%.

A history-independent and noise-immune modulated transformer-coupled gate control signaling method and apparatus provides robust design characteristics in switching power circuits having a transformer-coupled gate drive. A modulated control signal at a rate substantially higher than the switching circuit gate control rate is provided from the controller circuit to a demodulator via transformer coupling. Codes specified by relative timing of transitions in multiple periods of the modulated control are assigned to gate-on and gate-off timing events that control the switching transistor gate(s) and unassigned patterns are decoded as gate-off events, reducing the possibility that a switching transistor will be erroneously activated due to noise. The modulated signal is constructed so that signal history is not required for decoding, eliminating any requirement of a reference clock. Blanking may be employed to conserve power between codes and to avoid mis-triggering due to noise events during power switching.

A single switch PFC power supply (including forward and fly-back power supply) in single stage has two transformers: one forward transformer, one main transformer. The main transformer transfers electrical power from the primary circuit to secondary circuit. The forward transformer is used to correct input current waveform. The two transformer's primary windings are connected in series. An extra winding of the forward transformer, a capacitor and two diodes are formed a no loss snubber circuit to enhance the efficiency of the power supply.

The invention discloses a pure capacitive electromagnetic type voltage transformer induction withstand voltage tester. The pure capacitive electromagnetic type voltage transformer induction withstand voltage tester comprises a variable frequency power source, an isolation transformer, and a compensation inductor. Mains supply is connected to the variable frequency power source; the variable frequency power source rectifies the mains supply into direct current, and then performs inversion; frequency-adjustable alternating current of 0 to 150 V is output through a series of voltage stabilization control; the variable frequency power source outputs variable frequency alternating current to the isolation transformer; the isolation transformer adjusts an output voltage range; the isolation transformer is connected to a secondary winding a2*1 of an electromagnetic type voltage transformer; secondary windings a1*1 and a2*2 of the electromagnetic type voltage transformer are connected in series; a1 and x2 are short-circuited; the a2*1 is connected in parallel with the compensation inductor for reactive power compensation; and a high voltage tail end of the output of the isolation transformer is connected in series with an ampere meter for detecting output current of an instrument. The pure capacitive electromagnetic type voltage transformer induction withstand voltage tester carries a fixed inductor, has a small volume, and light weight, reduces loss, saves resources and can realizes multiple purposes.

The invention discloses a time scale-oriented distribution transformer heavy overload judgment method. The method comprises the following steps of 1, sampling original load operation data of a distribution transformer and discretizing the original load operation data into 24-point time series data; 2, performing feature extraction based on an LSTM-BP network on the time series data; 3, clusteringthe extracted features by using a fuzzy C-means clustering algorithm to obtain a plurality of clusters, wherein each cluster represents a feature rule of a certain specific heavy overload on a time scale; and 4, judging the heavy overload condition of the distribution transformer according to the heavy overload time characteristics of each distribution transformer. The method aims at distributiontransformers with different heavy overload characteristics; and different operation or transformation strategies such as operation mode adjustment, three-phase imbalance adjustment, selection of a short-time high-overload-resistant transformer, selection of an amorphous alloy transformer, selection of a dry-type transformer or an oil transformer, selection of an on-load capacity modulation transformer and the like are adopted in a more targeted manner, so that the scientificity and the economy of distribution transformer type selection and operation modes are improved.

The invention belongs to a compensation type alternating-current voltage-stabilized power supply. The power supply comprises a single phase and a three-phase, and the three-phase is formed by connecting three single phases in a star shape. A single-phase double-switch high-variable inverse-modulation power-variable compensation alternating-current voltage-stabilized power supply is composed of a high-frequency inverse-modulation transformer T1, a power frequency compensation transformer T2, two bidirectional switches S1 and S2, an inductor L, two capacitors C1 and C2 and a control circuit. TheS1 is composed of two diodes and two triodes or four diodes and one triode. The S2 is composed of two unidirectional thyristors V3 and V4 which are connected in an anti-parallel mode. Compared with aGong's half-bridge chopping voltage regulation power transformation compensation type alternating current voltage-stabilized power supply invented by the same inventor, by using the power supply of the invention, a high-frequency transformer is used for replacing a power frequency autotransformer with a center tap, a size is small, and weight is light.

The present invention proposes a power supply device for LED lamps, which mainly uses an isolation transformer to convert an input high-voltage AC signal into a low-voltage AC signal, and then generates a driving voltage for driving LED lamps, including: a waveform and frequency modulation module , which is set on the primary side of the isolation transformer, for modulating an input waveform and a frequency f, and the frequency f≥60Hz; and a secondary rectification and filtering module, which is set on the secondary side of the isolation transformer, for converting the The low-voltage AC signal after the isolation transformer is converted into the driving voltage, and the driving voltage is a low-voltage ripple signal, and a peak-to-peak value ΔV≧1 of the low-voltage ripple signal. In this way, the power supply device for LED lamps can still maintain normal operation by using the principle of persistence of vision of the human eye to modulate the voltage waveform and frequency for driving LEDs.

The invention discloses a comparator for measuring alternating current and direct current. The comparator includes a sensing head, a modulation transformer, a DC side standard resistor, an AC side standard resistor, a band pass filter, a synchronous demodulator, a DC power amplifier, an AC voltage amplifier, and an AC power amplifier; the measuring head includes three units having the same structure; each unit includes a ring detection iron core, a detection winding, an electrostatic shielding layer, a magnetic shielding iron core and a secondary winding; the first and second units, the modulation transformer, the band pass filter, the synchronous demodulator, the DC power amplifier and the DC side standard resistor constitute a DC detection system based on the double iron core magnetic modulator principle; the third unit, the AC side standard resistor, the AC voltage amplifier and the AC power amplifier constitute a single core based AC detection system. The comparator can measure DCand AC current, can also measure a DC component and an AC component of a mixed current formed by superposition of the DC current and the AC current.