90 results about "Cycloconverter" patented technology

A power-conversion control system includes an inverter, a cycloconverter, and a sliding mode controller. The inverter is operable to receive a DC voltage input and produce a first AC voltage output having a first frequency. The cycloconverter has a plurality of bidirectional switches, and is operable to receive the first AC voltage and to synthesize a second AC voltage having a second frequency that is lower than the first frequency. The sliding mode controller is operable to provide a control signal to command the plurality of bidirectional switches to turn OFF and ON when the first AC voltage is at a zero crossing condition. The sliding mode controller is also operable to selectively adjust the frequency and amplitude of the second AC voltage.

An electrical generator, consisting of a high phase order generator and a high phase order cycloconverter. Output from said cycloconverter may be high phase order, three phase, single phase, or direct current. Output from said cycloconverter may be of arbitrary frequency, voltage, and phase.Power electronic components are smaller and more efficiently used. Slower and therefor less expensive devices may be beneficially used. Variable speed resources may be used without the use of a DC to DC converter, enhancing power production efficiency.In a beneficial embodiment of the present invention, said cycloconverter is used to provide power directly to a high phase order motor, whereby diesel electric drive means may be constructed to higher specific power and higher efficiency.

The invention provides a high-frequency isolated three-phase cycloconverter type two-way converter and a control method thereof, which belongs to the three-phase high-frequency isolated converter in the field of power electronics and is suitable for charging and discharging a storage battery pack, a supercapcitor set and other energy storage devices. A main circuit is in a structure comprising an input filter, a three-phase cycloconverter, a high-frequency transformer, a full-bridge converter and an output direct current inductor, wherein a switch of the cycloconverter is in time-division drive to ensure the one-way flowing of the power and further realize the soft current conversion. The switching of two modes of rectification and inversion can be realized by changing the power flowing direction of the cycloconverter; the three-phase cycloconverter is modulated by digitalized alternating current space vector; and the alternating current adopts a control method of mixing a d-p decoupling, the proportional-integral (PI) and the repetition (RP). The two-way converter has the advantages of high power density, high efficiency, wide adjusting range of direct current side voltage and electrical isolation for input and output; and the input of unit power factors can be realized and the current harmonics can be effectively inhibited.

A generator system in accordance with the invention has two modes of operation, such as 120 VAC and 240/120 VAC modes of operation. The generator system has a permanent magnet generator with two independent sets of windings that each generate a three phase AC voltage. One three phase AC voltage is coupled to a first or master cycloconverter and the second three phase AC voltage is coupled to a second or slave cycloconverter. Live outputs of each cycloconverter are coupled to each other through a switch, such as a relay and neutral outputs of each cycloconverter are coupled to ground. A controller controls the cycloconverters to provide a first voltage, illustratively 120 VAC, across their respective outputs having the same amplitude. When in the 120 VAC mode, the switch across the live outputs of the first and second cycloconverters is closed, shorting the live outputs of the first and second cycloconverters together and the controller operates the first and second cycloconverters so their output voltages are in phase with each other. When in the 240/120 VAC mode, the switch across the live outputs of the first and second cycloconverters is open and the controller operates the first and second cycloconverters so that their output voltages are 180 degrees out of phase. The permanent magnet generator has rotor position sensors that are used by a brushless DC motor drive to drive the permanent magnet generator as a brushless DC motor to start the engine of the generator system and also to develop cosine wave information for use in controlling the cycloconverters.

A method of using a cycloconverter switches a first switch of the first topology type to an on state after a magnitude of a current through an output inductor becomes less than a predetermined current threshold, and switches a second switch of the first topology type to an off state a first time after switching the first switch to the on state. The cycloconverter includes nodes on a first port, nodes on a second port, a switch pair coupled between a first node of the first port and a first node of the second port, a switch pair coupled between a second node of the first port and a first node of the second port, a switch pair coupled between a first node of the first port and a second node of the second port, and a switch pair coupled between a second node of the first port and a second node of the second port. Each switch pair includes a switch of each topology type.

The present disclosure is concerned with a power supply system for railway traction applications including a multilevel AC/DC converter. The converter comprises a plurality of series-connected single-stage cycloconverters or direct AC frequency converters connected between an AC supply line and a traction transformer. The transformer is operable at a transformer nominal frequency below 3 kHz and above the AC line frequency. On the secondary side of the transformer, more than one parallel-connected secondary converter are provided and connected to a DC link. In case of failure of one of the secondary converters, the multilevel AC/DC converter may continue to operate with reduced power delivered by the remaining operating levels.

A PWM cycloconverter is disclosed that can switch power supplies without interrupting operation in the event of a power supply abnormality. When a power supply abnormality occurs in three-phase AC power supply 1, power supply abnormality detection circuit 30 outputs power supply abnormality detection signal 120, whereby power supply switch 20 selects and outputs the output voltage of uninterruptible power supply 10. Phase detection circuit switch 43 selects and outputs phase information that is output from uninterruptible power supply phase detection circuit 41. Uninterruptible power supply phase detection circuit 41 detects the phase of uninterruptible power supply 10 from before the occurrence of the power supply abnormality, whereby accurate phase information of uninterruptible power supply 10 can be output even immediately after phase detection circuit switch 43 switches the phase information that is output. As a result, operation is not interrupted when switching power supplies.

An apparatus for generating electronic signals for application in subsea electromagnetic exploration. A surface generated high-voltage low-current source signal stabilized at a first frequency is supplied to a deep-tow vehicle (18) via an umbilical cable (16). The high-voltage low-current signal is transformed at the deep-tow vehicle to a high-current low-voltage a.c. signal by a transformer (52) within a cycloconverter (30). A semiconductor relay bridge (104) provides switchable rectification of the high-current low-voltage a.c. signal to provide a quasi-square wave at a second frequency, lower than the first frequency, for supply to a transmitting antenna (22) towed by the deep-tow vehicle. The times of the rectification switching are dependent on zero crossings of the high-current low-voltage a.c. signal. Allowable rectification switching times may be gated to occur only within pre-determined time windows to avoid noise-induced zero-crossing switching. The apparatus allows multiple transmission frequencies to be derived from a single stabilized source and improves spectral integrity by avoiding rectification switching at zero-crossings not occurring at the first frequency.

Provided is an uninterruptible power supply for providing a sinusoidal-wave output AC voltage. The uninterruptible power supply is advantageous in terms of a DC/DC converter unit consisted of a plurality of DC/DC converter, in which the input terminals of the DC/DC converters are connected in parallel with each other and the output terminals of the DC/DC converters are connected in series with each other. The output DC voltages of the DC/DC converters are configured to sum up to form a full-wave rectified DC voltage, which can be converted into a sinusoidal-wave output AC voltage by an inverter. Furthermore, the uninterruptible power supply provides an energy recycle converter configured for recycling the redundant energy of the uninterruptible power supply to charge a battery pack.

The invention provides an energy storage system which comprises a controller, a main circuit, a push-pull converter, a cycloconverter, a filter inductor and a sampling circuit. The controller is used for controlling the generation of an SVPWM (Space Vector Pulse Width Modulation) signal and a PWM (Pulse Width Modulation) signal to obtain a discrete SVPWM signal, the main circuit comprises an energy storage device for storing and releasing electric energy, the push-pull converter comprises a high-frequency transformer and is boosted by adopting the high-frequency transformer to electrically isolate the input from the output of the energy storage system, the cycloconverter is used for converting a high-frequency alternating voltage into a power frequency alternating voltage, the filter inductor is used for filtering a grid current, and the sampling circuit is used for acquiring a voltage and a current of an external circuit. The energy storage system can generate discrete pulse-type SVPWM and has the advantages of higher utilization rate of the bus voltage, low total harmonic content and wide scope of application. The invention also provides a control method of the energy storage system.

A three phase full resonant cyclo-converter suitable for converting a three phase AC supply to a DC output. In one embodiment the cyclo-converter consists of two half bridge cyclo-converters driving a resonant circuit. The main switching sequence of the cyclo-converter may consist of a switching sequence in which the phases of a three phase supply are switched in a repeating sequence from the largest to the smallest absolute voltage value of the supply phases.

Methods and apparatus are provided for an analog converter. The apparatus comprises a first redundant signed digit (RSD) stage and a configurable block. The configurable block converts to a sample/hold circuit to sample a single ended analog signal. The sampled signal is then scaled, converted to a differential signal and provided to the first RSD stage. The first RSD stage outputs a bit value corresponding to the magnitude of the digital signal. In a next half clock cycle the first RSD stage calculates a residue that is provided to the configurable block. The configurable block is converted to a second redundant signed digit stage and generates a bit value corresponding to the magnitude of the residue provided by the first RSD stage. The first and second RSD stages cycle back and forth generating logic value each half clock cycle until the desired bit resolution is achieved. The configurable block is then converted back to a sample/hold circuit to start another conversion process.

A cyclic AD converter having a conversion processing speed or conversion accuracy designed no higher than necessary. In the AD converter, an input analog signal is held by a sample-and-hold circuit, and converted into a digital value by an AD conversion circuit. A DA conversion circuit converts the digital value output from the AD conversion circuit into an analog value. A subtractor circuit outputs the difference between the analog value output from the AD conversion circuit and the analog value held in the sample-and-hold circuit. An amplifier circuit amplifies the output of the subtractor circuit, and feeds back the resultant to the sample-and-hold circuit and the AD conversion circuit. In the course of this feedback-based cyclic processing, an amplification control circuit changes the gain of the amplifier circuit in accordance with the progress of the circulation.

An alternating current motor control system constituted of: a control unit; a cycloconverter functionality; a phase control functionality; and a semiconductor switching unit comprising a plurality of electronically controlled semiconductor switches each associated with a particular winding of a target alternating current motor and each independently responsive to the control unit. In one embodiment the semiconductor switching unit is arranged to connect the windings of the target alternating current motor to a three phase power input in one of a star and a delta configuration responsive to the control unit.

Apparatus and method for controlling reactive power. In one embodiment, the apparatus comprises a bidirectional power converter comprising a switched mode cycloconverter for generating AC power having a desired amount of a reactive power component.

A control unit controls an inverter circuit such that a positive voltage and a negative voltage are alternately applied to a primary winding. The control unit controls a cycloconverter so as to allow no power to be transmitted between the cycloconverter and the inverter circuit in a first period including an inversion period during which a voltage of the primary winding has its polarity inverted. The control unit also controls the cycloconverter so as to allow power to be transmitted either in a first direction from the cycloconverter toward the inverter circuit, or in a second direction opposite from the first direction, in a second period different from the first period.

An all-turn off detection circuit for a thyristor in a cycloconverter system, belongs to the technology of thyristor conversion, and consists of a voltage detection circuit and a logic judgment circuit; wherein, the input of a voltage detection circuit is the terminal voltage of the thyristor, an output signal is transmitted to a logic judgment circuit which outputs an all-turn off detection signal. Detection of voltage at the two terminals of the thyristor is realized through the voltage detection circuit. The logic judgment circuit makes logic judgment by utilizing a trigger signal and a voltage detection signal, providing an on-off signal of the thyristor. The utility model has the advantages of rapidly and precisely providing the zero current information of a main circuit, greatly shortening the dead time of zero current in the shift between positive and negative groups, reducing the negative impact on motor load.

A bidirectional inductive power transfer (IPT) power converter comprising a cycloconverter, coupled to an AC port, and a resonant circuit, coupled to the cycloconverter, for storing energy and coupling energy to an IPT port.