1437results about "Apparatus with intermediate ac conversion" patented technology

A multi-phase LLC resonant converter circuit (10) includes: first to third LLC resonant converters each including a series circuit (S1 to S3) of a first switch and a second switch that are connected in parallel to a DC power supply, a high-frequency transformer (T1 to T3) including a primary-side winding and a secondary-side winding, a resonant circuit including a resonant reactor (Lr1 to Lr3) connected between a connection point of the first switch and the second switch and one end of the primary-side winding, a resonant capacitor (Cr1 to Cr3) in which one end is connected to the other end of the primary-side winding, and a divided resonant capacitor (Cn1 to Cn3) in which one end is connected to a connection point of the primary-side winding and the resonant capacitor; a first neutral line (N1) that connects the other end of the resonant capacitor; a neutral line reactor (Ln) connected between the first neutral line and a power supply line of the DC power supply; and a second neutral line (N2) that connects the other end of the divided resonant capacitor.

The invention belongs to a transformer structure, and provides a direct-current transformer, a power transmission system and a control method of the power transmission system in order to solve the technical problems that a three-level circuit topology in a power module in an existing direct-current transformer is large in number of power devices, complex in structure and large in layout and wiring difficulty. Each power module comprises a first-stage circuit, a second-stage circuit, two first direct-current bus capacitors and two second direct-current bus capacitors, the two first direct-current bus capacitors are connected in series to form a first capacitor circuit, and the two second direct-current bus capacitors are connected in series to form a second capacitor circuit. The first-stage circuit comprises two first half-bridge circuits which are connected in series, and the second-stage circuit is a dual-active bridge converter based on a series half-bridge. The number of power devices is remarkably reduced, meanwhile, the layout and wiring difficulty of the whole circuit is simplified, and popularization and application of the direct-current transformer are easier.

The invention provides a frequency modulation and phase shift hybrid modulation method for high-frequency LLC and a related device, which are applied to an LLC resonant converter and comprise the following steps: setting initial parameters of the LLC resonant converter; different system working frequencies are selected; for each system working frequency, determining a required phase shift angle according to a load demand and the system working frequency; and then judging whether the gain of the converter can meet the load requirement under the phase-shifting angle and the frequency, if not, adjusting the phase-shifting angle until the load requirement is met, and if so, taking the phase-shifting angle as a parameter combination. And then calculating system loss under parameter combinations corresponding to different frequencies, and finally selecting the combination with the minimum loss as a modulation parameter basis. The phase shift control is added on the basis of the traditional frequency modulation strategy, the output voltage can be accurately controlled without changing the topology of the converter, the influence of a dead zone under high frequency on the system is reduced, the optimal working point is determined through the balanced frequency modulation and phase shift strategy, the system loss is minimized, and the operation efficiency is improved.

A resonant capacitor Crk (k is a natural number of one to n) of each circuit element has one end connected in series to a resonant reactor Lr and a primary winding N1 of a transformer T, and another end connected to the resonant capacitor Crk of another circuit element 10 so that a dimensional multiphase LLC converter having a phase difference of 360° / Pk is constructed by Pk (Pk is an optional natural number) of the circuit elements 10.

The invention discloses a solid-state transformer seamless fault-tolerant control method based on cascaded H-bridge pre-charging, and the method comprises the steps: carrying out the pre-charging of a bus capacitor of a redundant unit module based on a cascaded H-bridge, dynamically adjusting the modulation wave of a preceding-stage H-bridge of each unit module, and achieving the impact-free charging of the bus capacitor of the redundant unit module. And after the pre-charging of the redundant unit module is finished, controlling a modulation wave signal and a driving pulse of a pre-stage H bridge of the redundant unit module to intermittently charge a bus capacitor of the redundant unit module. According to the invention, the problems of long charging time of the redundant unit module, overload of the residual unit module and overlarge current impact of the alternating current inductor in the process of removing the fault unit module and inserting the redundant unit module in the cascade converter are solved. According to the method, no additional circuit needs to be added, the method is suitable for a power bidirectional flow and unidirectional flow system, quick and smooth switching of the unit modules can be achieved when a fault occurs, and reliable and stable operation of the whole system is guaranteed.

An active clamp flyback converter with safe operation is discussed. The active clamp flyback converter has a main power switch and an auxiliary switch integrated at a same IC chip. The active clamp flyback converter enables a first charge path from the power supply voltage to a floating capacitor when the main power switch is turned on. The first charge path is disabled and a second charge path from a second pin of the IC chip to the floating capacitor is enabled when a voltage at the second pin is higher than a reference voltage.

The invention discloses a dual-mode LLC resonant converter with a wide range and a narrow frequency band and a control method of the dual-mode LLC resonant converter. The dual-mode LLC resonant converter comprises a dual-output half-bridge inverter circuit, a first LLC series resonant cavity, a second LLC series resonant cavity, a first high-frequency transformer Tr1, a second high-frequency transformer Tr2 and a variable rectification output circuit. The dual-mode LLC resonant converter and the control method thereof aim at solving the problem that an existing LLC resonant converter and a control method thereof are difficult to achieve wide-range voltage output in a narrow frequency band, by adopting the dual-mode LLC resonant converter with the wide range and the narrow frequency band and the control method of the dual-mode LLC resonant converter, voltage gain exceeding 4 times can be achieved under the condition that the switching frequency range is smaller than 2 times; the circuit has the advantages of few switching tubes, small switching loss and high conversion efficiency.

Provided in the present invention is a multi-level isolated buck type DC / DC converter, comprising two transformers, wherein a primary side of each transformer is provided with a single winding, and a secondary side thereof is provided with two windings; the primary sides of the two transformers are connected in series and are then connected to an LLC resonant circuit, so as to implement isolation and voltage regulation; the other side of the LLC resonant circuit is connected to a flying-capacitor-clamped five-level half-bridge switch network, so as to reduce voltage stress; and the secondary sides of the two transformers are each sequentially connected to a rectifier bridge and a buck circuit, output ends of the two buck circuits are in interleaved parallel connection, and the buck circuits are responsible for closed-loop voltage stabilization regulation, thereby realizing high-gain buck of the converter. Compared with conventional LLC converters, the present invention can significantly reduce voltage stress, can achieve a wider input voltage range and high-gain buck, and can significantly reduce switching loss and improve the efficiency of the converter.

A power conversion device includes: a DC / DC converter; and a control circuit unit that controls the DC / DC converter, in which the DC / DC converter includes a first power output circuit that converts first direct current power into first alternating current power, an isolation transformer that converts the first alternating current power into second alternating current power, and one or a plurality of second power output circuits, each of which converts the second alternating current power into second direct current power, and the control circuit unit includes a resonance characteristic calculator that calculates a resonance characteristic of the second power output circuits based on a load for each of the second power output circuits to output the second direct current power, and determines a drive frequency of the first power output circuit based on an output request value of the second power output circuit and the resonance characteristic that is calculated.

The invention discloses a fractional-turn winding structure applied to a boost planar transformer and a design method, and relates to a fractional-turn winding structure and a design method. The planar transformer aims to solve the problems that an existing planar transformer is large in stray capacitance and large in work loss. The fractional turn winding structure applied to the boost type planar transformer comprises three winding units, and the three winding units are sequentially arranged between a first magnetic core and a second magnetic core of the boost type planar transformer in an overlapped mode from top to bottom. The invention belongs to the technical field of power conversion.

A triple-active bridge (TAB) converter and methods to optimize the same is disclosed. The TAB converter includes a high-frequency three-winding transformer and three active full bridges, each coupled to the high-frequency transformer through a different passive network. The converter also includes a centralized controller providing gating pulses to semiconductor switches within the active full bridges, a power pulsating buffer (PPB) configured to reduce capacitor requirements on the DC port, and an unfolder stage to convert rectified AC voltage to a pure sine wave. The centralized controller may optimize performance by varying at least one of a switching frequency, a duty cycle of bridge voltages, and a phase shift between bridge voltages. The PPB may include a buck active power decoupler with a half-bridge, inductor, and capacitors, and also a primary full bridge and a power transfer impedance block.

To provide a control device for a power converter capable of appropriately realizing a power conversion system in which a plurality of storage battery modules is electrically connected in parallel.SOLUTION: A control device 16 is applied to a power conversion system 10 in which a plurality of storage battery modules 30, 60 and 90 including storage batteries 31, 61 and 91 and power converters 40, 70 and 100 is electrically connected in parallel. The control device 16 comprises: a voltage acquisition section 16a which acquires a terminal voltage of at least one of the power converters 40, 70 and 100; and a control section 16c which performs switching control of the power converters 40, 70 and 100 in such a manner that a magnitude of the acquired terminal voltage is prevented from exceeding an upper limit voltage.SELECTED DRAWING: Figure 1

To disclose a power conversion device that can prevent occurrence of resonance on a secondary side of an insulating DC / DC converter circuit.SOLUTION: A power conversion device of the present invention comprises: a DC / DC converter having a first full-bridge circuit including a first switching leg and a second switching leg connected in parallel with a first input / output terminal pair, a second full-bridge circuit including a third switching leg and a fourth switching leg connected in parallel with a second input / output terminal pair, and a transformer including one winding connected with the first full-bridge circuit and the other winding connected with the second full-bridge circuit; and a control unit controlling the DC / DC converter. The control unit always turns on any one of a plurality of switching elements included on a low side of the full-bridge circuit on a secondary side, of the first full-bridge circuit and the second full-bridge circuit.SELECTED DRAWING: Figure 2

The utility model provides a magnetic element and a topological structure used for an interleaving flyback converter, and relates to the technical field of power electronics, and the magnetic element comprises a magnetic core structure and a coil structure. The magnetic core structure comprises an upper magnetic core base, a lower magnetic core base, N magnetic core middle columns and at least one side column, wherein the upper magnetic core base and the lower magnetic core base are oppositely arranged, the N magnetic core middle columns and the at least one side column are arranged between the upper magnetic core base and the lower magnetic core base, and N is a natural number larger than 1. The coil structure comprises N coils wound on the magnetic core middle columns respectively, the winding directions of the coils on the adjacent magnetic core middle columns are opposite, and an air gap is formed in at least one of the three positions including the position between the upper bottom face of each magnetic core middle column and the upper magnetic core base, the position between the lower bottom face of each magnetic core middle column and the lower magnetic core base and the side face of each magnetic core middle column. According to the magnetic element, the magnetic core columns are integrated on the same magnetic core base, and the winding directions of the coils of the adjacent magnetic core middle columns are opposite, so that the purposes of reducing the weight of the magnetic core and reducing the loss of the magnetic core can be achieved.

The invention relates to a direct-current transformer circuit topology based on a series three-phase bridge circuit and a control method thereof. A high-voltage side power unit comprises N three-phase series half-bridge circuits which are sequentially connected in series; the low-voltage side power unit comprises N three-phase parallel half-bridge circuits which correspond to the three-phase series half-bridge circuits and are sequentially connected in parallel, each three-phase series half-bridge circuit is connected with the corresponding three-phase parallel half-bridge circuit through a three-phase isolation transformer to form N groups of three-phase bridge modules, and meanwhile, the N groups of three-phase bridge modules are connected with the N groups of three-phase isolation transformers. A symmetrical duty ratio and phase shift hybrid control strategy is adopted to realize bidirectional flow of energy and soft switching in a full range, and intra-module and inter-module phase shift control is adopted to realize voltage sharing of a series side, reduce current ripples of a parallel side, reduce backflow power and improve the efficiency of the converter.

A system includes a converter that distributes electric energy from an energy source to a load. The converter includes a dual active bridge. The system includes interfaces coupled to the converter. The system also includes a controller system that includes the interfaces and a controller. The controller system includes processors that perform determining of modulation control attributes based on characteristics of the converter, the modulation control attributes including one or more modulation control parameters and one or more modulation control modes corresponding to one or more phase shift techniques, obtaining operational condition information within the converter, the operational condition information corresponding to a component within the converter or an output of the converter, iteratively adjusting the modulation control attributes based on the operational condition information and controlling the converter based on the iteratively adjusted modulation control attributes.

Bidirectional isolated universal topology (BIUT) high power DC-DC converter assemblies and systems balance voltages and control currents between high power DC sources and high power DC loads where at least some of the high power DC sources are alternative energy or renewable energy power supplies and high power DC loads associated with alternative energy or renewable energy. The BIUT high power DC-DC converter assemblies and systems are capable of reversing current flow direction where loads become the sources and sources become the load in DC power systems where the supplies and loads are all connected to a common DC voltage bus.

An adaptive synchronous rectification control method for a CLLLC resonant converter solves the problem of the relatively complex theoretical calculation process for synchronous rectification of a CLLLC resonant converter, and belongs to the field of CLLLC resonant converter control. Based on the circuit characteristics and operating process of the CLLLC converter, the present invention analyzes the influence of the converter's synchronous rectification drive signal on the output frequency of the converter when the converter outputs a stable output signal, derives an equation for the relationship between the change in the synchronous rectification signal and the change in the operating frequency near the ideal synchronous rectification signal, and utilizes the law of this equation to implement the synchronous rectification function of the CLLLC converter. In the rectification control, a certain disturbance signal is given to the synchronous rectification signal, and then the synchronous rectification signal of the converter is gradually brought closer to the ideal synchronous rectification state based on the change in the operating frequency before and after the converter reaches a stable output signal. The present invention does not require additional sensors and avoids complex theoretical calculations.

The invention relates to an isolated inverter circuit comprising an input capacitor Cbus which is connected in parallel with an input DC voltage source; the first bridge arm consists of switching tubes Q1 and Q2, the second bridge arm consists of switching tubes Q3 and Q4, the transformer T comprises a primary winding and a secondary winding, the third bridge arm consists of an inductor Lr and switching tubes S1 and S2, the fourth bridge arm consists of capacitors Cr1 and Cr2, and the fifth bridge arm consists of switching tubes S5 and S6, so that a cyclic wave overturning function is realized; and an output filter composed of Lf and Cf is used for filtering the alternating-current low-frequency voltage signal output by the cyclic wave turnover circuit to obtain a smooth alternating-current low-frequency output voltage signal vo. According to the invention, only one pair of switch bridge arms is needed to realize a cycle wave overturning function, so that the number of switch components is reduced.

The present disclosure relates to circuits for connecting components of a hydrogen plant to a power grid to power the components in an efficient manner. In one implementation, a power-side alternating current (AC) / direct current (DC) converter can be connected to a source power grid without the need for an isolation transformer by providing a separate bus between the power-side AC / DC converter and the load-side DC / DC converter, instead of a DC bus shared between the converters. Other implementations for connecting components of a hydrogen plant to a power grid may include an adjustable transformer, such as a tap-changing transformer or an autotransformer, for connecting any number of auxiliary loads of the plant to the power grid. The adjustable transformer may accommodate various types of auxiliary load devices for connecting to the power provided simultaneously by the transformer, including both three-phase and one-phase devices.

The invention relates to the technical field of electric energy conversion, and discloses a high-frequency resonant topology-driven isolation power conversion system, which comprises a power conversion circuit, a driving unit, a feature sensing unit and a logic regulation and control unit, and is characterized in that the logic regulation and control unit extracts a parasitic ringing extreme point of a voltage evolution waveform in dead time; a charge release balance point is determined by calculating an arithmetic mean value of the first wave crest and the first wave trough, and high-frequency parasitic parameter interference is stripped; and predicting a time domain window of a return-to-zero potential based on a charge release balance point, performing phase compensation on a driving pulse in the time domain window according to a voltage waveform second derivative feature, and locking the starting moment of a switching tube at a zero voltage point. Interference of high-frequency distribution electromagnetic parameters on conduction judgment is eliminated, and soft switching self-healing in a full-load domain is achieved.

The invention relates to a current-sharing control method for a two-way interleaving LLC converter, and the method comprises the steps: obtaining a first resonant current effective value of a first resonant conversion circuit of the two-way interleaving LLC converter and a second resonant current effective value of a second resonant conversion circuit of the two-way interleaving LLC converter, calculating a resonance current difference value based on the first resonance current effective value and the second resonance current effective value; and when the resonance current difference value is greater than a current-sharing dead-zone adjustment intervention value and the output power is greater than a dead-zone adjustment power threshold value, performing current-sharing dead-zone time adjustment to obtain a dead-zone time adjustment result. According to the current-sharing control method for the two-way interleaving LLC converter, current-sharing dead-zone time adjustment is carried out based on the resonance current difference value and the output power, so that current-sharing adjustment can be accurately realized, and the reliability of the two-way interleaving LLC converter is ensured.

The invention discloses a flyback conversion circuit, which comprises N flyback conversion sub-circuits and an input power supply circuit, and is characterized in that the input end of each flyback conversion sub-circuit is connected with the output end of the input power supply circuit; the flyback conversion sub-circuit comprises an input filter capacitor, a clamping capacitor, an output filter circuit, an active absorption circuit and M power conversion circuits; the first input end of the active absorption circuit is connected with the first end of the clamping capacitor, the second input end of the active absorption circuit is connected with the first end of the input filter capacitor or the second end of the input filter capacitor, and the first output end of the active absorption circuit is connected with the first input end of the output filter circuit. The second output end of the active absorption circuit is connected with the second input end of the output filter circuit. By adopting the design of multi-path staggered conduction control and unified energy absorption, the power conversion efficiency and power density of the circuit can be effectively improved, the voltage stress of the device is reduced, and the electromagnetic compatibility is improved.

The invention discloses a multi-mode electric energy conversion system and a method thereof, and relates to the technical field of power electronic conversion, the system comprises a signal acquisition module, a mode discrimination module, a soft switching control module and a switching execution module, the signal acquisition module acquires an input voltage, an output voltage, a load current and a switching tube temperature signal; the mode judgment module determines a target working mode according to an input voltage interval and a load rate interval, dynamic switching among a full-bridge phase shift mode, a half-bridge mode and an interleaving parallel mode is achieved, the soft switching control module generates a soft switching time sequence signal, a main power switch tube is enabled to achieve zero-voltage switching, and the main power switch tube is enabled to achieve zero-voltage switching. The switching execution module adopts a current ramp control strategy to execute mode switching, the switching time is less than 5ms, the voltage fluctuation is less than 3%, and the global efficiency is greater than 95% and the peak efficiency is greater than 98% under the conditions of wide voltage and wide load.

A control unit (50) controls a primary-side full-bridge circuit (30) and a secondary-side full-bridge circuit (40) such that one of the primary-side full-bridge circuit (30) and the secondary-side full-bridge circuit (40) applies a two-level voltage to a transformer unit (TS) and the other applies a three-level voltage to the transformer unit (TS). The control unit (50) controls the primary-side full-bridge circuit (30) and the secondary-side full-bridge circuit (40) such that a first phase difference, a second phase difference, the frequency of the two-level voltage, and the frequency of the three-level voltage are a combination that can output a required power and that satisfies condition 1 and condition 2.

In at least one embodiment, the voltage transformer (1) comprises: - an input series and output parallel, ISOP, connection (21) of input series and output series, ISOS, modules (32) and / or an ISOS connection (22) of ISOP modules (31), and - control means (4), wherein - at least one of the ISOP modules (31) or the ISOS modules (32) comprises a plurality of solid-state transformers, SSTs (33), and - the control means (4) are configured to perform a balancing control of intermediate voltages between individual ones of the SSTs (33) in the ISOS modules (32) of the ISOP connection (21) and / or between individual ones of the ISOP modules (31) in the ISOS connection (22).

The uninterruptible power supply device (10) is connected to an AC system (1) and a DC grid (6). The DC grid (6) includes a DC bus (7) connected to the AC system (1) via an AC / DC converter (5), a distributed power source (61) that outputs the generated DC power to the DC bus, and a DC load (65) that receives the DC power of the DC bus (7). The uninterruptible power supply device (10) includes a DC link (12) for exchanging DC power, a converter (11) that converts the AC power supplied from the AC system (1) into DC power and supplies it to the DC link (12), an inverter (14) that converts the DC power received from the DC link (12) into AC power and supplies it to an AC load (8), a first DC terminal (T1) connected to the DC link (12), a second DC terminal (T2) connected to a power storage device (9), and a third DC terminal (T3) connected to the DC bus (7), and a DC / DC converter (16) configured to transfer DC power among the first to third DC terminals.

The invention relates to a multi-phase switching power converter with low magnetic core loss and an associated method. A method for reducing magnetic core loss in a multi-phase switching power converter including a coupled inductor. The method includes (a) generating a plurality of periodic voltage waveforms, each periodic voltage waveform being applied on a respective one of a plurality of windings of the coupled inductor; and (b) distributing a varying magnetic flux flow in a magnetic core of the coupled inductor by controlling a phase shift between the plurality of periodic voltage waveforms, such that at least two consecutive peak size portions of the plurality of periodic voltage waveforms are not applied to respective ones of the plurality of windings of the coupled inductor that are physically adjacent to each other in close proximity.

The power conversion device includes: a DC-DC converter unit including a transformer having a coil substrate where a primary side coil is formed and a bus bar forming a secondary side coil, and converting a voltage of DC power input from a DC power supply into a different voltage; and a cooling portion where a cooling flow path through which a cooling liquid flows is provided and the DC-DC converter unit is disposed. The bus bar of the transformer has a cooling portion side fixed portion fixed to the cooling portion provided with the cooling flow path.

Provided in the present invention is a transformer structure for an LLC resonant converter. The transformer structure comprises a PFC rectifier circuit module, a high-frequency inverter circuit module, a resonant topology module, a rectifier circuit and a load, which are sequentially connected, wherein a transformer, a resonant inductor and a resonant capacitor in the resonant topology module are all integrated in one component to form a capacitor-inductor integrated transformer; and a multilayer thin-film capacitor is integrated inside the capacitor-inductor integrated transformer, the multilayer thin-film capacitor comprises an iron-based nanocrystalline strip, and an organic insulating thin film is disposed between nanocrystalline strip layers to serve as a dielectric. In the structure, iron-based nanocrystalline is introduced to replace ferrite to serve as a magnetic core, after a special lamination method is used, a nanocrystalline strip with high conductivity is used as an electrode plate, a substrate, i.e., an organic insulating thin film, of the strip is used as a dielectric, and a resonant capacitor is integrated in the magnetic core, so as to form a capacitor-inductor integrated transformer structure, such that the power density and economic efficiency of an LLC resonant converter can be significantly improved.