131 results about "Llc converter" patented technology

In a circuit element 10a, resonant circuits are arranged in parallel. A resonant capacitor Crkq of a q-th resonant circuit arranged in parallel has one end connected in series to a resonance reactor Lrq and a primary winding N1q of a transformer Trq. The resonant capacitor Crkq of the q-th resonance circuit arranged in parallel has another end connected to the resonant capacitor Crkq of a q-th one of the resonance circuit arranged in parallel in another one of the circuit elements 10a so that a k-dimensional multiphase LLC converter having a phase difference of 360° / Pk is constructed by Pk circuit elements.

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.

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.

The invention discloses an active battery equalization system and method, and belongs to the field of line detection. The system comprises a monitoring module, a microcontroller, a battery pack, a switch array and a half-bridge LLC converter. The microcontroller is used for receiving the voltage sampling value and the current sampling value acquired by the monitoring module; calculating the average charge state of the battery pack and the charge state of each single battery according to the voltage sampling value and the current sampling value; comparing a difference value between the average charge state of the battery pack and the charge state of the current single battery with a preset balance threshold value, and judging whether an unbalanced battery exists or not; and under the condition that the unbalanced battery exists, the switch array is controlled to gate the unbalanced battery to the input end of the half-bridge LLC converter, and the half-bridge LLC converter is controlled to perform energy conversion, so that the unbalanced battery performs energy transmission with other batteries of the battery pack through the half-bridge LLC converter. By implementing the invention, the problems of high cost and low balancing speed in the prior art can be solved.

The invention discloses a dual-LLC resonant converter based on a modulatable coupling inductor. The dual-LLC resonant converter aims to meet the wide-gain application requirements of an LLC converter in the high-efficiency and high-gain power supply application fields such as a data center, energy storage conversion, direct-current adaptation and photovoltaic application. According to the invention, two connected transformers are adopted to divide a resonant cavity into two parts to form two LLC units, series connection or parallel connection application of double LLC can be realized through different switch sequences, two common resonant inductors are replaced by coupling inductors, and split capacitors are adopted as input and output filters. For the two working modes, the resonant frequency can be configured at will, and the equivalent inductance value of the coupling inductor can be changed by changing the switching sequence, thereby changing the resonant cavity parameters in different modes, and enabling the resonant cavity parameters to meet the requirements of different requirements of the converter under light load / heavy load for the parameters. Therefore, the full-range efficiency of the converter can be improved on the basis that the working modes are switched according to light and heavy load conditions to achieve wide gain.

A battery pack charger may include a housing. The battery pack charger may include a battery pack interface provided on the housing and configured to removably receive a battery pack. The battery pack charger may include a power input. The battery pack charger may include an LLC converter including a dual transformer electrically connected between the power input and the battery pack interface. The battery pack charger may include a power factor correction (PFC) boost converter electrically connected between the power input and the battery pack interface. The battery pack charger may include an input inrush current control circuit electrically connected between the PFC boost converter and the battery pack interface.

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 an LLC converter rectification output current estimation method. According to the method, the rectification output current is estimated based on a model by sampling the output voltage of the LLC converter and the primary side alternating current of the isolation transformer. According to the method, a rectification output current sensor with a large size can be prevented from being adopted, the situation that the performance of the converter is reduced due to the fact that parasitic parameters are introduced is avoided, the power density of the converter is improved, meanwhile, universality is achieved, and the method can be suitable for various LLC converter topologies including two-level or multi-level full bridges, half bridges and the like.

The invention discloses a wide-gain narrow-band bipolar LLC converter based on a coupling inductor and a control method. The wide-gain narrow-band bipolar LLC converter based on the coupling inductor comprises a first half-bridge module, a second half-bridge module, the coupling inductor, a first transformer Tr1, a second transformer Tr2 and a variable rectifier bridge. The invention aims to solve the problem of narrow voltage gain range of the existing bipolar direct-current converter for the charging station. By adopting the coupling inductor and the dual-mode control method, a wide voltage gain range can be realized in a narrow switching frequency range, the method can realize more than 6 times of voltage gain in a switching frequency range less than 2 times, and the method has the characteristics of simple topological structure and easiness in control.

The invention discloses a wide-input single-stage Boost-LLC converter and a control method thereof, and relates to the field of power factor correction AC-DC converters. According to the wide-input single-stage Boost-LLC converter, a pulse frequency and pulse width hybrid modulation mode is introduced on the basis of basic pulse frequency modulation control, the voltage stress of a switching device can be reduced, and the input voltage range can be expanded; by introducing quasi-resonance control, the problem that the output of the single-stage AC-DC converter is seriously influenced by double power frequency ripples is solved, and the condition that the output voltage of the secondary side is unstable when the switching frequency is too low is suppressed by adopting a CLC filtering mode at the secondary side. The single-stage Boost-LLC converter has the beneficial effects that through a hybrid modulation mode, the single-stage Boost-LLC converter can realize wide-range input under the condition that the voltage stress requirement of a switching device is not high, double power frequency ripples on the output side are effectively reduced, the stability of the output voltage is ensured, only one-stage power conversion exists in a system, and the system is simple in structure and low in cost. The device has the advantages of small size, high efficiency and low cost.

The disclosure concerns a resonant LLC converter, comprising a transformer comprising a primary side and a secondary side; a primary side circuit comprising primary side switches connected to the primary side of the transformer; a secondary side circuit comprising secondary side switches connected to the secondary side of the transformer; and a control unit configured to control the primary side switches and the secondary side switches; wherein the control unit is configured to perform a steady-state operation where switching frequencies of the primary side switches and of the secondary side switches are controlled to regulate an output voltage of the converter; and the control unit is configured to perform an overshoot control operation where an output voltage spike during a load transient is reduced by setting a control signal for the secondary side switches to low or OFF. The invention also concerns a control method for driving the above-mentioned converter.

The invention discloses a control method of a bidirectional LLC converter, which is characterized in that the working frequency F of the bidirectional LLC converter is controlled, so that the bidirectional LLC converter always works in a discontinuous mode, and the gain M of the bidirectional LLC converter is monotonically changed along with the change of a load by adjusting the working frequency F. By controlling the working frequency F of the bidirectional LLC converter, the bidirectional LLC converter always works in the discontinuous mode, and the gain M is ensured to monotonically change along with the load, so that the control system can uniquely determine the target working frequency, the closed-loop regulation oscillation and out-of-control risk are avoided, the load adaptive capacity and dynamic response performance of the converter are improved, and the system reliability is improved. Therefore, the power supply quality and the system reliability are guaranteed.

The invention discloses a magnetic integrated structure suitable for a high-power LLC converter. The structure consists of two groups of magnetic cores which are symmetrically arranged up and down, wherein each group of magnetic cores comprises a U-shaped magnetic core and an I-shaped magnetic core which is matched with the inner side of a side column of the U-shaped magnetic core. The primary winding and the secondary winding of the transformer are both divided into two parts which are wound on the left magnetic core and the right magnetic core respectively, and the winding directions of the secondary winding on the magnetic column are opposite. Decoupling integration of functions of the inductor and the transformer is achieved by distributing the windings. In the design process of the PCB winding, the needed inductance value can be accurately adjusted by adjusting the area of the I-shaped strip-shaped magnetic core, and the inductance value error caused by the fact that the number of turns of the winding is the fraction is effectively avoided. Meanwhile, by changing the air gap of the magnetic core, the sizes of the excitation inductance and the resonance inductance can be flexibly adjusted in equal proportion. In addition, the planar windings are arranged on the two sides of the magnetic core respectively, the window area of the magnetic core is remarkably increased, the number of parallel stacking layers of the PCB windings on a single magnetic column is reduced, and therefore the heat dissipation performance of the transformer is improved.

The invention belongs to the technical field of power electronic converters, and particularly discloses a full-bridge T-type LLC converter parallel system and a wide-gain-range staggered current sharing method. The system comprises two phases of LLC converters connected in parallel, wherein each phase of LLC converter comprises an input capacitor, a primary side structure of a T-shaped full-bridge structure, a resonant cavity, a transformer and a secondary side structure which are connected in sequence; the primary side structure of the T-shaped full-bridge structure comprises an upper half bridge composed of four switch tubes Q1-Q4 and a lower half bridge composed of switch tubes Q5-Q8. By introducing the T-shaped full-bridge structure, the output gain range can be effectively improved, and staggered current sharing control in the wide output gain range is achieved.

The utility model relates to the technical field of photovoltaic inverters, in particular to an llc over-current hardware protection circuit which comprises a DC input, an llc converter circuit, a DC output, a drive circuit, a microprocessor, a hardware over-current comparison circuit and a CT sampler, one end of the DC input is connected with one end of the llc converter circuit, one end of the llc converter circuit is connected with one end of the DC output, and the other end of the llc converter circuit is connected with the drive circuit. The other end of the llc converter circuit is connected with one end of the drive circuit, one end of the drive circuit is connected with one end of the microprocessor, the other end of the drive circuit is connected with one end of the hardware overcurrent comparison circuit, one end of the hardware overcurrent comparison circuit is connected with the other end of the microprocessor, and the other end of the hardware overcurrent comparison circuit is connected with the other end of the microprocessor. The other end of the hardware over-current comparison circuit is connected with the CT sampling circuit, and a microprocessor on the llc over-current hardware protection circuit adopts a mode of combining hardware and software, so that the llc over-current hardware protection circuit can quickly protect the llc over-current hardware protection circuit.

The invention discloses an efficient LLC converter structure inverter which comprises a power switch, a resonant network, a high-frequency transformer and a diode rectifier. The power switch is composed of four switching tubes which are divided into two groups and connected in series, and on-off is controlled to convert direct-current voltage into square-wave voltage. The resonant network is combined with an adjustable resonant inductor, a capacitor and an excitation inductor, dynamic working parameters are obtained through voltage sampling and PI feedback adjustment, the resonant inductor is connected with a bias winding, and bias current is applied to change magnetic resistance; harmonic waves of the square wave voltage are eliminated through a resonance network, and fundamental frequency sine waves are output; the high-frequency transformer integrates a magnetic core, a primary side / secondary side coil and an air gap in a single magnetic structure; the diode rectifier converts alternating voltage output by the secondary side of the high-frequency transformer into direct current, outputs smoothing voltage of a filter capacitor, and reduces ripple waves; by optimizing the resonant network and the high-frequency transformer, a circuit soft switching technology is realized, so that the loss in an energy transmission process is reduced, and the overall efficiency of the inverter is improved.

The invention discloses a multi-resonant-state LLC converter based on an equal transformation ratio series transformer. The multi-resonant-state LLC converter comprises an inverter circuit, a resonant circuit, a transformer circuit and a rectifying circuit, the inverter circuit converts direct current into pulsating square waves, the resonance circuit comprises a resonance inductor, a resonance capacitor and excitation inductors or equivalent excitation inductors of the two transformers, and the resonance capacitor and the resonance inductor are connected in series and then matched with the excitation inductors to form an LLC resonance circuit. Different excitation inductance values of the two transformers are utilized to enable the resonant circuit to present a plurality of resonant states, and the multi-resonant states can effectively change current waveforms after secondary side rectification of the two transformers, so that rectification output current pulsation is reduced; the transformer circuit comprises two transformers with the same transformation ratio and different excitation inductances for electrical isolation and energy transfer; the rectifying circuit rectifies secondary alternating current of the transformer into direct current. According to the LLC converter, the problem of large rectification output current pulsation of the LLC converter can be solved, the consistency of the size of the transformer is realized, the power density and reliability of the converter can be improved, and the cost is reduced.

This application discloses a soft-start method, apparatus, device, and storage medium for a three-phase LLC converter. The soft-start method includes: responding to a start command, pre-charging the three phases of the three-phase LLC converter in a preset sequence; after the three phases have completed pre-charging, performing coordinated linear modulation on the duty cycle and frequency of the three phases so that the duty cycle of each phase approaches a preset target duty cycle, and the frequency of each phase approaches a preset target frequency; and controlling the three-phase regulated output when the duty cycle of each phase reaches the preset target duty cycle and the frequency of each phase reaches the preset target frequency. This application can achieve more stable and safer three-phase soft starting.

A power converter includes a transformer having a pair of secondary windings coupled together via a common node, a hold-up circuit that includes a first controllable switch coupled with the common node. The first controllable switch is controlled into a non-conduction mode during a first portion of a hold-up time condition to prevent current flowing through a first secondary winding of the pair of secondary windings from flowing from the common node through the hold-up circuit. The first controllable switch is also controlled into a conduction mode during a second portion of the hold-up time condition to enable current flowing through the first secondary winding to flow from the common node through the hold-up circuit. No portion of the current flowing through the first secondary winding flows through a second secondary winding of the pair of secondary windings during the control of the first controllable switch into the conduction mode.

This invention discloses a control method for a cascaded photovoltaic inverter under phase-to-phase short-circuit fault conditions in the power grid, belonging to photovoltaic power generation technology in the field of electrical engineering. The steps are as follows: First, determine the fault type of the three-phase power grid and detect the ratio of the line voltage amplitude of the two faulty phases after the voltage drop to that of the two faulty phases before the voltage drop. Then, use a proportional resonant controller to control the grid-connected current. Second, adopt an adaptive zero-sequence voltage compensation control strategy based on active current injection to adaptively compensate the zero-sequence voltage according to the maximum positive-sequence active current actually output by the inverter. Third, control the average value of the DC bus capacitor voltage of the H-bridge converter by controlling a two-level full-bridge LLC converter with one input and m outputs. When a phase-to-phase short-circuit fault occurs in the power grid, this control method improves the adaptability of the cascaded photovoltaic grid-connected inverter to different output power and different grid voltage drop depths, and improves the system's low-voltage ride-through capability.

The application provides an efficiency optimization control method and device of a bidirectional LLC converter, and belongs to the technical field of power electronic conversion. The method comprises the following steps: determining the converter working mode of the bidirectional LLC converter based on the low-voltage battery side current, and determining the on-off control instruction of the switching unit based on the converter working mode; the bidirectional LLC converter comprises a resonant inductor, a resonant capacitor, a transformer, an external excitation inductor and a switching unit; the resonant cavity instantaneous current is subjected to zero-crossing detection and reference timing extraction to obtain a resonant current zero-crossing time reference signal; the zero-crossing synchronization driving signal of the switching unit is obtained based on the on-off control instruction of the switching unit and the resonant current zero-crossing time reference signal; the switching state of the external excitation inductor is controlled based on the zero-crossing synchronization driving signal of the switching unit, and the resonant cavity topology structure state of the bidirectional LLC converter is determined based on the switching state. The application can reduce the off loss and improve the conversion efficiency.

To provide an LLC converter control circuit capable of accurately detecting a current value even in a region where an output current is minute.SOLUTION: An LLC converter control circuit 100 includes a current detection circuit 110 that outputs a zero cross signal ZC, and a synchronization signal generation circuit 120 that outputs a first signal Va indicating a value obtained by performing an exclusive OR operation on values of a first drive signal VgH and the zero cross signal ZC. The LLC converter control circuit 100 also includes an edge delay circuit 130 that outputs a delay signal Vd that is a signal obtained by delaying the first signal Va. The LLC converter control circuit 100 also includes a ramp voltage generation circuit 140 that charges and discharges a capacitor Ct with a feedback current Ifb based on a change in the level of the delay signal Vd and outputs a ramp voltage Vct. Further, the LLC converter control circuit 100 includes a drive signal generation circuit 160 that generates the first drive signal VgH and the second drive signal VgL based on the ramp voltage Vct.SELECTED DRAWING: Figure 3

The present invention discloses a short-circuit current cutoff control method and device for an LLC converter. When a short circuit is detected in the LLC converter, the primary and secondary switching tubes of the LLC converter are turned off. After a set duration, k pulse drive signals with set high-level durations and set low-level durations are generated to drive the primary switching tube, where k is a natural number not less than 2. After the k pulse drive signals with set high-level durations and set low-level durations have finished driving the primary switching tube, a pulse drive signal with a duty cycle of 50% is generated based on a pre-constructed output current small signal model to drive the primary switching tube until the output current of the LLC converter reaches a steady state. After the output current of the LLC converter reaches a steady state, the synchronous rectification of the LLC converter is turned on to complete the short-circuit current cutoff control of the LLC converter. The present invention has a fast control speed, a small dynamic resonant current, and a stable output current.

An LLC converter includes an LLC resonant tank, a first synchronous rectifier and a synchronous rectification controller. The LLC resonant tank includes a primary winding of a transformer including a first secondary winding. The first synchronous rectifier is connected in series with the first secondary winding through a first detection node and between an output power line and an output ground line. The synchronous rectification controller draws current from the first detection node and to raise an operation power source on a filter capacitor supplying power to the synchronous rectification controller.

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 resonant dual-active bridge converter and a control method, and the converter comprises a primary full-bridge circuit, a secondary full-bridge or half-bridge circuit, a transformer, and an LC resonant network composed of a resonant inductor and a resonant capacitor which are connected in series. The control method comprises the following steps: acquiring parameters of an input voltage V1, an output voltage V2, a transmission power P, a transformer turn ratio N, a resonant inductance Lm and a resonant capacitance Cr of the converter; and calculating a primary fundamental wave equivalent voltage and a secondary fundamental wave equivalent voltage, and calculating an inner phase shift angle alpha between a first bridge arm and a second bridge arm in the primary full-bridge circuit through the primary fundamental wave equivalent voltage and the secondary fundamental wave equivalent voltage. The LLC converter has the beneficial effects that the inherent defects that the gain range of a traditional LLC converter is narrow (generally only 0.8-1.2) and the circulating current is sharply increased and the efficiency is sharply reduced when the voltage is seriously mismatched in the traditional phase-shifting DAB are fundamentally overcome.

The present invention discloses a bidirectional constant power control structure and method for a full-bridge interleaved parallel bidirectional LLC converter, including a first bidirectional full-bridge LLC converter, a second bidirectional full-bridge LLC converter, a load R at the power supply output end load , an interleaving angle adjustment module STM, a PFM1 module, a PFM2 module, a commutation control module SPM, a primary-secondary asynchronous compensation angle adjustment module PIM, a constant voltage control loop of the LLC resonant converter, a constant current control loop of the LLC resonant converter, a first current sampling module, a second current sampling module, and a voltage sampling module. The control method of the present invention is simple and does not increase any hardware cost, and can achieve bidirectional constant power control of the interleaved parallel bidirectional LLC resonant converter.

An LLC (inductor-inductor-capacitor) converter, including: a primary current sensing circuit operable to sense a primary current of the LLC converter; and a protection circuit coupled between the primary current sensing circuit and power switches of the LLC converter, and operable to increase a switching frequency of the LLC converter when an amplitude of the primary current falls below a predefined low current reference value after a predefined blanking time after a phase transition of the LLC converter.

Provided in an embodiment is a control method in use of an LLC converter with high-side and low-side switches connected in series between two input power lines via a first node. Connected to the first node is a resonant circuit with a primary winding of a transformer and a resonant capacitor both connected to a second node, to which a voltage divider is connected to generate a feedback signal at a feedback node. First and second control signals are generated to control the high-side and low-side switches respectively in response to the feedback signal and a compensation signal controlled by an output voltage of the LLC converter. A first duty cycle of the first control signal is compared with a second duty cycle of the second control signal to provide an accumulation signal, in response to which an adjustment current is provided to adjust an average of the feedback signal.

The invention discloses a narrow pulse phase shift cooperative control method based on an LLC converter. The method comprises the following steps: acquiring a voltage signal in real time, and then judging whether closed-loop control is started or not; calculating an error signal according to the voltage signal; judging system working conditions based on the error signals; and implementing a corresponding control strategy and configuring PI parameters according to the system working condition. According to the narrow pulse phase shift cooperative control method based on the LLC converter, through combination of closed-loop control and soft start control and cooperation of narrow pulse and phase shift cooperative logic, the problem that the voltage of a high-voltage side bus is unstable and even is reduced during boost discharge in traditional phase shift control is effectively solved; meanwhile, the predefined minimum pulse width and dead time can prevent switch tube direct connection or signal loss, the system reliability is enhanced, and the requirements for wide-range change of power grid voltage and bidirectional efficient interaction of energy in the energy storage fields such as light storage and electric automobiles are met.