108 results about "Llc converter" patented technology

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 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 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 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 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.

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.

This invention belongs to the field of power electrical technology and relates to a wide voltage range clamped boost LLC resonant converter, comprising: an input DC bus voltage unit, an active clamped boost unit, an inverter bridge unit, an LLC resonant tank unit, a transformer T, and a rectification and filtering unit; the active clamped boost unit includes a first feed inductor, a second feed inductor, a clamping capacitor, a third switch S3, and a fourth switch S4; the LLC resonant tank unit includes a resonant inductor and a resonant capacitor connected in series, and a magnetizing inductor of the transformer T; the rectification and filtering unit includes a first rectifier diode, a second rectifier diode, and a filter capacitor C. o Load R L This invention solves the technical problem in the prior art that traditional LLC converters have a limited gain adjustment range and cannot simultaneously meet high boost requirements.

A control method, apparatus, and controller for an LLC converter are disclosed. When the output voltage of the LLC converter is less than a set lower threshold or greater than a set upper threshold, the controller can calculate a comparison voltage based on the output current or the slope of the output voltage at the LLC converter's output terminal. Since the output voltage has a certain delay, the controller can select the voltage with the smaller value between the output voltage and the comparison voltage at the same moment to adjust the output voltage. The controller calculates the transmission frequency based on the adjusted voltage, enabling rapid adjustment of the output voltage at the LLC converter's output terminal to maintain a stable output voltage.

The invention relates to the field of power electronic conversion, and provides a high-voltage transformer design method and system based on an LLC converter. The method comprises the following steps: determining size parameters of an iron core and size parameters of a winding according to resonance parameters of the LLC converter; determining parameters related to loss calculation according to the size parameters of the iron core and the size parameters of the winding so as to determine a loss formula; based on the resonance parameters of the LLC converter, solving the minimum value of the number of turns of the secondary side according to a loss formula, and obtaining the optimized number of turns of the secondary side; based on the resonance parameters of the LLC converter, solving a minimum value about the number of turns of the primary side according to a loss formula to obtain the optimized number of turns of the primary side; according to the excitation inductance parameter required by the LLC converter, the air gap with the set length is increased in combination with the iron core parameter; and performing flux density and temperature rise verification on the parameters calculated by the LLC converter, and obtaining a final design result after conditions are met. And the LLC converter can realize lower loss.

A method for operating a bidirectional DC-DC converter is provided. The bidirectional DC-DC converter can transfer energy both from a high-voltage network to a low-voltage battery and from the low-voltage battery to the high-voltage network. The bidirectional DC-DC converter comprises a first power stage with an LLC converter circuit and a second power stage with two cascaded buck converters. The two cascaded buck converters are controlled by a single PWM with the same duty cycle. The method includes operating the DC-DC converter in a buck mode, switching from buck mode to boost mode, and operating the DC-DC converter in a boost mode.The operation of the DC-DC converter in step-down mode and step-up mode includes the operation of the LLC converter circuit in open-loop operation at a resonant switching frequency and the operation of the two cascaded step-down converters using the same duty cycle.

The application provides an LLC converter and a wide-range voltage regulation method thereof. The LLC converter comprises an input voltage, an input inductor L in , a first half-bridge unit, a second half-bridge unit, a resonant cavity, a transformer, a rectifier circuit, an output capacitor and an output load. The first half-bridge unit is composed of a first switch S1, a second switch S2 and a bus capacitor C1, the second half-bridge unit is composed of a third switch S3, a fourth switch S4 and a bus capacitor C2, the resonant cavity is composed of a resonant capacitor C r , a resonant inductor L r and an excitation inductor L m , and the rectifier circuit is composed of a first rectifier diode D1, a second rectifier diode D2, a voltage doubler capacitor C3 and a voltage doubler capacitor C4. The application can realize soft switching of all power devices in a wide voltage gain range, the switching frequency is fixed at a series resonant frequency, which is beneficial to optimization and design of magnetic elements, and the capacitor voltage of the half-bridge unit in the LLC converter can be self-balanced.

The invention relates to the technical field of power electronics, and discloses a demodulation method and system for a load side of an LLC resonant converter, and the method comprises the following steps: receiving electric energy transmitted from the LLC converter by a load, and filtering out-of-band noise through a band-pass filter; s2, converting the carrier signal subjected to band-pass filtering into a discrete sampling sequence by an analog-to-digital converter; a low-pass filtering process after signal multiplication in coherent demodulation is replaced by an integration process; as a signal to be measured is converted into a discrete sequence through sampling, a sinusoidal signal multiplied by the discrete sequence in an integration process is converted into a sinusoidal sequence obtained by the same sampling frequency, and the integration process is converted into an accumulation process; the amplitude and the phase of the discrete signal are obtained; digital information is advanced from the output voltage of the LLC converter by analyzing the frequency, amplitude and phase of the signals.