645 results about "Zero voltage" patented technology

The invention relates to the technical field of power electronics, and discloses a soft switch of a high-frequency switch transformer and a distributed control method and system thereof, and the method comprises the steps: achieving the precise synchronization of nodes through the construction of a ring topology network, combining the monitoring of multiple physical quantities with the collaborative optimization of parameters, dynamically adjusting the parameters of a resonant network and a driving time sequence, and achieving the precise synchronization of the nodes. A zero-voltage switching state is maintained, and electromagnetic interference is suppressed by adopting the composite optimization model; the system comprises a network initialization module, a multi-physical-quantity monitoring module, a space-time synchronization control module, a resonance parameter adjustment module, an electromagnetic optimization decision module, a dynamic adjustment module and a parameter evolution module. The stability of the soft switch is improved through a distributed network and time-space synchronization, and the loss is reduced by adopting a dynamic optimization algorithm; constructing an electromagnetic interference optimization model to enhance compatibility; performing multi-parameter fusion and weight distribution to optimize dynamic response; the reliability is improved through a high-precision protocol and coevolution; and the tensor product framework realizes multi-dimensional intelligent cooperative control.

According to the SiC MOSFET global short circuit and overcurrent protection circuit and the control method thereof provided by the invention, when a short circuit fault occurs in the SiC MOSFET, the drain current ID is more than several times of the rated current of the SiC MOSFET. When a short circuit occurs, a transistor QDZ of the short circuit detection circuit is switched on by node voltage Vr of the resistance-capacitance filter circuit, a fault signal VFAULT is converted into a low level, grid voltage VGS output by the grid control unit is gradually converted into zero voltage from negative driving voltage VEE, and soft turn-off is performed on the SiC MOSFET; when an over-current fault occurs in the SiC MOSFET, drain current ID is higher than rated current, node voltage Vo of the resistance-capacitance filter circuit lasts for a long time, the maximum value of capacitor voltage Vch of the over-current detection circuit is higher than reference voltage Vref2, a fault signal VFAULT is converted into low level, grid voltage VGS output by the grid control unit is gradually converted into zero voltage from negative driving voltage VEE, and soft turn-off is performed on the SiC MOSFET. According to the invention, high-speed short circuit and over-current fault protection of the SiC MOSFET in all inductance regions of a commutation loop can be realized.

A method comprises: in an onboard charger of an electric vehicle, providing i) a direct current (DC) to DC stage including a dual-active bridge, and ii) a DC link capacitor having a DC bus voltage; and dynamically regulating the DC bus voltage to improve zero voltage switching (ZVS) in the onboard charger.

The invention discloses a TCM-mode-based Si-SiC hybrid power multi-phase staggered H-bridge converter structure and a control method thereof, according to the scheme, a three-phase staggered parallel topology of a two-phase low-frequency Si-IGBT bridge arm and a one-phase high-frequency SiC-MOSFET bridge arm is adopted, and a TCM control strategy is combined, so that zero voltage switching (ZVS) of a Si device is successfully realized, the switching loss is remarkably reduced, and the switching efficiency is improved. The system efficiency is greatly improved; and meanwhile, through pilot frequency interleaving and ripple compensation technologies, total output current ripples are greatly reduced, and optimal balance between system performance and manufacturing cost is realized while the power capacity of the converter is remarkably expanded and the dynamic response speed and the output electric energy quality are improved.

This power conversion device includes a multilevel inverter which outputs multilevel voltages by adding / subtracting voltage of a sub inverter to / from output voltage of a main inverter. The multilevel inverter can switch between PWM operation in which plural pulses are outputted in each of positive voltage output and negative voltage output in one cycle and a pulse width is controlled, and one-pulse operation in which one pulse is outputted in each of positive voltage output and negative voltage output in one cycle, and has a current-split switching mode in which current flowing between a neutral point and the sub inverter flows through a first switch group and a second switch group provided to the main inverter and connected in parallel, in a case where the main inverter outputs zero voltage which is the potential of the neutral point, in the one-pulse operation.

A method comprises: providing, in an onboard charger of an electric vehicle, a direct current (DC) to DC stage including a dual-active bridge having switches arranged in multiple legs, each of the multiple legs controlled by a corresponding one of pulse width modulation (PWM) signals; and dynamically modulating the PWM signals to improve zero voltage switching (ZVS) in the onboard charger.

A two-transistor flyback topology in which a portion of leakage inductance energy in the transformer is extracted and used to obtain zero voltage switching on both switching elements in any operating conditions, and in which a third low power switch eliminates parasitic oscillations and allows an operation at a determined frequency. In this topology, there are no switching losses and there are no spikes or glitches in any switching node, eliminating the need for snubbers. This topology is an “ideal two transistor flyback topology.”

The invention discloses a three-port soft switching optical storage servo all-in-one machine based on device multiplexing and a modulation method. The all-in-one machine comprises a DC-AC servo driver, a low-voltage DC energy storage module, an auxiliary unit, a bus capacitor and a photovoltaic module. The DC-AC servo driver comprises three bridge arms, and each bridge arm is provided with a bridge arm upper tube and a bridge arm lower tube; the low-voltage direct-current energy storage module comprises an energy storage battery, an energy storage switch tube S7 and a direct-current energy storage inductor; the photovoltaic module comprises a photovoltaic power generation panel, a photovoltaic inductor, a photovoltaic switch tube S8 and a diode D1; the auxiliary unit comprises an auxiliary switch tube Sa, an auxiliary resonant inductor Lr and an auxiliary capacitor Cr. According to the invention, an integrated resonant soft switching architecture is innovatively adopted, zero-voltage / zero-current switching of all power switching devices is realized, and the problem of loss caused by a traditional hard switch is thoroughly solved; and by optimizing a device multiplexing technology, the number of switching tubes is greatly reduced while the soft switching performance is ensured, so that the system efficiency is improved in a breakthrough manner.

The invention belongs to the technical field of power distribution, and discloses a direct current transformer soft switch and a control method.The direct current transformer soft switch comprises a medium-voltage direct current bus and low-voltage direct current buses, the medium-voltage direct current bus is electrically connected with a modular multi-level multi-port direct current converter, and the modular multi-level multi-port direct current converter is electrically connected with a plurality of low-voltage direct current converters; the plurality of low-voltage direct-current converters are electrically connected with a low-voltage direct-current bus and are used for realizing bidirectional power transmission from medium-voltage direct current to low-voltage direct current; according to the method, the medium-voltage side inductance value is reduced, the medium-voltage side current ripple is enabled to pass zero, the M3DC operates in an approximate critical conduction mode, a constant valley current control strategy is adopted, the minimum value of the medium-voltage side inductance current is controlled to be constant under different working conditions, and then zero-voltage switching-on of a switching device in a wide operation range and zero-current switching-off of an anti-parallel diode are achieved.

A piezoelectric actuator-system includes an inductor and driver-circuit having switches for transferring energy between first and second actuators and the inductor, and between a voltage-supply node and the inductor. Control circuitry determines whether a next phase in which to operate the driver-circuit is a charging-phase or a recovery-phase. Either the charging-phase or recovery-phase may include, after a freewheeling sub-phase, a pre-charge sub-phase to place a given one of the switches connected to the first actuator near a zero-voltage switching condition. Either the charging-phase or recovery-phase may include, after a sub-phase in which a parasitic capacitance is charged, an additional recovery sub-phase in which the charge from the parasitic capacitance is recovered to the voltage-supply node.

A switched capacitor converter includes an auxiliary circuit, a first branch and a second branch, the auxiliary circuit is connected between the first branch and the second branch, all power transistors of the first branch and the second branch are primary power transistors, and the auxiliary circuit transfers a charge or electric charges on one of the first branch and the second branch to another of the first branch and the second branch during a dead time when the primary power transistors are turned off, so as to the primary power transistors turn on at zero voltage and reduce a switching loss.

The invention discloses a sampling current bias error compensation method for a permanent magnet synchronous motor. The sampling current bias error compensation method comprises the following steps: step 1, acquiring the shortest duration required by sampling current bias; 2, the permanent magnet synchronous motor is controlled in a vector mode; 3, the zero-voltage vector holding time is obtained, a sampling current compensation mode is selected according to the zero-voltage vector holding time and the shortest time needed by sampling current bias, and the compensation mode comprises the steps that when the zero-voltage vector holding time is larger than or equal to the shortest time needed by sampling current bias, a direct compensation mode is carried out; when the zero voltage vector holding duration is smaller than the shortest duration required by sampling current bias, terminal voltage integration is carried out to judge a compensation mode; and 4, performing vector control on the permanent magnet synchronous motor through the compensated sampling current, and performing closed-loop control. According to the invention, the operation precision of the permanent magnet synchronous motor can be improved, and the motor operation system can adapt to the dynamic change of the offset error.

The invention discloses an extended double-side asymmetric phase shift modulation method for a dual-active bridge converter, and belongs to the technical field of isolated high-frequency power conversion in a power electronic technology. According to the symmetric phase shift modulation method, under the condition that the voltage conversion ratio is not matched, the zero voltage switching range of a switching tube is small, the light load efficiency is low, and variable abrupt change can occur during mode switching to cause the uncontrollable oscillation problem of inductive current. The invention provides an extended double-side asymmetric phase shift modulation method for a dual-active bridge converter in a wide voltage range. A multi-objective optimization scheme is established based on the provided modulation method, and an approximation method is provided to solve a full power range analytical solution. A smooth switching method between modes is realized, and uncontrollable oscillation of inductive current can be effectively avoided. And the conversion efficiency in a full-power range is improved.

The invention provides a zero-voltage ride-through control method for a self-synchronizing voltage source doubly-fed wind turbine generator, which comprises the following steps that: when the self-synchronizing voltage source doubly-fed wind turbine generator is in a transient state, a grid-side converter adopts vector control, and a rotor-side converter adopts additional virtual impedance and annular current limiting; the transient overcurrent of the grid-side converter and the rotor-side converter can be effectively suppressed, so that the continuous operation capability of the wind turbine generator in the zero-voltage ride-through period can be maintained; meanwhile, by improving the transient capacity and the transient reactive current amplitude of the converter, the transient voltage supporting capacity of the wind turbine generator during the zero voltage ride-through period can be effectively provided; when the self-synchronizing voltage source doubly-fed wind turbine generator set is in a transient state, overvoltage of direct-current bus voltage is limited by a Chopper circuit, active-priority current amplitude limiting control is adopted by a grid-side converter, parameters of a current inner ring PI controller of a rotor-side converter are optimized, energy balance of a direct-current side can be achieved in the zero-voltage ride-through period, and stability of the direct-current bus voltage is maintained.

The invention discloses a zero-voltage turn-on circuit and a zero-voltage turn-on method of a switching tube in a switching power supply, and belongs to the technical field of circuits. In a critical conduction mode, when a low-side power tube is turned off, the rising edge zero-voltage starting circuit compares a switch node voltage with an input voltage or compares the switch node voltage with an output voltage under the control of a low-side gate driving voltage, outputs a high level to a high-side gate driving end when the switch node voltage is equal to the input voltage or the output voltage, and outputs a low level to a low-side gate driving end when the high level is equal to the output voltage. A high-side power tube is controlled through a high level to realize zero-voltage starting; in a critical conduction mode, when the high-side power tube is turned off, the falling-edge zero-voltage starting circuit compares an induced voltage with a pull-up resistor voltage under the control of a high-side gate driving voltage, outputs a high level to a low-side gate driving end when the induced voltage is equal to the pull-up resistor voltage, and controls the low-side power tube to realize zero-voltage starting through the high level. The induced voltage is equal to the sum of the pull-up resistor voltage and the switch node voltage. According to the invention, the transmission delay can be reduced.

The invention discloses an electric field coupling wireless power transmission system and a control method thereof. The control method comprises the steps that autonomous multiphase current feed push-pull inverters with full-resonance and zero-voltage switching operation are symmetrically adopted at a transmitting end and a receiving end, and full-ZVS operation autonomy of the electric field coupling wireless power transmission system is achieved; the autonomous characteristic of the system is embodied in that the system can automatically track the frequency for realizing the same phase of voltage and current, the frequency is a constant-voltage and constant-current switching point, and the constant-current charging or constant-voltage charging of the system and the switching between the constant-current charging and the constant-voltage charging of the system can be realized by adjusting the frequency of the inverter, namely the working frequency of the system, based on the constant-voltage and constant-current switching point; according to the invention, the system is simple in structure, does not need to add an extra switching device or needs a complex control circuit, is higher in transmission efficiency and reliability, improves the flexibility and adaptability of the system, and also guarantees the high-efficiency energy transmission and low electromagnetic interference characteristics.

Disclosed is a system for zero voltage switching in a power converter with a first half-bridge and a second half-bridge. The first half-bridge has a first set of transistors and output inductor. The second half-bridge has a second set of transistors and auxiliary inductor. A current sensing means measures, at switching cycle scale, average and maximum current values of output inductor and average, minimum and maximum current values of auxiliary inductor. A voltage sensing means measures input and output voltages of first and second half-bridge. A controller is configured to compute dead times of pulse width modulation control signal of second half-bridge, generate pulse width modulation control signal of second half-bridge and to adapt dead times of first half-bridge.

The invention discloses a detection device and a detection system for harmonic oscillator capacitors of a hemispherical resonator gyroscope, and relates to the technical field of capacitor detection, the detection device comprises a signal detection circuit, a modulation compensation circuit, a differential amplification circuit and a control circuit, the signal detection circuit is connected with the output ends of the two harmonic oscillator capacitors; the modulation compensation circuit is correspondingly connected with two input ends of the signal detection circuit; the differential amplification circuit is correspondingly connected with two output ends of the signal detection circuit; the control circuit is configured to output modulation voltage to the two input ends of the modulation compensation circuit according to a voltage signal of the output end of the differential amplification circuit, and zero setting is carried out on voltage at the connecting positions of the two output ends of the modulation compensation circuit and the two input ends of the signal detection circuit. According to the invention, the modulation compensation circuit is adopted to enable the output ends of the two harmonic oscillator capacitors to work near zero voltage, the circuit has the characteristics of ultrahigh linearity, extremely low temperature drift, rapidness and stability, errors caused by power supply drift can be eliminated, and the detection precision is improved.

The invention discloses a half-bridge ZVS Buck-Boost converter and a control method thereof, and belongs to the technical field of power converters, the half-bridge ZVS Buck-Boost converter comprises a primary side conversion module, a voltage transformation module and a secondary side conversion module, and the primary side conversion module, the voltage transformation module and the secondary side conversion module are connected in sequence; the primary side conversion module comprises a first bridge arm, a second bridge arm, a first inductor and a bidirectional switch, the first bridge arm and the second bridge arm are connected in parallel, a bridge arm midpoint of the first bridge arm is connected with a first end of the first inductor, a second end of the first inductor is connected with a first end of the voltage transformation module, and a second end of the voltage transformation module is connected with a second end of the voltage transformation module. The second end of the voltage transformation module is connected with the bridge arm midpoint of the second bridge arm, the bridge arm midpoint of the first bridge arm is connected with the first end of the bidirectional switch, and the second end of the bidirectional switch is connected with the bridge arm midpoint of the second bridge arm. According to the invention, zero-voltage switching-on of the half-bridge circuit switching tube in a full-input, full-output and full-load range under a constant switching frequency can be realized.

The invention relates to the field of electronic power, particularly discloses a bridge resonant converter based on forward and reverse shock coordination of double transformers, and belongs to the technical field of power electronic conversion. Aiming at the problems of over-high peak current, high magnetic core saturation risk, remarkable switching loss and the like of a traditional LLC resonant converter under the requirements of a wide load range and high power density, the invention provides the following innovative schemes: a dual-transformer forward and reverse excitation collaborative structure, a zero voltage switching (ZVS) driving technology and resonant network parameter optimization.

Techniques are provided for controlling alternating current (AC) power which is supplied to an inductive load by an AC switch. For example, the AC power is controlled by a process which comprises detecting zero-voltage crossings of an AC voltage waveform of the AC power, monitoring a load voltage to detect for a presence of inductive flyback voltage when the AC switch is placed into a turned-off state, and determining a delay time to place the AC switch into the turned-off state subsequent to a detected zero-voltage crossing of the AC voltage waveform, when inductive flyback voltage is detected in the load voltage, so that the AC switch is placed into the turned-off state at a time which substantially coincides with a zero-current crossing of load current of the inductive load, to thereby suppress the generation of inductive flyback voltage when the AC switch is placed into the turned-off state.

The invention belongs to the technical field of electrochemical energy storage, and relates to a zero-voltage attenuation lithium-rich positive electrode material, a preparation method and application thereof, the chemical general formula is Lix (Li < 1-y-z > Mn < y > Ni < z >) O < 2 >, xlt; 0.85, 0.5 lt; yt; Yt; 0.7, 0.1 lt; zlt, zlt; 0.3 part; the preparation method comprises the following steps: 1, preparing a sodium ion positive electrode precursor; 2, screening a sodium ion positive electrode precursor for the first time; 3, preparing a lithium-rich positive electrode material by combining a molten salt ion exchange method with secondary screening; according to the method, the structure rearrangement reaction occurring in situ during ion exchange is maximized through two screening procedures, so that the finally obtained lithium-rich positive electrode has the zero-voltage attenuation characteristic while having high capacity retention rate, and the long-term voltage attenuation problem of the lithium-rich positive electrode is effectively solved.

The invention relates to an LLC resonant soft switching converter based on self-detection synchronous rectification and a control method thereof. The converter comprises an LLC resonance circuit, a secondary transformer with a center tap, a self-detection synchronous rectification circuit, an input filter circuit, an output filter circuit, an LLC resonance control circuit, a primary PFM drive circuit, an optocoupler isolation circuit, an output voltage sampling circuit and an operational amplifier compensation circuit. Switching tubes S1 and S2 in the primary PFM drive circuit adopt high-voltage MOS tubes, secondary synchronous rectifier tubes S3 and S4 adopt low-voltage MOS tubes, output voltage feedback control and secondary synchronous rectifier tube self-detection drive control are adopted, and the resonant soft switching converter with the 240V-300V input voltage range, the constant output of 28V / 300W and the full-load efficiency of 92% is realized. According to the invention, zero-voltage switching-on of the primary switch tube, zero-current switching-off of the secondary synchronous rectifier tube and accurate synchronous rectification control are realized, the loss of the rectifier circuit is reduced, the efficiency of the converter is improved, and the electromagnetic compatibility characteristic of the converter is optimized.

The invention discloses a multi-electric-level straight drive circuit of a depletion type switching device, which is characterized in that by dynamically switching positive voltage, zero voltage and deep and shallow negative voltage, the positive voltage is utilized to reduce on resistance in a conduction stage, the deep negative voltage is utilized to quickly cut off current in a turn-off stage, and then the shallow negative voltage is switched to maintain a turn-off state, so that the static power consumption is remarkably reduced. A surge suppression circuit and a power driver work cooperatively, surge current is suppressed through a current-limiting resistor and a fast bypass switch at the moment of starting, and a short circuit Ra is formed after negative voltage is established to reduce loss; and before power failure, the capacitor stored energy is released through the active discharge switch, so that mistaken switching-on caused by residual voltage is eliminated. Through system-level innovation, the direct connection problem of a depletion type device is effectively solved, and a high-efficiency, reliable and compact solution is provided for a high-power-density power supply system.

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 discloses a control method, and particularly relates to an energy storage power converter self-adaptive control method based on digital twinning, which comprises the following steps: step 1, digital twinning model synchronization and state sensing; step 2, multi-target collaborative optimization based on prediction; and step 3, optimizing instruction issuing and physical system execution. Through real-time prediction and optimization of the digital twinborn model, it is ensured that the power switch tube always works in a zero-voltage switching state, switching loss is effectively reduced, and overall efficiency is improved. Dynamic thermal balance management is realized by combining thermal model prediction, local overheating is avoided, the service life of devices is prolonged, and the reliability of long-term operation of the system is enhanced.

The invention provides a phase current reconstruction method and system, computer equipment and a readable storage medium, and belongs to the technical field of phase current reconstruction, and the method comprises the steps: installing a single current sensor on two branches of an inverter, so as to construct a dual-branch single current sensor circuit topological structure; dividing six sectors formed by the non-zero voltage vector to form twelve sub-sectors; and for each sub-sector, sampling the single current sensor in the action time of the non-zero voltage vector and the zero voltage vector of one PWM period to obtain current information of two different phases, and reconstructing a third-phase current of the motor according to the current information of the two different phases. The method has the advantages that the zero voltage vector and the non-zero voltage vector are introduced for each sub-sector in the twelve sub-sectors to perform current sampling and reconstruction, the problem of current reconstruction blind areas of a sector boundary area and a low modulation ratio area is solved, meanwhile, the current reconstruction mode is single, and the complexity of an algorithm during actual reconstruction is reduced.

The invention discloses an inductive current peak control method for a high-efficiency four-switch Buck-Boost converter capable of smoothly switching between a DCM mode and a CCM mode, which belongs to the technical field of a direct-current power transformation control system and is characterized in that smooth switching between the DCM mode and the CCM mode is determined on the basis of energy storage time and direct power transmission time of the four-switch Buck-Boost converter in the DCM mode and the CCM mode; a negative current value-IZVS turned on under zero voltage of a switching tube of the four-switch Buck-Boost converter and a current value of an inductor of the four-switch Buck-Boost converter are compared through a comparator, and follow current time T4 of the inductor current is output; and calculating and outputting control signals of four switches of the four-switch Buck-Boost converter on the basis of the determined duty ratio of the energy storage time in the DCM mode or the CCM mode, the duty ratio of the power direct transmission time, the phase shift delta D between two bridge arms of the converter and the follow current time T4 of the inductive current, so as to realize the high-efficiency control of the peak value of the inductive current of the four-switch Buck-Boost converter.

A buck topology operates in discontinuous mode in which energy contained in the parasitic oscillations is harvested as needed, with additional energy provided by a voltage injection source, the power switchers of the buck topology turn on at zero voltage in any operating conditions.

The invention provides a fixed-frequency inductive-current-sensor-free four-switch buck-boost soft switching control method, which comprises the following steps of: generating a regulating variable based on a deviation between an output voltage and a reference value, and determining a time sequence parameter of each stage of the period; charging and discharging in opposite directions are carried out on output junction capacitors of two switch elements of the same bridge arm by utilizing inductive current in a commutation dead zone; when it is detected that the duration of the free circulation stage of the current period does not exceed a preset lower limit, adjusting the time sequence of at least one stage to execute power expansion under a fixed switching frequency, and meanwhile, keeping on under a zero voltage condition; identifying a bias component of the inductive current based on indirect characterization of the output current to the inductive current, and performing correction by adjusting a timing sequence of at least one stage; and combining the outputs of the time sequence generation, the power expansion and the offset correction obtained in the previous steps into a time sequence parameter of the current period. According to the method, the microgrid conversion requirements of a wide voltage adaptation scene on high efficiency, high power density and high robustness are effectively met.