812 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 provides a synchronous zero voltage modulation system and method of a cascade system, a medium and equipment wherein the synchronous zero voltage modulation system of the cascade system comprises a power circuit module and a modulation system; the power circuit module comprises a front-stage four-switch buck-boost converter and a rear-stage LCC-LCC compensated bidirectional wireless charging system; the modulation system comprises a voltage compensation module, a current compensation module, a current comparison module, a synchronization module and a switch driving signal generation module, the output end of the voltage compensation module is connected with the input end of the synchronization module, and the output end of the current compensation module is connected with the input end of the synchronization module. The output end of the current comparison module is connected with the input end of the synchronization module, and the output end of the synchronization module is connected with the driving signal generation module. According to the invention, a plurality of time scales are adopted, the implementation condition of synchronous zero-voltage switch modulation is accurately calculated, the calculation speed is high, the memory occupation amount is small, and the zero-voltage switch synchronous modulation of the cascade system is realized.

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.

Systems, apparatuses, and methods are described for DC bus management. During startup, a power device may provide power at different voltages to the DC bus to ramp up the voltage of the DC bus from a zero voltage level to an operating voltage level. For example, the power device may be configured to provide power at different voltage levels during the ramp up. During the ramp up, the power device may send communications to query additional devices. Based on a response to the query the power device may set the voltage level. Protocols for over-current, sleep mode, and shutdown mode may include decreasing a higher voltage level to a lower voltage level.

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.

System and method for controlling synchronous rectification. For example, a system for controlling synchronous rectification includes: a first control-signal generator configured to generate a first control signal; a second control-signal generator configured to receive the first control signal for a first switching cycle and generate a second control signal for a second switching cycle based at least in part on the first control signal for the first switching cycle, the first switching cycle preceding the second switching cycle; and a driver configured to receive the first control signal and generate a drive voltage based at least in part on the first control signal; wherein the second control-signal generator is further configured to: process information associated with the first control signal; determine a first time duration when the first control signal remains at a first logic level during the first switching cycle.

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 discloses an IGBT full-bridge series inverter power supply control system, which relates to the technical field of inverter power supplies and comprises an inverter output module, the inverter output module inverts direct-current electric energy accessed by a power supply module, and when the detected electric energy is larger than a first voltage threshold value or smaller than a second voltage threshold value, the inverter output module outputs the inverted electric energy. The intelligent control module controls the soft switching module to carry out zero-voltage and zero-current soft switching-on processing on a switching element which is not switched on in the inversion output module, the terminal voltage change rate of the switching element in a switched-off state is reduced, zero-voltage soft switching-off is carried out, and when the detected electric energy is smaller than a first voltage threshold value or a second voltage threshold value, the soft switching-off is carried out. The soft switch module cooperates with the auxiliary capacitor module to carry out half-bridge inversion and carries out output compensation or enlarges the output voltage range through the electric energy output by the series compensation module and the inversion control module. According to the IGBT full-bridge series inverter power supply control system, the switching loss can be reduced, the electric energy conversion efficiency and the power supply precision are improved, and the power supply voltage range is enlarged.

According to the energy efficiency optimization model of the low-output variable-power power supply resonant converter, the element parameter selection method of the resonant converter is determined through the steady-state characteristics and the state expression of the converter, and the mathematical model is established for the power loss device of the resonant converter in combination with the operation parameters and the element parameters; converting an optimization objective function according to the established loss model, taking switching frequency as an optimization variable, taking inverter efficiency as an objective, combining element parameters and constraint conditions formed in a steady-state analysis expression, determining an optimization objective, and optimizing the overall energy efficiency of the resonant converter with variable output power; when the resonant converter operates at a high control frequency, the switching energy consumption is greatly reduced, zero-voltage turn-on and turn-off are easily completed, the converter can operate at the high control frequency, the energy efficiency of the power supply resonant converter can be optimized to the greatest extent under the condition of low output variable power, and the safety and stability of a power supply system can be ensured.

The embodiment of the invention provides a half-bridge flyback converter, a control method thereof, a control circuit and a chip. The control method comprises the steps that when the half-bridge flyback converter works in a free resonance state, in a first switching period, a second primary switching tube is controlled to be conducted for a first time length, and according to sampling voltage information of a secondary power loop, after it is detected that the second primary switching tube is conducted, a secondary switching tube is controlled to be conducted for a second time length, the half-bridge flyback converter can perform reverse excitation so as to generate negative excitation current, the zero voltage at the two ends of the first primary switch tube is reduced to zero, and when the first primary switch tube is controlled to be switched on, zero-voltage switching-on of the first primary switch tube can be realized. According to the method, the noise of the half-bridge flyback converter can be reduced, and zero-voltage switching-on of the first primary switching tube can be realized under the DCM of the wide-range output voltage of the half-bridge flyback converter, so that the efficiency of the half-bridge flyback converter under the DCM 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.

A method detects an electrical insulation fault between an electric power source and an electrical ground, via a circuit that includes a controllable voltage generator and an electrical measuring resistor connected in series between a terminal of the electric power source and the electrical ground. The method includes controlling the voltage generator to establish, between its terminals, a non-zero voltage value, and measuring the voltage at the terminals of the electrical measuring resistor to detect an electrical insulation fault between the electric power source and the electrical ground. The method further includes a computer determining, depending at least on the voltage measured at the terminals of the electrical measuring resistor, at least two parameters characteristic of a disturbance affecting the detection of the electrical insulation fault, and calculating a reliability level of the detection of the electrical insulation fault depending on at least one of the two parameters.

The invention discloses an isolated resonant converter and a control method thereof, and belongs to the technical field of electric energy conversion, and the method comprises the steps: comparing a primary side current i1 with a current reference value iref, carrying out PI adjustment, and adding the primary side current i1 with the current reference value iref to obtain a target current value it; comparing the external phase shift angle alpha with an external phase shift angle reference value alpha ref, and adding a feed-forward frequency fd after PI adjustment to obtain a switching frequency fs; and reactive current Irq and active current Irp of the primary side of the resonant cavity are calculated, a voltage phase difference phi and an internal phase shift angle theta are calculated according to the target current value it and the switching frequency fs, and a switch of the isolated resonant converter is driven according to the voltage phase difference phi, the internal phase shift angle theta, the external phase shift angle alpha and the switching frequency fs. According to the isolated resonant converter and the control method thereof, accurate control of transmission power and zero-voltage switching-on of all switches can be realized, and the efficiency of the converter is remarkably improved.

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.

The invention provides a zero-voltage starting control module, a driving circuit and an active clamping converter, and the module comprises a timing unit which carries out the timing of a first time length; the time length acquisition unit is used for acquiring the time length from the turn-off of the clamping tube to the complete release of the secondary inductive current of the transformer to obtain a second time length; the comparison unit is used for comparing the first duration with the second duration; and the dead time adjusting unit is used for adjusting the conduction time and the first duration of the clamping tube in the next period based on the comparison result of the current period so as to realize self-adaptive zero-voltage starting control. The circuit is realized by adopting a digital circuit, accurate control can be realized, the control range is relatively wide, zero-voltage conduction control is dynamically realized, the system efficiency is improved, the use of a capacitor in an analog circuit is reduced, and the area cost of a chip is reduced.

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.

A resonant inverter (1) is a three-level converter and operates under zero voltage turn-on control at a time of discharge. An auxiliary resonance circuit (2) includes a negative-side resonance path (rn) that has a current polarity limited to a direction from a resonance inductor (Lr) to a neutral point (A), and that is opened and closed by a switch element (Tr6). The auxiliary resonance circuit (2) includes a positive-side regeneration path (D5 + Dsp) that has a current polarity limited to a direction from the resonance inductor (Lr) to a positive-side DC line (P). The auxiliary resonance circuit (2) includes a negative-side regeneration path (D6 + Dsn) that has a current polarity limited to a direction from a negative-side DC line (N) to the resonance inductor (Lr).

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.