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170results about How to "Eliminate leakage current" patented technology

Non-isolated single-phase photovoltaic grid-connected inverter and on-off control timing sequence thereof

The invention provides a non-isolated single-phase photovoltaic grid-connected inverter which is low in conduction loss and leakage current, and an on-off control timing sequence of the non-isolated single-phase photovoltaic grid-connected inverter. The photovoltaic grid-connected inverter comprises a voltage-dividing capacitor branch (1), a full-bridge basic unit (2), a clamping branch (3) and a follow current branch, which are connected with each other. According to the non-isolated single-phase photovoltaic grid-connected inverter and the on-off control timing sequence thereof disclosed by the invention, two controllable switch tubes and two diodes are additionally arranged on the basis of the single-phase full-bridge inverter circuit respectively to form a zero-level flow current branch; two diodes and a voltage-dividing capacitor are additionally arranged in the zero-level flow current branch to form a dual-direction clamping branch; the dual-direction clamping branch is matched with the on-off timing sequence to realize that common-mode voltage is the same constant voltage value at a power transmission stage, a dead zone stage and a flow current stage, so that leakage current of the non-isolated grid-connected inverter is removed. Moreover, the output current is enabled to only flow through two power tubes at the power transmission stage and the flow current stage, so that the conduction loss is the lowest.
Owner:SOUTHEAST UNIV

Method and device for inhibiting and eliminating leakage current of photovoltaic grid connection system without transformer

The invention relates to a method and a device for inhibiting and eliminating leakage current of a photovoltaic grid connection system without a transformer. The device is composed of a leakage current detector, a central controller and a waveform generator, wherein, the central controller is provided with a waveform analyzing circuit, a command current computing circuit and a current tracking control circuit; the waveform generator is provided with a drive circuit and a power module; the leakage current detector is arranged on the direct-current side of an inverter and is connected with the central controller; the central controller is used for analyzing and processing the leakage current waveform and generating compensatory current control signals; and the waveform generator is arrangedin a photovoltaic array and is connected with the output end of the current tracking control circuit of the central controller, and is used for injecting the corresponding compensatory current generated according to the command of the central controller into a photovoltaic system. In the invention, the compensating current the size of which is the same as that of the leakage current, and the phase position of which is opposite to that of the leakage current is generated through detecting, analyzing and processing the leakage current waveform. The compensating current is overlaid and offset with the leakage current after being injected with circuit, thus achieving the purpose of inhibiting and eliminating the leakage current; and the method and device provided by the invention has the characteristics of real-time monitoring, tracking, less dynamic compensation power consumption and smaller environment influence, can effectively inhibit and eliminate the leakage current, and has large application prospects and economic effect.
Owner:FUDAN UNIV

Zero current switching full-bridge type non-isolated photovoltaic grid-connected inverter

The invention provides a non-isolated photovoltaic grid-connected inverter and switch control timing sequence thereof, wherein the non-isolated photovoltaic grid-connected inverter enables high-frequency soft switching work to be achievable and is low in leakage current. The non-isolated photovoltaic grid-connected inverter comprises a voltage division capacitance branch (1), a high-frequency master switch unit (2), a resonance network (3), a clamping branch (4) and a low-frequency change-over switch unit (5). According to the non-isolated photovoltaic grid-connected inverter and the switch control timing sequence thereof, two controllable switching tubes, a diode and two groups of inductor and capacitor series branches are added to a one-phase six-switch full bridge inversion circuit (also know as 'H6' topology) to form the resonance network to provide the zero current switching work condition for the master switch unit, and therefore the soft switching work of high-frequency switching is achieved, and switching loss can be reduced greatly; common-mode voltage values at a power transmission stage, at a resonance stage and at a follow current stage are enabled to be identical and constant by matching with the switch control timing sequence, and therefore the leakage current of the non-isolated photovoltaic grid-connected inverter is eliminated; and high frequency of the non-isolated photovoltaic grid-connected inverter is achieved, and size, weight and cost of a grid-connected inverter can be reduced greatly.
Owner:SOUTHEAST UNIV

Switching-loss-free full-bridge non-isolated photovoltaic grid-connected inverter and on-off control timing sequence

The invention discloses a switching-loss-free full-bridge non-isolated photovoltaic grid-connected inverter and an on-off control timing sequence. The inverter comprises a voltage division capacitance branch, a high-frequency main switching unit, a resonant network and a low-frequency change-over switch unit. Two sets of zero-current switching branches composed of the resonant network composed of full control switches, resonant capacitors and resonant inductors and auxiliary follow current clamping diodes are added, the on-off control timing sequence is matched, the zero-current turning-on and zero-current turning-off conditions of a fifth power switch tube S5 and a sixth power switch tube S6 can be achieved, the zero-current turning-on and zero-current turning-off conditions of a fifth auxiliary power switch tube Sa5 and a sixth auxiliary power switch tube Sa6 can be achieved, the reverse restoration of low-frequency change-over switch unit diodes D1-D4 can be eliminated, it is guaranteed that the common-mode voltage of the inverter is constantly one second of a battery voltage in the power transmission process, the resonance period and the follow current stage to eliminate leak currents, and therefore high frequency and minimization of the non-isolated photovoltaic grid-connected inverter can be achieved.
Owner:SOUTHEAST UNIV

High temperature pressure sensor and process method thereof

The invention discloses a high temperature pressure sensor and a process method thereof, the pressure sensor comprises a silicon-sensitive diaphragm, a pedestal and a TO tube case, wherein a SOI monocrystalline silicon wafer is used as a substrate of the silicon-sensitive diaphragm. A wheatstone bridge is formed by resistance processing and leading wire interconnection in a device layer, and a diaphragm structure which is sensitive to pressure is formed by conducting anisotropy corrosion at a substrate layer. Anodic bonding or silicon-silicon direct bonding or silicon-silicon medium bonding is conducted by the pedestal and the silicon-sensitive diaphragm, wherein the glass sheet or the monocrystalline silicon wafer is used as a substrate of the pedestal. Chip scale package is achieved by using the TO metal tube case for a shell. The high temperature pressure sensor and the process method thereof use a buried oxide layer of the SOI monocrystalline silicon wafer and an illuvial silicon dioxide/silicon nitride passivation layer to wrap and isolate a silicon resistor, and leakage current at high temperature is eliminated. A high temperature ohmic contact electrode structure of multiple layers of silicon dioxide/titanium/ silicon dioxide/ platinum/gold is grown in a spurting mode. Through high temperature resistance bonding and TO packaging technology, the working stability at high temperature is improved. The problem that long term working is difficult to conduct in a high temperature environment by a traditional silicon substrate sensor is solved.
Owner:PEKING UNIV

Zero-voltage transition full-bridge non-isolated photovoltaic grid-connected inverter

The invention provides a non-isolated photovoltaic grid-connected inverter capable of performing high-frequency soft switching operation, with low leakage current, and a switching control time sequence thereof. The non-isolated photovoltaic grid-connected inverter comprises voltage-dividing capacitance branch (1), a high-frequency main switch unit (2), a resonance network (3), a clamping branch (4) and a low-frequency reversing switching unit (5). The non-isolated photovoltaic grid-connected inverter has the advantages that two controllable switching tubes, a diode and two inductance-capacitance branches are respectively added on the basis of a single-phase six-switch full-bridge inverter circuit (known as 'H6' topology) to form the resonance network to provide zero-voltage switching operating conditions for the main switch unit, the soft switching operation of a high-frequency switch is realized, and the switch loss can be greatly reduced; common mode voltage can also be ensured to be a constant voltage value at a power transmission stage, a resonance stage and a continuous current stage through the switching time sequence, so that the leakage current of the non-isolated grid-connected inverter is eliminated; and the non-isolated photovoltaic grid-connected inverter can realize high frequency, and is beneficial to greatly reducing the volume, the weight and the cost.
Owner:SOUTHEAST UNIV

Complementary metal oxide semiconductor (CMOS) input/output interface circuit

The invention discloses a complementary metal oxide semiconductor (CMOS) input/output interface circuit. The CMOS input/output interface circuit comprises a first N-channel metal oxide semiconductor (NMOS) transistor, a second P-channel metal oxide semiconductor (PMOS) transistor, a third NMOS transistor, a fourth PMOS transistor, a fifth NMOS transistor, a resistor and a sixth PMOS transistor, wherein the grid electrode of the first NMOS transistor is connected with a power supply through the resistor; the source electrode of the first NMOS transistor is connected with a pin; the drain electrode of the first NMOS transistor is connected with the grid electrode of the second PMOS transistor and the grid electrode of the third NMOS transistor; the drain electrode of the second PMOS transistor is connected with the power supply; the source electrode of the third NMOS transistor is grounded; the source electrode of the second PMOS transistor and the drain electrode of the third NMOS transistor are connected with the grid electrode of the fourth PMOS transistor and the grid electrode of the fifth NMOS transistor; the drain electrode of the fourth PMOS transistor is connected with the power supply; the source electrode of the fifth NMOS transistor is grounded; the source electrode of the fourth PMOS transistor and the drain electrode of the fifth NMOS transistor are connected with an internal circuit; the grid electrode of the sixth PMOS transistor is connected with the source electrode of the second PMOS transistor and the drain electrode of the third NMOS transistor; the drain electrode of the sixth PMOS transistor is connected with the grid electrode of the second PMOS transistor and the grid electrode of the third NMOS transistor; and the source electrode of the sixth PMOS transistor is connected with the power supply. The CMOS input/output interface circuit can effectively avoid the generation of leakage current.
Owner:SHANGHAI HUA HONG NEC ELECTRONICS

Non-isolated photovoltaic grid-connected inverter and control method thereof

The invention discloses a non-isolated photovoltaic grid-connected inverter and a control method thereof and belongs to the technical field of power electronics converters. The inverter comprises a power supply circuit (10), a high-frequency chopper circuit (20) and a low frequency inverter circuit (30), wherein the power supply circuit (10) is formed by a photovoltaic array and an input filter capacitor, the high-frequency chopper circuit (20) is formed by a first to a second power switch tube, a first diode and a first to a second filter inductor, the low frequency inverter circuit comprises a third, a fourth, a fifth and a sixth power switch tube, the first power switch tube and the second power switch tube are high frequency switches, and the third power switch tube, the fourth power switch tube, the fifth power switch tube and the sixth power switch tube are low frequency switches. The non-isolated photovoltaic grid-connected inverter and the control method thereof have the advantages that leakage current of the grid-connected inverter can be eliminated, grid-connected current waveforms qualities are improved, simultaneously the efficiency is high, the controlling is simple, the reliability is high and the like.
Owner:SHANGHAI CONVERTERGY ENERGY TECH
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