Patents
Literature
Hiro is an intelligent assistant for R&D personnel, combined with Patent DNA, to facilitate innovative research.
Hiro

32results about How to "Strong boosting ability" patented technology

Booster circuit

Each boosting cell includes: a first n-transistor having a diode connection; a second n-transistor whose gate and drain are connected to a power supply voltage and whose source is connected to the source of the first n-transistor; and a boosting capacitor provided between the drain of the first n-transistor and a boosting clock input terminal to which a clock signal is input. The boosting capacitor is connected to n auxiliary boosting capacitors in parallel via connection switching circuits controlled with boosting ability switching signals as control signals input from the outside.
Owner:NORTH PLATE SEMICON LLC

Multi-stage single switch boost converter

The invention relates to the field of power electronics, in particular to a multi-stage single switch boost converter which is composed of a Boost circuit and a plurality of Switch-Capacitor networks. Voltages supplied by all the Switch-Capacitor networks are equal. Accumulation of the network voltages is achieved in an interleaving series connection mode, an output voltage is boosted, and the capacity of boosting is high. The converter is provided with only one active switch element, a control circuit is simple, and voltage stress of a switching tube is small and 1 / (1-D) times that of an input voltage. Capacitor voltages of all the Switch-Capacitor networks are equal and 1 / (1-D) times that of the input voltage, stress of the capacitor voltages is small, therefore, the size of the circuit is reduced, and integration is easy.
Owner:CHONGQING UNIV

Cascaded DC/DC converter for asymmetric boost unit of photovoltaic system

The invention discloses a cascaded DC / DC converter for an asymmetric boost unit of a photovoltaic system, which comprises an input power supply Vin, wherein a positive electrode of the input power supply Vin is connected with one end of an inductor L1, the other end of the inductor L1 is connected with an anode of a free-wheeling diode D1 and an anode of a free-wheeling diode D2, a cathode of thefree-wheeling diode D1 is connected with one end of an inductor L2, one end of a capacitor C1 and one end of a capacitor C2, the other end of the inductor L2 is connected with an anode of a free-wheeling diode D4, one end of a capacitor C3, a cathode of the free-wheeling diode D2 and a drain electrode of a switching tube S, the other end of the capacitor C2 is connected with a cathode of the free-wheeling diode D4 and an anode of a free-wheeling diode D3, the other end of the capacitor C3 is connected with a cathode of the free-wheeling diode D3 and an anode of an output rectifying diode Do,a cathode of the output rectifying diode Do is connected with one end of an output capacitor Co and one end of a load resistor R, and the other end of the output capacitor Co, the other end of the load resistor R, a source electrode of the switching tube S and the other end of the capacitor C1 are connected with a negative electrode of the input power supply Vin. The cascaded DC / DC converter can improve the efficiency and the gain ratio.
Owner:SOUTHEAST UNIV

Three-port flyback photovoltaic grid-connected micro-inverter with power decoupling circuit, and modulation method

The invention discloses a three-port flyback photovoltaic grid-connected micro-inverter with a power decoupling circuit, and a modulation method. The three-port flyback photovoltaic grid-connected micro-inverter comprises a three-port flyback conversion circuit, a full-bridge inverter circuit and an output filtering circuit, wherein a set of primary windings of the three-port flyback conversion circuit is connected with the novel power decoupling circuit to form a third port for realizing power decoupling, thereby effectively suppressing low frequency fluctuations on a DC bus and reducing thecapacitance of a decoupling capacitor, therefore, a thin film capacitor with long life and low capacitance is used instead of an electrolytic capacitor in the prior art. The three-port flyback photovoltaic grid-connected micro-inverter has the advantages of ensuring the life and reliability of the inverter, facilitating the realization of maximum power point tracking (MPPT), and improving the conversion efficiency of the inverter; meanwhile, the proposed decoupling circuit has simple structure, and only uses a switching tube and a capacitor, thereby reducing the cost and size of the inverter.
Owner:JIANGSU UNIV

Multi-input boost converter based on Switch-Capacitor networks

The invention discloses a multi-input boost converter based on Switch-Capacitor networks. The multi-input boost converter is mainly formed by connecting multiple Switch-Capacitor networks in parallel, the capacitor voltages in all the Switch-Capacitor networks are equal, and a larger output voltage is achieved through the mode of accumulating multiple network capacitor voltages. The multi-input boost converter is used for replacing multiple single-input boost converters. The multi-input boost converter allows the input of multiple energy sources, the properties, the amplitude values and the characters of input sources can be identical and can also be very different, the input sources can supply power to loads respectively or simultaneously, and therefore the stability and the flexibility of a system are improved, the preferential utilization of the energy sources is achieved, and system cost is lowered.
Owner:CHONGQING UNIV

Variable-structure multi-input high-gain direct-current converter

The invention aims to provide the circuit topology of a variable-structure multi-input high-gain direct-current converter. By means of the variable-structure multi-input high-gain direct-current converter, combined power generation of various renewable energy sources can be realized, high gain generated during independent solar power generation at a low voltage level can also be realized, and the cost and the complexity of a system are not increased at the same time.
Owner:CHONGQING UNIV +1

Secondary DC-DC converter of asymmetrical voltage boosting unit of fuel cell system

The invention discloses a secondary DC-DC converter of an asymmetrical voltage boosting unit of a fuel cell system. The converter comprises an input power supply V<in>; the positive electrode of the input power supply V<in> is connected with one end of an inductor L1 and the positive electrode of a fly-wheel diode D3; the other end of the inductor L1 is connected with the positive electrode of a fly-wheel diode D2 and one end of a capacitor C2 separately; the other end of the capacitor C2 is connected with the positive electrode of a fly-wheel diode D1 and the negative electrode of the fly-wheel diode D3 separately; the negative electrode of the fly-wheel diode D1 is connected with one end of an inductor L2, one end of a capacitor C1 and one end of a capacitor C4 separately; and the otherend of the inductor L2 is connected with the positive electrode of a fly-wheel diode D4, one end of a capacitor C3, the negative electrode of the fly-wheel diode D2 and the drain of a switching tube Sseparately.
Owner:SOUTHEAST UNIV

A kind of high step-up dc/dc converter

The invention provides a high voltage rise DC / DC converter. The high voltage rise DC / DC converter can convert a low voltage direct current into a high voltage direct current, can achieve soft switching, and has high work efficiency. The high pressure rise DC / DC converter comprises two portions which are respectively a boost circuit unit and a voltage rise unit. The boost circuit unit is composed of two power switches S1 and S2, and a primary side L 1 of a coupling inductor. A subsidiary side L 2 of the coupling inductor, a capacitor c and a diode D form the voltage rise unit of the high voltage rise DC / DC converter. The voltage rise unit is equivalent to a controllable direct current voltage source, and voltage of the voltage rise unit is related to turn ratios N of the subsidiary side and the primary side of the coupling inductor, and the duty ratio D of a switching tube S1. Compared with an existing high voltage rise DC / DC converter, the high voltage rise DC / DC converter is high in voltage gain, low in voltage stress of devices, and high in efficiency.
Owner:CHONGQING UNIV

O-Z source photovoltaic grid-connected inverter

The invention provides an O-Z source photovoltaic grid-connected inverter which comprises the components of a photovoltaic array module which serves as a power supply; an O-Z source network connectedwith the photovoltaic array module and provided with a power diode, a coupling inductance coil and an energy storage capacitor; an inverter bridge connected with the O-Z source network and connected with the negative electrode of the photovoltaic array module; a filter circuit connected with the inverter bridge; and a power grid, wherein the power grid is connected to the filter circuit. The powerdiode is provided with an anode and a cathode, the anode is connected with the anode of the photovoltaic array module, the coupling inductance coil is provided with an N1-side coil and an N2-side coil, the dotted terminal of the N1-side coil is connected with the cathode of the power diode, the energy storage capacitor is provided with an anode and a cathode, the anode is connected with the anodeof the photovoltaic array module, the cathode is connected with the dotted terminal of the N2 side coil, and the synonym terminal of the N1 side coil and the synonym terminal of the N2 side coil areconnected with the inverter bridge.
Owner:UNIV OF SHANGHAI FOR SCI & TECH

High-gain converter for photovoltaic direct-current module and control method of high-gain converter

The invention belongs to the technical field of converters, and discloses a high-gain converter for a photovoltaic direct-current module and a control method of the high-gain converter. The positive electrode of an input filter capacitor of the converter is connected with one end of a first inductor and one end of a second inductor; the other end of the first inductor is connected with the drain electrode of the first switch tube and the positive electrode of the first capacitor; the other end of the second inductor is connected with the drain electrode of the second switch tube, the anode of the second diode and the cathode of the second capacitor; the source electrode of the second switch tube is connected with the cathode of the first capacitor and the anode of the first diode; the cathode of the second diode is connected with one end of the third inductor and the anode of the third capacitor; the other end of the third inductor is connected with the anode of the third diode and the anode of the second capacitor; and the cathode of the third diode D3 is connected with the anode of the output filter capacitor. The high-gain converter has the advantages of being high in boosting capacity, few in power tubes, small in input current ripple and the like.
Owner:NANTONG UNIVERSITY

Multistage direct current circuit with controllable voltage

The invention discloses a multistage direct current circuit with controllable voltage and belongs to the technical field of power electronics. The multistage direct current circuit with controllable voltage comprises a rectifying circuit and an inverter circuit, wherein the rectifying circuit is composed of six rectifying units and a follow current unit, the six rectifying units are sequentially connected in series and based on reverse conducting switches, two paths of alternating current square wave voltages are input into the rectifying circuit, and a path of direct current voltage is output by the rectifying circuit. The direct current voltage is input into the inverter circuit, two paths of alternating current voltages with adjustable frequencies are output through a high frequency isolation transformer, and power is supplied to the rectifying circuit at the following stage. The multistage direct current circuit with controllable voltage has the boost function and the electrical isolation function, the more the number of stages is, the higher the class of the output direct current voltage is, and the multistage direct current circuit with controllable voltage has the advantages of high in boost performance, simple in structure, low in cost, high in power level and the like.
Owner:上海寰晟新能源科技有限公司

A three-port converter with soft switching capability and its control method

The invention belongs to the technical field of converter control, and discloses a three-port converter with soft switching capability. The converter includes two switch tubes, three capacitors, two diodes and two inductors. It can realize the flexible control of the power flow between the three ports, and can realize the zero-voltage turn-on of all switch tubes and the natural turn-off of all diodes. All power tubes are under low voltage stress, which effectively improves the off-grid photovoltaic system. Integration and conversion efficiency of power generation system. The invention also discloses the control method of the converter. The first inductance is designed to work in the current discontinuous mode, and the frequency conversion control is adopted to realize load constant voltage control; the second inductance is designed to work in the current bidirectional continuous conduction mode, and the variable duty ratio is adopted. Realize maximum power point tracking control of photovoltaic modules.
Owner:NANTONG UNIVERSITY

Three-port converter with high boosting capability and control method thereof

The invention belongs to the technical field of converter control, and discloses a three-port converter with high boosting capability, which comprises two switching tubes, three capacitors, two diodes and two inductors. The three-port converter has high boost capability, can realize flexible control of power flow among three ports, and can realize zero-voltage turn-on of all switching tubes and natural turn-off of a diode D1, all power tubes bear low voltage stress, and the integration level and conversion efficiency of the off-grid photovoltaic power generation system are effectively improved. The invention further discloses a control method of the converter, a first inductor is controlled to work in a current bidirectional continuous conduction mode, and the maximum power point tracking control of the photovoltaic module is realized by adopting a variable duty ratio; and a second inductor is controlled to work in a current discontinuous mode, and the load constant-voltage control is realized by adopting variable-frequency control.
Owner:NANTONG UNIVERSITY

Single-phase high-gain photovoltaic grid-connected inverter with continuous input current and control method

The invention discloses a single-phase high-gain photovoltaic grid-connected inverter with continuous input current and a control method. The inverter includes a boost circuit and a full-bridge inverter circuit. The boost circuit includes a first boost inductor L 1 , the second boost inductor L 2 , the first boost capacitor C 1 , the second boost capacitor C 2 and the first boost diode D 1 . Inductance L 1 One end of the diode D 1 The anode, capacitor C 2 connected to the cathode of the diode D 1 The cathode and capacitance C 1 positive pole, inductance L 2 connected at one end. The full-bridge inverter circuit includes a switch tube S 1 ‑S 4 , switch tube S 1 and S 2 connected in series to form the first bridge arm circuit, the switch tube S 3 and S 4 The second bridge arm circuit is formed in series, and the two bridge arm circuits are connected in parallel. The present invention realizes the high-gain step-up inverter under the condition of low duty ratio, and has the advantages of continuous input current, adapting to wide-ranging input voltage changes, high conversion efficiency, low capacitor voltage stress, simple structure, and low cost. It is especially suitable for small and medium power distributed photovoltaic grid-connected power generation systems.
Owner:NANTONG UNIVERSITY

Active Coupled Inductor Network Boost Converter

The invention provides an active coupling inductance network boost converter, and relates to the field of power electronic converters. The active coupling inductance network boost converter solves the problems that according to an existing boost converter of an active coupling inductance network structure, the number of conversion devices is large, the boost multiple is small, the conversion efficiency is low, the power density is large, and the voltage stress of a main power switch tube is low. According to the active coupling inductance network boost converter, the input end of an X-type active coupling inductance network is connected with a direct current voltage source, the output end of the X-type active coupling inductance network is connected with diodes and smoothing capacitors, and a passive lossless clamping circuit is inserted into the X-type active coupling inductance network. The active coupling inductance network boost converter can be applied to occasions of new energy power generation, fuel cells and the like.
Owner:HARBIN INST OF TECH

Passive rectifier circuit

The invention discloses a passive rectification circuit in the technical field of power electronics, which includes an AC power supply and a rectification circuit. The AC power supply includes a first voltage source and a second voltage source, both of which share a ground; the rectification circuit is composed of The cascaded at least one rectifier unit and one freewheeling unit input a two-phase AC voltage to generate a high-voltage DC voltage to supply the load of the subsequent stage. The invention has a rectification function, can generate a high-amplitude direct-current voltage, and the more stages there are, the higher the output direct-current voltage level is, and has the advantages of strong boosting capability, simple structure, low cost and the like.
Owner:SHANGHAI JIAOTONG UNIV

Three-inductor high-gain Boost converter

The invention discloses a three-inductor high-gain Boost converter. The anode of a direct-current power supply of the converter is connected with an anode of an input filter capacitor, one end of a first inductor, an anode of a second diode and an anode of a fourth diode; the other end of the first inductor is connected with the anode of a first diode and the cathode of a first capacitor; the cathode of the first diode is connected with one end of a second inductor and the cathode of the second diode; the other end of the second inductor is connected with the anode of a third diode and the cathode of a second capacitor ; the anode of the second capacitor is connected with the cathode of a fourth diode and one end of an third inductor; the other end of the third inductor is connected with the anode of the first capacitor, the cathode of the third diode, the anode of a fifth diode and the drain of a switching tube; the cathode of the fifth diode is connected with the anode of an output filter capacitor and one end of a direct-current load; and the other end of the direct-current load is connected with thecathode of the output filter capacitor, the source of the switching tube, the cathode of an input filter capacitor and the cathode of an input power supply.
Owner:JIANGSU UNIV

Non-isolated high-gain direct-current converter

The invention discloses a non-isolated high-gain direct current converter. A direct current power supply anode of the converter is connected with the anode of an input filter capacitor, one end of a first inductor and the anode of a third diode; the other end of the first inductor is connected with the anode of a first diode and the anode of a second diode; the cathode of the second diode is connected with one end of a second inductor and the cathode of the third diode; the other end of the second inductor is connected with the anode of a fourth diode and the anode of a fifth diode; the cathode of the fifth diode is connected with the anode of a first capacitor and one end of a third inductor; the other end of the third inductor is connected with the cathode of the first diode, the cathode of the fourth diode, the anode of a sixth diode and the drain of a switching tube; the cathode of the sixth diode is connected with the anode of an output filter capacitor and one end of a direct-current load; and the other end of the direct-current load is connected with the cathode of the output filter capacitor the source electrode of the switching tube, the cathode of the first capacitor, the cathode of the input filter capacitor and the cathode of an input power supply. The converter has the advantages of strong boost capability and low current stress.
Owner:JIANGSU UNIV

Passive rectifying circuit

The invention discloses a passive rectifying circuit in the technical field of power electronics. The passive rectifying circuit comprises an alternating current power source and a rectifying circuit body. The alternating current power source comprises a first voltage source and a second voltage source which are based on the same benchmark. The rectifying circuit body is composed of at least one rectifying unit and a flow current unit which are cascaded in sequence, and the two-phase alternating voltage is input to produce the high-voltage direct voltage to be used by a backward stage load. The passive rectifying circuit has the function of rectifying, the high-amplitude direct voltage can be produced, the more the number of series is, the higher the class of the direct voltage becomes, and the passive rectifying circuit has the advantages of being strong in boosting capacity, simple in structure, low in cost and the like.
Owner:SHANGHAI JIAO TONG UNIV

A non-isolated high-gain DC converter

The invention discloses a non-isolated high-gain DC converter. The positive pole of the DC power supply of the converter is connected to the positive pole of the input filter capacitor, one end of the first inductor, and the anode of the third diode; the other end of the first inductor is connected to the anode of the first diode and the anode of the second diode; The cathode of the tube is connected to one end of the second inductance and the cathode of the third diode; the other end of the second inductance is connected to the anode of the fourth diode and the anode of the fifth diode; the cathode of the fifth diode is connected to the anode of the first capacitor and the anode of the first capacitor One end of the three inductors is connected; the other end of the third inductor is connected to the cathode of the first diode, the cathode of the fourth diode, the anode of the sixth diode, and the drain of the switch tube; the cathode of the sixth diode is connected to the positive electrode of the output filter capacitor, One end of the DC load is connected; the other end of the DC load is connected to the negative pole of the output filter capacitor, the source of the switch tube, the negative pole of the first capacitor, the negative pole of the input filter capacitor, and the negative pole of the input power supply, with strong boosting capability and low current stress.
Owner:JIANGSU UNIV

A multi-temperature zone and large temperature cross-span heat pump circulation system using ejector efficiency

The invention discloses a multi-temperature-zone large-temperature-span heat pump circulating system adopting an injector for efficiency improvement. The multi-temperature-zone large-temperature-spanheat pump circulating system comprises a compressor with a middle air extraction function, series compressors and parallel compressors; a first condenser is used for heating of a low-temperature zone,and an inlet is connected with an air extraction opening of the compressor; a second condenser is used for heating of a high-temperature zone, and an inlet is connected with an air exhaust opening ofthe compressor; a high-pressure side inlet of a reheater is connected with an outlet of the first condenser, and a high-pressure side outlet of the reheater is connected with a throttling device; aninlet of a first evaporator is connected with an outlet of the throttling device, and an outlet of the first evaporator is connected with a secondary flowing inlet of the injector; an inlet of a second evaporator is connected with an outlet of the injector, and an outlet of the second evaporator is connected with a low-pressure side inlet of the reheater; and a nozzle inlet of the injector is connected with an outlet of the second condenser, and an outlet of the injector is connected with the inlet of the second evaporator. The circulating system can effectively utilize the middle air extraction function of the compressor to achieve double condensing pressure and condensing temperature and provide double temperature zones and large-temperature-difference heat supply, irreversible losses ofheat transfer of the evaporators can be decreased, and the whole performance of the system can be effectively improved.
Owner:XI AN JIAOTONG UNIV

Current-type DC-AC converter for driving low-input-voltage motor and soft switching control thereof

The invention discloses a current type DC-AC converter for driving a low-input-voltage motor. The current type DC-AC converter is formed by sequentially cascading a DC power supply, a high-gain buck-boost chopper circuit with a ZVS active clamp, an m-phase current type inverter circuit (m is a positive integer) and an output filter circuit. The DC power supply firstly passes through the high-gain buck-boost chopper circuit and then outputs high-frequency PWM current pulse waves, and then passes through the m-phase current type inverter circuit and the output filter circuit to obtain high-quality AC voltages. The high-gain buck-boost chopper circuit with the ZVS active clamp can work in a boost mode or a buck mode according to different output AC voltages, and an energy storage switch S can realize zero-voltage turn-on by controlling the turn-on time of an active clamp branch switch SC. The converter has the characteristics of single-stage boost inversion, high boost capability, wide output voltage regulation range, high conversion efficiency, high power density, small common-mode current and the like, and has a good application prospect in a low-input-voltage motor driving occasion.
Owner:QINGDAO UNIV

Novel capacitor energy storage isolation type single-stage four-quadrant inverter

The invention relates to a novel capacitor energy storage isolation type single-stage four-quadrant inverter, and belongs to an inverter in an electric energy conversion device. The adopted high-frequency transformer has the functions of boosting and electrical isolation; the primary side adopts an active clamping circuit to reduce the switching loss of a switching tube; the secondary side of the transformer adopts a full-bridge hybrid modulation inverter circuit, and a bus energy storage capacitor is connected in series with a switching tube, so that excess energy is prevented from being fed back to a primary side direct current bus side, the energy conversion stage number is reduced, energy is stored in the bus energy storage capacitor, and energy balance of the energy storage capacitor is realized in each power frequency period. Therefore, the function of four-quadrant operation is realized, the efficiency of the inverter is improved, and the size of the inverter is reduced.
Owner:NORTHWESTERN POLYTECHNICAL UNIV

Novel impedance source direct-drive permanent magnet wind power generation system and control method thereof

The invention discloses a novel impedance source direct-drive permanent magnet wind power generation system and a control method thereof. The impedance source direct-drive permanent magnet wind powergeneration system comprises fan blades, a permanent magnet synchronous generator, a three-phase uncontrollable rectifier, an impedance source network, a three-phase six-switch inverter bridge arm, a filtering inductor and a controller. The control method is characterized in that impedance source network inductive currents iL1, impedance source network capacitor voltage VC2, the position angle theta r and rotation speed omega r of the permanent magnet synchronous generator, three-phase grid connection voltage ega, egb and egc and three-phase grid connection currents ia, ib and ic are sampled, and permanent magnet synchronous generator rotation speed stability, impedance source network capacitor voltage stability and grid connection power factor control can be achieved by one controller. Bythe novel impedance source direct-drive permanent magnet wind power generation system and the control method thereof, effective grid connection under large wind speed change can be achieved, device voltage stress can be lowered, and accordingly system reliability can be increased, and cost can be lowered.
Owner:HUNAN UNIV OF TECH

Voltage Controllable Multilevel DC Circuit

The invention discloses a multistage direct current circuit with controllable voltage and belongs to the technical field of power electronics. The multistage direct current circuit with controllable voltage comprises a rectifying circuit and an inverter circuit, wherein the rectifying circuit is composed of six rectifying units and a follow current unit, the six rectifying units are sequentially connected in series and based on reverse conducting switches, two paths of alternating current square wave voltages are input into the rectifying circuit, and a path of direct current voltage is output by the rectifying circuit. The direct current voltage is input into the inverter circuit, two paths of alternating current voltages with adjustable frequencies are output through a high frequency isolation transformer, and power is supplied to the rectifying circuit at the following stage. The multistage direct current circuit with controllable voltage has the boost function and the electrical isolation function, the more the number of stages is, the higher the class of the output direct current voltage is, and the multistage direct current circuit with controllable voltage has the advantages of high in boost performance, simple in structure, low in cost, high in power level and the like.
Owner:上海寰晟新能源科技有限公司

Low voltage stress and low input current ripple high gain converter and control method

In the converter disclosed by the invention, the positive pole of the DC power supply is connected to the positive pole of the input filter capacitor and one end of the first and third inductors; the other end of the first inductor is connected to the drain of the first switch tube, the anode of the first diode, and the negative pole of the first capacitor; The other end of the three inductors is connected to the drain of the second switch tube, the anode of the second diode, and the cathode of the second capacitor; the anode of the first capacitor is connected to the anode of the third diode and one end of the second inductor; the cathode of the third diode is connected to the first The anode of the output filter capacitor and one end of the DC load; the cathode of the first output filter capacitor is connected to the other end of the second inductor, the cathode of the fourth diode, and the anode of the second output filter capacitor; the anode of the second capacitor is connected to the anode of the fourth diode and the anode of the fourth diode. One end of the inductor; the negative electrode of the second output filter capacitor is connected to the other end of the fourth inductor, the positive electrode of the third output filter capacitor, and the cathodes of the first and second diodes; the other end of the DC load is connected to the negative electrode of the input filter capacitor, the negative electrode of the third output filter capacitor, the first and second diodes The source of the two switch tubes and the negative pole of the DC power supply.
Owner:NANTONG UNIVERSITY
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Patsnap Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Patsnap Eureka Blog
Learn More
PatSnap group products