开关电源发展与压电材料应用展望.ppt

TRANSONER Overview. Piezoelectric transformers for CCFL backlighting,Face Electronics, LC., Virginia, USA,December 5, 2001,Dr. Alfredo Vzquez Carazo,427 W. 35th St. Norfolk, VA USA Phone: 757.624.2121 Fax: 757.624.2128 ,Charlie Elliott, Pulse Engineering,Piezoelectric Transformers,Transformers for CCFL backlighting,Piezoelectricity: Basic concepts,Piezoelectric Transformers,Rosen-type Piezoelectric Transformers,Technical literature refers the name of PIEZOTRANSFORMER to the device which was initially developed for Charles A. Rosen and Keith Fish (1954).,Source: Thesis Alfredo Vazquez,Background on Piezoelectric Transformers,Piezoelectric Transformers,Background on Piezoelectric Transformers,Piezoelectric Transformers,Types of Rosen-piezoelectric transformers,Piezoelectric Transformers,Family Photos,Background on Piezoelectric Transformers (PTs),Background on Piezoelectric Transformers,Piezoelectric Transformers,What was wrong with “those” Piezo-trafos,Material,Driving Circuitry,Manufacturing Process,Mounting,PZT-Material under development (1954) (low Q, high dielectric losses, low coupling coef.).,High Sintering Materials Expensive No tape-casting techniques Limit on sizes Double Polarization Process no optimized,Reliable housing techniques under development,Electronic circuit based on discrete components,Limited POWER CAPABILITIES ( 5 W/cm3),Power,High immunity to external EMI, low profile, compact,Background on Piezoelectric Transformers,Piezoelectric Transformers,How do they operate?. Resonance,fR,fA,Background on Piezoelectric Transformers,Piezoelectric Transformers,/2 mode,3/2 mode,Piezoelectric Transformers,Features: Simple construction without windings No winding shorts during operation No magnetic field involve in the operation (reduced RF and EMI) Low profile High efficiency Non-flammable 98% Typical Efficiency No High Voltage “Corona Effect” Pure Sine Wave Output (Minor Distortion) Surface Temperature raising T 35K due to their excellent thermal dissipation behavior.,Piezoelectric vs. Magnetic,5W,50W,100W,220W,1kV,10V,5kV,10,kV,Power Delivery W,Output,Voltage Vp,T6,T1,T3,USA 1998,TRANSONER,TECHNOLOGY,(Face Inter. Corp),New Piezo-Trafo technologies,Piezoelectric Transformers,T3-HV Transoner,CONSTRUCTION,COUPLING AREA,POLING DIRECTION,STRESS DIRECTION (LONGITUDINAL vs. RADIAL+SHEAR),Piezoelectric Transformers,Rosen vs. Transoner,Input Part,Output Part,k33 + k31,k33 + k31 + k15,K15 3.k31,Piezoelectric Transformers,Rosen vs. Transoner,TRANSONER ADVANTAGES Simple achievement of ISOLATION capabilities 35 kV by adding a isolation layer The stack concept allows a LARGER MECHANICAL COUPLING AREA and thus a higher power density INPUT AND INPUT CAPACITANCES can be independently designed without having the same thickness. Larger step-up ratios As a result SMALLER SIZES and more compact and efficient inverter can be developed,Rosen-type,Transoner-type,ELECTRICAL ENERGY,Voltage, current,ELECTRICAL ENERGY,Voltage, current,Transoner: Types and specifications,Piezoelectric Transformers,Patent Notice: Technology disclosed on this page covered by one or more issued or pending U.S. and International patents owned by face International Corporation, Norfolk, Virginia, USA.,T1-Type Transoner Large Power Step-up and Step-down Medium, low impedance loads 200-1k (Linear fluorescent),T3-Type Transoner Medium-low Power (5-8W) Very high Step-up (200) Large impedance loads 50k -300k (CCFL),MiniT1 Transoner Mini-size (5mm2 x 1mm) Step-up Mediumimpedance loads 200-1k (PDA, CellPhones),Transoner: Types and specifications,Piezoelectric Transformers,Typical High Voltage Transoner Type-3 Devices,Specifications,Type T3: High Voltage Transoner,Transoner: Types and specifications,Piezoelectric Transformers,Operation Point: Maximum Efficiency,Approach to the Operation Principle,Piezoelectric Transformers,General Behavior,Approach to the Operation Principle,Piezoelectric Transformers,Load Dependence: CCFL starting up and Continuous operation,Approach to the Operation Principle,Piezoelectric Transformers,General principle for driving a piezoelectric resonant transformer,General Block Diagram,Piezoelectric Transformers,Driving Circuitry for Piezoelectric Transformers,Piezo-Trafo Equivalent Circuit,C = Equivalent Stiffness R = Equivalent Mechanical Resistance L = Equivalent mass,Piezoelectric Transformers,Driving Circuitry for Piezoelectric Transformers,Piezoelectric transformer input sections are characterized by a shunt input capacitance which may exceed tens of nano-farads.,Two ways to drive a Piezoelectric Transformer,Square-wave signal: PWM converters,Sine-wave signal: Resonant converters,Large harmonic contents (Input drive harmonics may be rejected by the high-Q transformer thereby reducing drive efficiency. Drive harmonics can excite spurious modes in the PT which will be difficult to suppress. The circulating energy through the shunt input capacitance Cd1 characteristic of the input section of PT generate dielectric losses (turn-on losses).,Zero Voltage Switching Technique: use a square switching signal with ZVS technique to minimize switching losses.,DC-AC Driving Circuit Techniques,Piezoelectric Transformers,Driving Circuitry for Piezoelectric Transformers,Class-E DC/AC converter,Half-bridge DC/AC converter,Full-bridge DC/AC converter,Piezoelectric Transformers,Driving Circuitry for Piezoelectric Transformers,Push-pull DC/AC co