Prof. Ying-yu Tzou Digital Voltage Control Of Boost Crm Pfc Ac

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台灣新竹‧交通大學‧電機與控制工程研究所‧808實驗室 電源系統與晶片、數位電源、馬達控制驅動晶片、單晶片DSP/FPGA控制 Lab-808: Power Electronic Systems & Chips Lab., NCTU, Taiwan http://pemclab.cn.nctu.edu.tw/ Digital Voltage Control of Boost CRM PFC AC/DC Converters with TRIAC Phase Control Dimmer Prof. Ying-Yu Tzou Depart. of Electrical Engineering, National Chiao Tung Univ., Hsinchu, Taiwan Lab808: 電力電子系統與晶片實驗室 Power Electronic Systems & Chips, NCTU, TAIWAN LAB808 NCTU 台灣新竹•交通大學•電機與控制工程研究所 1/23 Contents      Introduction TRIAC Phase Control Dimming Method Digital Voltage Control Loop Design Simulation and Experimental Results Conclusion 2/23 TRIAC Dimming Control Circuit BRIGHT R 1  250 k vin (t ) DIM AC R 2  3.3 k vc TRIAC A DIAC G K ic C1  100 nF vtriac (t )  vin (t ) Delay  Basic TRIAC Dimmer The role of R1 to adjust the size of the capacitive current G(t ) Delay time of the decision by the C1 and (R1+R2) T  (R1  R2 )  C1 Line Voltage and Dimming Waveforms 3/23 TRIAC Dimmer Fired with Ideal Line Voltage in Different Load Conditions (a) resistive load (b) inductive load (c) capacitive load 4/23 LM3445 Triac Dimmable Offline LED Driver (NS) Features:  Triac dim decoder circuit for LED dimming  Application voltage range 80VAC – 270VAC  Capable of controlling LED currents greater than 1A  Adjustable switching frequency  Low quiescent current  Adaptive programmable off-time allows for constant ripple current  Thermal shutdown  No 120Hz flicker  Low profile 10 pin MSOP Package  Patent pending drive architecture Applications:     Retro Fit Triac Dimming Solid State Lighting Industrial and Commercial Lighting Residential Lighting 5/23 LT3799 Offline Isolated Flyback LED Controller with Active PFC 6/23 Digital vs. Analog PFC Controller IL Iin Vin Vin L C Vout Vin L Vin Vc-sam PWM Vc EA2 Viref Vp Vpwm Cvf Rvf Vv-sam Rvi MULT D S C A/D Kv  Rci Vc-sam Vin S Rcz Ccz Ki IL Iin D Vin A/D K K Vpwm(k )  Vpwm(k  1)  3 4 Vo (k ) K4 T  K3  K4 Vc  ( K4 )Vc (k  1) Viref MULT Vp  Vout A/D PWM Vpwm Vp (k)  Vp (k  1)  K1Vvsam( k)  (TK2  K1)Vvsam(k  1)  TK2Vvsam Vref Vv-sam Vref EA1 (a) Analog PFC Controller      (b) Digital PFC Controller Digital control provides flexibility for control algorithm realization Synchronous current sampling and feedback signal reconstruction Interleaved control for load current sharing Robust performance for line and load variations Efficient optimization across the entire load curves 7/23 Digital PFC Controller for LED Lighting Applications 85~265V 50~60 Hz Digital PFC controller Digital PWM Controller Digital Lighting Controller Digital PWM Controller 8/23 Proposed Digital Control Scheme for CRM Boost PFC Converters iL (t )  R1 R2 Conduction Angle  Vi [n] VZ , ref i Lb * (t ) Vcomp [n] vin (t ) R4 A/D S Q   D/A RL R Q isw (t ) i Lb * [n ] Vo Vo(t )    R3  Rs Dz  (t ) iin (t ) Co ZCD(t) A/D TRIAC DIMMING  Q RZCD   Vi (t ) io (t ) iQ Vi (t ) Cin LC LowPass Filter i D (t ) D L Voltage Loop Controller Vo[n] Verr [n ]  vref  9/23 Current Control Strategies for Boost PFC Converters iref Lf iL Vo D S iave Cf iL RL Peak Current Control iave high ref PFC Controller low ref Vr Variable Hysteresis Control TON iave iave Average Current Control Boundary Control Mode (CRM) 10/23 Comparison of PFC Technologies Small-Signal Modeling of Boost PFC Converters Z in (s ) Input Impedance of PFC Converter Z in (s ) Boost single-phase PFC converter with an inner current loop and an outer voltage loop. Small-signal model of the PFC converter Input Impedance In Consideration of Input Filter L TRIAC Dimmer vo D Vin(s) Q Vo Vm iL Input Impedance Z in' vg PFC Controller Iin(s) 1 sL L (s ) Hc (s) Rs Rl I ref (s) vo* Z in' ( s )  Z in ( s ) 1  ( C dc  C ac ) sZ in ( s ) Z in ( s )  Vin ( s ) R p( s)  s  Rs I in ( s ) gR l 1  s ( 1  )  z gR l L  n2 (a) The ringing input current greater than holding current of TRIAC (b) The ringing input current less than holding current of TRIAC. LC Filter with Damping Resistor Circuits Small-signal equivalent circuit of the boost PFC converter. I in (t ) Power Source + TRAIC Dimmer Rdamper LLPF + CLPF vin (t ) - I in (t ) Power + Source vtriac (t ) + TRAIC Dimmer FB + PFC L C Rdamper FB + PFC 14/23 Output Power as a Function of Conduction Angle Full power Dimming state T 2  ( degree ) (a) Full load and half load input voltage waveform. (b) Output power as a function of conduction angle.  The linear area of output power is from the conduction angle 30 degree to 150 degree.  When the conduction angle becomes smaller (<30°), the dc-link voltage can not maintain a constant value. And, this can be used for dimming control. 15/23 Dimming with Variable DC Link Voltage DC-link voltage as a function of conduction angle.   is the conduction angle, b is a parameter to adjust the drop slop.  The dc link voltage decrease from conduction angle 90 degree to 0 degree.  The minimum dc link voltage must greater than maximum input voltage, since the PFC is a boost circuit. 16/23 Modeling amd Control of the PFC Preregulator P(W) Control Signal (a) i1 Voltage Loop vo 3500 i1 Current Loop vo Current reference Multiplier C2 B X Sinusoidal waveform R2 vea R1 VREF vea Voltage Loop (b) (c) Vin  sin( t ) Sinusoid Vin  sin( t ) R AR    2 R1 1 fC  2  R2C2 Sinusoid 3000 2500 2000 fC=1kHz 1500 fC=500Hz 1000 fC=100Hz 500 0 10 20 30 40 50 60 70 80 90 100 AR Maximum power that complies with IEC 610003-2 regulations for different corner frequencies of the voltage regulator. Low-pass filter corner frequency Vea Current Reference V V ea  in  sin(  t ) k 4000 vea(t) Current Reference V ea  Vin  sin(  t ) k (a) Detail of the resistor emulator control scheme. (b) Ideal waveforms with no ripple on the error amplifier. (c) Real waveforms. 17/23 Frequency responses of the digital voltage loop gain Simulation Results of Steady-State Responses (a) no damping resistor. (b) with a 1 kΩ damping resistor. Simulation results of steady-state response of the input line current and the input voltage through the TRIAC dimmer with a rated load of 25 W. 19/23 Simulation Results of Transient Responses (a) Constant dc-link voltage. (b) Variable dc-link voltage. Simulation results of transient response of the output voltage for dimming time is 0.1s. Load changing from 25 W to 4 W 20/23 System Parameters and Experiment Setup PC Monitor DC power supply Emulator TMS320F2812 LEDs Load TRIAC FLYBACK Converter Interface Circuit AC In 21/23 Experimental results for the dimmable LED system with digital PFC control at different phase control angles. 50 45 40 (a)    150  O utp ut Po w er (W ) 35 30 25 20 15 10 5 Dimming Curve 0 0 (b)    90  20 40 60 80 100 120 140 160 180 Conductin Angle (degree) Output power as a function of phase conduction angle. (c)    30  22/23 Conclusion  Wide Dimming Control Range 5~100% Rated Power  No Flickering  Digital PFC Control Scheme for TRIAC Dimming Control  Passive Damping Technique to Reduce TRIAC Ringing  Variable DC-link Voltage Modulation Method  Experimental verification has been carried out on a DSP (TMS320F2812) controlled PFC CRM Converter. 23/23