DESULFATOR * LOW POWER DESULFATOR PSPICE MODEL v6.0 FROM BJACK * BASED ON THE ORIGINAL ALASTAIR'S PULSER DESIGN * * Group VP-RP-SU-SD-DA-DB accurately simulates NE555 timer * output (voltage, risetime and falltime), sourcing/sinking * current capabilities and power consumption: the complete * NE555 model is omitted to save valuable simulation time. * Using values found in the original scheme for R1-R2-C2 * (not in the model), NE555 generates a square wave having * T=785uS period and TL=33.6uS. VP 7 0 PULSE(1 0 0 350N 350N 33.6U 785U) RP 7 0 1MEG DA 8 4 DX DB 4 5 DX SU 5 6 7 0 SWITCH1 SD 6 1 7 0 SWITCH2 * * Group C3-R4 is the NE555-MOSFET coupling network. C3 6 9 47NF R4 6 9 330 * * D1 is the flyback fast switching diode. D1 0 10 GI826 * * Group L1-L2-RLS1-RLS2 models inductances and their ESR: I * set ESR to obtain correct DC resistance values for the * 1mH, 2474-37L Delevan inductor, and for the 220uH, * 4590-224K Delevan inductor. * Core saturation is also modeled for these inductors: * increasing current will linearly decrease inductance * values, being the incremental current value in good * agreement with Delevan datasheets. L1 11 12 LMOD1 220UH RSL1 10 11 162m L2 12 13 LMOD2 1MH RSL2 13 0 2.3 * * Group C4-RSC4-LSC4 models the shunt capacitor (being the * L2-C4 network an LC low-pass filter) and his ESR/ESL: * these quantities MUST be included for a realistic * simulation! * This is a low ESR/ESL, 100uF, 16V capacitor, intended for * switching stages: I used the datasheet value for ESR, and * a guess (but reasonable) value for ESL: (datasheets * seldom provide adequate informations on caps ESL). C4 8 15 100UF RSC4 15 14 .4 LSC4 14 12 100NH * * LOUT takes into account stray inductance for wires used * to connect the unit to batteries: LOUT causes degradation * on desulfating pulse currents slewrate, and please * consider I used two big (4mm^2 section) and short (25cm * each) wires for this simulation. * When simulating, you'll be interested on waveforms V(8) * and V(16): V(8) is the waveform you'll see connecting * scope to pulser output, V(16) is the waveform you'll see * at the modeled "dummy" battery terminals. * Please note the high voltage ringing at node (8) and * make your own considerations, being this ringing (in the * few MHz range) produced only by short thick connecting * wires inductance: real batteries have thick short wires * too in their inner side, to series connect cell elements. * You'll be also interested on I(LOUT) waveform, as it is * the current actually flowing between battery and pulser. LOUT 8 16 580NH * * Group VB-RB-LB crudely simulates a 12V, 50Ah, 250CA * healty and sulfate-free automotive lead acid battery, * being VB its voltage (at 27 Celsius degrees, and no * charger connected), RB its average ESR and LB its * "internal connections" minimum ESL (real batteries will * for sure exibit a bigger ESL, and other strange * behaviours we can't easily simulate here). RB 18 19 .022 LB 19 20 200NH VB 20 0 12.65V * * Group RSH-LSH-CSC-RSC simulates the measuring network * used for "real world" pulser testing, being CSC the input * scope reactance, RSC the input scope resistance, RSH the * shunt resistance, LSH the shunt ESL. * These values refer to a simple 1/4W, 0.1Ohm carbon film * resistor, connected to a scope using a compensated X10 * probe: should you use the X1 probe, just set RSC=1MEG and * CSC=130PF. * Beware of power shunt resistors: they are bigger, and * therefore will exibit bigger ESL values. * The waveform you will see on scope is V(16)-V(18): * multiply it by a factor 10, compare it with the "real" * flowing I(VB), then make your own considerations on * measure errors introduced by LSH. RSH 16 17 100m LSH 17 18 10NH CSC 16 18 13PF RSC 16 18 10MEG * * R3 gives power to NE555 timer. R3 1 0 330 * * C1 is the filter capacitor (with its own ESR and ESL): it * keeps pulses and spikes away from NE555 power supply. * I used a 33UF, 16V standard electrolytic capacitor here, * and again a guess value for ESL (the actual value may be * higher than 100nH). C1 1 2 33UF RSC1 2 3 6.42 LSC1 3 8 100NH * * MFT1 is the switching device used for this circuit: its * model (see below) is a LEVEL3 SPICE model, i.e. really * accurate, as well as the model used for D1. * I also modeled the avalanche Zener diode protection * inside MFT1 (PSpice doesn't include it in MOSPOWER * models). MFT1 10 9 8 8 IRF9Z34N DM1 10 8 DM * * Device models used for this simulation: * IRF9Z34N P-channel power HEXFET (International Rectifier) .model IRF9Z34N PMOS(Level=3 Gamma=0 Delta=0 Eta=0 Theta=0 + Kappa=0 Vmax=0 Xj=0 Tox=100n Uo=300 Phi=.6 Rs=97.08m + Kp=10.43u W=4.1 L=2u Vto=-3.99 Rd=50.62m Rds=2.2MEG + Cbd=974.6p Pb=.8 Mj=.5 Fc=.5 Cgso=264.4p Cgdo=169.3p + Rg=3.145 Is=1.481p N=1) .model DM D(Bv=55) * GI826 fast switching 5A rectifier diode (Vishay) .model GI826 D(Is=3.993p Rs=7.132m Ikf=0 N=1 Xti=3 Eg=1.11 + Cjo=555p M=.3333 Vj=.75 Fc=.5 Isr=21.91n Nr=2 Bv=600 + Ibv=100u Tt=111.6n) * Models used for NE555 IC timer simulation: .MODEL SWITCH1 VSWITCH(RON=5.288 ROFF=1.363k VON=1 VOFF=0) .MODEL SWITCH2 VSWITCH(RON=12 ROFF=1.37k VON=0 VOFF=1) .model DX D(Is=412.4f) * models used for Delevan inductances: .model LMOD1 IND(L=1 IL1=-4.167E-2) .model LMOD2 IND(L=1 IL1=-.25) * * TRANSIENT ANALYSIS options for this model: .tran 100.000n 50m 49.215m 100.000n ; *ipsp* .options itl5 = 0 ; *ipsp* .probe ; *ipsp* * * This model works just fine, as well as the real circuit. * Carefully evaluating simulation results, some limits may * be found for the AC desulfator; but, it remains the * starting point for further improvements: one may quickly * change values, run the simulation and see what happens. * Enjoy! .END