Modeling and Control of a Cascaded Boost Converter for a Battery - PowerPoint PPT Presentation

Modeling and Control of a Cascaded Boost Converter for a Battery Electric Vehicle � A. Ndtoungou, Ab. Hamadi, A. Missanda and K. Al-Haddad, Fellow member, IEEE EPEC 2012 OCTOBER 10-12

contents � � Introduction Introduction � � Comparison between boost and cascade boost Comparison between boost and cascade boost � Modeling and control of cascade boost converter � Modeling and control of cascade boost converter � � Space average model of the system Space average model of the system � � Control law for output voltage control Control law for output voltage control � � Design of the Design of the Proportional Proportional Integral Integral (PI) controller (PI) controller � Control Scheme of cascade boost for voltage control � Control Scheme of cascade boost for voltage control � � Simulation results Simulation results � � Control of Battery current Control of Battery current � Simulation results � Simulation results � � Cascade boost converter used as non polluting converter Cascade boost converter used as non polluting converter � � Control scheme Control scheme � � Simulation results Simulation results � � Conclusion Conclusion EPEC 2012 OCTOBER 10-12

INTRODUCTION I’s a new modeling technique of a cascade Boost converter; � The nonlinear control is applied and gives good performances in grid side � and in dc side. PI controller eliminates efficacy the steady state error of the dc bus voltages; � The configuration The configuration proposed proposed may may be be used used to to fast fast charging charging electrical electrical vehicle vehicle � � battery by battery by controlling controlling the the time time charging charging; The The configuration configuration connected connected to to the the grid grid compensates compensates current current harmonics, harmonics, � � reactive reactive power, power, the THD of the grid current is less than 5%. EPEC 2012 OCTOBER 10-12

Comparison between Boost and cascade Boost Characteristics of boost converter and cascade boost converter The boost converter provides high currents, while the cascade boost converter achieves high voltage. The advantage of the high voltage of the cascade boost converter make it very suitable for high battery voltage charging current. EPEC 2012 OCTOBER 10-12

Modeling and control of cascade boost converter D 2 i i i L L D D v L L 3 o 1 2 1 1 2 1 V v C Q C R o in 1 2 ON OFF i i v v i i i i v L L L L L L 2 o 1 i i 1 2 o 1 1 2 i i C C L L 1 2 C C 1 2 1 2 V V v v v v v v v v v C L C L R C R C o o in 1 in C C C C L L 1 1 1 2 2 2 1 2 1 2 1 2 EPEC 2012 OCTOBER 10-12

Space average model of the system  ( ) di − 1 d 1 L  = − + 1 v V C in dt L 1 L  1 1  ( ) di − 1 d 1 v  L 2 = − v C 0  dt L 1 L 2 2  ( ) dv  − 1 d 1 C 1 = − i i  L L dt C 1 C 2  1 1  ( ) − 1 d dv 1 o  = − i v L o  dt C 2 RC 2 2 EPEC 2012 OCTOBER 10-12

Control law for output voltage control : The dynamics of the output voltage is given by dv 1 ( ) 0 + = − = C v 1 d i u 2 o L 2 dt R The right term of this equation which is linear uses PI controller to regulate the voltage v0 and we extract the control law from this equation Where : The control law is u u is the output of the controller PI = − d 1 i i L is the current in inductance L L 2 2 2 EPEC 2012 OCTOBER 10-12

Design of the Proportional Integral (PI) controller v v + u + k s k k s k R k 0ref 0 p i = p i i = + + RC s 1 G (s) k s 2 p s s Closed loop output voltage regulation 1 1 ( ) ( ) + k s k + k s k p i G C p i C 0 2 = = G 2 = G F   + + 1 R k 1 G k F 0 p 2 2 2   i + ξ ω + ω + + s s s 2 s 0 0   R C C 2 2 The choice of the PI controller is based  + 1 Rk p   = ξω 2 1 on the desired performance of The 0   = ξω − k 2 C RC p 0 2 2   ⇔ R ω damping factor ζ and pulsation to  k  0 2 i 2 = ω = ω  k C  0 i 0 2 give best response.  C 2 EPEC 2012 OCTOBER 10-12

Control scheme of cascade boost for voltage control Output voltage v 0 1 d u v 0ref Output reference voltage is chosen i by user L2 EPEC 2012 OCTOBER 10-12

Simulation results Cascade boost converter is able to For the high voltage, the boost regulate the output voltage converter is not able to regulate the The best choice of inductance L2 can output voltage give iL2 positive Simulation results with cascade boost Simulation results with boost converter converter EPEC 2012 OCTOBER 10-12

C ONTROL O F B ATTERY C URRENT We test the cascade boost converter to charge the battery and to compare D 2 it with the boost converter i i i v L L D D L L 0 1 3 1 1 2 1 2 v V C C Q 1 2 0 in Control law : 1 ( ) = + − d 1 u V 1 in v C 1 Control scheme of cascade boost for current control EPEC 2012 OCTOBER 10-12

Simulation results The both system gives the same performance to charge the battery The slight difference is observed in the boost converter that the current flowing in the inductance presents the high ripple current compared of the cascade boost converter Simulation results of cascade boost Simulation results of boost with with battery current control battery current control EPEC 2012 OCTOBER 10-12

C ASCADE B OOST C ONVERTER U SED A S N ON P OLLUTING C ONVERTER D 2 D i i i v L D L 3 o L L 2 1 1 1 2 1 L f D D c a v V C C Q R o in 1 2 D D b d Spectrum of the grid current Cascade boost EPEC 2012 OCTOBER 10-12

Control Scheme Control law Reference current : i L1ref   1 v V ( ) = + − d 1 u V eq. 31 0  in  = + eq. 29 i u i i in   v L ref 1 v C 1 V  v  C 1 in 0 EPEC 2012 OCTOBER 10-12

Simulation results Grid current and grid voltage are in phase During the output reference voltage variation we see that The THD of the grid current is less than 5% the output voltage well regulated , that the grid voltage and the grid current are in phase and sinusoidal Steady state response of a non polluting Dynamic response of a non polluting converter: upper - voltage and current converter: upper- voltage and current source, lower - output voltage source, lower- output voltage and its reference EPEC 2012 OCTOBER 10-12

C ONCLUSION • The modeling of the cascade boost converter and the nonlinear control technique are presented. • The simulations results have shown good performances of the cascade Boost compared to the classical Boost converter. • The cascade Boost converter is suitable for high voltage battery. • The cascade Boost converter used as non polluting converter gives a THD less than 5% in the grid side. • The control of the battery current will help to control the charging time which may be used to fast charging electrical vehicle battery. EPEC 2012 OCTOBER 10-12

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