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Hydraulic-Electric (EMB) Hybrid Vehicle

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Hydraulic-Electric (EMB) Hybrid Vehicle

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25 Apr 2005 (Updated )

Physical system model of a hydraulic-electric energy storage device for hybrid automotive ...

setupfile_boost75kW.m
% SETUP FILE FOR ELECTRO-MECHANICAL BATTERY MODEL
% This script file loads in the parameters for COMBINED_DRIVE_CYCLE.mdl
% It is called by the OpenFcn of COMBINED_DRIVE_CYCLE
%
% Example: setupfile_boost75kW
%
% 
%   Written by Robyn Jackey 08-05-2004
%   Copyright 2004 - 2009 The MathWorks, Inc.

% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% HIGH-LEVEL DESIGN PARAMETERS
% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

% Performance parameters
EMBMaxPower_kW = 75; % Maximum power by EMB design (kW)
EMBMaxEnergy_kWh = 2.0; % Maximum energy stored by EMB design (kWh)
% Note: Usable energy kWh will be dictated by Max/Min operating pressures

% Derived parameters
EMBMaxPower_hp = EMBMaxPower_kW * 1.3404826; % Maximum power by EMB design (hp)
EMBMaxEnergy_J = EMBMaxEnergy_kWh * 3.6e6; % Maximum energy stored by EMB design (J)

% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% LOW-LEVEL DESIGN PARAMETERS AND SPECIFICATIONS
% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%% MOTOR 

% Performance parameters
MotorMaxRPM = 30000; % Maximum speed from Steven (RPM)
MotorMaxVolt = 750; % Maximum continuous voltage developed at terminals
MotorMaxCurrent = EMBMaxPower_kW *1000 / MotorMaxVolt; % Maximum current developed at terminals

% Physical parameters
MotorRa = 0.1; % Motor Armature Resistance estimate (Ohms)
MotorLa = 1e-3; % Motor Armature Inductance estimate (H)
MotorBm = 0.0001; % Viscous damping estimate (N.m.s)
MotorTf = 0; % Ignored - Coulomb friction torque estimate from SPS (N.m)

% Motor Inertia Estimate
% Calculation of estimated MotorJm: J = 1/2*m*r^2
% based on an iron rod radius 3.2cm x length 8 cm 
RodRad = 0.032; % m
RodLen = 0.08; % m
RodDens = 7000; % kg/m^3
RodVolume = pi*RodRad^2*RodLen; % m^3
RodMass = RodVolume * RodDens; % kg
MotorJm = 1/2*RodMass*RodRad^2; % kg/m^2
clear RodRad RodLen RodDens RodVolume RodMass

% Derived parameters
% The required motor torque constant can be derived by the max speed and
% max voltage requirements
MotorMaxSpeed_rad_s = MotorMaxRPM * (2*pi/60); % Motor max speed (rad/sec)
MotorKt = MotorMaxVolt/MotorMaxSpeed_rad_s; % Torque Constant (N.m/A) [assuming small Ra]


%% ACCUMULATOR (hydraulic fluid and inert nitrogen gas)

% Physical parameters for nitrogen gas
AccumCp = 1041.6; % Gas Specific Heat at Constant Pressure (NM/KgK)
AccumCv = 744.8; % Gas Specific Heat at Constant Volume (NM/KgK)
AccumInitialTemp_K = 300; % Initial Temperature (K)

% Performance parameters (Selected by Steven)
AccumMaxPress_PSI = 10500; % (SOC=1) Max Pressure (PSI)
AccumMinPress_PSI = 7000; % (SOC=0) Min Pressure (PSI)

% Derived parameters
AccumMaxPress_Pa = AccumMaxPress_PSI * 6894; % (SOC=1) Max pressure (Pascal)
AccumMinPress_Pa = AccumMinPress_PSI * 6894; % (SOC=0) Min pressure (Pascal)
AccumMinVol_m3 = ((AccumCp-AccumCv)*EMBMaxEnergy_J)/...
    (AccumMaxPress_Pa*AccumCv); % (SOC=1) Minimum gas volume (m^3) [Liters is *1000]
AccumMaxVol_m3 = ((AccumCp-AccumCv)*EMBMaxEnergy_J)/...
    (AccumMinPress_Pa*AccumCv); % (SOC=0) Maximum gas volume (m^3) [Liters is *1000]
AccumMaxVol_L = AccumMaxVol_m3 * 100;
ReservoirVol_L = (AccumMaxVol_m3 - AccumMinVol_m3) * 100;


%% HYDRAULIC PUMP

% Derived parameters
% The required pump displacement can be derived by the max accumulator
% pressure and the max power requirements. 
PumpDisp = (EMBMaxPower_kW*1000)/...
    (AccumMaxPress_Pa*MotorMaxSpeed_rad_s); % Pump displacement (m^3/rad)
PumpDisp_cm3_rev = PumpDisp * 2*pi * 1e6; % Pump displacement (cm^3/rev)
% Displacement could also be further increased to speed up the dynamics of
% the system and to still provide max power to the electric machine when
% the pressure & speed are not at the max.  This would need further
% research and a control strategy that ensures the pump power/torque output
% would never exceed that of the electric machines.

PumpEfficiency = 0.9; % Pump efficiency (one pass)
% This fixed efficiency is not always correct, because a variable
% displacement pump will be more efficient at higher displacement.  It
% should eventually be replaced with a lookup table, or an alternative pump
% design (multiple steps of fixed displacement?) should be considered.


%% VEHICLE

EMBtoTransGearRatio = 20;
DriveShaftInertia = 4; % kg*m^2
DiffRatio = 2; % gear ratio at differential output
WheelRadius = 15 *2.54/100; % m (in -> m)
WheelRelax = 2*WheelRadius/3; % m
WheelRatedLoad = 3000; % N
WheelPeakLong = 3500; % N (peak longitudinal force at rated load)
WheelSlip = 10; % Percent (at rated load, peak longitudinal force)
LateralInertia = 25*(WheelRadius)^2; % kg*m^2
VehicleMass = 3000 *0.4536; % kg (lbs. -> kg)
CGtoFront = 1.3; % m (dist to axle)
CGtoRear = 1.4; % m (dist to axle)
CGHeight = 0.5; % m (height from ground)
FrontalArea = 2.5; % m^2
DragCoefficient = 0.3;


% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% OTHER DATA
% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

% Load Drive Cycle Data
load FTP72.mat

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