Tutorial - HEV Design Suite

7/29/2019 Tutorial - HEV Design Suite

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PSIM Tutorial

HEV Design Suite

October 2012


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Tutorial on HEV Design Suite for HEV Powertrain Systems


The HEV Design Suite provides a one-stop solution from system specifications to a completely

designed HEV powertrain system. Using predefined templates, the HEV Design Suite automaticallydesigns the power circuit and the control circuit, and produces a system that is ready to simulate.

The HEV Design Suite allows users to quickly establish a baseline design for further optimization,

and helps speed up the development process significantly.Four design templates are provided in the HEV Design Suite: Series/Parallel HEV powertrainsystem with bi-directional dc-dc converter; Plug-in HEV (PHEV) powertrain system, HEV Traction

Motor Drive, and HEV Generator, as shown below:

In a series/parallel HEV powertrain system, the vehicle load torque is supplied from both the engine

and the traction motor, and it contains a bi-directional dc-dc converter. In a Plug-in HEV powertrain

system, on the other hand, the vehicle load torque is supplied from the traction motor only, andthere is no dc-dc converter.

A HEV traction motor drive template and generator drive template are provided so that each system

can be better studied individually.

This tutorial describes the procedure of how to use the HEV Design Suite, and explains the

functions of major building blocks.

Series/Parallel HEV

HEV Traction Motor

Plug-In HEV

HEV Generator


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1. Running HEV Design Suite

To run the HEV Design Suite, follow the steps below:

- In PSIM, go to Design Suites >> HEV Design Suite, and select the specific design

template. The design template interface will appear.

- Double click on each area that can be clicked, and enter the required parameters.- Go to Design Suites >> Generate Circuit. Select a folder for the generated files. The

generated main schematic file will be loaded into PSIM and is ready for simulation.

To illustrate this process, we will use the series/parallel HEV powertrain design template. The

complete procedure is described below :

- In PSIM, go to Design Suites >> HEV Design Suite, and select

HEV_powertrain_system. An interface will appear as below:

If you move the cursor into the interface Window, you will see certain areas highlighted.These areas can be double clicked for parameter input.

This HEV powertrain system consists of vehicle load, engine, PMSM-based generator,

PMSM-based traction motor, bi-directional dc/dc converter, lithium-ion battery bank,

and mode control.

- Double click on top of each area, and enter the following parameters:

ForMode Control:

Mode Selector (H_Mode_Selector): 5 [operation mode selector. It can be oneof the following:0: battery charge mode

1: battery drive mode

2: engine and motor drive mode

3: engine drive & battery charge mode4: engine & motor drive, and battery

charge mode


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5: full power mode (engine, motor, andbattery drive)

6: regeneration mode]

For Vehicle Load with Clutch:

Load Torque (T_load1): 150 [Vehicle load torque, in N*m]

Vehicle Moment of Inertia (J_vehicle): 0.01 [Vehicle moment of inertia, inkg*m2]

The vehicle load may be modified depending on the mode of operation. Forexample, in the battery drive mode, the load torque will be limited by the dc-dc

converter power rating.

ForEngine:

Engine Speed (nm_eng1): 2006 [Engine speed, in rpm]Engine Torque Limit to Vehicle (T_engine_lmt): 100 [Limit of the engine

torque to vehicle, in N*m]

The engine is modelled as a constant-speed source. Depending on the system

controller, part of the engine torque is delivered to the vehicle directly, and therest is delivered to the generator. The torque delivered to the vehicle directly is

limited by T_engine_lmt.

For Generator:

Stator Resistance (Rs_g): 0.065 [Generator stator resistance, in Ohm]d-axis Inductance Ld (Ld_g): 1.19e-3 [Generator inductance Ld, in H]

q-axis Inductance Lq (Lq_g): 5e-3 [Generator inductance Lq, in H]

Back EMF Constant (Vpk/krpm) (Ke_g): 244.905 [Line-to-line back emfconstant, in V/krpm]

Number of Poles (P_g): 8 [Number of poles of the generator]

Moment of Inertia (J_g): 2.5e-3 [Generator moment of inertia, in

kg*m2]Shaft Time Constant (T_shaft_g): 100 [Generator shaft time constant, in sec.]

Maximum Torque (T_max_g): 400 [Generator maximum torque, in N*m]Maximum Power (P_max_g): 40e3 [Generator maximum power, in W]

Base Speed (Nmb_g): 950 [Generator threshold mechanical speed

of the maximum torque and maximumpower operation regions, in rpm.

Assuming that the machine operates in

rated operating conditions, below thebase speed, the machine operates in the

maximum torque region, and beyond this

speed, the machine operates in themaximum power region.]

Maximum Speed (Nm_max_g): 5000 [Generator maximum speed, in rpm]

PWM Gain (Gpwm_g): 100 [Gain of the inverter and the PWM

generator, defined as the ratio betweenthe dc bus voltage Vdc and the peak-to-

peak carrier voltage. If the carrier wave

peak voltage is Vcarr (the signal is from


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-Vcarr to +Vcarr), te PWM gain isdefined as Vdc/(2*Vcarr). The PWM

gain is also the gain between the inverter

peak phase voltage Van and themodulation wave Vma, i.e. PWM Gain =

Van / Vma.]Switching Frequency (fsw_g): 10000 [Inverter switching frequency, in Hz]Sampling Frequency (fsam_g): 10000 [Inverter control sampling frequency, in

Hz]

Maximum Inverter Current (Ismax_g): 150 [Maximum inverter output peak

current, in A]Current Loop Crossover Frequency (fcr_i_g): 1500 [Current loop crossover

frequency, in Hz]

Speed Loop Crossover Frequency (fcr_w_g): 210 [Speed loop crossoverfrequency, in Hz]

For Traction Motor:

Stator Resistance (Rs_m): 0.065 [Motor stator resistance, in Ohm]d-axis Inductance Ld (Ld_m): 1.19e-3 [Motor inductance Ld, in H]q-axis Inductance Lq (Lq_m): 5e-3 [Motor inductance Lq, in H]

Back EMF Constant (Ke_m): 244.905 [Line-to-line back emf constant, in

V/krpm]Number of Poles (P_m): 8 [Number of poles of the motor]

Moment of Inertia (J_m): 2.5e-3 [Motor moment of inertia, in kg*m2]

Shaft Time Constant (T_shaft_m): 100 [Motor shaft time constant, in sec.]

Maximum Torque (T_max_m): 400 [Motor maximum torque, in N*m]Maximum Power (P_max_m): 40e3 [Motor maximum power, in W]Base speed (nmb_m): 950 [Motor base speed, in rpm. The

definition is the same as for thegenerator.]

Maximum speed (Nm_max_m): 5000 [Motor maximum speed, in rpm]PWM Gain (Gpwm_m): 100 [PWM gain of the inverter. The

definition is the same as for the

generator.]Switching Frequency (fsw_m): 10000 [Inverter switching frequency, in Hz]

Sampling Frequency (fsam_m): 10000 [Inverter control sampling frequency, in

Hz]Maximum Inverter Current (Ismax_m): 200 [Maximum inverter output current

(peak), in A]

Current Loop Crossover Frequency (fcr_i_m): 1000 [Current loop crossoverfrequency, in Hz]

Speed Loop Crossover Frequency (fcr_w_m): 300 [Speed loop crossover

frequency, in Hz]

Motor Speed Reference (nm_ref1_m): 2000 [Motor speed reference, in rpm]

The motor speed reference profile is defined by the source "Speedprofile" in the

subcircuit "block - motor.psimsch". To change the speed profile, one can edit this

source directly.


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ForDC Bus:DC Bus Voltage (Vdc): 500 [DC bus voltage, in V]

DC Capacitance (Cdc): 1150e-6 [DC bus capacitance, in F]

DC Capacitor ESR (Rc): 10e-3 [dc bus capacitor ESR, in Ohm]

ForDC/DC Converter:

Converter Rated Power (P): 10e3 [DC converter power rating, in W]Low-Voltage Side Rated Voltage (V_LV): 200 [Low-voltage side (battery side)

voltage rating, in V]Low-Voltage Side Inductance (L_LV): 800e-6 [Low-voltage side (battery side)

filter inductance, in H]

Low-Voltage Side Capacitance (C_LV): 10000e-6 [Low-voltage side (batteryside) capacitance, in F]

Switching Frequency (fsw): 20e3 [Converter switching frequency, in Hz]

Carrier Amplitude (V_ramp): 1 [Carrier voltage peak amplitude, in V]

ForLithium-Ion Battery:No. of Cells in Series (Ns): 60 [Number of cells in series]

No. of Cells in Parallel (Np): 12 [Number of cells in parallel]

Voltage Derating Factor (Ks): 1 [Voltage de-rating factor]

Current Derating Factor (Kp): 1 [Capacity de-rating factor]Rated Voltage (E_rated0): 3.7 [Battery rated voltage, in V]

Discharge Cutoff Voltage (E_cut0): 2.7 [Discharge cut-off voltage, in V]

Rated Capacity (Q_rated0): 5.4 [Battery rated capacity, in A*h]

Internal Resistance (R_batt0): 0.05 [Battery internal resistance, in Ohm]

Full Battery Voltage (E_full0): 4.2 [Full battery voltage, in V]Exponential Point Voltage (E_top0): 3.9 [Exponential point voltage, in V]

Nominal Voltage (E_nom0): 3.6 [Battery nominal voltage, in V]Maximum Capacity (Q_max0): 1.03 [Battery maximum capacity, in A*h]

Exponential Point Capacity (Q_top0): 0.2 [Exponential point capacity, in A*h]

A graphic description of the operation modes is shown below:

0: Battery Charge 1: Battery Drive 2: Engine/Motor Drive 3: Engine Drive & Charge

4: Engine/Motor Drive & Charge 5: Full Power 6: Regeneration


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- Select a folder to place the files generated by the Design Suite. For example, to place thefiles in the folder C:\HEV_example1, first create the folder "HEV_example1" in the C

drive in Windows Explorer. Then go to Design Suites >> Generate Circuit. Navigate

to the C drive, and select the folder "HEV_example1". Click on Select folder to enterthe folder HEV_example1. Once inside the folder, click on Select folder again. All the

schematic files will be generated and placed in this folder, and the main schematic willbe loaded into PSIM.

Double click on the parameter file element to change any parameters if needed. Thiscircuit is ready to simulate.

- Select Simulate >> Run Simulation to simulate the system. After simulation are

complete, select waveforms to display.

To change the operation mode after the circuit is generated, in the main schematic, double clickon the parameter file element, and change the value of the variable H_Mode_Selector (the value

can be from 0 to 6).

To better understand how each operation mode works, one can display and observe the

following key waveforms for each basic building block. If a waveform is in a subcircuit, thedisplayed name will have the subcircuit name as the prefix. For example, forIdc_LV, it will be

S24.Idc_LV.

- DC Bus:Vdc_bus: DC bus voltage

- DC/DC Converter (subcircuit S24) and Batteries:

Idc_LV, V_batt: DC converter low-voltage side current and battery voltageSOC: Battery State-Of-Charge

- Generator (subcircuit S17):Tem_S17.Generator: Generator developed torqueIdc_g: DC current of the generator converterIsa_g: Phase A ac current of the generator converter

- Traction Motor (subcircuit S13):Tem_S13.Motor: Traction motor developed torqueIsa_m: Phase A ac current of the tractor motor inverter

nm_ref_m, nm_m: Vehicle speed reference and the actual speed

- Vehicle Load (subcircuit S7):EngineTorque,MotorTorque, VehicleTorque: Engine torque, traction motor torque, andvehicle load torque

When a specific building block is involved in an operation, the corresponding waveforms would

be selected and displayed.

The simulation results in different operation modes can be interpreted as follows:

- Mode 0 (Battery Charge Mode):

The waveforms show that a positive current (Idc_LV) is flowing into the batteries,

charging the batteries and causing the battery SOC to increase. The high-voltage side dc

bus voltage (Vdc_bus) is regulated by the generator controller. The generator converter

current (Idc_g) is positive, indicating that the power is flowing from the engine to thedc/dc converter.


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- Mode 1 (Battery Drive Mode):

The waveforms show that, after initial transient, the current (Idc_LV) is negative,

indicating that it is flowing out of the batteries, discharging the batteries and causing the

battery SOC to decrease. The high-voltage side dc bus voltage (Vdc_bus) is regulated bythe dc/dc converter. The vehicle speed (nm_m) is regulated at the reference speed

(nm_ref_m). The three torque waveforms (EngineTorque, MotorTorque, andVehicleTorque) show that the vehicle load torque all comes from the traction motor.

- Mode 2 (Engine and Motor Drive Mode):

The three torque waveforms show that the engine will output the maximum output

torque to the vehicle load. The dc bus voltage is regulated by the generator controller,

and the vehicle speed is regulated by the traction motor controller.

- Mode 3 (Engine Drive and Battery Charge Mode):

The three torque waveforms show that the load torque only comes from the engine. The

dc current (Idc_LV) is flowing into the batteries, charging the batteries. The dc bus

voltage is regulated by the generator controller.

- Mode 4 (Engine and Motor Drive, and Battery Charge Mode):The three torque waveforms show that, whenever needed, the engine will output the

maximum output torque to the vehicle load. The dc current (Idc_LV) is flowing into the

batteries, charging the batteries. The dc bus voltage is regulated by the generator

controller.

- Mode 5 (Full Power Mode):

The three torque waveforms show that the engine will output the maximum output

torque to the vehicle load. The dc current (Idc_LV) is flowing out of the batteries, also

providing power to the vehicle load. The dc bus voltage is regulated by the generatorcontroller.

- Mode 6 (Regeneration Mode):Before 0.2 sec., the dc current (Idc_LV) is negative and the system operates in the

Battery Drive Mode. At 0.2 sec., the vehicle deaccelerates from 2000 rpm to 500. During

the deacceleration, the dc current Idc_LV becomes positive, feeding the energy back to

the batteries. At 0.3 sec., the vehicle accelerates again to 2000 rpm, and again the systemoperates in the Battery Drive Mode.

2. System Description

Basic building blocks of the HEV powertrain system are described below.

Vehicle Load with Clutch:

The vehicle load with clutches is modelled as a piecewise linear constant torque load.

Depending on the Mode Selector, either the engine or motor, or both of them, can deliver the

torque to the load.

Engine:

The internal combustion engine is modelled as a constant speed source. Engine dynamics arenot considered. The torque that the engine can deliver to the vehicle directly can be limited.


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Traction Motor:

The schematic diagram of the traction motor block is shown below.

It consists of a 3-phase PWM inverter, a PMSM traction motor, and the traction motorcontroller. The motor controller consists of space vector PWM, Current Control, Maximum

Torque-Per-Ampere (MTPA) Control, Field Weakening Control, Torque Control, Dynamic

Torque Limit Control, and Speed Control.

The traction motor operates in either speed control or torque control, depending on the flagF_torque_m. The Dynamic Torque Limit Control block determines the threshold speed. Below

the threshold speed, the motor operates in maximum-torque-per-ampere control, and beyond the

threshold speed, the motor operates in field weakening control. When the motor is in torquecontrol, a torque controller is used to generate the current reference instead.

The functions of the key control blocks are described below.

- Current Control:

Input: - Id, Iq: Currents id and iq feedback

- Idref, Iqref: id and iq current references from the Maximum-Torque-Per-Ampere Control block

- Idref_fw, Iqref_fw: id and iq current references from the Field Weakening

Control block- F_fw: Flag from the Dynamic Torque Limit Control block (1

when in field weakening control; otherwise 0).

Output: Vd, Vq: d-axis and q-axis voltage references

Description: The current control contains two loops, one for id and another for iq, to

generate the voltage references. Both loops are based on digital PI

controllers, with the gain and time constant as K_d and T_d for the idloop, and the gain and time constant K_q and T_q for the iq loop. When

the field weakening flag F_fw is 0, the current references Idref and Iqref


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are used, and when the flag is 1, the current references Idref_fw andIqref_fw are used.

- Maximum-Torque-Per-Ampere Control:

Input: - Is: Inverter current amplitude reference- +/-Te: Sign of the torque command (1 if the torque command ispositive, and -1 if the command is negative.)

Output: Id, Iq: d-axis and q-axis current references

Description: When the motor operates in the maximum torque region, Maximum-

Torque-Per-Ampere control is implemented. The block uses the motorparameters and the current reference Is to calculate the d-axis and q-axis

current reference values such that the maximum torque output is achieved.

- Field Weakening Control:

Input: - Is: Inverter current amplitude reference

- Vdc: Measured dc bus voltage, in V- Wm: Motor mechanical speed, in rad/sec.

- +/-Te: Sign of the torque command (1 if the torque command is

positive, and -1 if the command is negative.)

Output: Id, Iq: d-axis and q-axis current references

Description: When the motor operates in the maximum power region, field weakening

control is implemented. The technique uses the motor parameters and the

current reference Is to calculate the d-axis and q-axis reference values toachieve the constant power operation.

- Torque Control:

Input: - Id, Iq: d-axis and q-axis currents id and iq- Te: Torque reference

Output: - Is: Current reference, in A

- Tes: Estimated motor developed torque, in N*m

Description: This block estimates the motor torque from the current feedback and themotor parameters. A control loop based on a discrete integrator is used to

regulate the motor torque and generate the motor current reference.

- Dynamic Torque Limit Control:

Input: - Id, Iq: d-axis and q-axis currents id and iq, in A

- Vdc: Measured dc bus voltage, in V

- Wm: Motor mechanical speed, in rad/s- Tcmd: Torque command

Output: - Te: Torque reference- nmb: Calculated speed limit of the maximum torque region, in

rpm

- FW: Flag of field weakening (1: in field weakening region; 0:not in the field weakening region)


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Description: This block calculates the speed limit of the maximum torque region. Whenthe motor speed is less than this speed limit, the motor operates in the

maximum torque region. Otherwise, it operates in the maximum power

region with the field weakening control.

- Speed Control:

Input: - Wm_ref, Wm: Motor mechanical speed reference and feedback, inrad/sec

Output: - T_ref: Torque command, in N*m

Description: This block uses a digital PI controller to regulate the motor speed. The PIoutput is limited to the maximum torque T_max that the motor can

provide.

Generator:

The schematic diagram of the generator block is shown below.

It consists of a 3-phase PWM converter, PMSM generator, and the generator controller. The

generator controller in turn consists of space vector PWM, Current Control, Maximum Torque-Per-Ampere (MTPA) Control, Field Weakening Control, Dynamic Torque Limit Control, and

Voltage Control.

The generator controller is similar to the traction motor controller, except that it does not havethe torque control. Instead, it has the voltage control that regulate the dc bus voltage.

The functions of the Current Control, Maximum-Torque-Per-Ampere Control, Field Weakening

Control, and Dynamic Torque Limit Control are the same as in the traction motor controller.

The functions of the voltage control block are described below.

- Voltage Control:

Input: - Vdc*, Vdc: DC bus voltage reference Vdc* and feedback Vdc, in V


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- Idc: DC bus current, in A- Wm: Machine mechanical speed, in rad/s

Output: - Is: Current reference

Description: This block uses a discrete PI controller to regulate the dc bus voltage.

Together with the dc bus current and the machine speed, it generates the

machine current reference Is.

DC/DC Converter:

The schematic diagram of the bi-directional dc/dc converter block is shown below.

It consists of a charge controller, discharge controller, and regeneration controller. Their

functions are described below.

- Charge Control:

Input: - Vbatt: Battery-side voltage- Ibatt: Current flowing into the battery

Output: Vm: Modulation signal for PWM generator

Description: This block implements Constant-Voltage-Constant-Current battery

charging. When the battery voltage is less than the battery float voltage, itis constant current charging. The outer voltage loop is disabled and the

inner current loop charges the batteries at a constant current rate. When the

battery voltage reaches the battery float voltage, it is constant voltagecharging. The outer voltage loop generates the current reference for the

inner current loop.


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- Discharge Control:

Input: - Vdc: DC bus voltage

- Ibatt: Current flowing into the battery

Output: Vm: Modulation signal for PWM generator

Description: This block implements constant-voltage or constant-current battery

discharging. When the dc/dc converter control mode is set to VoltageMode (V_I_mode = 1), the converter regulates the dc bus voltage, and the

outer voltage loop generates the reference for the inner current loop. Whenthe control mode is set to Current Mode (V_I_mode = 0), the converter

regulates the current injected to the dc bus according to the current

reference I_HV_REF.

- Regeneration Control:

Input: - Vdc: DC bus voltage feedback

- Tes: Estimated traction motor torque

- Wm: Vehicle speed

Output: - Rgn: Regeneration flag (1: regeneration; 0: no regeneration)Description: This block generates the regeneration flag based on the motor power.

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Tutorial - HEV Design Suite