APEC 2018 PSIM Industry session - PSIM Support...

APEC 2018 – PSIM Industry session

Using the Right Device Model for the Right JobAlbert Dunford, Powersim Inc.

2 | www.powersimtech.com

What is PSIM?• PSIM is a simulation software specifically designed for power electronics,

motor drives, and energy conversion applications.

• Old version It is positioned between a device/circuit simulator (such as SPICE) and a system/control simulator (such as Matlab/Simulink).

• New version (v11) Integrated SPICE engine available.

SPICE Matlab/Simulink

Device and CircuitSimulation

System and ControlSimulation

• Fast• Easy to use• Affordable• Expandable


PSIM Simulation Environment

SmartCtrl

Design Suites

DESIGN

Loss Calculation

Digital ControlMotor Drives

Renewable Energy

SimCoder

SIMULATE

Simulink JMAG

SimCouplerMagCoupler/

MagCopuler RT

Processor-In-Loop (PIL)

IMPLEMENT

ModCoupler

TI Targets

F2833xF2803x

VHDLVerilog

Motor Control PMSM, ACIM

Hybrid ElectricVehicle

ThermalSwitchesInductors

Automated code generation

Control Loop Design

ModelSim

POWER ELECTRONICS SIMULATION

F2806xF2802x

S-domainmagnetics

Z-domain

TI C2000

SPICE

Native SPICE engine with novel SiC/GaN models

LTspice

SPICE


The Right Device for the Job

• Switch transitions require a nano-second timestep

• Switching converters require “many” cycles to reach steady state

• Thermal and loss estimates require the converter to be in steady state

• Control design require “many” cycles to properly understand

• EMI filters, snubber circuits, switching transients require a detailed switch model

• Using one device for all of these simulations is not practical


PSIM Device ModelsModel type Applications

Ideal Switch (PSIM) - Frequency sweeps- Control design- Digital control- Component sizing (L & C)- System level simulation

Level 2 Switch (PSIM) - Switching transient analysis- Gate drive- Digital control- Systems level with “details”

Thermal Switch (PSIM) - Loss estimation (switching & conduction- Junction temperature estimation- Heatsink requirements

SPICE - Manufactures SPICE model- Gate drive- Switching transient analysis


Ideal Switch

The switching transition does not need to be simulated in detail for most design simulations.

Switch transition is “instantaneous”Edge detection is used to ensure the switch changes state at the right instant.

20 points per switching cycle is “good” for most simulations


PSIM Level 2

- A “device level” switch defined by datasheet parameters

- Needs proper gate drive voltage referenced to source to overcome Vth

- Parasitic caps are linear

- Parameters must be defined for operating point of interest (Vds, Ids, Tj)

- MOSFET, IGBT, Diode

- Compatible with digital control and motor drive simulations


SPICE models

• Switching transients

• Gate drive

• Vast library of manufactures models

• Not compatible with digital control

• Not compatible with motor drive

• Not compatible with larger system level simulations


Design Process Ideal vs behavioural

• The switch transition takes many data points with a small timestep to simulate.

• This drives the time taken in real time

• Makes simulating events with a long time constant ‘impractical’


Dual Model Definitions

For switches and gate drive elements define a model for PSIM and a model to use for SPICE

Run PSIM, PSIM-spice, or LTspice


Switching losses – Thermal simulations

• Switching losses are the area under Vds*Id

• Generating these waveforms requires ~ns timestep

• It is impractical to simulate this level of detail when looking at thermal time constants


Thermal Switch Model

- Thermal steady state needs to be reached

- Converter steady state needs to be reached

- Typically after many switching cycles

- Switch transition is idealized

- Eon & Eoff is computed for each change of state

- I, V, Tj used to compute and scale the losses


Attributes - MOSFET

Ideal, Level 2, Thermal,SPICE


MOSFET in SPICE model

MOSFET in Level-1 or 2

Ideal MOSFET

Simulation with Different Complexity Levels

Vin

Increasing level ofmodel complexity


Ideal vs Level 2 & SPICE

Ideal switch

• Topology verification

• Component sizing –inductance, capacitance, etc.

• Control loop and stability

All of the above have long time constants, and need many cycles of the converter to be simulated.

Device model (level 2 & SPICE)

• Interaction between parasitic elements

• Gate drive requirements

• Efficiency

• Snubbing

• Conducted EMI

Simulations requiring “a few cycles”


Level 2 vs SPICE – C2M0280120D

Not any “major” differencesR load switchingData sheet operation conditions


Simulation Observations

Simulation speeds R = 133 Vds = 800V Fsw = 100k @ 50%

500us simulation length

Condition PSIM LTSPICE

Original settings 25s 10s

Vds = 400V 25s Simulation at 23 fs/s no results after 5 minutes

Rload = 13k 25s 5s

Vgs = 10V/-5V 25s 6s


Circuit Sync Buck Converter

Data source “A Performance Comparison of GaN E-HEMTs vs SiCMSOFET in Power Switching Applications” – J. Xu, D. Chen, L. Spaziani

PSIM schematic- Fsw = 200KHz- 400V->200V- Load varied- Tambient 25 oC


Results ComparisonP = 900W Tj PSIM Ploss PSIM Rtheta

C3M0065090J 124 oC 12.9W (12.1W sw) 7.7 oC/W

GS66508T 60.6 oC 7.13W (6.4W sw) 5 oC/W

Data from paper

The losses from PSIM for both the GaN and Cree device are comparable.


Thermal vs SPICE Loss Comparison

PSIM Thermal Circuit PSIM LTspice Circuit

400V 100kHz, 6/-3 Vgs with Ron = 10, Roff = 2, 20 Amp loadTj varied

GS66508B


Thermal vs SPICE: ResultsTj = 25 Manual Thermal SPICE LVL3 v2

P switching 6.32W 6.32W 3.4W

P conduction 10W 10.52W 10.38W

Simulation time N/A <1sec 13 seconds

Tj = 125 Manual Thermal SPICE LVL3 v2

P switching 8.6W 8.32W 6.38W

P conduction 24.2W 25.3W 25.4W

Simulation time N/A <1sec 13 seconds

VDS = 400Ids = 20Fsw = 100kHz

GS66508B


Thermal vs SPICE: Results


P switching 2.88W 2.79W 2.2W (10uJ off)

P conduction 10W 10.5W 10.4W

Simulation time N/A <1sec Hung @ 160us

VDS = 200Ids = 20Fsw = 100kHz


P switching 4.05W 3.77W 2.63W (3.5uJ off)

P conduction 25W 25.3W 25W

Simulation time N/A <1sec Hung @ 160us

The SPICE simulation hung up at 160u of 500u sim 13 fs/s same settings at 400V sim stopped sim after 15 minutes


LEVEL 2 with Motor Drive

Level 2 devices are compatible with digital and motor drives


Simulation Results

25ms sim10ns time step

25 minutes simulation


Summary

• Most of the design work can be done with Ideal devices

• Thermal device models provide a fast an “accurate” estimation of losses and heatsink requirements

• PSIM level 2 Models provide flexibility to add switch transition without convergence issues

• PSIM dual model definition and link with LTspice allow most manufactures SPICE models to be used.

APEC 2018 PSIM Industry session - PSIM Support...

Documents

Transcript of APEC 2018 PSIM Industry session - PSIM Support...