traction inverter bdom - future · pdf file 2020. 6. 10. · automotive traction...

Solution Description Product Recommendations Interactive Block Diagram (onsemi.com)

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Automotive Traction Inverter Solution Description

Introducing the Block Diagram of the Month for October 2019 – The Automotive Traction Inverter

Solution. Global legislation to reduce CO2 emissions and enhancement of fuel economy is driving

automotive manufacturers to design electrified powertrain systems with reduced size and weight

that exhibit optimal power efficiency. The primary function of the traction inverter is to convert the

DC voltage from the high voltage battery (350-800 VDC) to a three-phase AC sinusoidal current

that in turn rotates an electric induction motor and propels the vehicle. Our broad automotive

portfolio contains technologies to facilitate a cost effective, robust and competitive solution for

operation of the three-phase induction motor infull, plug-in hybrid and hybrid electric vehicles using

a traction inverter.

Primary blocks of the topology:

 Isolated Power Supplies

 Three Phase Inverter Stage

 Signal Processing and Conditioning

 Communication Bus

Isolated Power Supplies:

The function depicted by the power management block in the

traction inverter solution is to generate isolated power supplies

that create a barrier between the high and low voltage circuit

topologies contained within the system to prevent connection of

the grounds between the low voltage and high voltage batteries.

Resonant controllers, flyback controllers and linear voltage

regulators are used to generate power sources for digital circuits,

analog circuits, integrated circuit voltage references and high

voltage gate drivers used to control the conduction of the separate

phases in three-phase inverter. Numerous high efficiency

resonant and flyback controller topologies can be constructed

using the ON Semiconductor recommended solutions listed in the

product selection table depending on the system level

requirements.

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Three Phase Inverter Stage:

The primary components of the three-phase

inverter stage are the high and low side

switches of each of the inverter ½ bridge

phases and the corresponding high voltage

isolated gate drivers that turn on and off those

switches that generate a three-phase AC

sinusoidal waveform to operate the induction

motor. The high and low side switch control on

each inverter phase is managed through a

variable frequency drive control algorithm

deployed by a microprocessor. Besides

providing the galvanic isolation for separation

of the high voltage system from the low voltage

system, one of the key features of our high

voltage gate driver technology is the DESAT

(desaturation) detect feature that prevents a

“shoot through” effect during an IGBT short

circuit condition. In addition, our high voltage

gate drivers have miller clamp capability to

prevent un-intentional parasitic turn on of one

of the switches. For enhanced protection, the

device has fault indicator capability to inform the system of malfunction and an enable input. For the ½ bridge inverter stages, discrete and modular solutions

are offered in our automotive portfolio. The traction inverter phases can be constructed using discrete IGBT’s, integrated modules from the VE-TracTM

(vehicle electrification Traction) family and discrete SiC MOSFETS. All these solutions are able to interface with the high voltage gate driver. Bare die

products with the IGBT and fast recovery diode are also available to build the three-phase inverter stage and are included in the product selection table.

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ON Semiconductor offers AECQ-101 qualified 650V discrete IGBT parts rated at 120 and 160 Amps that exhibit superior thermal

and electric performance. Due to the IGBT having a characteristically low VCE(sat) and gate charge, conduction and switching losses

are minimized thereby translating into high efficiency operation. Our IGBT’s are co-packaged with a fast reverse recovery diode

and are constructed using the competitive field stop trench technology utilizing a fine cell pitch design to create a high power density

part with rugged immunity to dynamic latch-up conditions. Depending on the power requirement for the motor, multiple IGBT’s can

be placed in parallel on each high and low side switches of the inverter ½ bridge phases.

The VE-TracTM Dual Side Cooling ½ bridge modules consist of 2 IGBT’s co-packaged

with fast recovery diodes connected in a high and low side configuration. The IGBT’s are

constructed using the Field Stop 4 Trench Technology with characteristic low switching

and conduction losses. Each module represents one phase of the three separate phases

required for the traction inverter system. The device offers top side and bottom side

cooling with surfaces attaching to heat sinks encapsulated throughout the system

resulting in lower thermal resistance. The lower thermal resistance allows for higher

magnitudes of current to pass through a small, compact footprint translating into a high

power system with cost and size reductions. The dual side cooling modules allow for

modular scalability as units can be stacked in parallel configurations to create a higher

power solution. The module is capable of continuous operation up to 175°C, with wire

free bonding essential for higher reliability and longer part lifetime. The device features

overcurrent and over temperature protection.

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The VE-TracTM Single Side Direct Cooling Module

integrates IGBT’s in a six-pack configuration with each

IGBT having the co-packaged fast recovery diode. Like the

dual side cooling modules and the discrete IGBT parts, the

technology integrated in the design has characteristic low

conduction and switching losses resulting in high efficiency.

The device is configured in three high and low side ½ bridge

configurations that make up the three-phase inverter to

enable operation of the electric induction motor. The module

is a “plug and play” type of device targeting ease of

assembly and integration. The module has a direct cooling

surface with an integrated pin fin heat sink resulting in a lower thermal resistance that enables a high current operation.

The flip side of the device contains press-fit type pins on the signal terminals for ease of assembly and integration. This modular solution is not easily scalble

and limited to between 160-180kW power class operation. The module can operate continuously at 175°C with integrated temperature sensing for all ½

bridge inverter phases.

For electric vehicle systems with an 800V battery, discrete 1200V rated 20, 80 mΩ SiC MOSFETS released in D2PAK-7L and

TO-247 packages can be inserted into each high and low side switch in the three inverter phases. Compared to silicon, SiC

MOSFETS provide superior switching performance and higher reliability. The devices have low ON resistance and compact

chip size to ensure low capacitance and gate charge. These characteristics result in system benefits that include high efficiency,

fast operation frequency, increased power density, reduced EMI and facilitation of space reduction.

The Diode and IGBT bare die optimized for traction inverter applications is rated for continuous operation at 175°C having

low VCE(sat) and VF featuring enhanced reliability and ruggedness. The bare die selections are listed in the product selection

table.

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Signal Processing and Conditioning:

The primary function of the analog measurement and signal conditioning block is to process the current and temperature sense signals from the inverter along with the current and motor position sense signals from the induction motor. The isolated power supplies constructed using the resonant and flyback controllers can provide power sources to the microcontroller, signal conditioning and analog measurement circuits. ON Semiconductor offers AECQ qualified logic components, comparators, operational amplifiers and current sense amplifiers to construct the signal processing circuitry to interface with the microcontroller A/D converter unit to complete the closed loop system.

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Communication Bus:

ON Semiconductor offers CAN, CAN-FD, LIN, Flexray and SBC based transceivers that ensure robust in- vehicle communication at data rates beyond one Mbps to adhere to requirements of contemporary in-vehicle networks. In addition, ON Semiconductor offers AECQ- 101 qualified communication bus protection devices with a 175°C Tj Max rating designed to protect vehicle communication lines from ESD and