NXP 2021 19
FS6500 SYSTEM BASIS CHIP MPC5775B/MPC5775E
MICROCONTROLLERS
(MCUs)
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Electrification of the ICE powertrain electronics and
semiconductor content will continue to grow, and NXP
Semiconductorss will continue to support these engines.
However, the number of ICEs will decrease with the increase
in EVs. What is driving the growth in EVs? There are several
factors, but it starts with the need for cleaner emissions. This
is where government legislation and incentives play a part.
Battery costs are also being driven down, making the EV more
affordable. As battery performance improves, it becomes
possible to extend the driving range. Finally, considerable
investments by original equipment manufacturers (OEMs) in EV
technology are increasing inverter system efficiency.
Evaluating HV Power Inverters
One critical sub-system of the EV is the high-voltage (HV) power
inverter. A vehicle can have several HV power inverters, but
onboard charging (OBC), DC-to-DC battery boost circuit, and
the traction motor inverter are the most common. Several other
motors in the vehicle might require their inverter. One example
is the AC compressor pump.
The high-voltage traction inverter is a crucial focus for NXP.
It converts the DC from the HV battery to a multiphase AC
voltage to drive the traction motor(s). The traction motor moves
the vehicle. High-voltage traction inverters are safety-critical
as the typical voltage exceeds 300V. They also need to be
highly efficient in operation. Just a 1 percent improvement will
translate into more miles for the EV owner.
Given the need to be functionally safe, functional safety
standards are required. They are divided into levels depending
on the severity of harm to humans in case of system failure.
Levels are graded as Automotive Safety Integrity Levels
(ASIL) from A to D for automotive systems. Different elements
are considered in the functional safety standards, such as
the hardware, the software, and the system development
processes. Moreover, automotive system developers such as
Tier 1s and OEMs need to properly document these processes,
which require the support of functional safety-certified
components.
Because the traction power inverter is a highly critical safety
system, it must meet an ASIL-C/ASIL-D system certification.
An example of what could go wrong in a traction inverter is
unintended acceleration or stopping. These include losing
power while driving, unintended braking, and over-braking.
Imagine any of these scenarios while driving on a highway
and the system's criticality is easy to understand—hence
the need for these systems to comply with functional safety
specifications.
Conclusion
NXP offers functionally safe compliant components for the
HV traction inverter control. NXP does so with the MPC5775E
microcontroller, the FS6500 system basis chip to provide the
power for the controller, the TJA1051 redundant CAN bus
interface for communications, and the GD3100 advanced gate
driver with integrated HV isolation to handle the exacting
demands of the system. This combines with an insulated-gate
bipolar transistor (IGBT) or silicon carbide (SiC) module from
one of our partners. All the components are offered in a highly
efficient reference design.
■
Electrification of the ICE
powertrain electronics and
semiconductor content
will continue to grow, and
NXP Semiconductorss will
continue to support these
engines.
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