UM0432
System architecture
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1 System
architecture
A generic motor control system can be basically schematized as the arrangement of four
main blocks (see
Figure 2
).
●
A control block, whose main tasks are to accept user commands and motor drive
configuration parameters and to provide digital signals to implement the correct motor
driving strategy.
●
A power block that makes a power conversion from the DC bus transferring it into the
motor by means of a 3-phase inverter topology.
●
The motor itself. The STEVAL-IHM015V1 board can drive the following kinds of motors.
–
PMDC (or BLAC/BLDC) permanent magnet motors, 6-step current, both in
sensored and sensorless mode.
–
PMAC (or BLAC) permanent magnet motors, sinusoidal current, only in sensored
mode.
●
A power supply block that accepts a wide range of input voltages and provides the
appropriate levels to supply both the control block and power block devices.
Figure 2.
Motor control system architecture
The system proposed by the STEVAL-IHM015V1 includes all the above hardware blocks
(apart from the motor) plus a software GUI to configure the motor drive. Additionally, open-
source C code is available, derived from the ST7MC motor control libraries, allowing easy
customization and extension of the control algorithms.
The control block’s core consists of an ST7MC MCU that provides the driving signals to the
power block according to a driving strategy that is closely related to the motor type and
characteristics.
The driving signals consist of three complementary PWM signals (in the range of 0-5 V) for
providing logic inputs for the high-/low-side gate drivers that belong to the power block. The
proposed system has three legs (3-phase inverter).
The power block, based on the gate drivers L6387 and power MOSFET (STS8DNH3LL),
converts the control signals from the ST7MC MCU to power signals for the 3-phase inverter
in order to drive the motor.
The board can be supplied by a DC power supply from 5 up to 48 V with a maximum current
rating up to 25 A. Refer to
Section 6
for more information on the system’s architecture.
With the included power MOSFET device STS8DNH3LL, the maximum voltage rating is
30 V and the maximum current rating is 8 A.
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