Intelligent, Efficient and Precise Motor Control
The proliferation of electric motors in industrial and consumer applications has revolutionized the way we operate machines and equipment. This has helped to speed up the adoption of the intelligent manufacturing equipment used in Industry 4.0. These motors require sophisticated electronic control systems that need to be highly integrated and cost effective whilst at the same time provide the necessary current and voltages and achieve precise control and efficient operation. Josh Barton, Field Applications Engineer at Anglia gives an overview of the STMicroelectronics STSPIN and STDRIVE product families, their features and advantages, and how they can be used effectively to drive and control electric motors.
Intelligent, Efficient and Precise Motor Control
The proliferation of electric motors in industrial and consumer applications has revolutionized the way we operate machines and equipment. This has helped to speed up the adoption of the intelligent manufacturing equipment used in Industry 4.0. These motors require sophisticated electronic control systems that need to be highly integrated and cost effective whilst at the same time provide the necessary current and voltages and achieve precise control and efficient operation.
STMicroelectronics is a leading supplier of semiconductor solutions for various industries, including eMobility, industrial, and personal electronics. One of their key areas of expertise is the design and manufacture of motor control ICs.
The STMicroelectronics STSPIN and STDRIVE product families have been designed with the needs of modern industrial control applications in mind, such as industry 4.0, and are able to intelligently drive and control electric motors with high efficiency and precision.
Josh Barton, Field Applications Engineer at Anglia gives an overview of the STSPIN and STDRIVE product families, their features and advantages, and how they can be used effectively to drive and control electric motors.
Common Motor Types
Firstly, let’s look at some of the common motor types in use today and their specific strengths for different applications.
DC brush are the most common motor type; however, these are now being replaced in many applications by Brushless DC motors (BLDC) due to advantages such as higher efficiency, quieter operation and increased reliability. These versatile motors are used in applications that require high torque and high-speed operation such as robotics & power tools.
Three-phase induction motors (ACIM) are brushless motors commonly used in industrial drives, these motors feature self-starting, reliable and economical operation. Typical applications include industrial pumps and conveyer belt systems.
Stepper motors are designed to make small incremental movements/steps rather than just rotation like a traditional motor, they are widely used where precision position control is required such as in computer drives, security and industrial automation sectors.
Switched reluctance motors are more commonly used in traction, industrial pumps and domestic appliances. Their structure is similar to that of stepper motors, but they have fewer magnetic poles.
STMicroelectronics motor control and drive solutions are suitable for all of these common motor types and more besides.
STSPIN Product Family
Firstly, we will look at the STSPIN product family, this is a range of integrated motor drivers that are designed to drive and control 3-phase brushless DC (BLDC) motors, stepper motors, and single-phase DC motors. These products integrate the power electronics, control electronics, and protection features required for driving and controlling motors. The family also includes variants which have an embedded STM32 MCU offering a fully integrated System-In-Package solution.
The STSPIN product family includes various devices, each are tailored to the specific needs of different motor types. Below are some examples of a couple of devices which suit some of the more common applications.
This device is a low voltage triple half-bridge BLDC motor driver with a current rating of up to 1.3Arms, the device integrates control logic, drive FETs and protection into a single IC. See Fig.1.
It is designed to operate from a 1.8V to 10V supply voltage and its comprehensive suite of protection features include non-dissipative overcurrent protection, short-circuit protection, thermal shutdown and interlocking function to prevent damage to the motor during fault conditions. Another key feature of the STSPIN230 is its energy saving feature where less than 80nA is consumed in standby mode making it well suited to battery powered applications. All these features are squeezed into a compact VFQFPN16 package measuring just 3x3x1.0mm allowing for extremely compact designs.
Figure 1. STSPIN230 Block Diagram
Complementing this driver IC is the STSPIN233 which is a similar device but supports three shunt sensing topology and can be forced into a zero-consumption state, allowing a significant increase in battery life.
For more advanced motor control, the STSPIN830 is a compact and versatile field oriented control (FOC) ready three-phase motor driver. This device is housed in a compact 4 x 4 mm QFN package and integrates all the control logic and a fully protected low RDSon triple half-bridge power stage. See Fig.2.
Designed to operate from 7V to 45V supply voltage, the device can deliver a maximum output current of 1.5 Arms. The STSPIN830 supports both single and three shunt architectures and embeds a PWM current limiter based on user settable values of reference voltage and OFF time. The device can be forced into a low consumption state which reduces the total current consumption down to less than 45μA.
Figure 2. STSPIN830 Block Diagram
The STSPIN830 devices also have a dedicated MODE input pin which offers the freedom to decide whether to drive it through 6 inputs (one for each power switch) or using the more common 3 PWM direct driving inputs.
As with all other devices from the STSPIN family, the STSPIN830 integrates a complete set of protections for the power stages including non-dissipative overcurrent, thermal shutdown, short-circuit, undervoltage lockout and interlocking, making it a robust solution for demanding industrial applications.
The STSPIN family is also part of STMicroelectronics 15-year longevity commitment program (10 years for STM32 MCU fully integrated System-In-Package solutions), giving developers reassurance on the future availability of these products for their designs.
STDRIVE Product Family
The STDRIVE product family is designed for applications where the user wishes to drive external power N-channel MOSEFTs, GaN Transistors or IGBT devices in various motor control applications. These gate driver ICs provide the necessary current and voltage to switch the power devices, which in turn control the current and voltage applied to the motor. Again, the STDRIVE product family includes various devices to suit different application requirements.
This device is a single-channel low-side gate driver IC for low-voltage motor control applications. It is designed to operate from a 5.5V to 75V supply voltage and can deliver up to 600 mA (sink/source) current. It integrates a low drop linear regulator generating the supply voltage for both low-side and high-side gate drivers through its integrated bootstrap circuitry. See Fig.3.
The control logic integrated into the device allows two input strategies (high-side and low-side or enable and PWM driving signals). The driving method can be selected according to DT/MODE pin. In both cases, prevention from cross conduction is ensured by interlocking or internally generated deadtime.
Figure 3. STDRIVE101 Block Diagram
The device includes various protection features such as an overcurrent comparator, undervoltage lockout (UVLO) and thermal shutdown. The UVLO protection is included on both the low-side and high-side sections, preventing the power switches from operating in low efficiency or dangerous conditions. In addition, the device integrates an embedded VDS monitor for each external MOSFET.
At the other end of the STDRIVE family is the STDRIVEG600, a single chip half-bridge gate driver for Enhancement mode GaN FETs or N-channel power MOSFETs. It is designed to operate from 4.75 V to 20V supply voltage, the device can deliver up to 1.3/2.4 A (source/sink) current typ @ 25 °C, 6 V or up to 5.5/6 A (source/sink) current typ @ 25 °C, 15 V. See Fig.4.
The high-side section is designed to withstand a voltage up to 600 V and is suitable for designs with bus voltage up to 500 V. The device is designed for driving high-speed GaN and Si FETs thanks to its high current capability, short propagation delay and operation with supply voltages down to 5 V.
Figure 4. STDRIVEG600 Block Diagram
The STDRIVEG600 is also well equipped with protection features including UVLO on both the lower and upper driving sections, preventing the power switches from operating in low efficiency or dangerous conditions, and an interlocking function avoids cross-conduction conditions. The logic inputs on the device are CMOS/TTL compatible down to 3.3 V for easy interfacing with microcontrollers and DSPs.
The STSPIN and STDRIVE product families offer a significant opportunity to manufacturers of industrial systems to improve the performance and functionality of their products and reduce the operating cost. STMicroelectronics is continuously developing its range of motor control ICs with this in mind. They have a suitable, cost effective and efficient solution which gives robust and precise control for every motor drive requirement.
STMicroelectronics have also made available a range of affordable and easy-to-use STSPIN and STDRIVE based development tools and demonstration boards to assist designers. Many of these evaluation boards are also compatible with STMicroelectronics STM32 Nucleo boards and the associated software ecosystem.
In addition, Anglia offers support for customer designs with free evaluation kits, demonstration boards and samples of STMicroelectronics products via the EZYsample service which is available to all registered Anglia Live account customers.
Anglia’s engineering team are also available to support developers with motor control designs and can offer advice and support at component and system level. This expertise is available to support customers with all aspects of their designs, offering hands on design support along with access to a vast resource of STMicroelectronics application notes and reference designs.
Visit www.anglia-live.com or scan the QR code to see the full range of STMicroelectronics products available from Anglia.Intelligent, Efficient and Precise Motor ControlCommon Motor TypesDC brush Brushless DC motors (BLDC)Three-phase induction motors (ACIM)Stepper motorsSwitched reluctance motorsSTSPIN Product Family STSPIN230 Figure 1. STSPIN230 Block DiagramSTSPIN830Figure 2. STSPIN830 Block DiagramSTDRIVE Product FamilySTDRIVE101Figure 3. STDRIVE101 Block DiagramSTDRIVEG600Figure 4. STDRIVEG600 Block DiagramConclusionDesign support