Technology advancements in motor drive designs have opened many doors. For example, in motion control systems, greater precision, efficiency, and control provides many benefits in user experience and safety, resources optimization, and environmental friendliness.
The introduction of brushless motor technology was a major step toward overall greater efficiency.The transition from brushed to brushless started some time ago and continues to evolve as more new technologies and system components are introduced.
At the same time, however, new developments in electrical components enable better thermal management, higher power density and miniaturization while allowing the execution of more complex tasks at a competitive cost.
Using best-in-class semiconductor technology, electrical motor designs for low- and medium-voltage classes can be more efficient, smaller, and provide greater functionality to end users.
Here, engineers can choose from varying semiconductor solutions to fine-tune their motor drive designs.The technical parameters, such as switching frequency and thermal resistance of end products, set the requirements for drives.
Next, to build a well-optimized system that preferably improves power density and reduces size, designers have to minimize losses—both conduction and switching losses—and optimize thermal management.This article highlights three design venues for creating more compact, efficient, and higher-performing motor drives.
1. Improvements in power package technology
Following the trend of increasing battery voltages in robots and power tools, the power of the motor drive is also increasing. This translates into increasing requirements for power semiconductors in terms of high current rating, ruggedness, and extended lifetime.
A profound venue to tackle these needs is new packaging technology platforms, which comes in three different variations, depending on specific needs.
2. Three-phase gate drive controller ICs
The new 3-phase smart motor driver ICs enable the development of high-performance motor drives using brushless DC (BLDC) or permanent magnet synchronous (PMS) motors. These designs are especially suited for mobile robots, drones, and power tool applications.
3. GaN for improved efficiency and power density
In some cases, an important design goal is the integration of power electronics close to the motor or within the same housing. Potential benefits include increased power density, reduced bill-of-material (BoM) costs, as both motor and electronics can be placed in a smaller housing, and cost savings due to higher system efficiency.
Commonly, heat dissipation and bulk capacitance have been limiting factors in integrated motor drives (IMDs). The move to gallium nitride (GaN)-based designs provides the foundation to overcome the challenging trade-off between switching speed and maximum output power.
Higher switching frequencies that can be implemented by using field-oriented control (FOC) enable numerous system benefits, including reduced bulk capacitance, lower motor ripple current, lower torque ripple, and less acoustic noise. The higher frequency also enables lower motor temperature.
The combination leads to higher end-to-end system efficiency improvements.In drones, the system efficiency benefits not only make the design more efficient due to lower losses but also smaller, which is a key benefit to making drones lighter and thus fly longer.
