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Power Integrations Bundles New Three-Phase BLDC Control Software into Motor-Expert Suite

Power Integrations, the best choice in high-voltage integrated circuits (ICs) for energy-efficient power conversion, today unveiled new control software for three-phase BLDC motor drives. Coupled with Power Integrations' BridgeSwitch integrated half-bridge motor driver and easy-to-use Motor- Expert configuration and diagnostics tool, this entire hardware-software solution enables 98.2 percent efficiency, reduces board space by more than 70 percent and requires just three components for current feedback circuitry, when compared with 30 components inside a discrete solution. The solution is ideal for residential and commercial appliances with three-phase motors, for example air conditioner fans, high-speed hair dryers, refrigerator compressors, range hood fans and water pumps.

\”Traditional three-shunt field-oriented control (FOC) solutions require expensive and bulky operational amplifiers (op-amps) and matching circuity for motor-current signal conditioning,\” states Cristian Ionescu-Catrina, senior product marketing manager for Power Integrations. \”Our BridgeSwitch integrated half-bridge ICs provide lossless current feedback for that positive half cycle, and our three-phase FOC software reconstructs the negative half-cycle current information from data contained in the other phase current signals. This eliminates the need for costly and inefficient external current sense resistors, op-amps and matching circuitry and the associated complexity.\”

Power Integrations' new software adds three-phase FOC to the existing library of single-phase code. It allows real-time adjustment of motor speed and torque via the Motor-Expert graphical user interface (GUI). The code runs on any Arm Cortex-M0 at 48 MHz and doesn't need a hardware accelerator block. It is also ported to another equivalent MCUs. The present modeling algorithm is robust and reliable and has passed extensive static and dynamic test conditions, including low latency reaction to real-time events. The high amount of current accuracy ensures low jitter operation. The brand new code is MISRA C-compliant (Motor Industry Software Reliability Association), portable, modular and permits the user to modify the software layers.

How Three-Phase Motor Control Works with BridgeSwitch ICs

Power Integrations' BridgeSwitch ICs provide a motor current output signal that maps the current passing through the low-side FREDFET. An interior sense-FET provides lossless current sensing. The sense circuit cannot provide current information once the anti-parallel body diode is conducting during commutation. Built-in gain amplification allows direct connection of the current phase signal towards the microcontroller ADC input. The local sense circuit provides an accurate analog of current with a higher signal-to-noise ratio along with a correspondingly high degree of accuracy. The new software includes a reconstruction algorithm that utilizes the phase-shifted trigonometric relationship between current signals of all three phases to accurately deduce negative phase-current information.

Updated Motor-Expert Design Tool

Motor-Expert 2.0 is Power Integrations' easy-to-use motor control configuration and diagnostics tool for that BridgeSwitch IC family. It provides a GUI allowing easy manipulation of input parameters, in addition to a terminal emulator for getting together with the motor controller in serial mode. Additionally, a motion scope feature displays linear graphs of important controller variables that can be viewed in real-time.

Ionescu-Catrina adds: \”Precise control, tuning and optimization may take months of software development. Power Integrations created Motor-Expert 2.0 using the design engineer's needs in mind. The brand new tool cuts down on the cost and complexity of BLDC drive design and works with the newly released three-phase motor control software and reference design DER-964 to offer a complete tool for motor drive development.\”

Motor and application tuning is conducted with the Motor-Expert 2.0 GUI with control loop coefficients being updated in real-time without needing to recompile code. The interface also enables users to visualize system operation, displaying the status of information, including current, speed, status, current error, and speed error. A diagnostics field inside the software interface provides understanding of inverter and motor operation.