El Segundo, Calif.—International Rectifier's new iMOTION motor control platform for air conditioning applications promises mechanical simplicity, quieter operation, and very high efficiency. It facilitates variable-speed sinusoidal current control without the need for position sensors for smooth torque output and lower acoustic noise.
This platform combines the company's proprietary high voltage integrated circuit (HVIC) technology with analog, digital, and power building blocks, along with digital control algorithms, for sensor-free motor control applications using DC link phase-current sensing.
"IR’s iMOTION platform is one of the first of its kind to address energy-saving motion control from a systems level. The platform provides everything a designer needs to deploy the benefits of variable-speed motion control in air conditioners," said David Tam, vice president of the Energy Saving Products Segment.
"This means systems that were once about 60 percent efficient will become better than 90 percent efficient. This is particularly important in places like China where air conditioner usage has grown about fourfold—from 8 units to 31 units per hundred households—in the space of five years."
The air conditioning platform features a proprietary algorithm for interior permanent magnet synchronous motors (IPMSM) in the compressor as well as the fan, and includes power factor correction (PFC). The algorithm, combined with the company's application-specific HVICs and discrete trench IGBTs, achieves 95 percent converter efficiency.
iMOTION’s digital block consists of the IRMCF3xx family of digital control ICs. These ICs include a patented motion control engine (MCE) that implements the complex sensor-free PMSM algorithm in hardware, thus eliminating software coding from the development process. The IRMCF3xx also features an embedded analog signal engine (ASE) that integrates all signal conditioning and conversion circuits for single-current shunt sensor-free control. The motion control engine executes the field oriented control (FOC) algorithm in about 11 microseconds to facilitate simultaneous control of the fan and compressor motors as well as the PFC circuits. The IRMCF311 and the IRMCF312 are currently the only single devices in their class capable of simultaneously controlling all three systems, according to the company.
The IRMCF3xx also includes an application layer processor that defines the operation of the air conditioning system independently from the MCE engine that controls the fan and compressor motors. User friendly tools allow the engineer to evaluate controller performance and customize the algorithm with minimal effort
The product's analog block consists of the IRS2136D family of three-phase analog driver and protection ICs. These ICs incorporate three independent 600-volt half-bridge inverter gate drivers with built-in bootstrap diodes. The protection functions include inverter over-current trip and under-voltage lockout with an automatic fault clear function. These analog gate drivers maintain parameter stability over the product's lifetime as well as parameter matching, such as propagation delay for high- and low-side channels, and deadtime insertion. Separate power and signal ground connections enable a single DC line configuration on the low-side IGBTs for current sensing. Cross-conduction protection prevents accidental shoot-through to increase inverter reliability.
The power stage, the company's new IRS2136, is designed to work with IR’s range of depletion-stop trench IGBTs. Trench IGBTs have lower collector-to-emitter saturation voltage VCE(ON), and total switching loss ETS, than punch-through (PT) and non-punch-through (NPT) IGBTs.
The iMOTION platform is being sampled to qualified users. Pricing varies by power level, configuration, and selected chip set. A chip set comprising the IRMCF3xx controller and three power stages for controlling the compressor, fan, and PFC deliver more than a 20 percent savings in the overall air conditioning system. This chip set is priced at $19.95 each in 100k quantities for a system with a 2 kW input power rating. Prices are subject to change. Contact the Technical Assistance Center (tac.irf.com)for additional details. Click here for more details on the iMOTION platform.
International Rectifier, 1-310-252-7105, www.irf.com