International Rectifier (IR) introduces a motor control platform for air conditioning applications that enables 95 percent efficiency, quieter operation and mechanical simplicity. IR’s iMOTION integrated power design platform enables energy-saving, variable-speed sinusoidal current control without the need for position sensors for smooth torque output and lower acoustic noise in motors.
The International Rectifier power design platform is an optimized system architecture that combines IR’s proprietary high voltage integrated circuit (HVIC) technology with analog, digital and power building blocks, along with digital control algorithms, for sensor-less 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. 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 four fold – from 8 units to 31 units per hundred households – in the space of five years," said David Tam, vice president of International Rectifier’s Energy Saving Products Segment.
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). This, combined with IR’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 IR’s patented Motion Control Engine (MCE) that implements the complex sensor-less 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-less control. The Motion Control Engine executes the sensor-less field oriented control (FOC) algorithm in about 11micro-seconds, which is the key feature that enables 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.
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. Easy-to-use tools allow the engineer to evaluate controller performance and customize the algorithm with minimal effort, so the appliance engineer can focus his efforts on application issues rather than motor control functions.
The analog block consists of the IRS2136D family of three-phase analog driver and protection ICs. These ICs incorporate three independent 600V 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 deliver parameter stability during product lifetime and parameter matching, such as propagation delay for high- and low-side channels, 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.
Finally, the new IRS2136D is designed to work with IR's extensive range of highly efficient depletion-stop trench IGBTs offered in a wide range of configurations, including discrete and integrated modules. 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 new iMOTION air conditioner platform is being sampled to qualified users. Pricing varies by power level; configuration and chip set selection. A chip set comprising the IRMCF3xx controller and three power stages, controlling the compressor, fan and PFC will enable more than 20% savings in the overall air conditioning system. This chip set will cost US $19.95 each in 100K volumes for a system with a 2kW input power rating. Prices are subject to change. Contact your local International Rectifier sales representative or the International Rectifier Technical Assistance Center (TAC) for more details.
International Rectifier's iMOTION integrated design platform consists of a development system, mixed-signal analog chip sets and power stages, which when co-designed together, simplify motion control designs and bring energy-efficient, cost-effective solutions to market faster.
More details on the iMOTION platform, as well as links to design assistance, are posted on the iMOTION Web page.