Appliance Design - October 2007 - (Page 29)

MOTORS to protect IP in collaborative design environments by securing IP segments separately. CodeGuard security enables multiregional IP development, where each team develops its IP, and locks out that portion of DSC memory. In another example, when motor manufacturers sell motor-control algorithms to appliance manufacturers; using CodeGuard security, these drivers can be housed in a protected section on the DSC memory. In a clear departure from existing motorcontrol solutions that rely on costly custom ASICs to implement FOC and the PFC block, appliance makers now have a better choice. To enhance the efficiency of appliances and reduce their audible noise, controllers such as Microchip’s dsPIC DSCs can be deployed. These DSCs make it easy for appliance makers to efficiently and economically implement advanced algorithms such as FOC, on a wider range of appliances than ever before. Microchip provides a free FOC algorithm, with full source code. < For more information, enter number. . . . . . . . . . . . . 305 Or email: appliance@microchip.com Fig. 2. A 3-phase inverter drives PMSM windings, and also features current-sensing and fault-generation circuitry. rents are transformed to 2-axis vectors, as seen in a DC motor. The FOC process begins by measuring the three-phase motor currents. In practice, since the instantaneous sum of the three current values will be zero, by measuring only two of the three currents, the value of the third can be determined. Also, the hardware cost is reduced, because only two current sensors are required. This FOC technique will work with asynchronous motors, as well. A synchronous motor differs from an asynchronous motor in the relationship between the mechanical speed and the electrical speed. In a synchronous motor, the supplied voltages have the same frequency as the mechanical motor speed. In an asynchronous motor, the final mechanical speed is different from the input frequency, and the relationship between input frequency and mechanical speed varies, depending on the mechanical load applied to the motor. A major advantage of deploying DSCs in motor control is the practicality of a common design platform, which makes the production of appliances more efficient. Even with different varieties of motors, such as PMSM and ACIM, appliance makers can use the same motor-control board and only need to change the software on the DSC. Therefore, a single design platform can handle multiple types of motors, and appliance makers only need to develop different motor-control IP to handle many varieties of motors. As a result, appliance makers now have an economical way to offer a range of appliance models that use PMSMs, or other motor types, with sensor-less FOC algorithm control. Firmware IP protection is a major issue for manufacturers who frequently deploy appliance design teams that collaborate across www.applianceDESIGN.com many geographic regions. It is easy to imagine a scenario where multiple design teams based in different locations could work in tandem to implement FOC firmware, develop the appliance front panel, and get the final system integration done. While developing their firmware and designs, these teams will have claims to their own IP. Microchip’s dsPIC DSC family offers the CodeGuard security feature, which helps For more Information Enter 112 applianceDESIGN AD09074Sol.indd 1 October 2007 29 8/7/07 10:44:48 AM http://www.soler-palauinc.com http://www.soler-palauinc.com http://www.appliancedesign.com

Table of Contents Feed for the Digital Edition of Appliance Design - October 2007

Contents Editorial Shipments/Forecasts News Watch Applying Powder Coatings to Plastic Parts is No Longer a Pipe Dream New Technology Platform Provides the Ability for a single IC to Control Two- Motors in a Single Appliance, Simplifying Motor Control Design Advanced Motor-Control Techniques have Become More Accessible to a Wider Array of Appliances, Helping to Improve Efficiency and Reduce Noise Adding USB Host Capability to Appliances Permits In-Field Programming and Acquisition of Test Data ZigBee Modules Make it Easier to Design Wireless Connectivity into Applications New Concepts such as Rapid Tooling and Rapid Injection Molding Provide Stepping Stones Between Prototyping and Full Scale Production A Number of Factors and New Developments Affect the Decision on Whether to Build Prototypes In-House or Outsource to a Service Bureau DesignMart Advertiser’s Index Association Report: CEA

Appliance Design - October 2007

For optimal viewing of this digital publication, please enable JavaScript and then refresh the page. If you would like to try to load the digital publication without using Flash Player detection, please click here.