International Appliance Manufacturing 2007

Energy regulations. This active PFC block comprises an inductor, a power switch and a diode. The DSC’s ADCs are used to measure the current and voltage values from the DC bus. Based on these inputs, the DSC controls the power switch using a PWM module. This is accomplished by executing a PID loop in the DSC, to keep the PF value close to unity. The output-inverter section features a voltage-source inverter that is comprised of two power switches per phase, with freewheeling diodes connected across each switch. The motor winding is connected to the center of the switches. DC voltage from the ‘Input converter block’ is synthesized using this output inverter, to obtain a variable voltage and frequency power supply to control the motor. DSC to Washing Machine Interface Being able to access the DSC’s specialized, on-chip peripherals enables you to implement the control algorithms easily. Figure 6 shows an example of a washing mashing machine interface, based on the dsPIC DSC controller. The DSC’s ADC channels can be used to measure the motor current, the motor temperature and heat-sink temperature (connected to the power switches). Depending on the application requirement, additional ADC channels can be used to measure temperature or current, as shown in figure 6. General-purpose inputs and outputs (I/Os) are used for interface switches and LCD or LED displays. In some applications, the system can use a single controller to handle both motor and system controls. Serial ports on the dspIC DSC can also be used for system calibration and diagnosing any faults in the system. Securing Appliance IP In today’s global engineering environment, there could be design teams at multiple design locations working together on a family of appliances. For instance the FOC for washing machine control may be developed at location A; front-panel design and electronics could come from location B; at location C, there could be system integrators doing the final assembly and testing of appliances. All these design teams will have their own unique IP, which they would like to see it protected. Having anticipated this need, Microchip’s dsPIC DSC family offers the CodeGuard™ security feature, which enables the security of IP in environments where there is a collaborative design effort. Please visit www.microchip.com/codeguard to learn more about the CodeGuard security feature including how an appliance manufacturer can use it to improve IP protection. Conclusion By using DSCs in your appliance design, an efficient sensorless FOC algorithm can be implemented. By adopting FOC, higher efficiencies of up to 95 percent can be achieved in PMSM motor applications. Additionally, since FOC aids in controlling the stator current, torque ripple is greatly reduced, enabling the construction of quieter washing machines. This saves the energy and responds to dynamic load changes, while reducing audible noise. The manufacturing of washing machines can be made more efficient with Microchip’s dsPIC DSCs. The common dsPIC DSC production platform makes it easy and convenient for appliance makers to offer a range of washing machines models that use PMSM motors and the FOC algorithm for motor control. These softwarebased motor control designs allow rapid customization of newer appliance models to address multiple markets. The only changes you would need, in these cases are to FOC algorithm parameters and the power section of the control. Note: The dsPIC, Microchip name and logo, are registered trademarks of Microchip Technology Inc. in the U.S.A. and other countries. CodeGuard is a trademark of Microchip Technology Inc. Figure 6: DSC as the System controller in a Washing Machine 52 International Appliance Manufacturing 2007 http://www.microchip.com/codeguard

Table of Contents Feed for the Digital Edition of International Appliance Manufacturing 2007

Contents White Goods- made out of Germany Customer Benefits from Coil Coating Products with “Metal Looks” In Mould Labelling for the Appliance Industry Only Pay for What You Need with Trimmed Concept for Appliance Manufacturers New Lighting Trend in the Oven Innovation in Light and Design- An Introduction Influence of Recycled Material on the Mechanical Performance and Stabilization System of GB355WG Why Choose a Fast Diode Mosfet in a Three-Phase Inverter Topology Providing Six-step Current Commutation Appliance Motor Control Made More Efficient, Cost- Effective Through Sensorless FOC Control Save, Bright and Spotlessly Clean Stainless Steel Strip is Stepping Out with the Launch of Sandvik Decorex New Hot Melt Silicone Sealant Technology Reduces Time, Costs for Appliance Manufacturers IR Touch Controls- The 4th Generation Coil Coating Ensures White Goods at Leading Edge Design Coil Coating Ensures White Goods at Leading Edge Design New material Solutions That Help Satisfy Consumer Wants, Producer Needs and Regulatory Musts for Tomorrow’s Appliances Welcome to the Chinese Century Multibase PPμ Talc Switches and Sensors Rise to the Challenge Development by SKF of Value Added Solutions (VAS) for Washing Machine Applications Silicon Adhesives for Display Cabinet Construction Instantaneous Hot Water for Beverages A Very Small Real Time Scheduler for Both Cost Effective Home Appliance Controllers and Higher Level Firmware Development Dishwasher Circulation Pump Evolution Nucleated PP Opens the Door to Improvements in Design and Productivity of Molded Appliance Articles Energy Saving Solutions for Home Appliances Sensors Sensors Sensors and No Way Back An Integrated Driver for LED Panel Renders the Traditional MCU Obsolete Integrating Hall-effect Magnetic Sensor Technology into Modern Household Appliances High Efficiency, Low Cost BLDC Evaperoator Fan Motor with a Soft Magnetic Composite Stator and Bud TM Controller Household Dishwashers Energy Consumption Reduction- A Success Story Novel fan Design Offers Energy Savings to Refrigeration Market

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