Universal Motor Control with Z8 Encore! XP 8-Pin Highly Integrated Microcontroller

Transcription

1 Application Note Universal Motor Control with Z8 Encore! XP 8-Pin Highly Integrated Microcontroller AN Abstract This Application Note discusses programmable speed control of a Universal Motor using Zilog s Z8 Encore! XP 8-pin microcontroller unit (MCU). In this application, based on the array of innovative on-chip integrated digital and analog hardware blocks, speed control requires a minimum set of external components and firmware development. Note: The source code file associated with this application note, AN05- SC0.zip is available for download at Motor control attributes including synchronization of MCU output signals based on the Zero Crossing of the AC line voltage and Speed Control are also discussed in this document. Note: This application discussed in this document is tested with ZDS II version Subsequent releases of ZDS II may require you to modify code supplied with this Application Note. Z8 Encore! Flash Microcontrollers Z8 Encore! products are based on the ez8 CPU and introduce Flash memory to Zilog s extensive line of 8-bit MCU. Flash memory in-circuit programming capability allows for faster development time and program changes in the field. The highperformance register-to-register based architecture of the ez8 core maintains backward compatibility with Zilog s Z8 MCU. Z8 Encore! MCUs combine a 0 MHz core with Flash memory, linear-register SRAM, and an extensive array of on-chip peripherals. These peripherals make the Z8 Encore! MCU suitable for a variety of applications including motor control, security systems, home appliances, personal electronic devices, and sensors. MDS GP Application Board Overview Zilog's general-purpose modular development system application board (MDS GP) is a platform for designing innovative applications using the Z8 Encore! and ez80acclaim! MDS-compatible microcontroller modules. The MDS GP application board features a character LCD display, a keypad matrix, 5 KB of fast SRAM, two relays with a terminal block, six high-drive outputs with terminal blocks, and a RS-485 interface/screw terminal block. Battery operation is supported to add portability and mobility to your design. The MDS GP application board acts as the perfect foundation for innovative development ideas with compatible connectors for the optional Trimble Lasson SQ GPS module, the Maxstream Wireless Data module (900 MHz or.4 GHz), and the Dinsmore 490 Digital Compass, along with a large breadboard area. Discussion The Z8 Encore! XP Flash MCU is based on Zilog's advanced ez8 8-bit CPU core and is ideally suited for implementation in Universal Motor control systems. Target applications include home appliances, power tools, and industrial automation. Copyright 008 by Zilog, Inc. All rights reserved.

2 Figure displays a block diagram of the device. Here, the rich set of on-chip integrated analog peripherals allows for realization of a number of enhanced control features, and also provides for low overall system cost. TM Figure. Block Diagram of Z8 Encore! XP Flash MCU The 0-bit analog-to-digital converter (ADC) provides for data conversion of up to eight singleended/differential channels with the choice of x or 0x differential input gain. Also, for high precision current measurements, an integrated on-chip transimpedance amplifier is integrated in the ADC module, eliminating the need for an additional external component. Along with the multi-channel ADC, the device's two enhanced 6-bit timer blocks featuring PWM and Capture and Compare capability can be used to operate two loads (motors) simultaneously. The direct LED drive output can be used to trigger LEDs at the onset of a pre-defined event, without the need for additional hardware. Other features include the integrated analog comparator, the Fail- Safe oscillator mechanism providing for reliable operation, an on-chip integrated temperature sensor, and up to 8 B of NVDS. Theory of Operation Universal motors are used in a variety of applications. These motors require relatively simple electronic drive circuit topologies and exhibit good power density (power/weight ratio) characteristics. Typical applications that use Universal motors include portable power tools, food processors, and mixers. This section describes the motor s key control attributes such as Speed Control and determination of the AC line's Zero Crossing characteristics aimed at subsequent synchronization of the MCU output signals. AN Page of 8

3 Figure displays the block diagram of the Universal motor system. Figure on page 4 displays the Universal motor control application board. In reference to this system, ramping up of the power delivered to the motor is realized via controlling the triggering/firing angle of the TRIAC using a single I/O output of the MCU. For controlling the motor speed, the firing angle of TRIAC is to be synchronized with the AC line voltage, thus detecting the time instants for zero crossing of AC line voltage. In this case, the onchip integrated analog comparator is used. Figure 4 on page 5 displays the motor voltage for different TRIAC firing angles. 0 MHz ez8 TM CPU Figure. Block Diagram of Universal Motor Control System AN Page of 8

4 Power Supply Capacitors Potentiometer for Speed Adjustment 8-Pin Z8 Encore! XP MCU Universal Motor Control Debug Interface Motor and Line Connections TRIAC Heat Sink and Ground Plate Figure. Universal Motor Control Application Board AN Page 4 of 8

5 Summary This Application Note demonstrates the use of the Z8 Encore XP! MCU for Universal motor control applications. The MCU's wide array of innovative, integrated digital and analog modules result in optimized control of the motor speed along with fault protection during an overload condition. In addition, on-chip integration of these features provides for reduced system cost and faster development cycle time. References The documents associated with Z8 Encore! XP available on are provided below: Z8 Encore! XP F08A Series Product Brief (PB06) Errata for Z8 Encore! XP F08A Series Product Update (UP0069) Figure 4. Motor Voltage: 8, 90, and 6 Degree TRIAC Firing Angles AN Page 5 of 8

6 Appendix A Glossary Definitions for terms and abbreviations used in this Application Note that are not commonly used are listed Table. Table. Glossary Term/Abbreviation ADC MCU MDS GP NVDS PWM Definition Analog-to-Digital Converter Microcontroller unit General-purpose modular development system (application board) Non Volatile Data Storage Pulse Width Modulation AN Page 6 of 8

7 Appendix B Schematics Appendix B displays the schematics of Z8 Encore! XP Universal Motor Control reference design. 5 4 D C B A R 4.99k C6 0.uF Notes: R4 4.99k R 0k DBG VREF NRESET High Voltage Use 8 mil or greater spacing C9 0.uF 4 R 0k 06 9C06A0JLHFT HV_LIN_DIV R 0k SMA SMA 06 9C06A0JLHFT Z8F04ASB00EC SOIC8 HV_CAP High Voltage Nets (HV_) Use 8 mil or greater spacing CURRENT High Current Use 00 mil oz traces (enclosed in Boxes) All caps and resistors are 060 unless otherwise marked VDD PA0/DBG PA/T0OUT PA/RESET U VSS PA5/CINP PA4/ANA PA/TIN D USJ D USJ D4 + C7 R5 5 + C 0.0uF VLINE /4W Through Hole 6.8uF/400V PWR JACK Through Hole EKXG40ELL6R8MJ6S C Through Hole 6.8uF/400V D UVRCMED N448W-7 SOD N479A DO-4 C8 0.0uF HV_LINE C0 DRIVE VREF 0.0uF R7 0k C 0uF/6V R8 0 + R8 00K R 0k D5 R9.0k PULL_UP P Q MMBTA R7 6.k BZX84-C4V SOT R0 47 CAP GATE 0805 ECJ-FBC475K C4 0.uF C5 4.7uF/6V I_SENSE Q N TO-9 Keystone 86 SPADE CONN Keystone 86 Keystone 86 TO-0 Mounted on Underside of Board Through Hole R W FR005 Keystone 86 LINE MOTOR+ High Current Use 00 mil oz traces High Voltage Use 8 mil or greater spacing Q F FUSE HV_SWITCH BTA4-800BW MOTOR- NEUTRAL High Current Use 00 mil oz traces J4 SPADE CONN J5 J6 SPADE CONN J7 SPADE CONN DBG Title 0805 GRN DBG INTERFACE J Header x R6 00 D6 GRN G_LED NRESET E E E MTHOLE MTHOLE MTHOLE DRIVE XP UNIVERSAL MOTOR CONTROL REF DESIGN J HDR/PIN x E4 MTHOLE NRESET DBG 5" Mounting holes on four corners Size Document Number Rev B XXXXXXX-XXX A R4 0K R5 0K J HDR/PIN x D C B A Tuesday, September 0, 005 Date: Sheet of 5 4 Figure 5. Z8 Encore! XP Universal Motor Control Reference Design AN Page 7 of 8

8 Warning: DO NOT USE IN LIFE SUPPORT LIFE SUPPORT POLICY ZILOG'S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS PRIOR WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL COUNSEL OF ZILOG CORPORATION. As used herein Life support devices or systems are devices which (a) are intended for surgical implant into the body, or (b) support or sustain life and whose failure to perform when properly used in accordance with instructions for use provided in the labeling can be reasonably expected to result in a significant injury to the user. A critical component is any component in a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system or to affect its safety or effectiveness. Document Disclaimer 008 by Zilog, Inc. All rights reserved. Information in this publication concerning the devices, applications, or technology described is intended to suggest possible uses and may be superseded. ZILOG, INC. DOES NOT ASSUME LIABILITY FOR OR PROVIDE A REPRESENTATION OF ACCURACY OF THE INFORMATION, DEVICES, OR TECHNOLOGY DESCRIBED IN THIS DOCUMENT. ZILOG ALSO DOES NOT ASSUME LIABILITY FOR INTELLECTUAL PROPERTY INFRINGEMENT RELATED IN ANY MANNER TO USE OF INFORMATION, DEVICES, OR TECHNOLOGY DESCRIBED HEREIN OR OTHERWISE. The information contained within this document has been verified according to the general principles of electrical and mechanical engineering. ez8, Z8, Z8 Encore!, Z8 Encore! XP, and ez80acclaim! are trademarks or registered trademarks of Zilog, Inc. All other product or service names are the property of their respective owners. AN Page 8 of 8 8