AN1627 Freescale Semiconductor / Motorola, AN1627 Datasheet
AN1627
Related parts for AN1627
AN1627 Summary of contents
Page 1
... The three phase voltage system (see Figure 1-1.), with a rectangular shape, is used to create This document contains information on products under development. Motorola reserves the right to change or discontinue these products without notice. MOTOROLA LTD., 1999. All trademarks are recognized. For More Information On This Product, AN1627/D Go to: www.freescale.com Order this document by AN1627/D AN1627 ...
Page 2
... Real impossibility to make additional connections between position sensors and the control unit 2. Cost of the position sensors & wiring The first point might be solved by integration of the driver within the motor body. However a significant number of applications requiring a sensorless solution still remain. MOTOROLA 2 Three Phase Voltage System M electrical angle AN1627 REV 0.2 ...
Page 3
... The zero voltage level of the whole model is put at one half of the DC-Bus voltage. This simplifies the mathematical expressions when output waveforms from the power stage are calculated. For More Information On This Product, AN1627 REV 0.2 Power Stage - Motor Topology ). Six semiconductor switches ( to: www ...
Page 4
... --- - to: www.freescale.com (EQ 2-1.) (EQ 2-2.) (EQ 2-3.) AN1627 REV 0.2 ...
Page 5
... The Figure 2-2. shows branch and motor phase winding voltages during a 0-360°electrical interval. Shaded rectangles designate the validity of the equation (EQ 2-6.). In other words, the Back-EMF voltage can be sensed during designated intervals Figure 2-2. For More Information On This Product, AN1627 REV 0 PWM Ab Bt ...
Page 6
... A and u shows one interesting fact. These voltages can differ to: www.freescale.com 360 390 360 390 uVA uA 360 390 u0 360 390 id0 iA 360 390 Torque VA AN1627 REV 0.2 ...
Page 7
... Figure 2-4. For More Information On This Product, AN1627 REV 0.2 (see (EQ 2-1.)) explains how this depends on 0 uiA PsiA 120 150 180 210 240 270 300 330 120 150 180 210 240 270 300 330 ...
Page 8
... Go to: www.freescale.com 360 390 360 390 uVA uA 360 390 u0 360 390 id0 iA 360 390 Torque AN1627 REV 0.2 ...
Page 9
... The Table 3-1. summarizes the requirements of a typical (low-cost high-volume) application with a Brushless DC motor. Motor type: Motor characteristic: Drive input characteristic: Load characteristic: For More Information On This Product, AN1627 REV 0 The Average Motor Torque 6 stator poles, three-phases, four rotor poles Motor ...
Page 10
... A Simple power supply (rectified mains) contains a Line and a RF filter in order to fulfil the European Community Regulation (IEC555-1). As apparent, this concept uses a common ground (no isolation is used). For More Information On This Product, MOTOROLA 10 Power Supply Power Stage (3xdriver & 6xIGBT) I-sense U-adapt + Filter Control Board MC68HC705MC4 Figure 4-1. System Go to: www.freescale.com M Filter Position Recognition AN1627 REV 0.2 ...
Page 11
... Freescale Semiconductor, Inc strongly recommended to use opto-isolation (optocouplers and optoisolation amplifiers) during the development time to avoid any damage to the development equipment. For More Information On This Product, AN1627 REV 0.2 WARNING Go to: www.freescale.com MOTOROLA 11 ...
Page 12
... Then the PLL controller keeps the phase shift motor is now running with a good efficiency. Current measurement, over-current detection and motor stall detection is still continuously applied. For More Information On This Product, MOTOROLA the right value by controlling the phase voltage. The Go to: www.freescale.com < 180°) AN1627 REV 0.2 ...
Page 13
... The Input Capture Function and input pin (TCAP2) are initialized. initialization: Current Controller All registers used by PI type of Current Controller are cleared. initialization: Finally, interrupts are enabled. For More Information On This Product, AN1627 REV 0.2 Timer Input Capture 2 <5s 0.1s PLL Acquisition 2-3s - main routine ...
Page 14
... The current peak during one commutation is detected higher than the preset limit (2.5A), then the PWM duty cycle is decreased. The Timer Input Capture interrupt is enabled ~20 For More Information On This Product, MOTOROLA 14 s after new value of the DC-Bus current have s period), Speed Setting & DC-Bus Figure 5-2. PLL Acquisition Go to: www.freescale.com s after AN1627 REV 0.2 ...
Page 15
... The zero crossing feedback is handled and the angle feedback is captured between commutations, then the zero crossing comparator feedback (TCAP2 pin) is sampled directly, just before the commutation takes place (see Figure 5-3., For More Information On This Product, AN1627 REV 0.2 Figure 5-3. Control signals Go to: www.freescale.com < ...
Page 16
... For More Information On This Product, MOTOROLA 16 < 90° or > 180° > 180°) are counted (by EMF_Lo, EMF_OK and EMF_Hi E MF_Hi) then decrease PWM duty cycle else increase PWM duty cycle NOTE s . The PI controller calculates the PWM value Go to: www.freescale.com > 90°). AN1627 REV 0.2 ...
Page 17
... ISR. On the other hand Interrupt is caused by Timer2, then the preset values (calculated in Commutation subroutine) are put into the PWM registers (CtlA, CtlB) and the MUX command is output too. For More Information On This Product, AN1627 REV 0.2 Period PeriodStop ...
Page 18
... MOTOROLA then Timer2 obtains priority and the Measurement Synchronization with PWM in the PLL. Cycle time (6MHz clock frequency) Min. typical 22 s ~ ~80 s ---- ~25 s Table 5-1. Go to: www.freescale.com and is typically Max. 170 s 180 ---- AN1627 REV 0.2 ...
Page 19
... Bytes $00FF $0100 1.35 kB User EPROM/ROM 3584 Bytes $0EFF $0F00 Self-Check/ Bootstrap ROM 16 Bytes $0FEF $0FF0 User Vectors Eprom/ROM 16 Bytes $0FFF For More Information On This Product, AN1627 REV 0.2 kByte 1.20 1.00 0.80 0.60 0.40 0.20 0.00 Figure 5-6. Memory Mapping Go to: www.freescale.com Variables Tables INIT Start-Align Start-Ramp-up Start-Stabil Start-PLL lock ...
Page 20
... Detection signal is transferred to the microcontroller’s Input Capture pin (TCAP2). For More Information On This Product, MOTOROLA 20 560k 560k 560k MUX 1n 2x27k MUX Command Back-EMF Sensing Circuit Diagram The Zero Crossing Detection Go to: www.freescale.com Zero Crossing Detection signal × 1nF) filter prevents the AN1627 REV 0.2 ...
Page 21
... The Shut-down input of the IR2112 is used to switch off all IGBT’s when over-current detection is activated. Detailed information about the power stage board can be found in the application note: AN1590 - “High Voltage Medium Power Board for Three Phase Motors”. For More Information On This Product, AN1627 REV 0.2 +5V Power Stage AD_Volt ...
Page 22
... F (X2) 2×2500 pF (Y) Main Power Supply Filters Go to: www.freescale.com SW3 DIRECTION PWM - B bottom PWM - C top PWM - C bottom LED VCC 390 Fault (Over-current) TX RXD 390 Zero cross. det. 100nF VCC Analog (GND) 100nF VCC 10k + 10uF AD Current Analog (GND) AN1627 REV 0.2 ...
Page 23
... But, a complete system solution depends not only on a microcontroller. Motor control design can be drastically simplified using integrated parts, such as co-pack IGBT’s and integrated drivers, so that a low-cost target can be achieved. For More Information On This Product, AN1627 REV 0.2 Go to: www.freescale.com MOTOROLA 23 ...
Page 24
... For More Information On This Product, MOTOROLA 24 APPENDIX A Copack Results Motor phase current Temperature at the start of the test Temperature at the end of the test Max.temperature during 30min test Table 1. Measured waveforms Go to: www.freescale.com 1.13A mean 1.36A RMS 2.14A peak 30.8°C 80.0°C 81.1°C AN1627 REV 0.2 ...
Page 25
... Ch2 and Ch3 are divided by the resistor network down-to 0-15V level). The DC-Bus voltage is created by rectifying the mains and therefore channel 2 varies according to charging/discharging of the DC-Bus capacitor (10ms period). This variation has no impact on the Back-EMF zero crossing detection. For More Information On This Product, AN1627 REV 0.2 Figure 2. Figure 3. ...
Page 26
... TCAP2 - Zero cross. detection IRQ Wake up signal RESET RESET Table 2. Purpose PWM of motor phase voltage Measurement of Speed Setting, DC-Bus current, DC-Bus voltage Commutation (software Timer2) and synchroniza- tion of A/D conv. with PWM (software Timer1) Capture of edge of Zero Crossing Detection signal Table 3. Go to: www.freescale.com AN1627 REV 0.2 ...
Page 27
... The program was written with special care to reduce memory use in order to achieve the best result. Table 4. shows how much memory was needed to run the BLDC motor in the sensorless application. A significant part of memory is still available. Memory SRAM User EPROM/ROM For More Information On This Product, AN1627 REV 0.2 Available Used 176Bytes 60Bytes 3.5kBytes 1 ...
Page 28
... Motorola, Inc. Motorola, Inc Equal JAPAN: Nippon Motorola Ltd.; SPD, Strategic Planning Office, 141, 4–32–1 Nishi–Gotanda, Shinagawa–ku, Tokyo, Japan. 81–3–5487–8488 ASIA/PACIFIC: Motorola Semiconductors H.K. Ltd.; 8B Tai Ping Industrial Park, Go to: www.freescale.com Mfax is a trademark of Motorola, Inc. AN1627/D ...