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| STPM32高精度单相电表解决方案 |
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| 文章来源： 更新时间：2014/10/17 10:38:00 |
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ST公司的STPM32是采用Rogowski线圈,电流变压器或并联电流传感器在线测量电能的高精度集成电路,包括模拟和数字两部分.模拟部分包括两个可编低噪音低失调增益放大器,四个两阶24位sigmadelta ADC,两个带单独温度补偿的能带隙电压基准,低压降稳压器和DC缓冲器;数字部分包括数字滤波器,硬连接的DSP,连接输出的DFE和串行通信接口(UART/SPI).本文介绍了STPM32主要特性和框图,DSP框图, EVALSTPM32评估板主要特性,电路图和材料清单.
The STPM3x is an ASSP family designed for high accuracy measurement of power and energies in power line systems using the Rogowski coil, current transformer or shunt current sensors. The STPM3x provides instantaneous voltage and current waveforms and calculates RMS values of voltage and currents, active, reactive and apparent power and energies. The STPM3x is a mixed signal IC family consisting of an analog and a digital section. The analog section consists of up to two programmable gain low-noise low-offset amplifiers and up to four 2nd order 24-bit sigmadelta ADCs, two bandgap voltage references with independent temperature compensation, a low drop voltage regulator and DC buffers. The digital section consists of digital filtering stage, a hardwired DSP, DFE to the input and a serial communication interface (UART or SPI). The STPM3x is fully configurable and allows a fast digital system calibration in a single point over the entire current dynamic range.
STPM32主要特性:
• Active power accuracy:
– <0.1% error over 5000: 1 dynamic range
– <0.5% error over 10000: 1 dynamic range
• Exceeds 50-60 Hz EN 50470-x, IEC 62053-2x, ANSI12.2x standard requirements for AC watt meters
• Reactive power accuracy:
– <0.1% error over 2000:1 dynamic range
• Dual mode apparent energy calculation
• Instantaneous and averaged power
• RMS and instantaneous voltage and current
• Under and overvoltage detection (sag and swell) and monitoring
• Overcurrent detection and monitoring
• UART and SPI serial interface with programmable CRC polynomial verification
• Programmable LED and interrupt outputs
• Four independent 24-bit 2nd order sigma-delta ADCs
• Two programmable gain chopper stabilized low-noise and low-offset amplifiers
• Bandwidth 3.6 kHz @ -3 dB
• Vcc supply range 3.3 V±10%
• Supply current Icc 4 mA (STPM32)
• Input clock frequency 16 MHz, Xtal or external
• Twin precision voltage reference: 1.23 V with independent programmable TC, 10 ppm/℃ typ.
• Internal low drop regulator @ 3 V (typ.)
• QFN packages
• Operating temperature -40 ℃~+85 ℃
图1. STPM32框图
图2. STPM32 DSP框图
EVALSTPM32评估板
The STPM3x is an ASSP family of mixed signals designed for high accuracy measurement of power and energy in power line systems using the Rogowski coil, current transformer or shunt current sensors. According to p/n, the device has up to two voltages and two current channels, for energy measurement in dual-phase and single-phase (with or without neutral current monitoring) electricity metering systems.
The STPM3x devices provide instantaneous voltage and current waveforms and calculate voltage and current RMS values, active, reactive and apparent powers and energies for each channel. Moreover, they embed a full set of calibration and compensation parameters which allow the meter to fit tight accuracy standards (EN 50470-x, IEC 62053-2x, ANSI12.2x for AC watt meters). All calculated data, as well as configuration parameters, are stored in internal 32-bit registers accessible through SPI or UART peripheral.
Three boards are available for evaluation purpose:
• EVALSTPM34 board with 2 CT
• EVALSTPM33 board with CT + shunt
• EVALSTPM32 board with shunt
EVALSTPM32评估板主要特性:
• 0.2% accuracy single-phase meter reference design
• USB port for connection to the isolated hardware programmer STEVAL-IPE023V1 and PC GUI
• RS232 and UART isolated port for connection to PC GUI
• SPI/UART switch for device peripheral selection
• 2x programmable LEDs on-board
• Digital expansion to external system-on-chip or MCU
• Power supply 3.3 V: external or through the STEVAL-IPE023V1 isolated USB board
• IEC61000 standard compliant
图3. EVALSTPM32评估板外形图
图4. EVALSTPM32评估板电路图
图5. EVALSTPM3x评估板电路图(RS232/UART)
图6. EVALSTPM32评估板单相系统连接图 |
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