Power Quality Analyzer

• 3-phase voltage, current, frequency, measurement
• active, reactive, apparent power, power factor
• neutral current
• harmonics analysis up to 50th order
• quality - swell, dip, interruption, transient/over voltage, inrush current, unbalance rate
• real-time operation
• USB communication interface

• installation of esp-idf development environment

$ mkdir ~/esp
$ cd ~/esp
$ git clone -b v5.5.1 --recursive https://github.com/espressif/esp-idf.git
$ cd esp-idf
$ ./install.sh esp32s3

• pqa project configuration

$ cd ~/projects.local/elektro/pq-anal/fw/pqa
$ . ~/esp/esp-idf/export.sh
$ vim main/idf_component.yml
$ cat main/idf_component.yml
## IDF Component Manager Manifest File
dependencies:
...
espressif/esp-dsp: '*'
$ idf.menuconfig
  * Serial flasher config ---> Flash size (8MB)
  * Component config ---> ESP PSRAM ---> [*] Support for external, SPI-connected RAM
  * ---> SPI RAM Config ---> Mode (QUAD/OCT) of SPI RAM chip in use (Octal Mode PSRAM)
  * ---> SPI RAM Config ---> SPI RAM access method (Make RAM allocatable using malloc() as well)
  * ---> SPI RAM Config ---> (1024) Maximum malloc size, in bytes, to always put in internal memory
  * ---> SPI RAM Config ---> Allow .bss segment placed in external memory
  * Component config ---> ESP System Settings ---> CPU frequency (160MHz)
  * Component config ---> LWIP ---> SNTP ---> (2) Maximum number of NTP servers
  * Component config ---> DSP Library ---> DSP Optimization (ANSI C)
  * Component config ---> DSP Library ---> Maximum FFT length (4096)

• build, flash and monitor

$ idf.py fullclean
$ idf.py build ; echo $?
$ idf.py -p /dev/tty.usbmodem11101 flash
$ idf.py -p /dev/tty.usbmodem11101 monitor

<tikzjax> \usetikzlibrary{circuitikz} \begin{circuitikz}

  \draw (0,0) to[R, l=$R_1$] (2,0)
            to[C, l=$C_1$] (2,2)
            to[V, l=$V_s$] (0,2) -- (0,0);

\end{circuitikz} </tikzjax>

For three-phase balanced system, the sum of instantaneous values of phase voltages (as well as currents) is zero: $$v_{L1} + v_{L2} + v_{L3} = i_{L1} + i_{L2} + i_{L3} = 0$$ In such case also $$u_{N1} = u_{N2} = 0$$ and $$v_1 = v_{L1}\frac{R_{12}}{R_{11} + R_{12}}$$