Eload_cv_sweep_graph.py

#Eload CV Sweep graphing results - geared for solar panel testing

import pandas as pd
import matplotlib.pyplot as plt
import FileIO
import os

def calc_power(df):
	df['current_pos'] = -1 * df['current']
	df['power'] = df['voltage'] * df['current_pos']

def plot_power(df, test_name, save_filepath = ''):
    if df.size == 0:
        return

    fig, ax = plt.subplots()
    fig.set_size_inches(12,10)
    ax2 = ax.twinx()

    ax.plot('current_pos', 'voltage', '.-b', data = df, label = "Voltage (V)")
    ax2.plot('current_pos', 'power', '.-r', data = df, label = "Power (W)")

    title = "{} Power".format(test_name)

    fig.suptitle(title)
    ax.set_ylabel('Voltage (V)')
    ax2.set_ylabel('Power (W)')
    ax.set_xlabel('Current (A)')

    ax.grid(b=True, axis='both')

    #Add a point at the MPP and lines for mpp_v, mpp_i
    mpp_index = df['power'].argmax()
    mpp_p = df['power'].iat[mpp_index]
    mpp_i = df['current_pos'].iat[mpp_index]
    mpp_v = df['voltage'].iat[mpp_index]

    ax.hlines(y = mpp_v, xmin = min(df['current_pos']), xmax = max(df['current_pos']), color = 'g', label = 'MPP Voltage: {}V'.format(round(mpp_v, 2)))
    ax.vlines(x = mpp_i, ymin = min(df['voltage']), ymax = max(df['voltage']), color = 'g', label = 'MPP Current: {}A'.format(round(mpp_i, 2)))
    ax.plot(mpp_i, mpp_v, 'o', color = 'r', label = 'MPP Power: {}W'.format(round(mpp_p, 2)))
    
    fig.legend(loc = 'upper left')
    
    #save the file if specified
    if(save_filepath != ''):
        plt.savefig(os.path.splitext(save_filepath)[0])

    plt.show()
	

def create_graphs(filepaths = None, save_dir = None):
	if filepaths == None:
		#get all the files to graph
		filepaths = FileIO.get_multiple_filepaths()
	
	if save_dir == None:
		save_dir = FileIO.get_directory(title = "Choose a location to save the graphs")
		
	for filepath in filepaths:
		dir_name, filename = os.path.split(filepath)
		
		split_path = filename.split(" ")
		test_name = split_path[0]
		graph_filename = os.path.join(save_dir, "{}_Graph".format(test_name))
		
		#get the input voltage for this test
		df = pd.read_csv(filepath)
		
		calc_power(df)
		plot_power(df, test_name, graph_filename)

################ PROGRAM ###################

if __name__ == '__main__':
	create_graphs()