def METHOD_NAME(t):
    if t <= 300 * si.s:
        return 0
    if t <= 1500 * si.s:
        return 6e2 * (1 + np.cos(np.pi * ((t - 300) / 600 - 1)))
    return 5e2 * (1 + np.cos(np.pi * ((min(2400, t) - 1500) / 900 - 1)))