Пример #1
0
def system_var_R(use_ramp):
    T = 20e-6
    ki = 1
    Vin = 5
    Vref = 5
    C0 = 47e-6
    L0 = 10e-6
    R0 = 5

    t0 = 0
    t_end = 200 * T
    t_span = np.array([t0, t_end])

    #y0 = np.array([9.3124, 1.2804])
    y0 = np.array([10.154335434351671, 1.623030961224813])

    fun_rtol = 1e-12
    fun_atol = 1e-14

    def R_fun_square(t):
        n_period = int(t / T)
        if n_period % 100 < 75:
            return R0
        return 2 * R0

    def R_fun_sin(t):
        F = 500  # [Hz]
        dR0 = R0 / 10
        return R0 - dR0 / 2 + dR0 * np.sin(2 * np.pi * F * t)

    boost = Boost(0, T=T, ki=ki, Vin=Vin, Vref=Vref, C=C0*30, L=L0*2, \
                  R=R_fun_square, use_compensating_ramp=use_ramp)

    print('Vector field index at the beginning of the integration: %d.' %
          boost.vector_field_index)
    sol = solve_ivp_switch(boost, t_span, y0, \
                           method='BDF', jac=boost.jac, \
                           rtol=fun_rtol, atol=fun_atol)
    print('Vector field index at the end of the integration: %d.' %
          boost.vector_field_index)

    fig, (ax1, ax2) = plt.subplots(2, 1, sharex=True)
    ax1.plot(sol['t'] * 1e6, sol['y'][0], 'k', lw=1)
    ax1.set_ylabel(r'$V_C$ (V)')
    ax2.plot(sol['t'] * 1e6, sol['y'][1], 'k', lw=1)
    ax2.set_xlabel(r'Time ($\mu$s)')
    ax2.set_ylabel(r'$I_L$ (A)')
    ax2.set_xlim(t_span * 1e6)
    plt.show()
Пример #2
0
def shooting(use_ramp):

    T = 20e-6
    ki = 1
    Vin = 5
    Vref = 5

    boost = Boost(0,
                  T=T,
                  ki=ki,
                  Vin=Vin,
                  Vref=Vref,
                  clock_phase=0,
                  use_compensating_ramp=use_ramp)

    fun_rtol = 1e-10
    fun_atol = 1e-12

    y0_guess = np.array([Vin, 0])

    t_tran = 0.1 * T

    if t_tran > 0:
        tran = solve_ivp_switch(boost, [0,t_tran], y0_guess, method='BDF', \
                                jac=boost.jac, rtol=fun_rtol, atol=fun_atol)
        fig, (ax1, ax2) = plt.subplots(2, 1, sharex=True)
        ax1.plot(tran['t'] / T, tran['y'][0], 'k')
        ax1.set_ylabel(r'$V_C$ (V)')
        ax2.plot(tran['t'] / T, tran['y'][1], 'k')
        ax2.set_xlabel('No. of periods')
        ax2.set_ylabel(r'$I_L$ (A)')
        plt.show()

    T_large = 5 * T
    T_small = T

    estimate_T = False

    shoot = EnvelopeShooting(boost, T_large, estimate_T, T_small, \
                             tol=1e-3, env_solver=BEEnvelope, \
                             env_rtol=1e-2, env_atol=1e-3, \
                             var_rtol=1e-1, var_atol=1e-2, \
                             fun_solver=solve_ivp_switch, \
                             rtol=fun_rtol, atol=fun_atol, \
                             method='BDF', jac=boost.jac)
    sol_shoot = shoot.run(y0_guess)
    print('Number of iterations: %d.' % sol_shoot['n_iter'])

    t_span_var = [0, 1]
    boost.with_variational = True
    boost.variational_T = T_large

    col = 'krgbcmy'
    lw = 0.8
    fig, ax = plt.subplots(3, 2, sharex=True, figsize=(12, 7))

    for i, integr in enumerate(sol_shoot['integrations']):

        y0 = integr['y'][:2, 0]
        y0_var = np.concatenate((y0, np.eye(2).flatten()))
        sol = solve_ivp_switch(boost,
                               t_span_var,
                               y0_var,
                               method='BDF',
                               rtol=fun_rtol,
                               atol=fun_atol)

        for j in range(2):
            ax[0, j].plot(sol['t'],
                          sol['y'][j],
                          col[i],
                          lw=lw,
                          label='Iter #%d' % (i + 1))
            ax[0, j].plot(integr['t'],
                          integr['y'][j],
                          col[i] + 'o-',
                          lw=1,
                          ms=3)
            for k in range(2):
                n = j * 2 + k
                ax[j + 1, k].plot(sol['t'], sol['y'][n + 2], col[i], lw=lw)
                ax[j + 1, k].plot(integr['t'],
                                  integr['y'][n + 2],
                                  col[i] + 'o-',
                                  lw=1,
                                  ms=3)
                ax[j + 1, k].set_ylabel(r'$\Phi_{%d,%d}$' % (j + 1, k + 1))
                ax[j + 1, k].set_xlim([0, 1])
            ax[2, j].set_xlabel('Normalized time')
    ax[0, 0].legend(loc='best')
    ax[0, 0].set_ylabel(r'$V_C$ (V)')
    ax[0, 1].set_ylabel(r'$I_L$ (A)')
    plt.savefig('boost_shooting.pdf')
    plt.show()
Пример #3
0
def variational_envelope(use_ramp,
                         N_periods=100,
                         eig_vect=None,
                         compare=False):
    if compare and eig_vect is None:
        print(
            'You must provide the initial eigenvectors if compare is set to True.'
        )
        return

    T = 20e-6
    ki = 1
    Vin = 5
    Vref = 5

    boost = Boost(0,
                  T=T,
                  ki=ki,
                  Vin=Vin,
                  Vref=Vref,
                  clock_phase=0,
                  use_compensating_ramp=use_ramp)

    fun_rtol = 1e-10
    fun_atol = 1e-12

    t_tran = 50 * T

    if t_tran > 0:
        print(
            'Vector field index at the beginning of the first integration: %d.'
            % boost.vector_field_index)
        sol = solve_ivp_switch(boost, [0,t_tran], np.array([Vin,1]), \
                               method='BDF', jac=boost.jac, \
                               rtol=fun_rtol, atol=fun_atol)
        y0 = sol['y'][:, -1]
        print('Vector field index at the end of the first integration: %d.' %
              boost.vector_field_index)
        plt.figure()
        ax = plt.subplot(2, 1, 1)
        plt.plot(sol['t'] * 1e6, sol['y'][0], 'k')
        plt.ylabel(r'$V_C$ (V)')
        plt.subplot(2, 1, 2, sharex=ax)
        plt.plot(sol['t'] * 1e6, sol['y'][1], 'r')
        plt.xlabel(r'Time ($\mu$s)')
        plt.ylabel(r'$I_L$ (A)')
        plt.show()
    else:
        y0 = np.array([8.6542, 0.82007])

    T_large = N_periods * T
    T_small = T
    boost.with_variational = True
    boost.variational_T = T_large

    t_span_var = [0, 1]
    y0_var = np.concatenate((y0, np.eye(len(y0)).flatten()))

    sol = solve_ivp_switch(boost,
                           t_span_var,
                           y0_var,
                           method='BDF',
                           rtol=fun_rtol,
                           atol=fun_atol)

    rtol = 1e-1
    atol = 1e-2
    be_var_solver = BEEnvelope(boost, [0,T_large], y0, T_guess=None, T=T_small, \
                               env_rtol=rtol, env_atol=atol, max_step=1000,
                               is_variational=True, T_var_guess=None, T_var=None, \
                               var_rtol=rtol, var_atol=atol, solver=solve_ivp_switch, \
                               rtol=fun_rtol, atol=fun_atol, method='BDF')
    trap_var_solver = TrapEnvelope(boost, [0,T_large], y0, T_guess=None, T=T_small, \
                                   env_rtol=rtol, env_atol=atol, max_step=1000,
                                   is_variational=True, T_var_guess=None, T_var=None, \
                                   var_rtol=rtol, var_atol=atol, solver=solve_ivp_switch, \
                                   rtol=fun_rtol, atol=fun_atol, method='BDF')
    print('-' * 100)
    var_sol_be = be_var_solver.solve()
    print('-' * 100)
    var_sol_trap = trap_var_solver.solve()
    print('-' * 100)

    eig, _ = np.linalg.eig(np.reshape(sol['y'][2:, -1], (2, 2)))
    print('         correct eigenvalues:', eig)
    eig, _ = np.linalg.eig(np.reshape(var_sol_be['y'][2:, -1], (2, 2)))
    print('  BE approximate eigenvalues:', eig)
    eig, _ = np.linalg.eig(np.reshape(var_sol_trap['y'][2:, -1], (2, 2)))
    print('TRAP approximate eigenvalues:', eig)

    if compare:
        data = np.loadtxt('EigFuncDaniele.txt')
        t = (data[:, 0] - T_large) / T_large

        n_steps = len(var_sol_be['M'])
        y = np.zeros((boost.n_dim**2, n_steps + 1))
        y[:, 0] = eig_vect.flatten()
        for i, mat in enumerate(var_sol_be['M']):
            y[:, i +
              1] = (mat @ np.reshape(y[:, i],
                                     (boost.n_dim, boost.n_dim))).flatten()

        fig, ax = plt.subplots(boost.n_dim, boost.n_dim, sharex=True)
        ax[0, 0].plot(t, data[:, 1], 'k.-')
        ax[0, 0].plot(var_sol_be['t'], y[0, :], 'ro')
        ax[0, 1].plot(t, data[:, 3], 'k.-')
        ax[0, 1].plot(var_sol_be['t'], y[1, :], 'ro')
        ax[1, 0].plot(t, data[:, 2], 'k.-')
        ax[1, 0].plot(var_sol_be['t'], y[2, :], 'ro')
        ax[1, 1].plot(t, data[:, 4], 'k.-')
        ax[1, 1].plot(var_sol_be['t'], y[3, :], 'ro')
        for i in range(2):
            for j in range(2):
                ax[i, j].set_xlim([0, 1])
                ax[i, j].set_ylim([-1, 1])

    labels = [r'$V_C$ (V)', r'$I_L$ (A)']
    fig, ax = plt.subplots(3, 2, sharex=True)
    for i in range(2):
        ax[0, i].plot(sol['t'], sol['y'][i], 'k', lw=1)
        ax[0, i].plot(var_sol_be['t'], var_sol_be['y'][i], 'rs-', ms=3)
        ax[0, i].plot(var_sol_trap['t'], var_sol_trap['y'][i], 'go-', ms=3)
        ax[0, i].set_ylabel(labels[i])
        ax[0, i].set_xlim([0, 1])
        for j in range(2):
            k = i * 2 + j
            ax[i + 1, j].plot(sol['t'], sol['y'][k + 2], 'k', lw=1)
            ax[i + 1, j].set_ylabel(r'$\Phi_{%d,%d}$' % (i + 1, j + 1))
            ax[i + 1, j].plot(var_sol_be['t'],
                              var_sol_be['y'][k + 2],
                              'rs',
                              ms=3)
            ax[i + 1, j].plot(var_sol_trap['t'],
                              var_sol_trap['y'][k + 2],
                              'go',
                              ms=3)
            ax[i + 1, j].set_xlim([0, 1])
        ax[2, i].set_xlabel('Normalized time')

    plt.show()
Пример #4
0
def variational_integration_var_R(use_ramp, N_periods=100, compare=False):

    T = 20e-6
    ki = 1
    Vin = 5
    Vref = 5
    C0 = 47e-6
    L0 = 10e-6
    R0 = 5

    def R_fun(t):
        n_period = int(t / T)
        if n_period % 100 < 75:
            return R0
        return 2 * R0

    boost = Boost(0,
                  T=T,
                  ki=ki,
                  Vin=Vin,
                  Vref=Vref,
                  C=C0 * 30,
                  L=L0 * 2,
                  R=R_fun,
                  use_compensating_ramp=use_ramp)

    fun_rtol = 1e-12
    fun_atol = 1e-14

    t_tran = 0 * T

    if t_tran > 0:
        y0 = np.array([Vin, 1])
        print(
            'Vector field index at the beginning of the first integration: %d.'
            % boost.vector_field_index)
        sol = solve_ivp_switch(boost, [0,t_tran], y0, \
                           method='BDF', jac=boost.jac, \
                           rtol=fun_rtol, atol=fun_atol)
        print('Vector field index at the end of the first integration: %d.' %
              boost.vector_field_index)
        plt.figure()
        ax = plt.subplot(2, 1, 1)
        plt.plot(sol['t'] * 1e6, sol['y'][0], 'k')
        plt.ylabel(r'$V_C$ (V)')
        plt.subplot(2, 1, 2, sharex=ax)
        plt.plot(sol['t'] * 1e6, sol['y'][1], 'r')
        plt.xlabel(r'Time ($\mu$s)')
        plt.ylabel(r'$I_L$ (A)')
        plt.show()
        y0 = sol['y'][:, -1]
    else:
        #y0 = np.array([8.6542,0.82007])
        y0 = np.array([10.154335434351671, 1.623030961224813])

    T_large = N_periods * T
    boost.with_variational = True
    boost.variational_T = T_large

    t_span_var = [0, 1]
    y0_var = np.concatenate((y0, np.eye(len(y0)).flatten()))

    sol = solve_ivp_switch(boost,
                           t_span_var,
                           y0_var,
                           method='BDF',
                           rtol=fun_rtol,
                           atol=fun_atol)
    #t_events = np.sort(np.r_[sol['t_sys_events'][0], sol['t_sys_events'][1]])
    #np.savetxt('t_events_beat.txt',t_events,fmt='%14.6e')

    #np.savetxt('boost_variational.txt', pack(sol['t'],sol['y']), fmt='%.3e')

    w, v = np.linalg.eig(np.reshape(sol['y'][2:, -1], (2, 2)))
    print('eigenvalues:')
    print('   ' + ' %14.5e' * boost.n_dim % tuple(w))
    print('eigenvectors:')
    for i in range(boost.n_dim):
        print('   ' + ' %14.5e' * boost.n_dim % tuple(v[i, :]))

    if compare:
        print('Loading PAN data...')
        data = np.loadtxt('DanieleTest.txt')
        t = data[:, 0] - data[0, 0]
        idx, = np.where(t < T_large)

    labels = [r'$V_C$ (V)', r'$I_L$ (A)']
    fig, ax = plt.subplots(3, 2, sharex=True, figsize=(9, 5))
    for i in range(2):
        if i == 1:
            ax[0, i].plot([sol['t'][0], sol['t'][-1]], [0, 0], 'r--')
        ax[0, i].plot(sol['t'], sol['y'][i], 'k', lw=1)
        ax[0, i].set_ylabel(labels[i])
        ax[0, i].set_xlim([0, 1])
        for j in range(2):
            k = i * 2 + j
            if compare:
                ax[i + 1, j].plot(t[idx] / T_large,
                                  data[idx, (k + 1) * 2],
                                  'r',
                                  lw=1,
                                  label='PAN')
            ax[i + 1, j].plot(sol['t'],
                              sol['y'][k + 2],
                              'k',
                              lw=1,
                              label='Python')
            ax[i + 1, j].set_ylabel(r'$\Phi_{%d,%d}$' % (i + 1, j + 1))
            ax[i + 1, j].set_xlim([0, 1])
        ax[2, i].set_xlabel('Normalized time')
    if compare:
        ax[1, 0].legend(loc='best')

    #plt.savefig('boost_const_Vref.pdf')
    plt.show()

    return v
Пример #5
0
def envelope_var_R(use_ramp):
    T = 40e-6
    ki = 1
    Vin = 5
    Vref = 5
    C0 = 47e-6
    L0 = 10e-6
    R0 = 5

    fun_rtol = 1e-12
    fun_atol = 1e-14

    def R_fun(t):
        n_period = int(t / T)
        if n_period % 100 < 75:
            return R0
        return 2 * R0

    def R_fun_sin(t):
        F = 500  # [Hz]
        dR0 = R0 / 10
        return R0 - dR0 / 2 + dR0 * np.sin(2 * np.pi * F * t)

    boost = Boost(0, T=T, ki=ki, Vin=Vin, Vref=Vref, C=C0*30, L=L0*2, \
                  R=R_fun_sin, use_compensating_ramp=use_ramp)

    t_tran = 100.1 * T

    #y0 = np.array([9.3124, 1.2804])
    y0 = np.array([10.154335434351671, 1.623030961224813])

    sol = solve_ivp_switch(boost, [0,t_tran], y0, \
                           method='BDF', jac=boost.jac, \
                           rtol=fun_rtol, atol=fun_atol)
    #plt.plot(sol['t']*1e6,sol['y'][0],'k')
    #plt.plot(sol['t']*1e6,sol['y'][1],'r')
    #plt.show()

    t_span = sol['t'][-1] + np.array([0, 100 * T])
    y0 = sol['y'][:, -1]
    print('t_span =', t_span)
    print('y0 =', y0)
    print('index =', boost.vector_field_index)

    print('-' * 81)
    be_solver = BEEnvelope(boost, t_span, y0, max_step=1000, \
                           T_guess=None, T=T, \
                           env_rtol=1e-2, env_atol=1e-3, \
                           solver=solve_ivp_switch, \
                           jac=boost.jac, method='BDF', \
                           rtol=fun_rtol, atol=fun_atol)
    sol_be = be_solver.solve()
    print('-' * 81)
    trap_solver = TrapEnvelope(boost, t_span, y0, max_step=1000, \
                               T_guess=None, T=T, \
                               env_rtol=1e-3, env_atol=1e-4, \
                               solver=solve_ivp_switch, \
                               jac=boost.jac, method='BDF', \
                               rtol=fun_rtol, atol=fun_atol)
    sol_trap = trap_solver.solve()
    print('-' * 81)

    sys.stdout.write('Integrating the original system... ')
    sys.stdout.flush()
    sol = solve_ivp_switch(boost,
                           t_span,
                           y0,
                           method='BDF',
                           jac=boost.jac,
                           rtol=fun_rtol,
                           atol=fun_atol)
    sys.stdout.write('done.\n')

    labels = [r'$V_C$ (V)', r'$I_L$ (A)']
    fig, ax = plt.subplots(2, 1, sharex=True)
    for i in range(2):
        ax[i].plot(sol['t'] * 1e6, sol['y'][i], 'k', lw=1)
        ax[i].plot(sol_be['t'] * 1e6, sol_be['y'][i], 'ro-', ms=3)
        ax[i].plot(sol_trap['t'] * 1e6, sol_trap['y'][i], 'go-', ms=3)
        ax[i].set_ylabel(labels[i])
    ax[1].set_xlabel(r'Time ($\mu$s)')
    ax[1].set_xlim(t_span * 1e6)
    plt.show()
Пример #6
0
def system(use_ramp):
    T = 20e-6
    ki = 1
    Vin = 5
    Vref = 5

    def Vref_fun(t):
        n_period = int(t / T)
        if n_period > 50 and n_period < 75:
            return Vref * 0.8
        return Vref

    t0 = 0
    t_end = 50 * T
    t_span = np.array([t0, t_end])

    y0 = np.array([Vin, 1])

    fun_rtol = 1e-10
    fun_atol = 1e-12

    boost = Boost(0,
                  T=T,
                  ki=ki,
                  Vin=Vin,
                  Vref=Vref,
                  clock_phase=0,
                  use_compensating_ramp=use_ramp)

    print('Vector field index at the beginning of the first integration: %d.' %
          boost.vector_field_index)
    sol_a = solve_ivp_switch(boost, t_span, y0, \
                             method='BDF', jac=boost.jac, \
                             rtol=fun_rtol, atol=fun_atol)
    print('Vector field index at the end of the first integration: %d.' %
          boost.vector_field_index)

    print(
        'Vector field index at the beginning of the second integration: %d.' %
        boost.vector_field_index)
    sol_b = solve_ivp_switch(boost, sol_a['t'][-1]+t_span, sol_a['y'][:,-1], \
                             method='BDF', jac=boost.jac, \
                             rtol=fun_rtol, atol=fun_atol)
    print('Vector field index at the end of the second integration: %d.' %
          boost.vector_field_index)

    show_manifold = True
    if show_manifold:
        n_rows = 3
    else:
        n_rows = 2

    fig, ax = plt.subplots(n_rows, 1, sharex=True, figsize=(6, 4))
    ax[0].plot([0, sol_b['t'][-1] * 1e6], [Vin, Vin], 'b')
    ax[0].plot(sol_a['t'] * 1e6, sol_a['y'][0], 'k', lw=1)
    ax[0].plot(sol_b['t'] * 1e6, sol_b['y'][0], 'r', lw=1)
    ax[0].set_ylabel(r'$V_C$ (V)')
    ax[1].plot(sol_a['t'] * 1e6, sol_a['y'][1], 'k', lw=1)
    ax[1].plot(sol_b['t'] * 1e6, sol_b['y'][1], 'r', lw=1)
    ax[1].set_ylabel(r'$I_L$ (A)')
    ax[1].set_xlim(t_span * 2 * 1e6)
    if show_manifold:
        iL = sol_a['y'][1]
        t = sol_a['t']
        n = len(t)
        ramp = np.zeros(n)
        k = 0
        for i in range(n):
            if t[i] >= (k + 1) * T:
                k += 1
            ramp[i] = (t[i] - k * T) / T
        ax[2].plot(sol_a['t'] * 1e6,
                   -Vref + ki * iL,
                   'c--',
                   lw=1,
                   label=r'$k_i I_L - V_{ref}$')
        ax[2].plot(sol_a['t'] * 1e6,
                   Vref - ki * iL,
                   'g',
                   lw=1,
                   label=r'$V_{ref} - k_i I_L$')
        ax[2].plot(sol_a['t'] * 1e6, ramp, 'm', lw=1, label=r'$V_{ramp}$')
        ax[2].plot(sol_a['t'] * 1e6,
                   ramp - (Vref - ki * iL),
                   'y',
                   lw=1,
                   label='Manifold')
        ax[2].plot([0, sol_a['t'][-1] * 1e6], [0, 0], 'b')
        ax[2].set_xlabel(r'Time ($\mu$s)')
        ax[2].legend(loc='best')
    else:
        ax[1].set_xlabel(r'Time ($\mu$s)')
    plt.show()
Пример #7
0
def envelope(use_ramp):
    T = 20e-6
    ki = 1
    Vin = 5
    Vref = 5

    boost = Boost(0,
                  T=T,
                  ki=ki,
                  Vin=Vin,
                  Vref=Vref,
                  clock_phase=0,
                  use_compensating_ramp=use_ramp)

    fun_rtol = 1e-10
    fun_atol = 1e-12

    y0 = np.array([Vin, 0])
    t_span = np.array([0, 500 * T])

    t_tran = 0. * T
    if t_tran > 0:
        sol = solve_ivp_switch(boost, [0,t_tran], y0, \
                               method='BDF', jac=boost.jac, \
                               rtol=fun_rtol, atol=fun_atol)
        #plt.plot(sol['t']*1e6,sol['y'][0],'k')
        #plt.plot(sol['t']*1e6,sol['y'][1],'r')
        #plt.show()
        t_span += sol['t'][-1]
        y0 = sol['y'][:, -1]

    print('t_span =', t_span)
    print('y0 =', y0)
    print('index =', boost.vector_field_index)

    print('-' * 81)
    be_solver = BEEnvelope(boost, t_span, y0, max_step=1000, \
                           T_guess=None, T=T, \
                           env_rtol=1e-2, env_atol=1e-3, \
                           solver=solve_ivp_switch, \
                           jac=boost.jac, method='BDF', \
                           rtol=fun_rtol, atol=fun_atol)
    sol_be = be_solver.solve()
    print('-' * 81)
    trap_solver = TrapEnvelope(boost, t_span, y0, max_step=1000, \
                               T_guess=None, T=T, \
                               env_rtol=1e-2, env_atol=1e-3, \
                               solver=solve_ivp_switch, \
                               jac=boost.jac, method='BDF', \
                               rtol=fun_rtol, atol=fun_atol)
    sol_trap = trap_solver.solve()
    print('-' * 81)

    sys.stdout.write('Integrating the original system... ')
    sys.stdout.flush()
    sol = solve_ivp_switch(boost,
                           t_span,
                           y0,
                           method='BDF',
                           jac=boost.jac,
                           rtol=fun_rtol,
                           atol=fun_atol)
    sys.stdout.write('done.\n')

    labels = [r'$V_C$ (V)', r'$I_L$ (A)']
    fig, ax = plt.subplots(2, 1, sharex=True)
    for i in range(2):
        ax[i].plot(sol['t'] * 1e6, sol['y'][i], 'k', lw=1)
        ax[i].plot(sol_be['t'] * 1e6, sol_be['y'][i], 'ro-', ms=3)
        ax[i].plot(sol_trap['t'] * 1e6, sol_trap['y'][i], 'go-', ms=3)
        ax[i].set_ylabel(labels[i])
    ax[1].set_xlabel(r'Time ($\mu$s)')
    ax[1].set_xlim(t_span * 1e6)
    plt.show()