Method for controlling battery power interface converter with ultra-wideband EIS measurement function

A method for controlling a battery power interface converter with an ultra-wideband Electrochemical Impedance Spectroscopy (EIS) measurement function, wherein the battery EIS measurement function is embedded in a charging control system of a battery power interface, the charging control system of the battery power interface comprising the battery power interface converter, a sampling module, a charging control module, an EIS measurement module, and a driving circuit;

• the battery power interface converter adopts a DC-DC converter topology;
• the sampling module samples an output current ibat and an output voltage ubat of the battery power interface converter, wherein the output current and output voltage of the battery power interface converter are the battery charging current and the battery charging voltage;
• the charging control module comprises an operating mode determination circuit, an output current comparator, a duty ratio generator, a duty ratio selector and a PWM circuit;
• the operating mode determination circuit determines whether the battery charging control system is operating in a constant-current charging mode or in an EIS measurement mode according to the output current ibat and the output voltage ubat of the battery power interface converter;
• the output current comparator compares the output current ibat sampled by the current sampling circuit with the output reference current iref to output a comparison signal vc, and inputs the comparison signal vc into the duty ratio selector;
• the duty ratio generator generates two discrete duty ratio signals dH and dL according to the output voltage ubat, an output signal of the operating mode determination circuit and a discrete duty ratio function, and inputs the two discrete duty ratio signals dH and dL into the duty ratio selector;
• in the constant-current charging mode, the discrete duty ratio function is:
• dH=KHddc, dL=KLddc;
• in the EIS measurement mode, the discrete duty ratio function is:
• d
• H
• =
• K
• H
• ⁢
• d
• dc
• +
• d
• ac
• ,
• d
• L
• =
• K
• L
• ⁢
• d
• dc
• +
• d
• ac
• ;
• wherein, ddc=f(Uin, ubat, R), dac=f(Uin, iref_ac, Z);
• in which, KH and KL are two preset constant discrete control parameters;
• ddc and dac are a DC duty ratio function and an AC disturbance duty ratio function in a corresponding target duty ratio function, respectively, when the output current ibat of the battery power interface converter accurately tracks a hybrid reference current Iref_dc+iref_ac;
• Uin is an input voltage of the battery power interface converter;
• ubat is an output voltage of the battery power interface converter;
• iref_ac is a sinusoidal AC disturbance reference current, Iref_dc is a DC charging reference current of the battery power interface converter;
• R is a circuit parameter set related to the DC duty ratio function ddc in the battery power interface converter;
• and Z is a circuit parameter set related to the AC disturbance duty ratio function dac in the battery power interface converter;
• the duty ratio selector selects one of the two discrete duty ratio signals dH and dL as an effective duty ratio signal da outputted by the duty ratio selector according to the comparison signal vc, and inputs the effective duty ratio signal da into the PWM circuit;
• the PWM circuit generates a control pulse signal vpl of the power switching device of the battery power interface converter according to the effective duty ratio signal da, and inputs the control pulse signal vpl into the driving circuit;
• the driving circuit generates a driving signal vl of the power switching device of the battery power interface converter according to the control pulse signal vpl.