An electrical power converter comprising: a power converter configured to receive power from a power source, wherein the power converter is configured to operate at a switching frequency; a resonant tank circuit operatively connected to the power converter, wherein the resonant tank circuit is configured to operate at a tank resonant frequency; a controller operatively connected to the resonant tank circuit; and a variable inductor including a plurality of inductor coil loops having a plurality of turns and operatively connected to the resonant tank circuit and to the controller, wherein in operation the controller is configured to change the inductance of the variable inductor based on the switching frequency of the power converter by causing turns to be added to or subtracted from the inductor coil so that the controller is configured to modify the tank resonant frequency to match the switching frequency within a predetermined margin; wherein the variable inductor further comprises an inductor core having a cavity extending along a length of the inductor core, wherein the plurality of inductor coil loops are wrapped around the inductor core; one or more coil switches that connect two predetermined portions of the inductor coil loops; and wherein the variable inductor is configured to receive, from the controller, a control signal; and actuate, based on the control signal, the one or more coil switches to modify the inductance of the resonant tank circuit by adding or subtracting the operable turns in the inductor coil, characterised in that the controller is configured to: determine a target inductance adjustment based on the switching frequency and the tank resonant frequency; and modify, via the variable inductor, an inductance of the resonant tank circuit until the tank resonant frequency matches the switching frequency within the predetermined margin. a power converter configured to receive power from a power source, wherein the power converter is configured to operate at a switching frequency; a resonant tank circuit operatively connected to the power converter, wherein the resonant tank circuit is configured to operate at a tank resonant frequency; a controller operatively connected to the resonant tank circuit; and a variable inductor including a plurality of inductor coil loops having a plurality of turns and operatively connected to the resonant tank circuit and to the controller, wherein in operation the controller is configured to change the inductance of the variable inductor based on the switching frequency of the power converter by causing turns to be added to or subtracted from the inductor coil so that the controller is configured to modify the tank resonant frequency to match the switching frequency within a predetermined margin; wherein the variable inductor further comprises an inductor core having a cavity extending along a length of the inductor core, wherein the plurality of inductor coil loops are wrapped around the inductor core; one or more coil switches that connect two predetermined portions of the inductor coil loops; and wherein the variable inductor is configured to receive, from the controller, a control signal; and actuate, based on the control signal, the one or more coil switches to modify the inductance of the resonant tank circuit by adding or subtracting the operable turns in the inductor coil, determine a target inductance adjustment based on the switching frequency and the tank resonant frequency; and modify, via the variable inductor, an inductance of the resonant tank circuit until the tank resonant frequency matches the switching frequency within the predetermined margin.