A vehicle electrical power system comprising: a battery operable to power a load of a vehicle over a direct current DC Bus ; a battery switching circuit (S1), said switching circuit operable to connect a node of the battery to either a battery charger or a node (N) of a multiphase alternating current AC machine ; said multiphase alternating current AC machine comprising a plurality of windings; and a power converter comprising a plurality of power switches and a controller , wherein the controller is configured to: in a first mode, operate the power converter as an active rectifier of electrical current induced in the plurality of windings of the multiphase AC machine operated as a generator to provide current to the DC bus to supply DC loads, and charge the battery by means of battery charger from the current on the DC bus ; and in a second mode, operate the power converter as a boost converter that converts a variable voltage of the battery to a constant voltage on the DC bus; wherein the power converter utilizes the plurality of windings of the AC machine when operated as active rectifier and boost converter; characterized in that the controller is configured to: in the second mode, power the DC bus by connecting a node of the battery to the DC bus through the plurality of windings and the power converter by means of connecting battery to neutral node (N) of the AC machine . a battery operable to power a load of a vehicle over a direct current DC Bus ; a battery switching circuit (S1), said switching circuit operable to connect a node of the battery to either a battery charger or a node (N) of a multiphase alternating current AC machine ; said multiphase alternating current AC machine comprising a plurality of windings; and a power converter comprising a plurality of power switches and a controller , wherein the controller is configured to: in a first mode, operate the power converter as an active rectifier of electrical current induced in the plurality of windings of the multiphase AC machine operated as a generator to provide current to the DC bus to supply DC loads, and charge the battery by means of battery charger from the current on the DC bus ; and in a second mode, operate the power converter as a boost converter that converts a variable voltage of the battery to a constant voltage on the DC bus; wherein the power converter utilizes the plurality of windings of the AC machine when operated as active rectifier and boost converter; in a first mode, operate the power converter as an active rectifier of electrical current induced in the plurality of windings of the multiphase AC machine operated as a generator to provide current to the DC bus to supply DC loads, and charge the battery by means of battery charger from the current on the DC bus ; and in a second mode, operate the power converter as a boost converter that converts a variable voltage of the battery to a constant voltage on the DC bus; wherein the power converter utilizes the plurality of windings of the AC machine when operated as active rectifier and boost converter; characterized in that the controller is configured to: in the second mode, power the DC bus by connecting a node of the battery to the DC bus through the plurality of windings and the power converter by means of connecting battery to neutral node (N) of the AC machine . <EOS>