An apparatus to provide welding power, comprising: a direct current-alternate current, DC-AC, power converter to output a primary current; a transformer stage comprising: at least one power transformer to receive the primary current from the (DC- AC) power converter on a primary side of the transformer stage and to output a first voltage through a first rectifier (V7, V8) and a first set of secondary windings disposed on a secondary side of the transformer stage; an auxiliary set of secondary windings disposed on the secondary- side to output a second voltage; and a pair of active unidirectional switches (V5, V9; V6, V10) disposed on the secondary side to receive the second voltage from the auxiliary set of secondary windings, wherein the at least one power transformer comprises: a first power transformer having a primary side comprising a set of primary windings, and a secondary side comprising the first set of secondary windings and the auxiliary set of secondary windings, characterised in that the apparatus further comprises: a primary current sensor disposed on the primary side of the transformer stage to generate a primary current sense signal based upon the primary current; a first auxiliary current sensor disposed between a first end of the auxiliary set of secondary windings and a first switch (V5, V9) of the pair of active unidirectional switches (V5, V9; V6, V10); and a second auxiliary current sensor disposed between a second end of the auxiliary set of secondary windings and a second switch (V6, V10) of the pair of active unidirectional switches (V5, V9; V6, V10), wherein the first auxiliary current sensor is configured to output a first current sense signal from the first switch (V5, V9) and the second auxiliary current sensor is configured to output a second current sense signal from the second switch (V6, V10), and wherein the apparatus is configured to combine the first current sense signal from the first switch (V5,V9) and the second current sense signal from the second switch (V6,V10) with the primary current sense signal, and to generate PWM signals for the DC-AC converter and the active unidirectional switches (V5,V9; V6,V10). a direct current-alternate current, DC-AC, power converter to output a primary current; a transformer stage comprising: at least one power transformer to receive the primary current from the (DC- AC) power converter on a primary side of the transformer stage and to output a first voltage through a first rectifier (V7, V8) and a first set of secondary windings disposed on a secondary side of the transformer stage; an auxiliary set of secondary windings disposed on the secondary- side to output a second voltage; and a pair of active unidirectional switches (V5, V9; V6, V10) disposed on the secondary side to receive the second voltage from the auxiliary set of secondary windings, wherein the at least one power transformer comprises: a first power transformer having a primary side comprising a set of primary windings, and a secondary side comprising the first set of secondary windings and the auxiliary set of secondary windings, characterised in that the apparatus further comprises: a primary current sensor disposed on the primary side of the transformer stage to generate a primary current sense signal based upon the primary current; a first auxiliary current sensor disposed between a first end of the auxiliary set of secondary windings and a first switch (V5, V9) of the pair of active unidirectional switches (V5, V9; V6, V10); and a second auxiliary current sensor disposed between a second end of the auxiliary set of secondary windings and a second switch (V6, V10) of the pair of active unidirectional switches (V5, V9; V6, V10), wherein the first auxiliary current sensor is configured to output a first current sense signal from the first switch (V5, V9) and the second auxiliary current sensor is configured to output a second current sense signal from the second switch (V6, V10), and a primary current sensor disposed on the primary side of the transformer stage to generate a primary current sense signal based upon the primary current; a first auxiliary current sensor disposed between a first end of the auxiliary set of secondary windings and a first switch (V5, V9) of the pair of active unidirectional switches (V5, V9; V6, V10); and a second auxiliary current sensor disposed between a second end of the auxiliary set of secondary windings and a second switch (V6, V10) of the pair of active unidirectional switches (V5, V9; V6, V10), wherein the first auxiliary current sensor is configured to output a first current sense signal from the first switch (V5, V9) and the second auxiliary current sensor is configured to output a second current sense signal from the second switch (V6, V10), and wherein the apparatus is configured to combine the first current sense signal from the first switch (V5,V9) and the second current sense signal from the second switch (V6,V10) with the primary current sense signal, and to generate PWM signals for the DC-AC converter and the active unidirectional switches (V5,V9; V6,V10).