Motor drive unit for an in-wheel motor, comprising a housing and one or more capacitors and solid state switching devices arranged within the housing , the housing comprising: a lower compartment comprising a bottom plate , sidewalls which extend from the bottom plate , and end sides at the transverse ends of the sidewalls and bottom plate , wherein the bottom plate is provided with cooling channels for receiving a liquid coolant; a separation plate covering the lower compartment , wherein the separation plate is in thermal contact with the sidewalls and with the one or more capacitors ; an upper compartment having a top plate and sidewalls , wherein the capacitors are arranged in the upper compartment between the top plate and the separation plate , wherein the upper compartment , the separation plate , and the lower compartment together enclose the one or more capacitors and the solid state switching devices ; characterized in that the separation plate makes direct contact with the sidewalls or makes contact with the sidewalls via a thermal paste or grease applied between the separation plate and the sidewalls ; wherein the motor drive unit further comprises DC bus bars which are electrically connected to the one or more capacitors , wherein the DC bus bars are mechanically fixed to the separation plate and thermally conductively connected thereto; and wherein the solid state switching devices are arranged in the lower compartment between the bottom plate and the separation plate and in thermal contact with the bottom plate , wherein the capacitors are arranged at a side of the separation plate that faces away from the lower compartment and are mounted on and substantially supported by the DC bus bars . a lower compartment comprising a bottom plate , sidewalls which extend from the bottom plate , and end sides at the transverse ends of the sidewalls and bottom plate , wherein the bottom plate is provided with cooling channels for receiving a liquid coolant; a separation plate covering the lower compartment , wherein the separation plate is in thermal contact with the sidewalls and with the one or more capacitors ; an upper compartment having a top plate and sidewalls , wherein the capacitors are arranged in the upper compartment between the top plate and the separation plate , wherein the upper compartment , the separation plate , and the lower compartment together enclose the one or more capacitors and the solid state switching devices ; characterized in that the separation plate makes direct contact with the sidewalls or makes contact with the sidewalls via a thermal paste or grease applied between the separation plate and the sidewalls ; wherein the motor drive unit further comprises DC bus bars which are electrically connected to the one or more capacitors , wherein the DC bus bars are mechanically fixed to the separation plate and thermally conductively connected thereto; and wherein the solid state switching devices are arranged in the lower compartment between the bottom plate and the separation plate and in thermal contact with the bottom plate , wherein the capacitors are arranged at a side of the separation plate that faces away from the lower compartment and are mounted on and substantially supported by the DC bus bars . <EOS>