A hybrid electric locomotive comprising: an internal combustion engine ; a dynamo connected with the internal combustion engine and capable of converting power of the internal combustion engine into alternating current power; a converter connected with the dynamo and capable of converting the alternating current power of the dynamo into direct current power; an inverter capable of converting the direct current power into alternating current power; a direct current link connecting the converter and the inverter ; a battery electrically connected with the direct current link ; wherein a maximum power that can be input to the inverter equals to a maximum power that the converter can output, plus a maximum power that the battery can output; a first map (T1) storing therein a correspondence relationship between an upper limit of output power of the battery and a temperature and a state of charge of the battery , characterised in that the upper limit of output power of the battery is determined based on a maximum value of current that the converter can output, and an output characteristic of the battery , to achieve a maximum use of the battery up to the upper limit of the output power of the battery which leads to a reduction in a current of the converter , wherein the output characteristic of the battery changes with a temperature and a state of charge of the battery ; and a controller that controls the internal combustion engine and the dynamo in accordance with the temperature and the state of charge of the battery based on the first map (T1) so that the output power of the battery is not higher than the upper limit stored in the first map (T1). an internal combustion engine ; a dynamo connected with the internal combustion engine and capable of converting power of the internal combustion engine into alternating current power; a converter connected with the dynamo and capable of converting the alternating current power of the dynamo into direct current power; an inverter capable of converting the direct current power into alternating current power; a direct current link connecting the converter and the inverter ; a battery electrically connected with the direct current link ; wherein a maximum power that can be input to the inverter equals to a maximum power that the converter can output, plus a maximum power that the battery can output; a first map (T1) storing therein a correspondence relationship between an upper limit of output power of the battery and a temperature and a state of charge of the battery , characterised in that the upper limit of output power of the battery is determined based on a maximum value of current that the converter can output, and an output characteristic of the battery , characterised in that the upper limit of output power of the battery is determined based on a maximum value of current that the converter can output, and an output characteristic of the battery , to achieve a maximum use of the battery up to the upper limit of the output power of the battery which leads to a reduction in a current of the converter , wherein the output characteristic of the battery changes with a temperature and a state of charge of the battery ; and a controller that controls the internal combustion engine and the dynamo in accordance with the temperature and the state of charge of the battery based on the first map (T1) so that the output power of the battery is not higher than the upper limit stored in the first map (T1). <EOS>