Abstract: A motor driving device includes a motor driving circuit, an element temperature sensor, a control circuit, an ambient-temperature estimator, and an overheat protection processor. The motor driving circuit has a plurality of switching elements. The element temperature sensor is configured to detect a temperature of each of the switching elements. The ambient-temperature estimator is configured to estimate an ambient temperature around the control circuit based on a temperature of at least one of the switching elements detected by the element temperature sensor if the at least one of the switching elements is not performing the switching operation. The overheat protection processor is configured to execute a first overheat protection process to protect the control circuit from overheating if the ambient temperature around the control circuit estimated by the ambient-temperature estimator exceeds a first overheat criterion temperature.

Abstract: A motor driving device includes a motor driving circuit, an element temperature sensor, a control circuit, an ambient-temperature estimator, and an overheat protection processor. The motor driving circuit has a plurality of switching elements. The element temperature sensor is configured to detect a temperature of each of the switching elements. The ambient-temperature estimator is configured to estimate an ambient temperature around the control circuit based on a temperature of at least one of the switching elements detected by the element temperature sensor if the at least one of the switching elements is not performing the switching operation. The overheat protection processor is configured to execute a first overheat protection process to protect the control circuit from overheating if the ambient temperature around the control circuit estimated by the ambient-temperature estimator exceeds a first overheat criterion temperature.

Abstract: An electric power source in which a plurality of inverters operate on the same frequency and the plurality of inverters are connected in parallel so that a resistance value expressed by (1??·G)/(?·G) where ? is the output voltage feedback gain, ? is the output current feed forward gain, and G is the inverter current gain, is made to be the equivalent output impedance; and is an electrical power source in which the cross-current between the inverters are made to be an acceptable value or below by adjusting the output of each of the inverters by controlling the equivalent output impedance by modifying both or either one of the output voltage feedback gain ? or the output current feed forward gain ?.

Abstract: The present invention is an electric power source in which a plurality of inverters operate on the same frequency and the plurality of inverters are connected in parallel so that a resistance value expressed by (1??·G)/(?·G) where ? is the output voltage feedback gain, ? is the output current feed forward gain, and G is the inverter current gain, is made to be the equivalent output impedance; and is an electrical power source in which the cross-current between the inverters are made to be an acceptable value or below by adjusting the output of each of the inverters by controlling the equivalent output impedance by modifying both or either one of the output voltage feedback gain ? or the output current feed forward gain ?.

Abstract: The present invention is an electric power source in which a plurality of inverters operate on the same frequency and the plurality of inverters are connected in parallel so that a resistance value expressed by (1??·G)/(?·G) where ? is the output voltage feedback gain, ? is the output current feed forward gain, and G is the inverter current gain, is made to be the equivalent output impedance; and is an electrical power source in which the cross-current between the inverters are made to be an acceptable value or below by adjusting the output of each of the inverters by controlling the equivalent output impedance by modifying both or either one of the output voltage feedback gain ? or the output current feed forward gain ?.

Abstract: A three-phase voltage-fed AC/DC converter includes a conversion circuit which converts power from a DC voltage source to three-phase AC power. The converter further includes a UM conversion circuit which carries out dq conversion of the three-phase output voltage, a superior voltage control circuit which outputs a voltage reference vector based on a superior reference vector and an output voltage vector obtained by the UM conversion circuit, an inferior voltage control circuit which outputs a PWM reference based on the voltage reference vector and the output voltage vector, and a frequency control circuit which synchronizes a value generated based on a q-axis component from the UM conversion circuit with a rotation angle of a conversion matrix in the UM conversion circuit.

Abstract: A three-phase voltage-fed AC/DC converter includes a conversion circuit which converts power from a DC voltage source to three-phase AC power. The converter further includes a UM conversion circuit which carries out dq conversion of the three-phase output voltage, a superior voltage control circuit which outputs a voltage reference vector based on a superior reference vector and an output voltage vector obtained by the UM conversion circuit, an inferior voltage control circuit which outputs a PWM reference based on the voltage reference vector and the output voltage vector, and a frequency control circuit which synchronizes a value generated based on a q-axis component from the UM conversion circuit with a rotation angle of a conversion matrix in the UM conversion circuit.

Abstract: The objective of the present invention is to provide a power source and operational method in which a plurality of inverters are connected in parallel with the ability to suppress the crosscurrent with a very simple means. The present invention is an electric power source in which a plurality of inverted operate on the same frequency and the plurality of inverters are connected in parallel so that a resistance value expressed by (1??·G)/(?·G) here ? is the output voltage feedback gain, ? is the output current feed forward gain, and G is the inverter current gain, is made to be the equivalent output impedance; and is an electrical power source in which the cross-current between the inverters are made to be an acceptable value or below by adjusting the output of each of the inverters by controlling the equivalent output impedance by modifying both or either one of the output voltage feedback gain ? or the output current feed forward gain ?.