Abstract: A converter controller of a thyristor starter includes: a current controller that generates a voltage command value of an output voltage of a converter by performing a control operation using an integral element of a deviation of a direct current with respect to a current command value; a corrector that adds a correction value to the voltage command value; and a control angle calculator that calculates a phase control angle of a thyristor in the converter based on the voltage command value to which the correction value is added. In an intermittent commutation mode, the correction value is set to increase as a rotation speed of a synchronous machine increases.

Abstract: A converter controller configured to control a firing phase of a converter includes an integral element integrating a deviation of DC current from a current command value and generates a voltage command value of output voltage of the converter by performing control calculation of the deviation. In a first mode of performing commutation of an inverter by intermittently setting DC current to zero, the converter controller sets DC current to zero for a predetermined pause time by narrowing a phase control angle simultaneously with a commutation command for the inverter. When the control calculation is resumed immediately after the pause time, the converter controller uses a control amount calculated in control calculation immediately before the pause time as a preset value of the integral element immediately after the pause time.

Abstract: In a thyristor starter, an inverter converts DC power provided from a converter through a DC reactor into AC power having a variable frequency, and supplies the AC power to a synchronous machine. A controller controls the inverter based on a phase control angle. A voltage regulator regulates an induced voltage of the synchronous machine by supplying a field current to the synchronous machine. When a rotation speed of the synchronous machine exceeds a reference rotation speed during acceleration of the synchronous machine, the voltage regulator controls the field current such that the induced voltage increases with an increase in the rotation speed of the synchronous machine. The controller decreases a rate of increase in the phase control angle relative to the rotation speed of the synchronous machine, as compared with when the rotation speed of the synchronous machine is less than the reference rotation speed.

Abstract: A thyristor starter accelerates a synchronous machine from a stop state to a predetermined rotation speed by sequentially performing a first mode of performing commutation of an inverter by intermittently setting DC output current to zero and a second mode of performing commutation of the inverter by induced voltage of the synchronous machine. A second controller controls the firing phase of a thyristor in a converter such that DC output current of the converter matches a current command value, based on a detection signal of a position detector. In the first mode, the current command value is set such that the current value is higher as the rotation speed of the synchronous machine is higher.

Abstract: A thyristor starter is configured to accelerate a synchronous machine from a stop state to a predetermined rotation speed by sequentially performing a first mode of performing commutation of an inverter by intermittently setting DC output current of a converter to zero and a second mode of performing commutation of the inverter by induced voltage of the synchronous machine. The thyristor starter is further configured to raise induced voltage in proportion to the rotation speed of the synchronous machine by keeping field current constant and to suppress rise of the induced voltage by reducing the field current after the induced voltage reaches a first voltage value, in the first mode.

Abstract: A thyristor starter accelerates a synchronous machine from a stop state to a predetermined rotation speed by sequentially performing a first mode of performing commutation of an inverter by intermittently setting DC output current of a converter to zero and a second mode of performing commutation of the inverter by induced voltage of the synchronous machine. In the thyristor starter, during a first time period from start of performance of the second mode to arrival of the induced voltage of the synchronous machine at a first voltage value, a phase control angle of the inverter is changed such that a value thereof becomes larger as a rotation speed of the synchronous machine becomes higher.

Abstract: In a thyristor starter, an inverter converts DC power provided from a converter through a DC reactor into AC power having a variable frequency, and supplies the AC power to a synchronous machine. A controller controls the inverter based on a phase control angle. A voltage regulator regulates an induced voltage of the synchronous machine by supplying a field current to the synchronous machine. When a rotation speed of the synchronous machine exceeds a reference rotation speed during acceleration of the synchronous machine, the voltage regulator controls the field current such that the induced voltage increases with an increase in the rotation speed of the synchronous machine. The controller decreases a rate of increase in the phase control angle relative to the rotation speed of the synchronous machine, as compared with when the rotation speed of the synchronous machine is less than the reference rotation speed.

Abstract: A thyristor starter accelerates a synchronous machine from a stop state to a predetermined rotation speed by sequentially performing a first mode of performing commutation of an inverter by intermittently setting DC output current of a converter to zero and a second mode of performing commutation of the inverter by induced voltage of the synchronous machine. In the thyristor starter, during a first time period from start of performance of the second mode to arrival of the induced voltage of the synchronous machine at a first voltage value, a phase control angle of the inverter is changed such that a value thereof becomes larger as a rotation speed of the synchronous machine becomes higher.

Abstract: A converter controller configured to control a firing phase of a converter includes an integral element integrating a deviation of DC current from a current command value and generates a voltage command value of output voltage of the converter by performing control calculation of the deviation. In a first mode of performing commutation of an inverter by intermittently setting DC current to zero, the converter controller sets DC current to zero for a predetermined pause time by narrowing a phase control angle simultaneously with a commutation command for the inverter. When the control calculation is resumed immediately after the pause time, the converter controller uses a control amount calculated in control calculation immediately before the pause time as a preset value of the integral element immediately after the pause time.

Abstract: A thyristor starter is configured to accelerate a synchronous machine from a stop state to a predetermined rotation speed by sequentially performing a first mode of performing commutation of an inverter by intermittently setting DC output current of a converter to zero and a second mode of performing commutation of the inverter by induced voltage of the synchronous machine. The thyristor starter is further configured to raise induced voltage in proportion to the rotation speed of the synchronous machine by keeping field current constant and to suppress rise of the induced voltage by reducing the field current after the induced voltage reaches a first voltage value, in the first mode.

Abstract: A thyristor starter is configured to accelerate a synchronous machine from a stop state to a predetermined rotation speed by sequentially performing a first mode of performing commutation of an inverter by intermittently setting DC output current of a converter to zero and a second mode of performing commutation of the inverter by induced voltage of the synchronous machine. In a first case in which a first synchronous machine having a first inductance is started, a switching rotation speed for switching from the first mode to the second mode is set to a higher rotation speed, compared with a second case in which a second synchronous machine having a second inductance larger than the first inductance is started.

Abstract: A thyristor starter accelerates a synchronous machine from a stop state to a predetermined rotation speed by sequentially performing a first mode of performing commutation of an inverter by intermittently setting DC output current to zero and a second mode of performing commutation of the inverter by induced voltage of the synchronous machine. A second controller controls the firing phase of a thyristor in a converter such that DC output current of the converter matches a current command value, based on a detection signal of a position detector. In the first mode, the current command value is set such that the current value is higher as the rotation speed of the synchronous machine is higher.

Abstract: A thyristor starter is configured to accelerate a synchronous machine from a stop state to a predetermined rotation speed by sequentially performing a first mode of performing commutation of an inverter by intermittently setting DC output current of a converter to zero and a second mode of performing commutation of the inverter by induced voltage of the synchronous machine. In a first case in which a first synchronous machine having a first inductance is started, a switching rotation speed for switching from the first mode to the second mode is set to a higher rotation speed, compared with a second case in which a second synchronous machine having a second inductance larger than the first inductance is started.

Abstract: A thyristor switch is constituted of a pair of arms connected in anti-parallel, each of the arms including a plurality of thyristors connected in series. A controller includes a phase detecting unit configured to detect a phase of a power supply voltage supplied from an alternating-current power supply, and a gate signal generating unit configured to interrupt a gate signal when an open command is provided to the static switch and the phase of the power supply voltage detected by the phase detecting unit matches a target phase. The target phase is set outside of a phase range where interruption of the gate signal is prohibited, the phase range being set so as to include a zero crossing point at which a load current is switched in polarity.

Abstract: A thyristor starting device includes: a converter which converts AC power supplied from an AC power source into DC power; a DC reactor which smooths a DC current; an inverter which converts the DC power provided from the converter into AC power, and supplies the AC power to a synchronous machine; a gate pulse generation circuit which generates a gate pulse to be provided to thyristors of the converter and the inverter; a control unit which sets a phase control angle of the gate pulse to be provided to the thyristors of the converter, by controlling a current of the converter such that the DC current flowing into the DC reactor matches a current command value; and an abnormality detection unit which compares a detection value of the DC current with the current command value, and determines an abnormality in the gate pulse based on a comparison result.

Abstract: A thyristor switch is constituted of a pair of arms connected in anti-parallel, each of the anus including a plurality of thyristors connected in series. A controller includes a phase detecting unit configured to detect a phase of a power supply voltage supplied from an alternating-current power supply, and a gate signal generating unit configured to interrupt a gate signal when an open command is provided to the static switch and the phase of the power supply voltage detected by the phase detecting unit matches a target phase. The target phase is set outside of a phase range where interruption of the gate signal is prohibited, the phase range being set so as to include a zero crossing point at which a load current is switched in polarity.

Abstract: In the ground fault detecting circuit, one terminals of first to third resistance elements are connected to first to third AC lines, respectively, the other terminals of the first to third resistance elements are commonly connected to one terminal of a fourth resistance element, and the other terminal of the fourth resistance element is connected to a line of a ground voltage. On the basis of a voltage across the terminals of the fourth resistance element, the ground fault detecting circuit detects whether a ground fault has occurred or not. Since a current does not flow through the fourth resistance element in the normal state and flows through the fourth resistance element after the occurrence of a ground fault, it is possible to detect the occurrence of the ground fault at a high accuracy.

Abstract: In a thyristor control device which converts a first AC voltage to a DC voltage and converts the DC voltage to a second AC voltage to be supplied to a synchronous motor, a DC voltage detector is configured to detect the DC voltage, and is provided with an AC voltage detector configured to detect the second AC voltage and an arithmetic circuit configured to determine the DC voltage on the basis of the second AC voltage detected by the AC voltage detector. As a result, there is no need to separately provide a DV voltage detector, which makes it possible to make the device compact in size and cheap in price.

Abstract: A thyristor starting device includes: a converter which converts AC power supplied from an AC power source into DC power; a DC reactor which smooths a DC current; an inverter which converts the DC power provided from the converter into AC power, and supplies the AC power to a synchronous machine; a gate pulse generation circuit which generates a gate pulse to be provided to thyristors of the converter and the inverter; a control unit which sets a phase control angle of the gate pulse to be provided to the thyristors of the converter, by controlling a current of the converter such that the DC current flowing into the DC reactor matches a current command value; and an abnormality detection unit which compares a detection value of the DC current with the current command value, and determines an abnormality in the gate pulse based on a comparison result.

Abstract: A power conversion device includes a converter, a DC reactor, and an inverter. A control unit controls the converter according to a sum of a feedback control amount and a feedforward control amount, the feedback control amount being calculated based on a deviation between a current command value and the DC current flowing into the DC reactor, the feedforward control amount being set in accordance with a DC voltage provided from the converter through the DC reactor. When an output frequency of the inverter is in a first region, the control unit reduces a control gain used to calculate the feedforward control amount, as compared to when the output frequency is in a second region having a frequency lower than that of the first region.