Matrix converter

A matrix converter comprising:

• a power converter that includes a plurality of bidirectional switches configured to couple respective phases of an AC power supply and respective phases of a load together;
• and
• a controller configured to selectively execute:
• a first control mode in which the controller is configured to perform power conversion between the AC power supply and the load by performing a PWM control on the plurality of bidirectional switches;
• and
• a second control mode in which the controller is configured to directly combine the AC power supply with the load by controlling the plurality of bidirectional switches, wherein
• the controller is configured to:
• perform a voltage increase control and a follow-up control in a case where a difference between a frequency of an output voltage from the power converter to the load and a frequency of the AC power supply becomes within a predetermined range, the voltage increase control increasing the output voltage, the follow-up control causing a phase of the output voltage to follow a voltage phase of the AC power supply;
• and
• make a transition of a mode for driving the plurality of bidirectional switches from the first control mode to the second control mode in a case where the voltage increase control and the follow-up control terminate, wherein
• the controller further includes:
• a frequency determiner configured to output a frequency coincidence signal in a case where the difference between the frequency of the output voltage and the frequency of the AC power supply is within the predetermined range;
• a voltage-limitation controller configured to perform the voltage increase control in a case where the frequency coincidence signal is output from the frequency determiner;
• a voltage determiner configured to output a voltage coincidence signal in a case where a difference between an amplitude of the output voltage and a voltage amplitude of the AC power supply is within a predetermined range;
• a phase operator configured to perform the follow-up control in a case where the frequency coincidence signal is output from the frequency determiner;
• a phase determiner configured to output a phase coincidence signal in a case where a difference between the phase of the output voltage and the voltage phase of the AC power supply is within a predetermined range;
• and
• a switch driver configured to make a transition of the mode for driving the plurality of bidirectional switches from the first control mode to the second control mode in a case where the matrix converter outputs the voltage coincidence signal and outputs the phase coincidence signal.

A matrix converter, comprising:

• a power converter that includes a plurality of bidirectional switches configured to couple respective phases of an AC power supply and respective phases of a load together;
• and
• a controller configured to selectively execute:
• a first control mode in which the controller is configured to perform power conversion between the AC power supply and the load by performing a PWM control on the plurality of bidirectional switches;
• and
• a second control mode in which the controller is configured to directly combine the AC power supply and the load by controlling the plurality of bidirectional switches, wherein
• in a state where the controller is controlling the plurality of bidirectional switches in the second control mode, in response to a determination that a difference between:
• a set frequency that is a target value of a frequency of an output voltage from the power converter to the load, and a frequency of the AC power supply is out of a predetermined range, the controller makes a transition to the first control mode and performs a voltage decrease control that decreases the output voltage to a predetermined voltage and a phase follow-up stop control that makes a transition of a phase of the output voltage from a state coincident with a voltage phase of the AC power supply to a state of non-coincidence.

A matrix converter comprising:

• a power converter that includes a plurality of bidirectional switches configured to couple respective phases of an AC power supply and respective phases of a load together;
• and
• a controller configured to selectively execute:
• a first control mode in which the controller is configured to perform power conversion between the AC power supply and the load by performing a PWM control on the plurality of bidirectional switches;
• and
• a second control mode in which the controller is configured to directly combine the AC power supply and the load by controlling the plurality of bidirectional switches, wherein
• in a state where the controller is controlling the plurality of bidirectional switches in the second control mode, in a case where a difference between:
• a set frequency that is a target value of a frequency of an output voltage from the power converter to the load, and a frequency of the AC power supply becomes out of a predetermined range, the controller makes a transition to the first control mode and performs a voltage decrease control that decreases the output voltage to a predetermined voltage and a phase follow-up stop control that makes a transition of a phase of the output voltage from a state coincident with a voltage phase of the AC power supply to a state of non-coincidence, wherein
• the controller further includes:
• a frequency-command generation device configured to generate a frequency command such that the frequency of the output voltage approaches a set frequency as time passes;
• a voltage-command generator configured to generate a voltage command for controlling the output voltage based on the frequency command;
• a frequency determiner configured to:
• output a frequency coincidence signal in a case where the difference between the set frequency and the frequency of the AC power supply is within the predetermined range;
• and
• stop the output of the frequency coincidence signal in a case where the difference between the set frequency and the frequency of the AC power supply becomes out of the predetermined range;
• a voltage-limitation controller configured to perform the voltage decrease control in a case where the output of the frequency coincidence signal stops;
• and
• a phase operator configured to perform the phase follow-up stop control in a case where the output of the frequency coincidence signal stops, and
• in a case where the set frequency decreases, the frequency-command generation device generates the frequency command such that the frequency of the output voltage approaches the set frequency as time passes on a condition that the voltage decrease control and the phase follow-up stop control terminate.

A matrix converter, comprising control means for selectively executing:

• a first control mode in which the control means is configured to perform power conversion between an AC power supply and a load by performing a PWM control on a plurality of bidirectional switches configured to couple respective phases of the AC power supply and respective phases of the load together;
• and
• a second control mode in which the control means is configured to directly combine the AC power supply and the load by controlling the plurality of bidirectional switches, wherein
• the control means is configured to:
• perform a voltage increase control and a follow-up control in response to a determination that a difference between a frequency of an output voltage from the power conversion means to the load and a frequency of the AC power supply is within a predetermined range, the voltage increase control increasing the output voltage, the follow-up control causing a phase of the output voltage to follow a voltage phase of the AC power supply;
• and
• make a transition of a mode for driving the plurality of bidirectional switches from the first control mode to the second control mode in a case where the voltage increase control and the follow-up control terminate.