Power conversion device

A power conversion device comprising:

• a power conversion circuitry including a plurality of legs each formed by connecting a pair of two arms on upper and lower sides, each arm including a switching element, where current flowing through a path connected to a middle point between the two arms in each leg is defined as phase current, both ends of each of the plurality of legs being connected to a common DC bus;
• a current detector to measure current flowing through the common DC bus;
• a PWM control circuitry to generate ON/OFF signals for controlling the switching elements of the upper and lower arms in the legs;
• a current estimation circuitry to estimate the phase current;
• and
• a current control circuitry to control the phase current, wherein
• a transformer path on a primary side or a secondary side of an isolation converter that operates with a phase shift is connected to a plurality of the paths for the phase currents of the power conversion circuitry,
• the PWM control circuitry generates the ON/OFF signals for controlling the switching elements in the legs based on a magnitude relationship between individual phase shift commands for the respective legs and triangular wave carriers having different initial phases for the respective legs and having a common cycle,
• the current estimation circuitry acquires detected values from the current detector at a sampling cycle different from the carrier cycle of the triangular wave carriers and synchronized with a timing coinciding with a maximum value and a minimum value of a plurality of the triangular wave carriers, and estimates the phase currents, and
• the current control circuitry adjusts the phase shift commands so that the estimated phase currents coincide with target values for the phase currents.

A power conversion device comprising:

• a power conversion circuitry including a plurality of legs each formed by connecting a pair of two arms on upper and lower sides, each arm including a switching element, where current flowing through a path connected to a middle point between the two arms in each leg is defined as phase current, both ends of each of the plurality of legs being connected to a common DC bus;
• a current detector to measure current flowing through the common DC bus;
• a PWM control circuitry to generate ON/OFF signals for controlling the switching elements of the upper and lower arms in the legs;
• a current estimation circuitry to estimate the phase current;
• and
• a current control circuitry to control the phase current, wherein
• the PWM control circuitry generates the ON/OFF signals for controlling the switching elements in the legs based on a magnitude relationship between individual Duty commands for the respective legs and triangular wave carriers having different initial phases for the respective legs and having a common cycle,
• the current estimation circuitry acquires detected values from the current detector at a sampling cycle different from the carrier cycle of the triangular wave carriers, and estimates the phase currents of the legs, and
• the current control circuitry adjusts the Duty commands so that the estimated phase currents coincide with target values for the phase currents, and wherein
• the current control circuitry adjusts the Duty commands so that the estimated phase currents coincide with the target values for the phase currents, at a cycle synchronized with a time equal to or greater than a least common multiple of the carrier cycle and the sampling cycle.

A power conversion device comprising:

• a power conversion circuitry including a plurality of legs each formed by connecting a pair of two arms on upper and lower sides, each arm including a switching element, where current flowing through a path connected to a middle point between the two arms in each leg is defined as phase current, both ends of each of the plurality of legs being connected to a common DC bus;
• a current detector to measure current flowing through the common DC bus;
• a PWM control circuitry to generate ON/OFF signals for controlling the switching elements of the upper and lower arms in the legs;
• a current estimation circuitry to estimate the phase current;
• and
• a current control circuitry to control the phase current, wherein
• the PWM control circuitry generates the ON/OFF signals for controlling the switching elements in the legs based on a magnitude relationship between individual Duty commands for the respective legs and triangular wave carriers having different initial phases for the respective legs and having a common cycle,
• the current estimation circuitry acquires detected values from the current detector at a sampling cycle different from the carrier cycle of the triangular wave carriers, and estimates the phase currents of the legs, and
• the current control circuitry adjusts the Duty commands so that the estimated phase currents coincide with target values for the phase currents, wherein
• a DC power supply and an AC power supply are connected to a plurality of the paths for the phase currents of the power conversion circuitry, and wherein
• the PWM control circuitry generates the ON/OFF signals for controlling the switching elements in the legs, such that the ON/OFF signals have a same pulse waveform with different initial phases for the respective legs, based on individual phase shift commands for the respective legs,
• the current estimation circuitry acquires the detected values from the current detector at a sampling cycle different from a cycle of the ON/OFF signals, and estimates the phase currents for the respective legs at a cycle synchronized with a time equal to or greater than a least common multiple of the sampling cycle and the cycle of the ON/OFF signals, and
• the current control circuitry adjusts the phase shift commands so that the estimated phase currents coincide with the target values for the phase currents.