Meidensha Corporation

Shizunori Hamada

Toshimichi Takahashi

Kenji Kobori

Ryuichi Ogawa

Yasuhiro Yamamoto

Takeshi Kondo

Shota Urushibata

Isamu Hasegawa

Keiichi Kodachi

Hiromi Sako

Takashi Kodama

Kuniaki Hirao

Yasuhiro Kanazashi

An inverter system includes a level skip prevention control section. The level skip prevention control section is configured to: in response to an upward shift of an output voltage level of a first one of phases, set a counter for inhibiting upward shifting of the output voltage level of the first phase during a predetermined duration, and set a counter for inhibiting downward shifting of an output voltage level of a second one of the phases other than the first phase during a predetermined duration; and in response to a downward shift of the output voltage level of the first phase, set a counter for inhibiting downward shifting of the output voltage level of the first phase during a predetermined duration, and set a counter for inhibiting upward shifting of the output voltage level of the second phase during a predetermined duration.

Inverter system and inverter system control method

A controller for a power conversion circuit includes a first limiter for limiting a compensating voltage component within a compensating voltage switching level. A delay time measurement section measures an ON-delay time and an OFF-delay time, based on a binarized digital value and a PWM command value. A multiplier calculates an error voltage component average value by multiplying an average value of the ON-delay time and the OFF-delay time by a value that is obtained by dividing a direct-current power supply voltage by a half cycle of a triangular wave carrier signal. A second limiter extracts a component of the error voltage component average value that is beyond the compensating voltage switching level in absolute value. An adder sets a combined compensating voltage component to a sum of a limited compensating voltage component outputted by the first limiter and a limited error voltage component outputted by the second limiter.

Device for controlling power conversion circuit

Current control sectionperforms PI control based on deviation between d-axis command current Id_cmd and d-axis detected current Id_det and deviation between q-axis command current Iq_cmd and q-axis detected current Iq_det. Neutral point potential control sectioncalculates corrected command voltage V_cmd' by addition of neutral point control compensation quantity V_cmp to three-phase command voltage V_cmd. Limiter LMToutputs limiter processed command voltage V_cmd&#x2033; by liming the output of corrected command voltage V_cmd&#x2032;. Three-phase to two-phase converteroutputs feedback quantities Vd_back, Vq_back by three-phase to two-phase conversion of the limiter processed command voltage V_cmd&#x2033;. Current control sectionperforms integral control in accordance with quantities resulting from addition of the feedback quantities Vd_back, Vq_back to the deviations. Accordingly, the three-phase neutral point clamed power conversion apparatus performing the PWM control suppresses interference between the current control and the neutral point potential control.

Three-phase neutral-point-clamped power conversion device

A multilevel power conversion device includes: N (N&#x2265;1) direct current voltage sources; a first flying capacitor; a second flying capacitor; and a phase module of a M phase (M&#x2265;2) being configured to output, from the output terminal, a potential of one of the input terminals, or a potential obtained by adding or subtracting the voltage of the capacitor to or from the potential of the one of the input terminals, by selectively controlling the respective switching elements in an ON/OFF manner.

Multilevel power conversion device with flying capacitor

To perform an anti-windup control without interference with a cross current compensating function even in case of voltage saturation. There is provided a feedback value calculating section to calculate an average of voltage commands V_cmd, V_cmd after output limitation, as a feedback value. As a deviation used for an integral calculation of a current control section, a sum obtained by adding a product to a deviation between a current command value Id_cmd, Iq_cmd and a current detection value Id_det, Iq_det is used. The product is a quantity obtained by multiplying a saturation quantity by a feedback gain Kfb. The saturation quantity is a saturation quantity of an operation quantity limited by a voltage command limiting section, and the saturation quantity is a deviation or difference between a feedback value V_fb (Vd_fb, Vq_fb) and the voltage command Vd_cmd.

Apparatus for parallel operation of pulse-width modulation power converters

Position control device for electric motor inputs deviation signal between angle command and angle detection value to position control section and calculates angular velocity command, inputs deviation signal between this angular velocity command and angular velocity detection value to speed control section and calculates torque current command, and controls, according to this torque current command, the electric motor current control section. The Position control device has disturbance observer section which inputs the torque current command and the angular velocity detection value and estimates signal corresponding to disturbance torque; rate-of-change limitation section which has limiter inputting disturbance observer output value by this disturbance observer section and performing rate-of-change limitation of upper and lower limit values of the angle command; and target value filter section which is configured by control gain equivalent to the speed control section and through which the angular velocity command from the position control section passes.

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Numazu, Japan

Shizunori Hamada