Toshiba Mitsubishi-electric Industrial Systems Corporation

The Ritsumeikan Trust

Kazuki Nishimura

Toshihide Nakano

Masahiro Kinoshita

Hiroshi Masunaga

Kazunori Sanada

Takao Kawabata

Yoshitaka Kawabata

First to n-th (n is an integer of 2 or more) power conversion devices are connected in parallel to a load. First to n-th fuses are provided in first to n-th wirings, respectively. Each of the first to n-th power conversion devices includes a converter, an inverter, and a DC bus supplying a DC voltage from the converter to the inverter, and capacitors connected to the DC bus. An i-th (1&#x2264;i&#x2264;n&#x2212;1) wiring includes the DC bus of an i-th power conversion device and the DC bus of an (i+1)-th power conversion device. The n-th wiring is connected between the DC bus of the n-th power conversion device and the DC bus of the first power conversion device.

Power conversion system

A power conversion device includes a converter, a first capacitor, and a second capacitor. The first capacitor is connected between a DC positive bus and a DC neutral point bus. The second capacitor is connected between the DC neutral point bus and a DC negative bus. The converter includes a diode rectifier connected between an AC power supply and each of the DC positive bus and the DC negative bus, and a first AC switch electrically connected between the AC power supply and the DC neutral point bus. The power conversion device further includes a first fuse electrically connected between the first AC switch and a connection point between the first and second capacitors.

Power conversion device

This uninterruptible power supply includes: a cooler () that dissipates heat of a converter () and an inverter (); and a controller () that causes, when output power (Po) from the inverter () exceeds an upper limit value (PoH), reduces input power (Pi) to the converter () by power (&#x394;Po=Po&#x2212;PoH) corresponding to a difference between them, and increases input power (Pb) to a bidirectional chopper () by power (2&#xd7;PoH) that is twice as high as the power (&#x394;Po) corresponding to the difference.

First to third-phase converters convert first to third-phase AC voltages into DC voltages, respectively. First to third DC positive buses and first to third DC negative buses are electrically connected to the first to third-phase converters. Fourth to sixth-phase inverters convert the DC voltages into fourth to sixth-phase AC voltages. The first to third-phase converters include diode rectifiers. First to third fuses are connected between an AC power supply and the first to third-phase converters, respectively. Fourth to sixth fuses are inserted into the first to third DC positive buses, respectively. Seventh to ninth fuses are inserted into the first to third DC negative buses, respectively.

A first wire (WP, WN, WC) is provided between a first converter unit (U) and a DC bus line (PL, NL, CL). A second wire (WP, WN, WC) is provided between a second converter unit (U) and a DC bus line (PL, NL, CL). A third wire (WP, WN, WC) is provided between a third converter unit (U) and a DC bus line (PL, NL, CL). A first fuse (FP, FN, FC) is inserted in each of the first wire (WP, WN, WC). A second fuse (FP, FN, FC) is inserted in each of the second wire (WP, WN, WC). A third fuse (FP, FN, FC) is inserted in each of the third wire (WP, WN, WC).

A bidirectional insulated DC/DC converter includes a first single-phase 3-level inverter, a second single-phase 3-level inverter, and an insulated transformer. The first single-phase 3-level inverter generates a first AC voltage between output terminals based on a first DC voltage received from a first DC circuit. The second single-phase 3-level inverter generates a second AC voltage between output terminals based on a second DC voltage received from a second DC circuit. The insulated transformer includes a primary winding that receives the first AC voltage from the output terminals and a secondary winding that receives the second AC voltage from the output terminals.

Bidirectional insulated DC/DC converter and smart network

A power conversion apparatus in which wiring lines are provided between DC buses of a first converter unit and DC buses of a second converter unit. The wiring lines are provided between the DC buses of the second converter unit and DC buses of a third converter unit. Fuses are interposed in the wiring lines, respectively.

Power conversion apparatus

An uninterruptible power supply device () does not have a wire connecting a bidirectional chopper () to a neutral point (NP). The bidirectional chopper () includes first and second capacitors (C, C), first to fourth transistors (Q-Q), and a normal mode reactor (). In a discharging mode, a controller () causes the second and third transistors (Q, Q) to be complementarily turned on and controls the ON period of each of the second and third transistors (Q, Q) so that terminal-to-terminal voltages (V, V) of the first and second capacitors (C, C) are equal to each other.

Uninterruptible power supply device and uninterruptible power supply system using the same

An uninterruptible power supply device (U) includes a converter (), an inverter (), a bidirectional chopper (), and a controller (). The bidirectional chopper () includes first to fourth transistors (Q-Q), first to fourth diodes (D-D), and first and second, coils (). In a charging mode, the controller () causes the first and fourth transistors (QQ) to be complementarily turned on and controls the ON period of each of the first and fourth transistors (QQ) so as to cause respective detected values of first current and second current () flowing through the first coil and the second coil () to be equal to each other.

Growing community of inventors

Chuo-ku, Japan

Kazuki Nishimura