Hitachi AN091802-1 User Manual

Application Note: 
Powering Inverters from a 
DC Supply

Hitachi America, Ltd.

AN091802-1

Please refer also to the

Inverter Instruction Manual

© 2002 Hitachi America, Ltd.

Powering Inverters from DC

INV #2

M 2

INV #n

M n

INV #1

M 1

INV

M

INV

M

It is possible to power inverters from a DC Power source, or to connect the DC Bus of multiple inverters together to

achieve energy savings, since inverters in power driving mode can use power from those that are in regeneration mode.

[1] Connection method

There are several ways for DC bus connection of the inverters. (Examples of 3-phase 200V or 400V class inverter.)

Case 1 : Connected in parallel to a common DC bus

DC power
supply

INV #1

M 1

INV #2

M 2

INV #n

M n

Case 3 : AC & DC Connected together

AC power
supply

Case 2 : Connected in parallel to an A-fed inverter

AC power
supply

INV #1

+

M 1

­INV #2

M 2

INV #n

M n

DC supply connection methods

+

-

+

-

ΠConnecting to + and - terminal

+

-

• Connecting to AC inputs and - terminal

Ø Advantage and disadvantages of each connection method.

Item Contents Advantage Disadvantage

Connecting to + & - terminal Ÿ No concern for the

Œ

Connecting to AC inputs and - terminal Ÿ Integrated inrush current

•

rectifier bridge diodes.

limiting circuit is used.

Ÿ There will be no inrush

current limiting.

Ÿ Rectifier bridge diodes

of the main inverter may
need to be up-sized.