The advantages of optical ctric coupler isolation are:
① The duty ratio is arbitrarily adjustable;
② High isolation and pressure resistance;
③ Anti-interference ability is strong, the optical coupler
with electrostatic shielding is easy to buy at present and isolation performance between strong and weak electric is very good. In addition, the optical coupler belongs to current type of device, which can restrain the voltage noise effectively;
④ The range of transmission signals from DC to the number of MHz and the linear optical coupler is especially applicable to signal feedback.
The disadvantages are:
① In the full bridge topology, there are 4 switch devices, and it requires 3-4 optical couplers. Each opticalcoupler needs independent power supply, it increases the complexity of the circuit, cost but reliability is reduced;
②Because photoelectric coupler transmission delay is larger and in order to ensure the precision of the switch device opened and shut off, the various structural parameters must be consistent and get the same delay. But it is often difficult to do well;
The switch speed of the photoelectric coupler is low, and the front and a rear edge of the driving pulse has a large delay, which affects the control precision.