Power transmission device of OFDM (orthogonal frequency division multiplexing) power line carrier communication

Abstract

The invention discloses a power transmission device of OFDM (orthogonal frequency division multiplexing) power line carrier communication. The device comprises an adjustable gain amplification unit, a differential output power driving unit, a coupling unit, a power source voltage detection unit and a gain control unit, wherein the power source voltage detection unit is used for sampling a power source voltage value, and inputting a sampling result into the gain control unit; and calculating a reasonable gain control signal by the gain control unit according to the power source voltage valve, and feeding the reasonable gain control signal back to the adjustable gain amplification unit. With the adoption of the power transmission device of the OFDM power line carrier communication, the problem that output power is not insufficient due to the fact that OFDM signal peak-to-average ratio is larger is overcome, and meanwhile, communication interrupt caused by power source voltage reduction when a power line load is heavier is prevented. Compared with the traditional signal detection technology, through detecting the power source voltage, the problem that the power transmission device is not easily constricted as the peak-to-average ratio of the OFDM signal is larger is avoided.

Description

technical field [0001] The invention relates to power line communication technology, in particular to a power transmission device for OFDM power line carrier communication. Background technique [0002] Power line communication is the use of existing power lines to transmit data, especially the use of low-voltage power line distribution network for carrier communication. The cost is low, but compared with other communication methods, power lines have many characteristics as a communication medium: strong time-varying, equivalent impedance transformation range Large, large channel attenuation, strong interference and noise, etc. In power line carrier communication, in order to obtain higher rate and anti-narrowband interference, adopt orthogonal frequency division multiplexing technology (OFDM). OFDM divides information into several parallel data streams, and then modulates the data onto a single subcarrier that is orthogonal to each other for transmission. OFDM reduces int...

AI Technical Summary

Problems solved by technology

However, the OFDM modulated signal has a large peak-to-average ratio, and the effective signal power in the transmitted signal is low. In order to improve the communication distance of OFDM technology and better exert its rate and anti-narrowband interference performance, it is necessary for the power transmission unit to be able to transmit a large peak signal, but in the current domestic carrier communication standards, there are clear requirements for the power supply voltage of the carrier communication module, which limits the range of the power supply voltage, so it is impossible to increase the transmission power by increasing the power supply voltage

Even if the problem of sending power is solved, since the equivalent load of the power line varies widely, in some cases, even as small as 1 ohm, the power supply is required to have a very strong power supply capability, but in the current standard of domestic carrier communication Among them, there are clear requirements for the transmission power of the power supply of the carrier communication module, which makes the power easily exceed the standard under heavy load, and the power supply voltage is passively reduced. At this time, it is necessary to reduce the transmission power to reduce the requirements for the power supply, so a kind of Adaptive power transmission device to adapt to different situations and loads

The conventional method for automatically adjusting the amplification gain is to detect the output signal, but because the OFDM signal has a large peak-to-average ratio, the detection results are prone to fluctuations, which makes the control loop difficult to converge

Images