Method, based on composite modulation, of data transmission between power electronic devices without communication line
A method of data transmission between power electronic devices without a communication line involves generation of a digital signal in a data transmission process. The digital signal enables PWM modulation of specific data information via a composite modulation method. The composite modulation superimposes PWM modulation waves after modulating the PWM carrier frequency or conducting high-frequency modulation on the data. The composite modulation generates a PWM drive pulse signal which is transmitted to a power circuit via a main power electronic circuit to complete the data transmission process. In the data receiving process, signals are extracted on the voltage and current of a power line via software or hardware, and data demodulated to obtain the data information to complete the data receiving process.
1. A method based on composite modulation of data transmission between power electronic devices without communication line, comprising: in a data transmitting process, utilizing a composite modulation method to include specific data information in a pulse width modulation (PWM) process, and then transmitting the specific data information to a power line through a main power electronic circuit by means of driving pulse signals, so as to accomplish the data transmission process; in a data receiving process, extracting signals from voltage and current in the power line, and then obtaining data information through data demodulation, so as to accomplish the data receiving process, wherein, a control module of the power electronic device comprises a main control algorithm module, a signal extraction module, a data demodulation module, a communication processing module, and a composite modulation module, and wherein, the following control scheme is used in the data transmission process:
1) the communication processing module is configured to receive, transmit, process, and judge communication signals transmitted through the power line, and the communication processing module generates data signals when data needs to be transmitted;
2) the main control algorithm module of the power electronic device employs a pulse width modulation (PWM) mode to control the main power electronic circuit, and the controller contains a main control algorithm, which generates a raw modulation wave according to the voltage and current in the power line and control commands;
3) the data signals generated by the communication processing module and the raw modulation wave generated by the main control algorithm are fed into a composite modulation module to accomplish composite modulation.
2. The method based on composite modulation of data transmission between power electronic devices without communication line according to claim 1 , wherein, the main circuit of the power electronic devices is connected with the power line in series or in shunt.
3. The method based on composite modulation of data transmission between power electronic devices without communication line according to claim 1 , wherein, the composite modulation is carried out as follows: the data signals are processed by frequency shift keying (FSK) to generate a carrier wave that has varying frequencies, and then the carrier wave is compared with the raw modulation wave to generate the driving pulse signals.
4. The method based on composite modulation of data transmission between power electronic devices without communication line according to claim 1 , wherein, the composite modulation is carried out as follows: the data signals are modulated into a high-frequency modulation wave, and are superposed on the raw modulation wave to form a new modulation wave, and then the new modulation wave is compared with the carrier wave with a fixed frequency to form the driving pulse signals; the driving pulse signals drive the main power electronic circuit to accomplish the data transmitting process.
5. The method based on composite modulation of data transmission between power electronic devices without communication line according to claim 1 , wherein, the following control scheme is used in the data receiving process:
1) the voltage and the current on line side are acquired, and the communication data information contained in the voltage and current are extracted;
2) the data information is demodulated to obtain demodulated communication data, and then the demodulated data is sent into the communication processing module, so as to accomplish receiving of the communication data.