A low voltage DC power line communication system

Abstract

The invention discloses a low-voltage direct current power line communication system, comprising a pair of low-voltage direct current power lines V+ and V‑, wherein the power lines V+ and V‑ are connected with a core control unit / functional unit; the core control unit / functional unit comprises a power supply unit B01, wherein the power supply unit B01 is connected with a filter inductor L01 and a filter capacitor C01, and is respectively connected with the power lines V+ and V‑; the power supply unit B01 is also connected with a processing unit B02 for processing communication data and executing the main functions of the machine, wherein the processing unit B02 is connected with an amplitude modulation unit B03, and adopts amplitude modulation to meet the communication reliability requirements of the control system in a large noise environment; the circuit is simple, and the components are all conventional components that are easy to obtain, easy to mass produce, and low in cost; when the communication logic is at a high level, the output unit is in a high impedance state, and the high level corresponds to an idle state of the communication, so in the idle state, the communication circuit has no interference with the control system.

Description

Technical Field

[0001] The present invention relates to the technical field of a control system performing low-speed communication via a low-voltage direct current power line, and in particular to a low-voltage direct current power line communication system. Background Art

[0002] Control systems often require interconnection, such as the interconnection between the core control unit and distributed sensors, or the interconnection between distributed actuators. These interconnections not only include power lines, but often also require communication lines, and these interconnections are usually far away, and the existence of communication lines increases the cost of wires. Power lines and communication lines generally require a certain distance, which increases the complexity of wiring and the space required for wiring.

[0003] Based on these reasons, it becomes a reasonable choice to omit the communication line and merge the communication function into the power line, and many patents disclose related circuits and methods.

[0004] These existing circuits have some mismatching problems in the application scenario of low-speed communication interconnection of control systems;

[0005] There are mainly the following categories:

[0006] 1. Too simple and unable to meet the communication reliability requirements of the control system in a high noise environment;

[0007] 2. Too complicated, requiring the use of a dedicated power line carrier communication processor, which makes it difficult to purchase components and is costly;

[0008] 3. When frequency modulation is used, the interference of the carrier signal to the control system continues to exist.

[0009] Therefore, it is necessary to develop a power line carrier communication technology suitable for low-speed communication of control systems. Summary of the invention

[0010] The purpose of the present invention is to propose a power line carrier communication technology suitable for low-speed communication of a control system, which meets the requirements of reliable communication in a large interference environment required for low-speed communication of the control system, easy availability of devices, low cost, and no interference to the system when communication is not required.

[0011] To achieve the above object, the present invention provides the following technical solution: a low-voltage DC power line communication system, comprising a pair of low-voltage DC power lines V+ and V-, wherein the power lines V+ and V- are connected to a core control unit / functional unit;

[0012] The core control unit / functional unit includes a power supply unit B01, and the power supply unit B01 is connected to a filter inductor L01 and a filter capacitor C01, and is respectively connected to power lines V+ and V-;

[0013] The power supply unit B01 is also connected to a processing unit B02 that processes communication data and executes the main functions of the machine, and the processing unit B02 is connected to an amplitude modulation unit B03, and the amplitude modulation unit B03 is connected to a coupling capacitor C02 and is connected to a power line V+;

[0014] The power line V+ is also connected to a coupling capacitor C03, and the coupling capacitor C03 is connected to a frequency-selective amplification unit B04 that amplifies the carrier frequency signal and attenuates other frequency signals;

[0015] The frequency-selective amplification unit B04 is connected to a rectifying and filtering unit B05 which rectifies the signal into a DC signal and filters out some high-frequency components;

[0016] The rectifying and filtering unit B05 is connected to a filtering and amplifying unit B06 which further filters out high frequency components and amplifies DC components so that the output signal amplitude matches the level of the processing unit B02;

[0017] The filtering and amplifying unit B06 is connected to the processing unit B02.

[0018] Preferably: the processing unit B02 is provided with three ports, namely a receiving port RX and a transmitting port TX of a universal asynchronous receiver / transmitter, and a carrier signal output port LO;

[0019] The processing unit B02 is connected to the amplitude modulation unit B03 via the TX terminal and the LO terminal, and is connected to the filtering and amplifying unit B06 via the RX terminal.

[0020] Preferably: the power supply unit B01 adopts DCDC power supply U2, the DCDC power supply U2 is connected with a filter inductor L01 and a filter capacitor C01, the filter inductor L01 is connected to the power line V+, the filter capacitor C01 is connected to the power line V-, and the output power supplies VCC and VDD of the DCDC power supply U2 are used for power supply.

[0021] Preferably: the processing unit B02 adopts a single chip microcomputer U3, and the amplitude modulation unit B03 adopts a three-state gate U1;

[0022] The TX terminal and the LO terminal of the single-chip microcomputer U3 are connected to the tri-state gate U1, and the output terminal of the tri-state gate U1 is connected to the damping resistor R11 and the coupling capacitor C02 and is connected to the power line V+.

[0023] Preferably: the frequency selective amplification unit B04 includes an operational amplifier X1, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a capacitor C1 and a capacitor C2;

[0024] One end of the resistor R1 is connected to one end of the capacitor C2 and one end of the resistor R2, the other end of the resistor R2 is connected to the output end of the operational amplifier X1, the other end of the capacitor C2 is connected to one end of the resistor R3, one end of the capacitor C1 and the in-phase end of the operational amplifier X1, the other ends of the resistor R3 and the capacitor C1 are connected and connected to one end of the resistor R4 and the 1 / 2VCC end, the other end of the resistor R4 is connected to one end of the resistor R5 and the inverting end of the operational amplifier X1, the other end of the resistor R5 is connected to the output end of the operational amplifier X1, and the power supply end and the ground pin of the operational amplifier X1 are connected to VCC and ground respectively.

[0025] Preferably, the other end of the resistor R1 is connected to a coupling capacitor C03 and is connected to a power line V+.

[0026] Preferably: the rectifying and filtering unit B05 comprises a current limiting resistor R8, a rectifying diode D1, a rectifying diode D2, a capacitor C4 and a capacitor C5;

[0027] One end of the current limiting resistor R8 is connected to the output end of the operational amplifier X1, and the other end is connected to the anode of the rectifier diode D1 and the cathode of the rectifier diode D2. The cathode of the rectifier diode D1 is connected to the capacitor C4, and the anode of the rectifier diode D2 is connected to the capacitor C5. The other ends of the capacitors C4 and C5 are connected and connected to the 1 / 2VCC terminal.

[0028] Preferably: the filtering and amplifying unit B06 comprises an operational amplifier X2, a resistor R6, a resistor R7, a resistor R9, a resistor R10, a capacitor C6 and a capacitor C7;

[0029] One end of the resistor R10 is connected to the capacitor C5, and the other end is connected to the in-phase terminal of the operational amplifier X2, one end of the resistor R7 and one end of the capacitor C6. The other ends of the resistor R7 and the capacitor C6 are connected and connected to the VDD terminal.

[0030] One end of the resistor R9 is connected to the capacitor C4, and the other end is connected to the inverting end of the operational amplifier X2, one end of the resistor R6 and one end of the capacitor C7. The other ends of the resistor R6 and the capacitor C7 are connected and connected to the output end of the operational amplifier X2.

[0031] The power supply terminal and ground pin of operational amplifier X2 are connected to VCC and ground respectively.

[0032] Preferably, the output terminal of the operational amplifier X2 is connected to the RX terminal of the single-chip microcomputer U3.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] 1. Amplitude modulation can meet the communication reliability requirements of the control system in a high noise environment.

[0035] 2. The circuit is simple, and the components are all readily available conventional components, which are easy to mass produce and low in cost.

[0036] 3. When the communication logic is at a high level, the output unit is in a high impedance state, and the high level corresponds to the idle state of the communication. Therefore, in the idle state, the communication circuit has no interference with the control system. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is a circuit block diagram of the present invention;

[0038] Figure 2 It is a circuit diagram of the present invention. DETAILED DESCRIPTION

[0039] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0040] See also Figure 1-2 , the present invention provides a technical solution:

[0041] The circuit diagram of the present invention is shown in Figure 1 .

[0042] V+ and V- are a pair of low-voltage DC power lines, and are also the medium for system communication, which contains DC voltage and high-frequency communication voltage signals. The core control unit / functional unit is connected to V+ and V-.

[0043] V+ is connected to the power supply unit B01 and the power supply filter capacitor C01 through the filter inductor L01. The power supply unit B01 can receive power from V+ and V-, and can also provide power to V+ and V- in turn. The other end of the filter capacitor C01 and the power supply unit B01 is connected to the signal ground, which is also connected to V-. The power supply unit B01 supplies power to the rest of the circuit.

[0044] Processing unit B02 is a single-chip microcomputer. In addition to processing communication data, processing unit B02 also needs to execute the main functions of the machine, such as control function, sensor function, and actuator function. Processing unit B02 processes communication data involving three ports. The RX and TX ends are the receiving and sending ports of the universal asynchronous receiver and transmitter (UART), and the LO end is the carrier signal output port.

[0045] The TX and LO terminals of the processing unit B02 are connected to the amplitude modulation unit B03. When TX is high, the output of the amplitude modulation unit B03 is high impedance. When TX is low, the amplitude modulation unit B03 outputs a carrier signal. The output of the amplitude modulation unit B03 is connected to V+ through the output coupling capacitor C02.

[0046] The high-frequency communication voltage signal on V+ enters the frequency-selective amplifier unit B04 after being DC-isolated and coupled by the input coupling capacitor C03. The frequency-selective amplifier unit B04 amplifies the carrier frequency signal and attenuates other frequency signals.

[0047] The output of the frequency-selective amplifier unit B04 enters the rectifier and filter unit B05, where the signal is full-wave rectified into a DC signal and some high-frequency components are filtered out to facilitate subsequent processing.

[0048] The output of the rectification and filtering unit B05 enters the filtering and amplification unit B06, which further filters out the high-frequency component and amplifies the DC component so that the output signal amplitude matches the level of the processing unit B02.

[0049] The output of the filter amplification unit B06 enters the RX port of the processing unit B02.

[0050] Specific implementation:

[0051] The unit circuit of the present invention is further described below in conjunction with specific embodiments. Figure 2 .

[0052] V+ is connected to DCDC power supply U2 and power supply filter capacitor C9 through filter inductor L1. The other end of DCDC power supply U2 and filter capacitor C9 is connected to signal ground, which is also connected to V-. DCDC power supply U2 outputs power supply VCC and VDD to power other circuits.

[0053] The processing unit B02 uses a single-chip microcomputer (MCU) U3. In addition to processing communication data, the single-chip microcomputer U3 also needs to execute the main functions of the machine, such as control function, sensor function, and actuator function. The single-chip microcomputer U3 processes communication data involving three ports. The RX and TX ends are the receiving and sending ports of the universal asynchronous receiver and transmitter (UART), and the LO end is the carrier signal output port.

[0054] The TX port and LO port of the single-chip microcomputer U3 are connected to the three-state gate U1. When TX is at a high level, the output of the three-state gate U1 is a high-impedance state. When the TX end is at a low level, the three-state gate U1 outputs a carrier signal.

[0055] The output of U1 is connected to V+ through damping resistor R11 and output coupling capacitor C8.

[0056] The high-frequency communication voltage signal on V+ enters the frequency-selective amplifier unit B04 after being DC-isolated and coupled by the input coupling capacitor C3.

[0057] The frequency-selective amplifying unit B04 is composed of an operational amplifier X1 and peripheral resistor-capacitor components, which include resistor R1, resistor R2, resistor R3, resistor R4, resistor R5, capacitor C1 and capacitor C2.

[0058] The input signal passes through resistor R1 and is connected to resistor R2 and capacitor C2. The other end of resistor R2 is connected to the output of op amp X1. The other end of capacitor C2 is connected to resistor R3, capacitor C1 and the in-phase end of op amp X1. The other ends of resistor R3 and capacitor C1 are connected and connected to resistor R4 and 1 / 2VCC. The other end of resistor R4 is connected to resistor R5 and the inverting end of op amp X1. The other end of resistor R5 is connected to the output of op amp X1. The power supply and ground pins of op amp X1 are connected to VCC and ground respectively. The frequency selective amplifier circuit amplifies the carrier frequency signal and attenuates the other frequency signals.

[0059] The output of operational amplifier X1 enters the rectifier and filter unit B05;

[0060] The rectifying and filtering unit B05 is composed of a current limiting resistor R8, a rectifying diode D1, a rectifying diode D2, a capacitor C4 and a capacitor C5.

[0061] The output of the operational amplifier X1 is connected to the anode of the rectifier diode D1 and the cathode of the rectifier diode D2 after passing through the resistor R8. The cathode of the rectifier diode D1 is connected to the capacitor C4 as the inverting end of the output of the rectifier filter unit. The anode of the rectifier diode D2 is connected to the capacitor C5 as the non-inverting end of the output of the rectifier filter unit. The other ends of the capacitors C4 and C5 are connected and connected to 1 / 2VCC. The output signal of the operational amplifier X1 is full-wave rectified to become a DC signal, and some high-frequency components are filtered out to facilitate subsequent processing.

[0062] The output of the rectifier filter unit B05 enters the filter amplifier unit B06;

[0063] The filter amplification unit B06 is composed of an operational amplifier X2 and peripheral resistor and capacitor elements, which include resistor R6, resistor R7, resistor R9, resistor R10, capacitor C6 and capacitor C7.

[0064] The in-phase end of the output of the rectifier and filter unit B05 is connected to the resistor R10, the other end of the resistor R10 is connected to the in-phase end of the operational amplifier X2, the resistor R7 and the capacitor C6, the other ends of the resistor R7 and the capacitor C6 are connected and connected to VDD; the inverting end of the output of the rectifier and filter unit B05 is connected to the resistor R9, the other end of the resistor R9 is connected to the inverting end of the operational amplifier X2, the resistor R6 and the capacitor C7, the other ends of the resistor R6 and the capacitor C7 are connected and connected to the output end of the operational amplifier X2; the power supply and ground pins of the operational amplifier X2 are connected to VCC and ground respectively.

[0065] The filtering and amplifying unit B06 further filters out the high frequency component and amplifies the DC component so that the output signal amplitude matches the level of U3.

[0066] The output of op amp X2 goes into the RX port of microcontroller U3.

[0067] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A low voltage DC power line communication system, comprising a pair of low voltage DC power lines V+ and V-, characterized in that: The power lines V+ and V- are connected to a core control unit / functional unit; The core control unit / functional unit includes a power supply unit B01, and the power supply unit B01 is connected to a filter inductor L01 and a filter capacitor C01, and is respectively connected to power lines V+ and V-; The power supply unit B01 is also connected to a processing unit B02 that processes communication data and executes the main functions of the machine, and the processing unit B02 is connected to an amplitude modulation unit B03, and the amplitude modulation unit B03 is connected to a coupling capacitor C02 and is connected to a power line V+; The power line V+ is also connected to a coupling capacitor C03, and the coupling capacitor C03 is connected to a frequency-selective amplification unit B04 that amplifies the carrier frequency signal and attenuates other frequency signals; The frequency-selective amplification unit B04 is connected to a rectifying and filtering unit B05 which rectifies the signal into a DC signal and filters out some high-frequency components; The rectifying and filtering unit B05 is connected to a filtering and amplifying unit B06 which further filters out high frequency components and amplifies DC components so that the output signal amplitude matches the level of the processing unit B02; The filtering and amplifying unit B06 is connected to the processing unit B02.

2. A low voltage DC power line communication system according to claim 1, characterized in that: The processing unit B02 is provided with three ports, namely, a receiving port RX end and a transmitting port TX end of a universal asynchronous receiver / transmitter, and a carrier signal output port LO end; The processing unit B02 is connected to the amplitude modulation unit B03 via the TX terminal and the LO terminal, and is connected to the filtering and amplifying unit B06 via the RX terminal.

3. A low voltage DC power line communication system according to claim 1, characterized in that: The power supply unit B01 adopts DCDC power supply U2, and the DCDC power supply U2 is connected with a filter inductor L01 and a filter capacitor C01. The filter inductor L01 is connected to the power line V+, and the filter capacitor C01 is connected to the power line V-. The output power supplies VCC and VDD of the DCDC power supply U2 are used for power supply.

4. A low voltage DC power line communication system according to claim 2, characterized in that: The processing unit B02 adopts a single-chip microcomputer U3, and the amplitude modulation unit B03 adopts a three-state gate U1; The TX terminal and the LO terminal of the single-chip microcomputer U3 are connected to the tri-state gate U1 , and the output terminal of the tri-state gate U1 is connected to the damping resistor R11 and the coupling capacitor C02 and is connected to the power line V+.

5. A low voltage DC power line communication system according to claim 1, characterized in that: The frequency selective amplification unit B04 includes an operational amplifier X1, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a capacitor C1 and a capacitor C2; One end of the resistor R1 is connected to one end of the capacitor C2 and one end of the resistor R2, the other end of the resistor R2 is connected to the output end of the operational amplifier X1, the other end of the capacitor C2 is connected to one end of the resistor R3, one end of the capacitor C1 and the in-phase end of the operational amplifier X1, the other ends of the resistor R3 and the capacitor C1 are connected and connected to one end of the resistor R4 and the 1 / 2VCC end, the other end of the resistor R4 is connected to one end of the resistor R5 and the inverting end of the operational amplifier X1, the other end of the resistor R5 is connected to the output end of the operational amplifier X1, and the power supply end and the ground pin of the operational amplifier X1 are connected to VCC and ground respectively.

6. A low voltage DC power line communication system according to claim 5, characterized in that: The other end of the resistor R1 is connected to a coupling capacitor C03 and is connected to a power line V+.

7. A low voltage DC power line communication system according to claim 5, characterized in that: The rectifying and filtering unit B05 includes a current limiting resistor R8, a rectifying diode D1, a rectifying diode D2, a capacitor C4 and a capacitor C5; One end of the current limiting resistor R8 is connected to the output end of the operational amplifier X1, and the other end is connected to the anode of the rectifier diode D1 and the cathode of the rectifier diode D2. The cathode of the rectifier diode D1 is connected to the capacitor C4, and the anode of the rectifier diode D2 is connected to the capacitor C5. The other ends of the capacitors C4 and C5 are connected and connected to the 1 / 2VCC terminal.

8. A low voltage DC power line communication system according to claim 7, characterized in that: The filtering and amplifying unit B06 includes an operational amplifier X2, a resistor R6, a resistor R7, a resistor R9, a resistor R10, a capacitor C6 and a capacitor C7; One end of the resistor R10 is connected to the capacitor C5, and the other end is connected to the in-phase terminal of the operational amplifier X2, one end of the resistor R7 and one end of the capacitor C6. The other ends of the resistor R7 and the capacitor C6 are connected and connected to the VDD terminal. One end of the resistor R9 is connected to the capacitor C4, and the other end is connected to the inverting end of the operational amplifier X2, one end of the resistor R6 and one end of the capacitor C7. The other ends of the resistor R6 and the capacitor C7 are connected and connected to the output end of the operational amplifier X2. The power supply terminal and ground pin of operational amplifier X2 are connected to VCC and ground respectively.

9. A low voltage DC power line communication system according to claim 8, characterized in that: The output terminal of the operational amplifier X2 is connected to the RX terminal of the microcontroller U3.

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