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EP-4736332-A1 - TRANSMISSION UNIT AND METHOD FOR COUPLING AN ELECTRICAL TRANSMISSION SIGNAL INTO A DC VOLTAGE LINE

EP4736332A1EP 4736332 A1EP4736332 A1EP 4736332A1EP-4736332-A1

Abstract

The application relates to a transmission unit (10) for coupling a transmission signal into a DC voltage line (26.1, 26.2) with two output terminals (20) between which the transmission signal is applied and which are provided for connecting to a coupling means (21) in the DC voltage line (26.1, 26.2), wherein the transmission unit (10) comprises an amplifier circuit (12) with a clocked amplifier and the amplitude of the transmission signal is proportional to a supply voltage (Vcc) of the clocked amplifier. The transmission unit (10) comprises a compensation circuit (14) which is configured to measure the amplitude of the transmission signal via a differential voltage measurement at the output terminals (20) and to adjust the supply voltage (Vcc) of the clocked amplifier on the basis of the amplitude of the transmission signal. The application also relates to a photovoltaic inverter (30) having a transmission unit (10) and to a method for coupling a transmission signal into a DC voltage line (26.1, 26.2).

Inventors

  • BAUER, DANTE
  • SCHNARE, Karsten

Assignees

  • SMA Solar Technology AG

Dates

Publication Date
20260506
Application Date
20240627

Claims (17)

  1. 1. Transmission unit (10) for coupling an electrical transmission signal into a direct voltage line (26.1, 26.2) with two output connections (20) between which the transmission signal is present and which are provided for connection to a coupling means (21) in the direct voltage line (26.1, 26.2), wherein the transmission unit (10) has an amplifier circuit (12) with a clocked amplifier and the amplitude of the transmission signal is proportional to a supply voltage (Vcc) of the clocked amplifier, wherein the transmission unit (10) comprises a compensation circuit (14) which is set up to detect the amplitude of the transmission signal via a differential voltage measurement at the output connections (20) and to adjust the supply voltage (Vcc) of the clocked amplifier depending on the amplitude of the transmission signal.
  2. 2. Transmission unit (10) according to claim 1, wherein the compensation circuit (14) is arranged to output a compensation signal (SFB) depending on the amplitude of the transmission signal in order to adjust the supply voltage (Vcc) of the clocked amplifier.
  3. 3. A transmitting unit (10) according to claim 2, wherein a nominal DC supply voltage is provided, wherein the supply voltage (Vcc) of the clocked amplifier is adjustable in a range between half the nominal DC supply voltage and twice the nominal DC supply voltage depending on the nominal DC supply voltage and on the compensation signal (SFB).
  4. 4. Transmitter unit (10) according to claim 3, wherein the supply voltage (Vcc) is adjustable in a range from approximately 4 volts to approximately 10 volts.
  5. 5. Transmission unit (10) according to one of the preceding claims, comprising a DC/DC converter (24) which is configured to generate the supply voltage (Vcc) from a higher-level vehicle electrical system voltage (VB) as a function of the amplitude of the transmission signal or as a function of the compensation signal (SFB).
  6. 6. Transmission unit (10) according to one of the preceding claims, wherein the compensation signal (SFB) output by the compensation circuit (14) is analog or digital.
  7. 7. Transmission unit (10) according to one of claims 2 to 6, wherein the transmission unit (10) has a processor (16) which is designed to generate the compensation signal (SFB) in digital form as a clock sequence with a duty cycle and to send it to the compensation Circuit (14), wherein the duty cycle is adjusted by the processor (16) depending on the amplitude of the transmission signal.
  8. 8. Transmission unit (10) according to claim 7, wherein the compensation circuit (14) outputs the clock sequence as a compensation signal (SFB) in digital form as a control signal for semiconductor switches of the DC/DC converter (24).
  9. 9. Transmission unit (10) according to claim 7, wherein the compensation circuit (14) comprises a filter which generates the compensation signal (SFB) from the clock sequence as a voltage level in analog form and outputs it to a control input of the DC/DC converter (24).
  10. 10. Transmission unit (10) according to one of the preceding claims, wherein two transmission channels can be coupled in via the transmission signal, wherein the transmission unit (10) can be switched between the two transmission channels, and wherein the supply voltage (Vcc) of the clocked amplifier or the compensation signal can be switched alternately between a first and a second supply voltage or between a first and a second compensation signal (SFB) depending on the transmission channel.
  11. 11. Transmission unit (10) according to one of the preceding claims, wherein the compensation circuit (14) has a temperature sensor for temperature detection (508) and wherein the supply voltage (Vcc) of the clocked amplifier or the compensation signal (SFB) depends on the detected temperature.
  12. 12. Transmission unit (10) according to one of the preceding claims, wherein the amplifier circuit (12) is arranged to generate a modulation of the transmission signal in dependence on a binary specification signal (TX0, TX1).
  13. 13. Transmission unit (10) according to one of the preceding claims, wherein the clocked amplifier comprises a half-bridge circuit with semiconductor power switches.
  14. 14. Transmission unit (10) according to one of the preceding claims, wherein the amplifier circuit (12) comprises a class D amplifier circuit.
  15. 15. Photovoltaic inverter (30) with a transmitting unit (10) according to one of the preceding claims, wherein the transmitting unit (10) is provided for coupling the transmitting signal into the direct voltage line (26.1, 26.2), wherein a DC bus (26) has the direct voltage line (26.1, 26.2), and the DC bus (26) connects the inverter (30) to at least one photovoltaic generator (36) for electrical power exchange.
  16. 16. Photovoltaic system (40) with an inverter (30) according to claim 15, the at least one photovoltaic generator (36) and the DC bus (26) for electrical power transfer.
  17. 17. Method for coupling a transmission signal into a DC voltage line (26.1, 26.2), wherein the transmission signal is present between two output terminals (20) which are connected to a coupling means (21) in the DC voltage line (26.1, 26.2), wherein an amplifier circuit (12) with a clocked amplifier generates the transmission signal with an amplitude proportional to a supply voltage (Vcc) of the clocked amplifier, wherein a compensation circuit (14) detects the amplitude of the transmission signal via a differential voltage measurement at the output terminals (20) and adjusts the supply voltage (Vcc) of the clocked amplifier.

Description

TRANSMITTING UNIT AND METHOD FOR COUPLING AN ELECTRICAL TRANSMITTING SIGNAL INTO A DC VOLTAGE LINE TECHNICAL FIELD The application relates to a transmitting unit for coupling an electrical transmission signal into a direct voltage line and to a photovoltaic inverter with such a transmitting unit. The application further relates to a method for coupling an electrical transmission signal into a direct voltage line. STATE OF THE ART Electrical transmission signals can be impressed, transmitted and coupled out of the direct voltage lines of an electrical installation, for example a power generation system, in particular for powerline communication between different devices connected to the direct voltage lines. In the case of a photovoltaic system, for example, the so-called SunSpec specification of the SunSpec Alliance defines requirements for powerline communication (Powerline Communication PLC) between photovoltaic inverters and electronic units on or near the photovoltaic generators. Photovoltaic systems in particular therefore regularly include a transmission unit in the inverter, which generates a defined electrical transmission signal and couples it onto the direct voltage lines. TASK The application is based on the object of improving such a transmitting unit and such a method for coupling a transmitting signal into a direct voltage line. SOLUTION The object is achieved by a transmitting unit having the features of claim 1 and a method having the features of claim 17. Embodiments are specified in the dependent claims. DESCRIPTION OF THE INVENTION A transmitting unit couples an electrical transmission signal into a DC voltage line. Two output connections are provided for coupling, between which the transmission signal is present. The output connections are provided for connection to a coupling means in the DC voltage line. The transmitting unit has an amplifier circuit with a clocked amplifier. The amplitude of the transmission signal is proportional to a Supply voltage of the clocked amplifier, wherein the transmitting unit comprises a compensation circuit which is configured to detect the amplitude of the transmitted signal via a differential voltage measurement at the output terminals and to adjust the supply voltage of the clocked amplifier depending on the amplitude of the transmitted signal. The electrical transmission signal is thus generated by the transmission unit, output via the output connections and coupled into the DC voltage line via the coupling means. The coupling can basically be inductive or capacitive, whereby the coupling means can in particular comprise a coil for inductive coupling. The clocked amplifier of the amplifier circuit can, for example, have a bridge circuit with switches which are controlled in a clocked manner. The compensation circuit can in particular have an analog circuit part for differential voltage measurement. The differential voltage measurement has the advantage that the amplitude of the transmission signal can be recorded, even if the output connections between which the transmission signal is present do not have a defined ground reference. Optionally, the compensation circuit can rectify and smooth the measurement signal. With a registered transmitter unit, it is possible to automatically set the transmission signal to a desired amplitude value and to compensate for any deviations from this that may be caused, for example, by component tolerances, changes in the ambient conditions or changes to the DC units connected to the DC voltage lines. This improves the quality of the electrical transmission signal and thus the data transmission without the need for manual intervention in the transmitter unit, for example after installing the transmitter unit or the inverter or after making changes to the photovoltaic system. In a further development of the transmitting unit, the compensation circuit is designed to output a compensation signal depending on the amplitude of the transmitting signal in order to adjust the supply voltage of the clocked amplifier. By means of such a compensation signal depending on the amplitude of the transmitting signal, the real amplitude of the transmitting signal at the output terminals can be taken into account when adjusting the supply voltage of the clocked amplifier, even if the supply voltage is generated separately, i.e. not by the compensation circuit itself but by a separate voltage supply. The transmitting unit, in turn, is designed so that the amplitude of the transmitting signal is proportional to the supply voltage of the clocked amplifier, so that the amplitude can be adjusted to the desired value by means of the described design of the compensation circuit. In one embodiment of the transmission unit, a nominal DC supply voltage is provided, wherein the supply voltage of the clocked amplifier can be set depending on the nominal DC supply voltage and the compensation signal in a range between half the nominal DC supply vo