High-precision parallel current sharing circuit and implementation method thereof

Abstract

The invention discloses a high-precision parallel current sharing circuit and an implementation method thereof, the circuit comprises a plurality of PSU modules and a main control unit in communication connection with each PSU module, each PSU module comprises a DC power supply unit, an ideal diode, a signal processing unit, a following / anti-backflow unit, an output current sampling unit and a TRIM driving unit, a direct-current power supply is input to the input end of the direct-current power supply unit, a preset + A voltage is output after conversion, then a + Abus bus voltage is formed after isolation of an ideal diode, and all PSU modules are connected in parallel through a + Abus bus and provide a driving power supply for the LED module. According to the high-precision parallel current sharing circuit and the implementation method thereof disclosed by the invention, precise regulation and control of output current of each PSU module are realized, and the reliability and the stability of a system are improved.

Description

Technical Field

[0001] This invention belongs to the field of power supply current sharing technology, specifically relating to a high-precision parallel current sharing circuit and its implementation method. Background Technology

[0002] In modern rail transit vehicles, LED lighting systems have become the mainstream choice due to their high efficiency and long lifespan. To ensure the high reliability of the lighting system, the driver power supply often adopts an "N+X" redundant architecture with multiple modules connected in parallel. When some modules fail, the remaining modules can maintain the normal operation of the system.

[0003] However, the existing parallel power supply architecture has key problems: differences in component parameters, aging levels, connection impedance, and bus voltage fluctuations between modules can easily lead to uneven output current across modules. Some modules operating under overload can cause overheating, accelerated aging, or even failure, while others operate under light load, wasting redundancy. This not only reduces the reliability and lifespan of the power system but may also cause localized overheating safety hazards, leading to fluctuations in lighting brightness and affecting passenger experience and system stability.

[0004] Therefore, there is an urgent need to develop an efficient, reliable and easy-to-implement parallel current sharing technology to ensure that each power module can share the load consistently under all operating conditions, so as to improve the overall performance of the rail transit car lighting system. Summary of the Invention

[0005] The main objective of this invention is to provide a high-precision parallel current sharing circuit and its implementation method, so as to achieve precise control of the output current of each PSU module and improve the system reliability and stability.

[0006] To achieve the above objectives, this invention discloses a high-precision parallel current sharing method, comprising the following steps: Step S1: Construct circuits for each PSU module to achieve parallel current sharing; In step S1, each PSU module includes a DC power supply unit, an ideal diode, a signal processing unit, a follower / anti-reverse current unit, an output current sampling unit, and a TRIM drive unit. The parallel current sharing is implemented in the following steps: Step S1.1: Input the DC power supply to the input terminal of the DC power supply unit, and output the preset +A voltage after conversion. Then, after isolation by an ideal diode, the +A_bus bus voltage is formed. Each PSU module is connected in parallel through the +A_bus bus and provides driving power to the LED module. Step S1.2: The output current sampling unit monitors and samples the output current of the DC power supply unit, converts the I_sense signal into the I_dete output current signal, and generates the Is_bus bus current signal after being processed by the follower / anti-backflow unit. The Is_bus bus current signals of each PSU module are connected in parallel and used as the current sharing reference. Step S1.3: The signal processing unit collects the +A_bus bus voltage, +A output voltage, I_dete output current signal and Is_bus bus current signal in real time. The signal processing unit outputs a PWM control signal, which is converted by the TRIM drive unit to roughly control the output voltage and current of the DC power supply unit, so that the output voltage and current of each PSU module are basically consistent. At the same time, data interaction with the main control unit is realized through RS485 communication. Step S1.4: The main control unit communicates with each PSU module via RS485 to obtain the I_dete output current signal, calculates the average current parameter according to the current sharing algorithm and sends it to the signal processing unit of each PSU module so that the signal processing unit adjusts the output of the corresponding PWM control signal. After conversion by the TRIM drive unit, the output voltage and current of the DC power supply unit are precisely controlled so that the final output voltage and current of each PSU module are kept accurate and consistent and stable. Step S1.5: When a PSU module malfunctions, the signal processing unit shuts down the current PSU module through the TRIM drive unit and reports the fault information to the main control unit via RS485. The main control unit recalculates the average current parameters to the signal processing units of the remaining PSU modules, readjusts the output parameters of the remaining PSU modules to maintain stable output, and at the same time, the main control unit issues a PSU module malfunction alarm signal and replaces the malfunctioning PSU module in a timely manner.

[0007] As a further preferred technical solution to the above technical solution, the current sharing algorithm in step S1.4 is implemented with high-precision current sharing through master-slave communication, with the master control unit acting as the master and the signal processing unit acting as the slave. Specifically, the implementation is as follows: The slave device acquires the output current of the I_dete sampling unit of the output current sampling unit of this PSU module and the Is_bus bus current signal of the follower / anti-backflow unit. After calculating the difference, the fast current error value I_diff_fast is obtained, and a coarse PWM duty cycle signal is output. Simultaneously, the host periodically collects the I_dete output current signal of each PSU module, calculates the average current, and sends it to each slave. After receiving the average current signal sent by the host, the slave calculates the slow current error value I_diff_slow, accumulates the fast current error value and the slow current error value, and calculates Error = I_diff_fast + I_diff_slow. The PID algorithm is then used to calculate the adjustment amount u(k) = Kp*error(k) + Ki*∑error(i) + Kd*[error(k) - error(k-1)], where: Kp is the proportional coefficient, Ki is the integral coefficient, Kd is the derivative coefficient, error(k) is the error value at the k-th sampling time, ∑error(i) is the sum of all error values ​​from the 1st to the k-th sampling time (reflecting the accumulation of error), and error(k-1) is the error value at the (k-1)-th sampling time (used to calculate the change in error). Based on this adjustment, the output parameters are corrected to obtain a precise PWM duty cycle signal. This allows each slave device to adjust its output PWM control signal to the corresponding TRIM drive unit, thereby adjusting the output current to achieve current sharing.

[0008] As a further preferred technical solution to the above technical solution, each PSU module is identified by ADD coding.

[0009] This invention also provides a high-precision parallel current sharing circuit, comprising multiple PSU modules and a main control unit communicatively connected to each PSU module. Each PSU module includes a DC power supply unit, an ideal diode, a signal processing unit, a follower / anti-reverse current unit, an output current sampling unit, and a TRIM drive unit, wherein: The DC power supply is input to the input terminal of the DC power supply unit, and after conversion, the preset +A voltage is output. Then, after isolation by an ideal diode, the +A_bus bus voltage is formed. Each PSU module is connected in parallel through the +A_bus bus and provides driving power to the LED module. The output current sampling unit monitors and samples the output current of the DC power supply unit, converts the I_sense signal into the I_dete output current signal, and generates the Is_bus bus current signal after being processed by the follower / anti-backflow unit. The Is_bus bus current signals of each PSU module are connected in parallel and used as the current sharing reference. The signal processing unit collects the +A_bus bus voltage, +A output voltage, I_dete output current signal and Is_bus bus current signal in real time. The signal processing unit outputs a PWM control signal, which is converted by the TRIM drive unit to roughly control the output voltage and current of the DC power supply unit, so that the output voltage and current of each PSU module are basically consistent. At the same time, it realizes data interaction with the main control unit through RS485 communication. The main control unit communicates with each PSU module via RS485 to obtain the I_dete output current signal. It calculates the average current parameter according to the current sharing algorithm and sends it to the signal processing unit of each PSU module so that the signal processing unit can adjust the output of the corresponding PWM control signal. After conversion by the TRIM drive unit, the output voltage and current of the DC power supply unit are precisely controlled so that the final output voltage and current of each PSU module are kept accurate and consistent and stable. When a PSU module malfunctions, the signal processing unit shuts down the current PSU module through the TRIM drive unit and reports the fault information to the main control unit via RS485. The main control unit recalculates the average current parameters and sends them to the signal processing unit of the remaining PSU modules, readjusts the output parameters of the remaining PSU modules to maintain stable output, and at the same time, the main control unit issues a PSU module malfunction alarm signal to replace the malfunctioning PSU module in a timely manner.

[0010] As a further preferred technical solution to the above technical solution, each PSU module is identified by ADD coding.

[0011] The beneficial effects of this invention are as follows: 1. Supports parallel output of multiple modules, enabling multiple PSU modules to work together and meet redundancy design requirements.

[0012] 2. High current sharing accuracy, with the output current error of each module controlled within 1%, ensuring even load distribution.

[0013] 3. Supports hot-swapping of PSU modules, with millisecond-level fast current sharing response, ensuring system stability during hot-swapping.

[0014] 4. It has multiple protection functions, including overvoltage, undervoltage, overcurrent and short circuit protection, to improve system safety.

[0015] 5. Enables real-time detection and communication of output information from each module, timely fault reporting, and facilitates maintenance. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the high-precision parallel current sharing circuit of the present invention.

[0017] Figure 2 This is a flowchart illustrating the flow sharing algorithm of this invention. Detailed Implementation

[0018] The following description is intended to disclose the present invention and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art. The basic principles of the invention defined in the following description can be applied to other embodiments, modifications, improvements, equivalents, and other technical solutions that do not depart from the spirit and scope of the invention.

[0019] In the preferred embodiments of the present invention, those skilled in the art should note that the LED modules and the like involved in the present invention can be considered as prior art.

[0020] Preferred embodiment.

[0021] like Figure 1-2 As shown, this invention discloses a high-precision parallel current sharing method, comprising the following steps: Step S1: Construct circuits for each PSU module (power supply unit) to achieve parallel current sharing; In step S1, each PSU module includes a DC power supply unit, an ideal diode, a signal processing unit, a follower / anti-reverse current unit, an output current sampling unit, and a TRIM drive unit. The parallel current sharing is implemented in the following steps: Step S1.1: Input a DC power supply (preferably +110V) to the input terminal of the DC power supply unit. After conversion, output a preset +A (preferably +48V) voltage. Then, after isolation by an ideal diode, form the +A_bus bus voltage. Each PSU module is connected in parallel through the +A_bus bus and provides driving power to the LED module. Step S1.2: The output current sampling unit monitors and samples the output current of the DC power supply unit, converts the I_sense signal into the I_dete output current signal, and generates the Is_bus bus current signal after being processed by the follower / anti-backflow unit. The Is_bus bus current signals of each PSU module are connected in parallel and used as the current sharing reference. Step S1.3: The signal processing unit collects the +A_bus bus voltage, +A output voltage, I_dete output current signal and Is_bus bus current signal in real time. The signal processing unit outputs a PWM control signal, which is converted by the TRIM drive unit to roughly control the output voltage and current of the DC power supply unit, so that the output voltage and current of each PSU module are basically consistent (within 5% error). At the same time, data interaction with the main control unit is realized through RS485 communication. Step S1.4: The main control unit communicates with each PSU module via RS485 to obtain the I_dete output current signal, calculates the average current parameter according to the current sharing algorithm, and sends it to the signal processing unit of each PSU module so that the signal processing unit adjusts the output of the corresponding PWM control signal. After conversion by the TRIM drive unit, the output voltage and current of the DC power supply unit are precisely controlled, so that the final output voltage and current of each PSU module are kept accurate and consistent and stable (error controlled within 1%). Step S1.5: When a PSU module malfunctions, the signal processing unit shuts down the current PSU module through the TRIM drive unit and reports the fault information to the main control unit via RS485. The main control unit recalculates the average current parameters to the signal processing units of the remaining PSU modules, readjusts the output parameters of the remaining PSU modules to maintain stable output, and at the same time, the main control unit issues a PSU module malfunction alarm signal and replaces the malfunctioning PSU module in a timely manner.

[0022] Specifically, for the current sharing algorithm in step S1.4, high-precision current sharing is achieved through master-slave communication, with the master control unit acting as the master and the signal processing unit acting as the slave. The specific implementation is as follows: The slave device acquires the output current of the I_dete sampling unit of the output current sampling unit of this PSU module and the Is_bus bus current signal of the follower / anti-backflow unit. After calculating the difference, the fast current error value I_diff_fast is obtained, and a coarse PWM duty cycle signal is output. Simultaneously, the host periodically collects the I_dete output current signal of each PSU module, calculates the average current, and sends it to each slave. After receiving the average current signal sent by the host, the slave calculates the slow current error value I_diff_slow, accumulates the fast current error value and the slow current error value, and calculates Error = I_diff_fast + I_diff_slow. The PID algorithm is then used to calculate the adjustment amount u(k) = Kp*error(k) + Ki*∑error(i) + Kd*[error(k) - error(k-1)], where: Kp is the proportional coefficient, Ki is the integral coefficient, Kd is the derivative coefficient, error(k) is the error value at the k-th sampling time, ∑error(i) is the sum of all error values ​​from the 1st to the k-th sampling time (reflecting the accumulation of error), and error(k-1) is the error value at the (k-1)-th sampling time (used to calculate the change in error). Based on this adjustment, the output parameters are corrected to obtain a precise PWM duty cycle signal. This allows each slave device to adjust its output PWM control signal to the corresponding TRIM drive unit, thereby adjusting the output current to achieve current sharing.

[0023] Fast current sharing can achieve millisecond-level response, quickly adjusting the current during module hot-swapping. Slow current sharing, through periodic master-slave data interaction, reduces errors caused by voltage drop and interference on the ground wire and current sharing bus, further improving the current sharing accuracy under steady-state conditions.

[0024] More specifically, each PSU module is identified through ADD coding.

[0025] This invention also discloses a high-precision parallel current sharing circuit, comprising multiple PSU modules and a main control unit communicatively connected to each PSU module. Each PSU module includes a DC power supply unit, an ideal diode, a signal processing unit, a follower / anti-reverse current unit, an output current sampling unit, and a TRIM drive unit, wherein: The DC power supply is input to the input terminal of the DC power supply unit, and after conversion, the preset +A voltage is output. Then, after isolation by an ideal diode, the +A_bus bus voltage is formed. Each PSU module is connected in parallel through the +A_bus bus and provides driving power to the LED module. The output current sampling unit monitors and samples the output current of the DC power supply unit, converts the I_sense signal into the I_dete output current signal, and generates the Is_bus bus current signal after being processed by the follower / anti-backflow unit. The Is_bus bus current signals of each PSU module are connected in parallel and used as the current sharing reference. The signal processing unit collects the +A_bus bus voltage, +A output voltage, I_dete output current signal and Is_bus bus current signal in real time. The signal processing unit outputs a PWM control signal, which is converted by the TRIM drive unit to roughly control the output voltage and current of the DC power supply unit, so that the output voltage and current of each PSU module are basically consistent. At the same time, it realizes data interaction with the main control unit through RS485 communication. The main control unit communicates with each PSU module via RS485 to obtain the I_dete output current signal. It calculates the average current parameters according to the current sharing algorithm and sends them to the signal processing unit of each PSU module so that the signal processing unit can adjust the output of the corresponding PWM control signal. After conversion by the TRIM drive unit, the output voltage and current of the DC power supply unit are precisely controlled so that the final output voltage and current of each PSU module are kept accurate and consistent and stable. When a PSU module malfunctions, the signal processing unit shuts down the current PSU module through the TRIM drive unit and reports the fault information to the main control unit via RS485. The main control unit recalculates the average current parameters for the signal processing units of the remaining PSU modules, readjusts the output parameters of the remaining PSU modules to maintain stable output, and at the same time issues a PSU module malfunction alarm signal to replace the malfunctioning PSU module in a timely manner.

[0026] Specifically, each PSU module is identified through ADD coding.

[0027] It is worth mentioning that the technical features such as LED modules involved in this patent application should be regarded as prior art. The specific structure, working principle, and possible control methods and spatial arrangement of these technical features can be adopted using conventional choices in the field, and should not be regarded as the inventive point of this patent. This patent will not be further elaborated in detail.

[0028] For those skilled in the art, modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this invention should be included within the protection scope of this invention.

Claims

1. A high-precision parallel current sharing implementation method, characterized in that, Includes the following steps: Step S1: Construct circuits for each PSU module to achieve parallel current sharing; In step S1, each PSU module includes a DC power supply unit, an ideal diode, a signal processing unit, a follower / anti-reverse current unit, an output current sampling unit, and a TRIM drive unit. The parallel current sharing is implemented in the following steps: Step S1.1: Input the DC power supply to the input terminal of the DC power supply unit, and output the preset +A voltage after conversion. Then, after isolation by an ideal diode, the +A_bus bus voltage is formed. Each PSU module is connected in parallel through the +A_bus bus and provides driving power to the LED module. Step S1.2: The output current sampling unit monitors and samples the output current of the DC power supply unit, converts the I_sense signal into the I_dete output current signal, and generates the Is_bus bus current signal after being processed by the follower / anti-backflow unit. The Is_bus bus current signals of each PSU module are connected in parallel and used as the current sharing reference. Step S1.3: The signal processing unit collects the +A_bus bus voltage, +A output voltage, I_dete output current signal and Is_bus bus current signal in real time. The signal processing unit outputs a PWM control signal, which is converted by the TRIM drive unit to roughly control the output voltage and current of the DC power supply unit, so that the output voltage and current of each PSU module are basically consistent. At the same time, data interaction with the main control unit is realized through RS485 communication. Step S1.4: The main control unit communicates with each PSU module via RS485 to obtain the I_dete output current signal, calculates the average current parameter according to the current sharing algorithm and sends it to the signal processing unit of each PSU module so that the signal processing unit adjusts the output of the corresponding PWM control signal. After conversion by the TRIM drive unit, the output voltage and current of the DC power supply unit are precisely controlled so that the final output voltage and current of each PSU module are kept accurate and consistent and stable. Step S1.5: When a PSU module malfunctions, the signal processing unit shuts down the current PSU module through the TRIM drive unit and reports the fault information to the main control unit via RS485. The main control unit recalculates the average current parameters to the signal processing units of the remaining PSU modules, readjusts the output parameters of the remaining PSU modules to maintain stable output, and at the same time, the main control unit issues a PSU module malfunction alarm signal and replaces the malfunctioning PSU module in a timely manner.

2. The high-precision parallel current sharing method according to claim 1, characterized in that, For the current sharing algorithm in step S1.4, high-precision current sharing is achieved through master-slave communication, with the master control unit acting as the master and the signal processing unit acting as the slave. The specific implementation is as follows: The slave device acquires the output current of the I_dete sampling unit of the output current sampling unit of this PSU module and the Is_bus bus current signal of the follower / anti-backflow unit. After calculating the difference, the fast current error value I_diff_fast is obtained, and a coarse PWM duty cycle signal is output. Simultaneously, the host periodically collects the I_dete output current signal of each PSU module, calculates the average current, and sends it to each slave. After receiving the average current signal sent by the host, the slave calculates the slow current error value I_diff_slow, accumulates the fast current error value and the slow current error value, and calculates Error=I_diff_fast+I_diff_slow. The PID algorithm is then used to calculate the adjustment amount u(k)=Kp*error(k)+Ki*∑error(i)+Kd*[error(k)-error(k-1)], where: Kp is the proportional coefficient, Ki is the integral coefficient, Kd is the derivative coefficient, error(k) is the error value at the k-th sampling time, ∑error(i) is the sum of all error values ​​from the 1st to the k-th sampling time, and error(k-1) is the error value at the (k-1)-th sampling time. Based on this adjustment, the output parameters are corrected to obtain a precise PWM duty cycle signal. This allows each slave device to adjust its output PWM control signal to the corresponding TRIM drive unit, thereby adjusting the output current to achieve current sharing.

3. The high-precision parallel current sharing method according to claim 2, characterized in that, Each PSU module is identified by ADD coding.

4. A high-precision parallel current sharing circuit, applied to the high-precision parallel current sharing implementation method according to any one of claims 1-3, characterized in that, It includes multiple PSU modules and a main control unit that communicates with each PSU module. Each PSU module includes a DC power supply unit, an ideal diode, a signal processing unit, a follower / reverse current protection unit, an output current sampling unit, and a TRIM drive unit, wherein: The DC power supply is input to the input terminal of the DC power supply unit, and after conversion, the preset +A voltage is output. Then, after isolation by an ideal diode, the +A_bus bus voltage is formed. Each PSU module is connected in parallel through the +A_bus bus and provides driving power to the LED module. The output current sampling unit monitors and samples the output current of the DC power supply unit, converts the I_sense signal into the I_dete output current signal, and generates the Is_bus bus current signal after being processed by the follower / anti-backflow unit. The Is_bus bus current signals of each PSU module are connected in parallel and used as the current sharing reference. The signal processing unit collects the +A_bus bus voltage, +A output voltage, I_dete output current signal and Is_bus bus current signal in real time. The signal processing unit outputs a PWM control signal, which is converted by the TRIM drive unit to roughly control the output voltage and current of the DC power supply unit, so that the output voltage and current of each PSU module are basically consistent. At the same time, it realizes data interaction with the main control unit through RS485 communication. The main control unit communicates with each PSU module via RS485 to obtain the I_dete output current signal. It calculates the average current parameters according to the current sharing algorithm and sends them to the signal processing unit of each PSU module so that the signal processing unit can adjust the output of the corresponding PWM control signal. After conversion by the TRIM drive unit, the output voltage and current of the DC power supply unit are precisely controlled so that the final output voltage and current of each PSU module are kept accurate and consistent and stable. When a PSU module malfunctions, the signal processing unit shuts down the current PSU module through the TRIM drive unit and reports the fault information to the main control unit via RS485. The main control unit recalculates the average current parameters for the signal processing units of the remaining PSU modules, readjusts the output parameters of the remaining PSU modules to maintain stable output, and at the same time issues a PSU module malfunction alarm signal to replace the malfunctioning PSU module in a timely manner.

5. A high-precision parallel current sharing circuit according to claim 4, characterized in that, Each PSU module is identified by ADD coding.

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