Current sharing control method and system

Abstract

The invention relates to the technical field of motor homes, in particular to a current sharing control method and system. Comprising the following steps: acquiring PID values of total constant voltage output, total current output, first current output, first constant voltage input, second current output and second constant voltage input; the minimum value in the first path and the second path of related PID values is taken as the corresponding reference control quantity; the reference control quantity and the current-sharing compensation quantity are superposed to obtain a corresponding outer-loop control signal, the inductive current is tracked according to the outer-loop control signal to obtain a corresponding inner-loop control signal, the inner-loop control signal and the feed-forward quantity are superposed to obtain two paths of corresponding PWM driving signals, and control is performed based on the PWM driving signals; according to the scheme, a system safety boundary is constructed through a minimum value competition mechanism, and an adjustment mode of independent PID current sharing compensation, reference control quantity and feedforward quantity superposition is combined, so that the response time for generator voltage fluctuation and load abrupt change is shortened, and the current sharing precision and the system stability are effectively improved.

Description

Technical Field

[0001] This invention relates to the field of RV technology, and in particular to a flow sharing control method and system. Background Technology

[0002] With the increasing popularity of RV travel and outdoor living, the complexity and reliability requirements of RV energy systems are rising. RV charging systems not only need to cope with drastic fluctuations in generator input, but also need to adapt to sudden load changes in batteries under high current charging and discharging. Their operating conditions are far more stringent than those of conventional charging equipment. Existing RV chargers generally adopt a single-stage or slow-responding dual-loop control architecture, which has insufficient dynamic response performance. Furthermore, existing RV charging solutions usually adopt a multi-parallel topology. Due to the inherent tolerances of the component parameters in each parallel branch, the asymmetrical layout inside the RV can easily lead to sampling and driving differences, resulting in unbalanced output current in each branch and poor current sharing accuracy.

[0003] Therefore, there is an urgent need in this field for a flow control method and system that can be deeply adapted to the complex working conditions of RVs and has high dynamic response speed and high flow sharing accuracy. Summary of the Invention

[0004] This invention provides a flow sharing control method and system that can be deeply adapted to the complex working conditions of RVs and has high dynamic response speed and high flow sharing accuracy, so as to solve the problems of insufficient dynamic response performance and poor parallel flow sharing accuracy in the prior art.

[0005] To address the problems existing in the prior art, this invention provides a current sharing control method applied to a dual-channel DC charging system for RVs. The method includes the following steps: Obtain the PID values ​​of the total constant voltage output, total current output, first current output, first constant voltage input, second current output, and second constant voltage input; The minimum value among the PID values ​​of the total constant voltage output, total current output, first current output, and first constant voltage input is used as the first reference control quantity, and the minimum value among the PID values ​​of the total constant voltage output, total current output, second current output, and second constant voltage input is used as the second reference control quantity. Calculate the difference between the first output current and the second output current, and perform independent PID calculations on the difference to obtain the current sharing compensation amount; The first reference control quantity is superimposed with the current sharing compensation quantity to obtain the first outer loop control signal, and the second reference control quantity is superimposed with the current sharing compensation quantity to obtain the second outer loop control signal. The first outer loop control signal is used as the target value of the first inductor current, and the first inductor current is tracked and controlled to obtain the first inner loop control signal. The second outer loop control signal is used as the target value of the second inductor current, and the second inductor current is tracked and controlled to obtain the second inner loop control signal. The system acquires the input and output voltages and uses the ratio of the input voltage to the output voltage or the ratio of the output voltage to the input voltage as a feedforward quantity. The first inner loop control signal is superimposed with the feedforward quantity to obtain the first PWM drive signal, and the second inner loop control signal is superimposed with the feedforward quantity to obtain the second PWM drive signal. Based on the first PWM drive signal and the second PWM drive signal, the first power circuit and the second power circuit are controlled respectively.

[0006] Optionally, the following steps are also included: When the output voltage of the RV generator fluctuates, the ratio of the system's input voltage to its output voltage is used as the boost feedforward. The first inner loop control signal and the second inner loop control signal are superimposed on the boost feedforward to obtain the first PWM drive signal and the second PWM drive signal. When the RV load changes and causes the output voltage to fluctuate, the ratio of the system's output voltage to the input voltage is used as the buck feedforward. The first inner loop control signal and the second inner loop control signal are superimposed on the buck feedforward to obtain the first PWM drive signal and the second PWM drive signal.

[0007] Optionally, the following steps are also included: The first outer loop control signal and the second outer loop control signal are obtained by a high-bandwidth proportional controller, and are used as the target values ​​of the first inductor current and the second inductor current, respectively. The first inductor current and the second inductor current are tracked and controlled to output the first inner loop control signal and the second inner loop control signal.

[0008] Optionally, the following steps are also included: The first and second output currents are collected in real time, and the current difference is calculated. The current difference is then input into the PID controller for calculation to obtain the dynamically changing current sharing compensation.

[0009] To address the problems existing in the prior art, this invention also provides a current sharing control system applied to a dual-channel DC charging system for RVs. The solution comprises: the current sharing control system for implementing the current sharing control method described above, including an outer loop control module, an inner loop control module, a feedforward compensation module, and a drive module. The outer loop control module acquires the PID values ​​of the total constant voltage output, total current output, first-channel current output, first-channel constant voltage input, second-channel current output, and second-channel constant voltage input, and calculates and outputs the first and second outer loop control signals based on each PID value. The inner loop control module is connected to the outer loop control module to track the inductor currents of the first and second channels based on the first and second outer loop control signals, and outputs the first and second inner loop control signals. The feedforward compensation module calculates the feedforward amount. The drive module is connected to both the inner loop control module and the feedforward compensation module to acquire the first and second inner loop control signals and the feedforward amount, and calculates and outputs the first and second PWM drive signals.

[0010] Optionally, the outer loop control module includes a total constant voltage output PID loop, a total current output PID loop, a first current output PID loop, a first constant voltage input PID loop, a second current output PID loop, and a second constant voltage input PID loop, for real-time acquisition of the PID values ​​of the total constant voltage output, total current output, first current output, first constant voltage input, second current output, and second constant voltage input.

[0011] Optionally, the outer loop control module further includes a current sampling unit and a current sharing compensation unit. The current sampling unit is used to collect the output current of the first channel and the second channel, and the current sharing compensation unit is used to calculate the current sharing compensation amount based on the output current of the first channel and the second channel.

[0012] Optionally, the inner loop control module includes two proportional controllers for receiving the first outer loop control signal and the second outer loop control signal output by the outer loop control module, respectively, and for tracking and controlling the inductor current of the first and second channels.

[0013] Optionally, the feedforward compensation module includes a voltage acquisition unit and a calculation unit. The voltage acquisition unit is used to acquire the input voltage and output voltage of the RV's dual-channel DC charging system, and the calculation unit is used to calculate and output the feedforward quantity.

[0014] Optionally, the sampling frequency of the voltage acquisition unit is consistent with the operation frequency of the total constant voltage output PID loop, the total current output PID loop, the first current output PID loop, the first constant voltage input PID loop, the second current output PID loop, and the second constant voltage input PID loop.

[0015] The beneficial effects of the current sharing control method provided in this invention are as follows: It constructs a system safety boundary through a minimum value competition mechanism, eliminating overstress damage to components at its source and adapting to the harsh environment of RV vibration and alternating high and low temperatures; it solves the problem of local thermal stress concentration caused by parameter dispersion and asymmetrical layout in traditional parallel architectures through an active adjustment method of independent PID current sharing compensation and superposition of reference control quantities, thus extending the system's service life; and through the collaborative design of high-bandwidth proportional control and differentiated feedforward compensation, it significantly shortens the response time to generator voltage fluctuations and load changes, effectively suppressing voltage overshoot and current spikes, and providing stable power for the precision electronic equipment of the RV. Attached Figure Description

[0016] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. In the accompanying drawings: Figure 1 This is the flow chart of the flow equalization control method in this embodiment of the invention. Figure 1 ; Figure 2 This is the flow chart of the flow equalization control method in this embodiment of the invention. Figure 2 ; Figure 3 This is the flow chart of the flow equalization control method in this embodiment of the invention. Figure 3 ; Figure 4 This is a structural block diagram of the flow equalization control system in an embodiment of the present invention.

[0017] The labels for the attached figures are as follows: 100. Outer loop control module; 200. Inner loop control module; 300. Feedforward compensation module; 400. Drive module; 100. Outer loop control module; 110. Total constant voltage output PID loop; 120. Total current output PID loop; 130. First current output PID loop; 140. First constant voltage input PID loop; 150. Second current output PID loop; 160. Second constant voltage input PID loop; 310. Voltage acquisition unit; 320. Calculation unit. Detailed Implementation

[0018] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0019] like Figures 1 to 3 As shown, the present invention provides a specific embodiment of a flow sharing control method.

[0020] A current sharing control method is applied to a dual-channel DC charging system for RVs, referenced. Figure 1 The flow sharing control method includes the following steps: S1. Obtain the PID values ​​of the total constant voltage output, total current output, first current output, first constant voltage input, second current output, and second constant voltage input; S2. Take the minimum value among the PID values ​​of the total constant voltage output, total current output, first current output and first constant voltage input as the first reference control quantity, and take the minimum value among the PID values ​​of the total constant voltage output, total current output, second current output and second constant voltage input as the second reference control quantity. S3. Calculate the difference between the first output current and the second output current, and perform independent PID calculation on the difference to obtain the current sharing compensation amount. S4. Superimpose the first reference control quantity with the current sharing compensation quantity to obtain the first outer loop control signal, and superimpose the second reference control quantity with the current sharing compensation quantity to obtain the second outer loop control signal. S5. Use the first outer loop control signal as the target value of the first inductor current, and perform tracking control on the first inductor current to obtain the first inner loop control signal. Use the second outer loop control signal as the target value of the second inductor current, and perform tracking control on the second inductor current to obtain the second inner loop control signal. S6. Acquire the input voltage and output voltage of the system, and use the ratio of the input voltage to the output voltage or the ratio of the output voltage to the input voltage as the feedforward quantity; S7. Superimpose the first inner loop control signal with the feedforward quantity to obtain the first PWM drive signal, and superimpose the second inner loop control signal with the feedforward quantity to obtain the second PWM drive signal. S8. Based on the first PWM drive signal and the second PWM drive signal, control the first power circuit and the second power circuit respectively.

[0021] Step 1 The system acquires the PID values ​​for the total constant voltage output, total current output, first current output, first constant voltage input, second current output, and second constant voltage input. The PID value for the total constant voltage input corresponds to the adjustment parameter for the overall output voltage of the dual-channel DC charging system; the PID value for the total current output corresponds to the adjustment parameter for the overall output current of the dual-channel DC charging system; the PID value for the first constant voltage input corresponds to the adjustment parameter for the input voltage of the first circuit generator in the dual-channel DC charging system; the PID value for the second constant voltage input corresponds to the adjustment parameter for the input voltage of the second circuit generator in the dual-channel DC charging system; the PID value for the first current output corresponds to the adjustment parameter for the output current of the first circuit in the dual-channel DC charging system; and the PID value for the second current output corresponds to the adjustment parameter for the output current of the second circuit in the dual-channel DC charging system.

[0022] The core function of this step is to comprehensively capture the status of the core electrical parameters of the dual-path DC charging system, providing basic data support for subsequent safety control and current sharing regulation. By acquiring the PID regulation parameters of the total constant voltage, voltage and current of each branch, it achieves full coverage monitoring of the overall and branch operating conditions of the dual-path DC charging system, avoiding control blind spots caused by missing local parameters, and adapting to complex operating conditions such as RV generator input fluctuations and load changes.

[0023] Step Two The minimum value among the PID values ​​of the total constant voltage output, the total current output, the first current output, and the first constant voltage input is used as the first reference control value. The minimum value among the PID values ​​of the total constant voltage output, the total current output, the second current output, and the second constant voltage input is used as the second reference control value.

[0024] The core function of this step is to establish a safe operating boundary for the dual-path DC charging system, thereby preventing damage to components from overstress. RV charging conditions are highly variable, and single-parameter control can easily lead to overload risks. By selecting the minimum value among the PID values ​​of each branch as the benchmark control quantity, it can ensure that the dual-path DC charging system automatically follows the strictest voltage and current limits under any operating condition. Even if a loop experiences a response delay, the minimum value can be used to screen and ensure the safety of core components, adapting to the harsh environment of RV vibration and alternating high and low temperatures.

[0025] Step 3 The difference between the first output current and the second output current is calculated, and an independent PID calculation is performed on the difference to obtain the current sharing compensation. The proportional coefficient, integral coefficient and derivative coefficient of the independent PID calculation are preset according to the power level and inductor parameters of the dual-channel DC charging system.

[0026] The core function of this step is to accurately identify the degree of DC imbalance between the two paths, providing a basis for adjustment of active current sharing. In response to the problem of poor current sharing caused by discrete device parameters and asymmetrical layout in the existing technology, the current difference between the two paths is calculated in real time and independent PID calculation is performed to generate a dynamically changing current sharing compensation amount, thereby achieving accurate quantification of the current sharing deviation and providing accurate input for subsequent compensation adjustment.

[0027] Step Four The first reference control quantity is superimposed with the current sharing compensation quantity to obtain the first outer loop control signal, and the second reference control quantity is superimposed with the current sharing compensation quantity to obtain the second outer loop control signal.

[0028] The core function of this step is to achieve coordinated control of safety optimization and precise current sharing. Based on the safety benchmark determined in step two, the current sharing compensation generated in step three is superimposed, which not only ensures that the system always operates within the safe range, but also eliminates the current deviation between the two paths through active compensation, thus solving the problem of mutual constraints between safety control and current sharing control in traditional technologies.

[0029] Step 5 The first outer loop control signal is used as the target value of the first inductor current. A high-bandwidth proportional control strategy is used to perform hysteresis-free tracking control on the first inductor current to obtain the first inner loop control signal. The second outer loop control signal is used as the target value of the second inductor current. The same high-bandwidth proportional control strategy is used to perform hysteresis-free tracking control on the second inductor current to obtain the second inner loop control signal. The bandwidth of the high-bandwidth proportional control is not less than a preset threshold to ensure a fast response when the load changes suddenly.

[0030] The core function of this step is to improve the dynamic response speed of the system, cope with sudden load changes in the RV, and use a high-bandwidth proportional control strategy to track the inductor current without hysteresis. This quickly converts the outer loop control signal into precise control of the power stage, avoiding voltage overshoot and current spikes caused by slow response, and ensuring that the system can still operate stably when the load changes, providing stable power to precision electronic equipment.

[0031] Step Six The system acquires the input and output voltages, namely the generator output voltage and the battery charging voltage of the dual-channel DC charging system. The feedforward quantity is selected according to the working mode of the dual-channel DC charging system. When the system is in boost mode, the ratio of the input voltage to the output voltage is used as the boost feedforward quantity. When the system is in buck mode, the ratio of the output voltage to the input voltage is used as the buck feedforward quantity.

[0032] The core function of this step is to proactively suppress typical disturbances in RVs and reduce the system's adjustment pressure. Targeting two major disturbances—input voltage fluctuations caused by unstable generator speed and load changes caused by the start-up and shutdown of high-power equipment—it collects voltage ratios as feedforward quantities to predict disturbances in advance. This avoids the lag problem of traditional feedback control where deviations occur first and adjustments are made accordingly, thus adapting to the complex and ever-changing outdoor charging environment of RVs.

[0033] Step Seven The first inner loop control signal is superimposed with the feedforward quantity to obtain the first PWM drive signal, and the second inner loop control signal is superimposed with the feedforward quantity to obtain the second PWM drive signal; the superposition is carried out in a linear superposition manner to ensure the stability of the control signal.

[0034] The core function of this step is to integrate rapid response and disturbance compensation to generate a precise driving signal basis. By superimposing the rapid tracking signal of the inner loop with the disturbance compensation signal of the feedforward, the driving signal can not only respond quickly to load changes, but also offset the impact of input fluctuations in advance, thereby further improving control accuracy and system stability.

[0035] Step 8 Based on the first PWM drive signal and the second PWM drive signal, the switching devices of the first power circuit and the second power circuit are controlled to switch on and off respectively, so as to realize the current sharing coordination of dual-channel charging.

[0036] The core function of this step is to convert the control signal into actual charging actions, achieve the current sharing control target, and precisely control the switching devices of the dual power circuit through the PWM drive signal to implement the control logic of the preceding stages, ensuring that the dual power circuit outputs a balanced current, and ultimately achieving the core purpose of improving charging efficiency and ensuring system safety.

[0037] In this embodiment, the above-mentioned current sharing control method is designed for the special operating conditions of the dual-channel DC charging system for RVs. Through the coordinated control of the entire process, including safety benchmark selection, active current sharing compensation, fast current tracking, and disturbance feedforward suppression, it has the following significant advantages compared to the prior art: 1. The current sharing accuracy is greatly improved, effectively solving the problem of local overheating. Through the independent PID current sharing compensation in step three and the signal superposition in step four, the deviation control of the dual-output current is realized, which solves the problem of poor current sharing caused by parameter dispersion and layout imbalance in the existing technology. It avoids the phenomenon of overload of some devices and local thermal stress concentration. In the compact space of the RV and under the condition of limited heat dissipation, it significantly delays the aging of devices and improves the service life of the system.

[0038] 2. The dynamic response speed is significantly accelerated, adapting to the complex operating conditions of RVs. Through the high-bandwidth current tracking control in step five and the bidirectional feedforward compensation in step six, the system's response time to generator voltage fluctuations and load changes is greatly shortened, and the output voltage overshoot and drop amplitude are effectively suppressed. This avoids key components from being subjected to excessive electrical stress, reduces the risk of component failure, and provides more stable charging power for the precision electronic equipment of RVs.

[0039] 3. Enhanced safety and reliability: Through the minimum value competition mechanism in step two, the system has the ability to adaptively select the most stringent safety boundary. No matter what dynamic operating conditions the RV is in, it can eliminate the damage to components caused by voltage overshoot and current spikes from the root. With the addition of complementary symmetrical control, the operation safety of the power circuit is further guaranteed, making it suitable for the harsh outdoor environment of RV vibration and alternating high and low temperatures.

[0040] 4. The control logic is highly efficient and reduces system losses. Through the synergy of feedforward compensation and feedback control, the adjustment pressure of the outer loop PID controller is greatly reduced, control delay and energy loss are reduced, and the precise current sharing control can improve the utilization rate of dual power devices, avoid the uneven phenomenon of some branches being idle and others being overloaded, and further improve the energy conversion efficiency of the entire charging system.

[0041] In one embodiment, reference Figure 2 It also includes the following steps: S71. When the output voltage of the RV generator fluctuates, the ratio of the system's input voltage to its output voltage is used as the boost feedforward. The first inner loop control signal and the second inner loop control signal are superimposed on the boost feedforward to obtain the first PWM drive signal and the second PWM drive signal. S72. When the load change of the RV causes the output voltage to fluctuate, the ratio of the system's output voltage to the input voltage is used as the step-down feedforward. The first inner loop control signal and the second inner loop control signal are superimposed on the step-down feedforward to obtain the first PWM drive signal and the second PWM drive signal.

[0042] Specifically, steps 71 and 72 are the core improvement steps of the dual-path DC charging current sharing control scheme for RVs. For the two types of high-frequency core disturbances in the RV charging system, namely the generator output voltage fluctuation and the output voltage fluctuation caused by load changes, a differentiated feedforward superposition strategy is designed. By accurately matching the disturbance type, the corresponding feedforward quantity is selected and superimposed with the inner loop control signal to achieve rapid suppression of disturbances, while ensuring the synergy of dual-path current sharing.

[0043] Step 71 The system compares the real-time input voltage with a preset voltage threshold. When the voltage change exceeds the preset threshold, it is determined to be a generator output voltage fluctuation. When a fluctuation in the RV generator output voltage is detected, the ratio of the input voltage to the output voltage collected by the system is identified as the boost feedforward. Furthermore, the first inner loop control signal acquired in the previous step is superimposed with the boost feedforward to generate the first PWM drive signal. At the same time, the second inner loop control signal is superimposed with the boost feedforward to generate the second PWM drive signal.

[0044] Step 72 The output voltage is compared with the corresponding preset voltage threshold in real time. When the voltage change exceeds the preset threshold, it is determined to be a load output voltage fluctuation. When the RV load output voltage fluctuation is detected, the ratio of the output voltage to the input voltage collected by the system is confirmed as the buck feedforward. Furthermore, the first inner loop control signal obtained in the previous step is superimposed with the buck feedforward to generate the first PWM drive signal. At the same time, the second inner loop control signal is superimposed with the buck feedforward to generate the second PWM drive signal.

[0045] By designing the above steps, the following functions were achieved: 1. Precisely adapts to different disturbance types; for two different disturbances, namely generator voltage fluctuations and load changes, boost and buck feedforwards are matched respectively to avoid the problem of insufficient adaptation of general feedforwards and improve the accuracy of disturbance compensation.

[0046] 2. Quickly suppress disturbances; no complex mode judgment logic is required. After disturbance detection, the matching feedforward quantity is directly called to superimpose, shortening the compensation delay and effectively avoiding voltage overshoot, drop or current spike, ensuring system stability.

[0047] 3. Ensure current sharing coordination; synchronously superimpose the same type of feedforward quantity on the dual inner loop control signals to ensure the coordination of the dual drive signals, avoid current sharing deviation during the compensation process, and maintain the balance of dual output current.

[0048] In one embodiment, reference Figure 3 It also includes the following steps: S51. The first outer loop control signal and the second outer loop control signal are obtained by the high-bandwidth proportional controller, and are used as the target values ​​of the first inductor current and the second inductor current, respectively. The first inductor current and the second inductor current are tracked and controlled to output the first inner loop control signal and the second inner loop control signal.

[0049] Specifically, step 51 is used to convert the control signal output from the outer loop into a precise inner loop current control signal, and to achieve fast and hysteresis-free tracking of the dual inductor currents through a high-bandwidth proportional controller. This can be achieved by deploying two independent high-bandwidth proportional controllers to receive the first outer loop control signal and the second outer loop control signal generated earlier, respectively; and to directly use the received first outer loop control signal as the target value of the first inductor current, and directly use the second outer loop control signal as the target value of the second inductor current.

[0050] Furthermore, the two high-bandwidth proportional controllers start working synchronously, respectively tracking and controlling the first and second inductor currents in the dual-channel DC charging system of the RV in real time. According to the preset high-bandwidth gain parameters, the controllers compare the deviation between the actual sampled value of the inductor current and the target value (outer loop control signal) in real time, and quickly output adjustment signals. Through the above tracking and adjustment process, the two high-bandwidth proportional controllers output the first and second inner loop control signals respectively, completing the precise control of the inner loop current, and providing the core input for the subsequent superposition with the feedforward quantity to generate the PWM drive signal.

[0051] The function of using a high-bandwidth proportional controller is as follows: 1. Significantly improves dynamic response speed and adapts to sudden load changes in RVs: The high-bandwidth proportional controller has extremely high signal response bandwidth. Compared with traditional controllers, it can significantly shorten the delay from receiving the outer loop control signal to outputting the inner loop adjustment signal. It can quickly respond to load changes caused by the start-up and shutdown of high-power electrical equipment in RVs and avoid problems such as voltage overshoot and current spikes caused by slow response.

[0052] 2. Ensuring current tracking accuracy: Proportional control has the advantages of no integral saturation and simple and direct control logic. Combined with high bandwidth characteristics, it can achieve hysteresis-free and accurate tracking of the target value of inductor current, ensuring that the dual-path inductor current stably follows the changes of the corresponding outer loop control signal. At the same time, the synchronous working mode of the two independent controllers can ensure the coordination of the dual-path inner loop control signals, providing key support for the stability of subsequent current sharing accuracy.

[0053] 3. Reduce system regulation pressure and improve operational stability: The high-bandwidth proportional controller can quickly and accurately control the inductor current, which can suppress some current deviations caused by circuit parameter fluctuations and environmental disturbances in advance, reducing the regulation burden of the outer loop controller; at the same time, the simple and direct control logic reduces the controller's own calculation delay and failure risk, adapts to the harsh operating environment of RV vibration and alternating high and low temperatures, and improves the reliability of the entire charging system.

[0054] like Figure 4 As shown, the present invention also provides a specific embodiment of a flow sharing control system.

[0055] A current sharing control system is applied to a dual-channel DC charging system for RVs, reference Figure 4The current sharing control system is used to implement the above-mentioned current sharing control method. It includes an outer loop control module 100, an inner loop control module 200, a feedforward compensation module 300, and a drive module 400. The outer loop control module 100 is used to acquire the PID values ​​of the total constant voltage output, total current output, first current output, first constant voltage input, second current output, and second constant voltage input, and calculates and outputs the first outer loop control signal and the second outer loop control signal based on each PID value. The inner loop control module 200 is connected to the outer loop control module 100 to track the inductor currents of the first and second channels based on the first and second outer loop control signals, and outputs the first and second inner loop control signals. The feedforward compensation module 300 is used to calculate the feedforward quantity. The drive module 400 is connected to the inner loop control module 200 and the feedforward compensation module 300 respectively to acquire the first inner loop control signal, the second inner loop control signal, and the feedforward quantity, and calculates and outputs the first and second PWM drive signals.

[0056] Specifically, the outer loop control module 100 is used to construct a safe operating boundary and achieve initial current sharing. The outer loop control module 100 includes a total constant voltage output PID loop 110, a total current output PID loop 120, a first current output PID loop 130, a first constant voltage input PID loop 140, a second current output PID loop 150, and a second constant voltage input PID loop 160. The total constant voltage output PID loop 110 is used to collect the PID value of the total constant voltage output of the RV's dual-channel DC charging system in real time. The total current output PID loop 120 is used to collect the PID value of the RV's dual-channel DC charging system in real time. The system collects the PID values ​​of the total current output of the system. The first current output PID loop 130 is used to collect the PID values ​​of the current output of the first branch in the dual-channel DC charging system of the RV in real time. The first constant voltage input PID loop 140 is used to collect the PID values ​​of the constant voltage input of the first branch in the dual-channel DC charging system of the RV in real time. The second current output PID loop 150 is used to collect the PID values ​​of the current output of the second branch in the dual-channel DC charging system of the RV in real time. The second constant voltage input PID loop 160 is used to collect the PID values ​​of the constant voltage input of the second branch in the dual-channel DC charging system of the RV in real time.

[0057] Furthermore, the outer loop control module 100 comprehensively monitors the voltage and current status of the entire system and the dual branches through the PID values ​​obtained from each PID loop, and performs calculations based on each PID value to select the dual-path safety reference control quantity. The outer loop control module 100 also includes a current sampling unit and a current sharing compensation unit. The current sampling unit is used to collect the output current of the first and second paths, and the current sharing compensation unit is used to calculate the current sharing compensation quantity based on the output current of the first and second paths. After the outer loop control module 100 selects the dual-path safety reference control quantity, it superimposes the dual-path safety reference control quantity with the current sharing compensation quantity, and finally outputs the first path outer loop control signal and the second path outer loop control signal, providing accurate target parameter input for the inner loop control module 200.

[0058] Furthermore, the inner loop control module 200 is used to achieve fast and accurate tracking of the inductor current. It is connected to the outer loop control module 100, receives the first outer loop control signal and the second outer loop control signal, and uses the first outer loop control signal as the target value of the first inductor current and the second outer loop control signal as the target value of the second inductor current. The inner loop control module 200 has two built-in proportional controllers. Through the built-in two independent high-bandwidth proportional controllers, it tracks and adjusts the first and second inductor currents in real time, quickly eliminates current deviation, and outputs stable first and second inner loop control signals.

[0059] Furthermore, the feedforward compensation module 300 serves as the core of the system's disturbance prediction, used to suppress typical disturbances in RV charging in advance. It collects the RV generator input voltage and system output voltage in real time, and generates targeted feedforward quantities by calculating the ratio of input voltage to output voltage or the ratio of output voltage to input voltage. This accurately matches two core operating conditions: generator voltage fluctuation and load change, providing a compensation basis for improving the system's dynamic response capability.

[0060] The feedforward compensation module 300 includes a voltage acquisition unit 310 and a calculation unit 320. The voltage acquisition unit 310 is used to acquire the input voltage and output voltage of the RV dual-channel DC charging system, and the calculation unit 320 is used to calculate and output the feedforward quantity.

[0061] Furthermore, the drive module 400 is used to convert the control signal into a drive signal for the power circuit. It is connected to the inner loop control module 200 and the feedforward compensation module 300 respectively, and synchronously acquires two inner loop control signals and feedforward quantities. By superimposing and integrating the two types of signals, the corresponding first PWM drive signal and second PWM drive signal are generated to precisely control the switching devices of the dual power circuits, and finally realize dual-channel current sharing charging.

[0062] In the actual current sharing control process, the outer loop control module 100 first completes the acquisition and calculation of multi-parameter PID values, generating two outer loop control signals that combine safety and current sharing guidance, transforming the overall system control requirements into specific current control targets, which are then transmitted to the inner loop control module 200. When the inner loop control module 200 receives the outer loop control signals, it responds quickly through a high-bandwidth proportional controller, performing real-time tracking and adjustment of the dual inductor currents, transforming the outer loop decision target into a stable inner loop control signal. Simultaneously, the feedforward compensation module 300 synchronously acquires voltage parameters and generates targeted feedforward quantities. Finally, the drive module 400 synchronously receives the execution signal from the inner loop control module 200 and the compensation signal from the feedforward compensation module 300, and after signal superposition and integration, generates a precise PWM drive signal and outputs it to the dual power circuit, ultimately completing the dual-channel current sharing charging control.

[0063] By designing the above-mentioned flow sharing control system, the following functions were achieved: 1. High current sharing accuracy solves the problem of local overheating. Through the coordination of the current sharing decision of the outer loop control module 100 and the precise current tracking of the inner loop control module 200, combined with the synchronous drive control of the drive module 400, the problem of poor current sharing caused by parameter dispersion and asymmetrical layout in traditional systems is solved, avoiding overload of some power devices and local thermal stress concentration, and extending the service life of the system.

[0064] 2. Fast dynamic response, adaptable to complex working conditions of RVs. The high bandwidth proportional control of the inner loop control module 200 and the disturbance prediction of the feedforward compensation module 300 form a synergistic advantage, which greatly shortens the system's response time to generator voltage fluctuations and load changes, effectively suppresses voltage overshoot, drop and current spike, avoids key components from bearing excessive electrical stress, and adapts to the dynamic and changing working conditions during RV driving.

[0065] 3. High safety and reliability, adaptable to harsh environments. The multi-parameter monitoring of the outer loop control module 100 constructs multiple safety boundaries, while the simple control logic of the inner loop and drive module 400 reduces the risk of failure. The coordinated cooperation of each module enables the system to adapt to complex working conditions and stably cope with the harsh outdoor environment of RV vibration and alternating high and low temperatures, ensuring the safety and stability of the charging process.

[0066] In one embodiment, the sampling frequency of the voltage acquisition unit 310 is consistent with the operation frequency of the total constant voltage output PID loop 110, the total current output PID loop 120, the first current output PID loop 130, the first constant voltage input PID loop 140, the second current output PID loop 150, and the second constant voltage input PID loop 160; in order to ensure the timing synchronization and parameter matching of the system control signals and avoid control deviations caused by frequency mismatch.

[0067] It should be understood that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Those skilled in the art can modify the technical solutions described in the above embodiments, or make equivalent substitutions for some of the technical features; and all such modifications and substitutions should fall within the protection scope of the appended claims of the present invention.

Claims

1. A current sharing control method applied to a dual-channel DC charging system for RVs, characterized in that, Includes the following steps: Obtain the PID values ​​of the total constant voltage output, total current output, first current output, first constant voltage input, second current output, and second constant voltage input; The minimum value among the PID values ​​of the total constant voltage output, total current output, first current output, and first constant voltage input is used as the first reference control quantity, and the minimum value among the PID values ​​of the total constant voltage output, total current output, second current output, and second constant voltage input is used as the second reference control quantity. Calculate the difference between the first output current and the second output current, and perform independent PID calculations on the difference to obtain the current sharing compensation amount; The first reference control quantity is superimposed with the current sharing compensation quantity to obtain the first outer loop control signal, and the second reference control quantity is superimposed with the current sharing compensation quantity to obtain the second outer loop control signal. The first outer loop control signal is used as the target value of the first inductor current, and the first inductor current is tracked and controlled to obtain the first inner loop control signal. The second outer loop control signal is used as the target value of the second inductor current, and the second inductor current is tracked and controlled to obtain the second inner loop control signal. The system acquires the input and output voltages and uses the ratio of the input voltage to the output voltage or the ratio of the output voltage to the input voltage as a feedforward quantity. The first inner loop control signal is superimposed with the feedforward quantity to obtain the first PWM drive signal, and the second inner loop control signal is superimposed with the feedforward quantity to obtain the second PWM drive signal. Based on the first PWM drive signal and the second PWM drive signal, the first power circuit and the second power circuit are controlled respectively.

2. The flow sharing control method according to claim 1, characterized in that, It also includes the following steps: When the output voltage of the RV generator fluctuates, the ratio of the system's input voltage to its output voltage is used as the boost feedforward. The first inner loop control signal and the second inner loop control signal are superimposed on the boost feedforward to obtain the first PWM drive signal and the second PWM drive signal. When the RV load changes and causes the output voltage to fluctuate, the ratio of the system's output voltage to the input voltage is used as the buck feedforward. The first inner loop control signal and the second inner loop control signal are superimposed on the buck feedforward to obtain the first PWM drive signal and the second PWM drive signal.

3. The flow sharing control method according to claim 1, characterized in that, It also includes the following steps: The first outer loop control signal and the second outer loop control signal are obtained by a high-bandwidth proportional controller, and are used as the target values ​​of the first inductor current and the second inductor current, respectively. The first inductor current and the second inductor current are tracked and controlled to output the first inner loop control signal and the second inner loop control signal.

4. The flow sharing control method according to claim 1, characterized in that, It also includes the following steps: The first and second output currents are collected in real time, and the current difference is calculated. The current difference is then input into the PID controller for calculation to obtain the dynamically changing current sharing compensation amount.

5. A current sharing control system applied to a dual-channel DC charging system for RVs, characterized in that: The current sharing control system is used to implement the current sharing control method as described in any one of claims 1-4, comprising an outer loop control module, an inner loop control module, a feedforward compensation module, and a drive module. The outer loop control module is used to acquire the PID values ​​of the total constant voltage output, total current output, first current output, first constant voltage input, second current output, and second constant voltage input, and calculates and outputs the first outer loop control signal and the second outer loop control signal based on each PID value. The inner loop control module is connected to the outer loop control module to track the inductor currents of the first and second channels based on the first and second outer loop control signals, and outputs the first and second inner loop control signals. The feedforward compensation module is used to calculate the feedforward amount. The drive module is connected to the inner loop control module and the feedforward compensation module respectively to acquire the first inner loop control signal, the second inner loop control signal, and the feedforward amount, and calculates and outputs the first and second PWM drive signals.

6. The flow sharing control system according to claim 5, characterized in that, The outer loop control module includes a total constant voltage output PID loop, a total current output PID loop, a first current output PID loop, a first constant voltage input PID loop, a second current output PID loop, and a second constant voltage input PID loop, for real-time acquisition of the PID values ​​of the total constant voltage output, total current output, first current output, first constant voltage input, second current output, and second constant voltage input.

7. The flow sharing control system according to claim 6, characterized in that, The outer loop control module also includes a current sampling unit and a current sharing compensation unit. The current sampling unit is used to collect the output current of the first channel and the second channel, and the current sharing compensation unit is used to calculate the current sharing compensation amount based on the output current of the first channel and the second channel.

8. The flow sharing control system according to claim 5, characterized in that, The inner loop control module includes two proportional controllers, which are used to receive the first outer loop control signal and the second outer loop control signal output by the outer loop control module, respectively, and to track and control the inductor current of the first and second channels.

9. The flow sharing control system according to claim 5, characterized in that, The feedforward compensation module includes a voltage acquisition unit and a calculation unit. The voltage acquisition unit is used to acquire the input voltage and output voltage of the RV's dual-channel DC charging system, and the calculation unit is used to calculate and output the feedforward quantity.

10. The flow sharing control system according to claim 9, characterized in that, The sampling frequency of the voltage acquisition unit is consistent with the operation frequency of the total constant voltage output PID loop, the total current output PID loop, the first current output PID loop, the first constant voltage input PID loop, the second current output PID loop, and the second constant voltage input PID loop.

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