Motor cooperative power supply control method for special vehicle auxiliary equipment

Abstract

The application relates to the technical field of power supply control of electric vehicles and discloses a motor cooperative power supply control method for special vehicle auxiliary equipment, which comprises the following steps: the method multiplexes inherent switch harmonics of a motor inverter into physical layer signals bearing the intention of the working condition of the motor inverter, and broadcasts the signals before power operation; and other device controllers accurately decode the intention signals from a strong interference background through adaptive noise cancellation and spectrum analysis technology, so that a predictive cooperative response at the physical layer level is realized; the application solves the problems of system cooperative passivity caused by the millisecond-level delay of inherent traditional digital buses and large-amplitude fluctuation of bus voltages, and improves the ability of efficient cooperative transmission of direct-current bus energy and information.

Description

TECHNICAL FIELD

[0001] The application relates to a motor cooperative power supply control method of special vehicle auxiliary equipment and belongs to the technical field of power supply control of electric vehicles. BACKGROUND

[0002] At present, in the design of modern special vehicles, a direct current bus is used to provide electric energy for multiple motor-driven auxiliary equipment, which has become a mainstream technical method. The advantage of this method is that the structure is concentrated and the energy scheduling is flexible. At the same time, in order to realize the cooperative work between the auxiliary equipment, the system usually relies on an independent digital communication network, such as a controller area network (CAN bus), to transmit state information and control instructions. This power and information separation architecture has provided effective support for the modular design and function implementation of the system for a long time. However, as the operation tasks of special vehicles become more complex and sophisticated, higher requirements are put forward for the speed and accuracy of cooperative response. At this time, the inherent implicit cost of the above-mentioned seemingly mature technical method begins to highlight. The information packaging arbitration and transmission process inherent in the digital communication network creates a millisecond time delay that cannot be eliminated between the intention of a high-power action of the controller and the awareness of the intention by other system units, such as the main generator or energy storage unit. When a high-power motor is about to start or brake, the power supply system is always in a passive response state of knowing after the fact. This persistent response time difference directly leads to a large fluctuation in the direct current bus voltage. This is not only a temporary power quality problem, but also causes cumulative physical damage to power electronic components, affecting the long-term reliability of the vehicle.

[0003] To shorten this response time difference, those skilled in the art usually consider two seemingly direct improvement paths. One is to replace the CAN bus with a higher bandwidth communication network, and the other is to add a more complex physical filter device to the direct current bus. However, in-depth analysis shows that the former will significantly increase the hardware cost, software complexity and overall power consumption of the system, forming a cost wall that hinders the popularization of technology. The latter will increase the dead weight and space occupation of the vehicle, which is extremely disadvantageous for mobile platforms. Therefore, these linear improvement ideas do not touch the root of the problem, that is, the physical medium of information interaction and the physical medium of energy transmission are artificially separated.

[0004] Specifically, existing technologies have the following shortcomings: 1. There is an inherent time delay in system coordination. This delay stems from the need for control information to be transmitted in an independent communication network, which can cause bus voltage surges and damage component lifespan; 2. Higher-level hardware used to mitigate time delays drastically increases system cost and complexity, lacking general engineering economics; 3. The high-frequency switching harmonics generated by the motor inverter itself contain the most immediate and accurate information about the motor's operating conditions and intentions, but these are all treated as noise that must be filtered out, resulting in a waste of the system's intrinsic information. Therefore, how to avoid using expensive high-speed communication networks or bulky physical filters, and instead utilize the system's existing physical carriers and intrinsic signals to construct a low-cost and efficient collaborative control information interaction method, thereby avoiding bus voltage fluctuations and component damage caused by response time differences, is the technical problem this invention aims to solve. Summary of the Invention

[0005] This invention provides a motor-assisted power supply control method for auxiliary equipment of special vehicles. Its main purpose is to solve the problems of response delay, bus voltage fluctuation and high coordination cost caused by the separation of control information and power transmission in the prior art.

[0006] To achieve the above objectives, this invention provides a motor cooperative power supply control method for auxiliary equipment of special vehicles. This method establishes a procedure on a DC bus that multiplexes the unavoidable switching harmonics of each motor controller from noise into zero-delay physical layer broadcast signals carrying their own operational intentions, and achieves predictive coordination through distributed spectrum interpretation. The method is applied to a power supply system comprising a DC bus, a main power supply unit, and multiple motor controllers. The method includes:

[0007] The controller of the main power supply unit determines the background harmonic ripple characteristics corresponding to the current state from a pre-established noise model that characterizes the harmonic ripple characteristics of the main power supply unit under different operating states, based on its own real-time operating state, and broadcasts the background harmonic ripple characteristics as noise template information.

[0008] When the first motor controller receives a condition change command, before executing the power operation corresponding to the condition change command, it first listens to the energy level of the harmonic communication frequency band on the DC bus through spectrum analysis. Only when the listened energy level is lower than the silence threshold will it control its own inverter to inject a characteristic harmonic signature that uniquely corresponds to the condition change command into the DC bus.

[0009] The at least one second device controller continuously monitors the DC bus signal and performs adaptive canceling filtering on the monitored DC bus signal according to the received noise template information, and then performs spectral analysis on the filtered signal to detect the characteristic harmonic signature, and adjusts its own working state before the DC bus voltage fluctuation caused by the power operation is detected.

[0010] Preferably, the characteristic harmonic signature is a narrowband harmonic current signal with a uniquely determined center frequency and bandwidth combination, and the frequency of the harmonic communication band is higher than the frequency of the main harmonic generated by power transmission when the power supply system is normally working.

[0011] Preferably, when the first motor controller detects that the energy level of the harmonic communication band is not lower than the silence threshold, the first motor controller gives up the current injection operation, and delays a time generated by the first motor controller internal pseudo-random number generator, and then re-executes the step of detecting the energy level of the harmonic communication band on the DC bus through spectral analysis.

[0012] Preferably, the adaptive canceling filtering is realized by an adaptive noise canceler, which takes the noise template information as the reference input and the monitored DC bus signal as the main input, and continuously adjusts the internal filter weight coefficient so that the estimated noise signal output by the adaptive noise canceler approximates the actual form of the background harmonic ripple in form, and the filtered signal is obtained by the following formula: wherein, is the monitored DC bus signal, is the estimated noise signal output by the adaptive noise canceler.

[0013] Preferably, the method further comprises the step of evaluating the health status of the transmitting end: the second device controller and other receiving controllers in the system, when detecting the characteristic harmonic signature, quantize the spectral purity of the characteristic harmonic signature signal by calculating the ratio of the main lobe energy of the characteristic harmonic signature signal to the total energy of the signal; when more than a predetermined number of receiving controllers in the system consistently quantify that the spectral purity of the characteristic harmonic signature originating from the first motor controller continuously falls below the health status threshold in a continuous time period, a health status warning for the first motor controller is generated.

[0014] Preferably, the method further comprises a step of monitoring the health of the power supply system shared channel: during the silence period when no characteristic harmonic signature is injected into the DC bus, all controllers jointly and continuously acquire the background harmonic spectrum profile of the DC bus by spectrum analysis, and calculate the background harmonic energy entropy representing the degree of disorder of the spectrum profile; compare the real-time background harmonic energy entropy with the baseline entropy value representing the initial state of the system health pre-stored, and generate a power supply system health state warning when the cumulative change trend of the difference between the two exceeds the degradation judgment threshold.

[0015] Preferably, the second device controller adjusts its own working state, specifically: if the second device controller is the controller of the main power supply unit, it adjusts the excitation current to increase the power output capability; if the second device controller is the controller of the energy storage unit, it controls the working state of the internal bidirectional converter to enter the pre-charging or pre-discharging preparation mode; if the second device controller is another motor controller, it reduces its inverter switching frequency or enters a preset standby mode to reduce its own power consumption.

[0016] Preferably, the method further comprises a step of channel state self-calibration: a controller in the system is pre-designated as an echo reference point; when the echo reference point detects the characteristic harmonic signature injected by the first motor controller, it immediately controls its own inverter to inject an identical echo harmonic signature into the DC bus; other controllers determine the channel attenuation degree between the first motor controller and themselves by calculating the ratio between the signal strength of the received characteristic harmonic signature and the signal strength of the echo harmonic signature, and adjust their own signal strength judgment threshold for detecting the characteristic harmonic signature according to the channel attenuation degree.

[0017] Preferably, the step of controlling the inverter to inject a characteristic harmonic signature into the DC bus is specifically: a kind of preset non-power control micro-modulation is performed on the pulse width modulation signal used to control the internal power switch tube of the inverter, to generate a current with a characteristic harmonic signature on the DC bus.

[0018] Preferably, the spectrum analysis is achieved by performing fast Fourier transform on the voltage signal of the DC bus or the current signal of the DC bus to obtain the frequency spectrum information of the DC bus signal in the harmonic communication frequency band.

[0019] Compared with the prior art, the present application has the following advantages:

[0020] 1. The method provides a way to make the DC bus as an energy carrier, at the same time, can carry stable and clear intention information, in the system with a large power main power supply unit, the continuously changing operating state of the main power supply unit will introduce strong wide spectrum harmonics to the bus, the strength and form of such harmonics are unpredictable for other auxiliary power equipment, the method establishes a coordination mechanism, the controller of the main power supply unit broadcasts the harmonic characteristics under its current working condition through another communication bus, and other controllers process the bus signals collected by themselves according to the received characteristic information, before identifying any specific intention harmonic signature, the noise characteristics of the active broadcast are separated, which makes the weak harmonic signature carrying the working condition intention of each motor clearly appear in the purified information background, so that the DC bus changes from a mixed medium of energy and information interference to a structured transmission environment with independent information channel and energy channel, which guarantees a stable and reliable decision basis for subsequent cooperative action.

[0021] 2. The method further introduces a distributed non-centralized channel access order, when multiple motor controllers may generate cooperative demand at similar time points, any controller will first use its own spectrum analysis ability to listen to the harmonic frequency band to be used before injecting its harmonic signature, only when the frequency band is in a silent state, the controller will perform the injection operation, if the channel is detected to be occupied, it will delay a non-fixed time decided by itself and try again, this listen-before-talk, conflict-then-retreat access mode, converts the situation that multiple harmonic signatures may be mixed and overlapped due to high-density instruction concurrency, which cannot be read, into an ordered intention broadcast sequence, the system's cooperative ability is no longer limited by the number and frequency of concurrent instructions, and in complex and high-intensity operation scenarios, the system can still maintain clear and stable information interaction.

[0022] 3、The spectrum analysis and information interaction mechanism established by the method not only completes the main collaborative control function, but also provides a health state evaluation approach for the entire power supply system. In the silent window period where there is no active harmonic signature broadcast, all controllers can continuously monitor the overall form change of the DC bus background harmonic spectrum, track its long-term slow evolution trend, and perceive the early physical property degradation of key passive devices such as large-capacity filter capacitors due to aging. At the same time, in each successful harmonic signature interaction, all receiving controllers not only interpret the intended information, but also evaluate the spectral form purity of the signature. A persistent decline in the quality of the signature from a specific transmitting end, which is confirmed by multiple receivers, reflects that the health of the power semiconductor devices at the transmitting end is changing. Thus, the method uses the same hardware and core algorithm to time-multiplex in time, building a two-dimensional diagnostic system: one monitors the public health of the shared channel, and the other evaluates the individual health of independent nodes, so that some hardware degradation processes that are not easy to measure directly and gradual can be perceived in the form of explicit early warning information. BRIEF DESCRIPTION OF DRAWINGS

[0023] Fig. 1 Flow chart of the predictive collaborative control of the present application based on harmonic communication;

[0024] Fig. 2 System architecture diagram of the present application for harmonic information and power common bus;

[0025] Fig. 3 Comparison chart of bus voltage response under load impact. DETAILED DESCRIPTION

[0026] To make the technical solutions and advantages of the present application clearer, the technical solutions of the present application will be described in detail below with reference to the drawings. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0027] The application discloses a motor cooperative power supply control method of special vehicle auxiliary equipment, which is applied to a power supply system containing a DC bus, a main power supply unit and a plurality of motor controllers. The method encodes and broadcasts the switching harmonics generated by the motor controllers in the power conversion process, and the distributed decoding is performed by other device controllers, so that an intention prediction and cooperative response procedure running in the physical layer is established. The main stages of the procedure include broadcasting the background harmonic ripple characteristics as noise templates by the main power supply unit, injecting characteristic harmonic signatures by the motor controllers after performing channel access control, and decoding the intention by other device controllers through adaptive noise cancellation and spectrum analysis to realize predictive self-working state adjustment. In a specific application scene, for example, a heavy engineering vehicle equipped with a main lifting arm, a rotating platform and a plurality of motor-driven auxiliary equipment such as a hydraulic pump station, all the auxiliary equipment are powered by a high-power diesel generator as the main power supply unit through a common DC bus. In such a system, maintaining the stability of the DC bus voltage is an important consideration for system operation. However, the main power supply unit itself runs under different loads and injects harmonic ripple with high intensity and wide spectrum into the bus. This ripple constitutes a significant structural noise source for devices that need to interact with weak signals. Therefore, the method of the application is configured to first query and determine the background harmonic ripple characteristics corresponding to the current state from a noise model established in the non-volatile memory of the main power supply unit controller according to the working state parameters such as the rotational speed and load rate monitored in real time. The noise model is a data structure which maps the discrete working state interval of the main power supply unit to a group of frequency points and corresponding amplitude parameters describing the main harmonic ripple in the state. The controller further broadcasts the background harmonic ripple characteristics containing frequency and amplitude information as noise template information through the controller area network (CAN) bus periodically. Since the working condition change rate of the main power supply unit is usually lower than the transmission rate of the CAN bus, this method can provide a quasi-real-time reference information about the main interference source for the whole network with low communication overhead, thereby providing necessary prior conditions for subsequent signal purification processing.

[0028] Further, when any motor controller in the system, for example the first motor controller of the main boom, receives a work condition change instruction of full power hoisting, it needs to reliably inform other units in the system of this power consumption intention for their coordinated response; To achieve this purpose, the first motor controller does not immediately adjust the main power output of its inverter, but first executes a channel access control process, which uses the fast Fourier transform analysis unit built into its microcontroller to perform a fast energy listening on a pre-set harmonic communication frequency band higher than the main harmonic frequency of the system's normal power transmission, for example 100kHz-200kHz, and compares the energy level listened to with a pre-set silence threshold, which is determined in the self-calibration phase when the system is powered on for the first time by collecting the background noise baseline of the harmonic communication frequency band without any active injection signal, and taking a certain multiple of the peak value, for example 1.5 times, If the energy level listened to is lower than the silence threshold, it indicates that the channel is idle, and the controller controls its own inverter to actively inject a characteristic harmonic signature corresponding only to the work condition change instruction of full power hoisting into the DC bus by performing a pre-set small modulation on the pulse width modulation signal used to control the internal power switch tube, The characteristic harmonic signature is a narrow-band harmonic current signal with a unique combination of center frequency and bandwidth, which has a lower energy but a recognizable morphology in the frequency spectrum, thereby completing the physical layer broadcast of its own work condition intention; Correspondingly, if the energy level is not lower than the silence threshold in the channel listening step, it indicates that the channel is being occupied, at which time the first motor controller gives up this injection operation, and delays a random time generated by its internal pseudo-random number generator and lasting between 5 and 50 microseconds before returning to the listening step, This access mechanism helps to avoid harmonic signal collision and information aliasing that may occur when multiple intentions are concurrent.

[0029] All other device controllers in the system, such as the main power supply unit controller, the energy storage unit controller or the second device controller of the slewing platform, do not need to be modified in hardware, but only need to continuously sample and monitor the DC bus voltage or current signal at the software level; When they receive the noise template information broadcast by the main power supply unit, they construct and run a self-adaptive cancellation filter in real time in their respective microcontrollers, which takes the received noise template information as the reference input and its real-time monitored DC bus signal as the main input, and continuously adjusts its internal filter weight coefficients according to the least mean square algorithm, so that the estimated noise signal output by it dynamically tracks and approaches the actual background harmonic ripple on the bus in shape. In this way, these controllers can obtain a purified signal by subtracting the estimated noise signal output by the filter from the original bus signal monitored, and the mathematical relationship can be expressed as where, for the monitored DC bus signal, for the estimated noise signal outputted by the adaptive noise canceller, and i.e. the filtered background noise suppressed signal, the controller then performs a fast Fourier transform on the cleaned signal to detect whether a specific signature harmonic is present within the pre-defined harmonic communication band; when a full power lift-off harmonic signature at e.g. 150 kHz is detected, the controller is aware of the upcoming power demand in the system and adjusts its own operating state before the voltage fluctuation on the DC bus caused by the actual power operation of the first motor controller, in particular, if the second device controller is the controller of the main power supply unit, it can adjust its field current to prepare for an increased power output; if it is the controller of an energy storage unit, it can adjust its internal circuit state to prepare for releasing electrical energy to the bus; and if it is another motor controller that is running at light load, it can adjust its operating mode to temporarily reduce its own power consumption.

[0030] It should be noted that the information interaction mechanism established by the present application can also be reused to evaluate the health status of the system without conflict, one is to monitor the health of the shared channel, during the silence period when there is no any characteristic harmonic signature injection in the DC bus, all controllers can jointly and continuously obtain the spectral form of the background harmonic of the bus through spectral analysis, and calculate the background harmonic energy entropy which can represent the disorder degree of the spectral form, by comparing the real-time background harmonic energy entropy with a baseline entropy value stored in the initial health state of the system, when the difference between the two changes cumulatively and the trend exceeds a preset degradation judgment threshold, the system can generate a power supply system health status warning; the second is to evaluate the health of the individual transmitter, when the second device controller and other receiving controllers in the system detect a certain characteristic harmonic signature, they can also calculate the ratio of the main lobe energy of the signature signal to the total energy of the signal in parallel, to quantify the spectral purity, when more than a predetermined number of receiving controllers in the system consistently quantify the spectral purity of the characteristic harmonic signature from the same first motor controller to be continuously below a health status threshold within a continuous time period, a health status warning for the first motor controller can be generated; in addition, to cope with the uncertainty of channel attenuation caused by the dynamic change of the vehicle electrical topology, the method can further configure a channel state self-calibration step, by pre-designating a controller with a fixed electrical position as an echo reference point in the system, when the echo reference point detects any characteristic harmonic signature, it injects an identical echo harmonic signature into the bus, other controllers calculate the signal strength ratio of the original characteristic harmonic signature they receive and the echo harmonic signature to determine the channel attenuation between the signal initiator and itself, and dynamically adjust the signal strength judgment threshold used to detect the harmonic signature according to the attenuation degree, to improve the reliability of information interaction in a variable electrical environment.

[0031] Example 1: This example illustrates the operation and effect in a specific application scenario where multitasking concurrency and strong electrical interference exist; in a fully electrically driven automated port, a rail-mounted gantry container crane is performing work, and the main power supply unit, main hoisting motor, trolley traveling motor and trolley traveling motor of the crane are connected to the same high-voltage DC bus; in a work cycle, a working condition that tests the stability of the bus occurs: the main hoisting motor controller receives a full-speed hoisting instruction for a full load container, and in the same microsecond window, the trolley traveling motor controller also receives a full-speed translation instruction; this working condition means that two high-power motors will simultaneously request considerable starting current from the bus, and also means that there is a high probability that the two motor controllers will simultaneously attempt to broadcast their working condition intentions to the harmonic channel, which may cause information collision; at the time of this working condition, the main power supply unit controller of the crane is continuously broadcasting the background harmonic ripple characteristics under its current state through the CAN bus according to its own operating load, and all other controllers in the system, including the main hoisting motor and trolley traveling motor controllers, have received this noise template information and processed the monitored DC bus signal using their respective adaptive cancellation filters; a harmonic communication channel that suppresses the main background noise is thus maintained, which provides a decision basis with a high signal-to-noise ratio for the subsequent channel listening operations performed by the main hoisting and trolley traveling motor controllers; after the two working condition change instructions are issued, the main hoisting motor controller and the trolley traveling motor controller simultaneously attempt to inject their respective characteristic harmonic signatures; before performing the injection operation, both of them perform energy listening on the harmonic communication band; due to the slight time difference in physics, the main hoisting motor controller completes the listening before the trolley traveling motor controller, and it detects that the channel energy is below the silence threshold, and then injects the characteristic harmonic signature representing heavy load starting; immediately after, the trolley traveling motor controller performs listening and detects the harmonic energy injected by the main hoisting motor, which is higher than the silence threshold, so it gives up this injection and starts its internal pseudo-random timer to enter a short random silent waiting period.

[0032] Within tens of microseconds after the main hoisting motor injects its characteristic harmonic signature, all other controllers in the system including the main power supply unit, the energy storage unit and the trolley traveling motor, have detected the heavy load starting signature from the bus signal after adaptive cancellation filtering, the main power supply unit controller increases its power output before the bus voltage changes significantly, and the energy storage unit is also ready to release energy; then, the main hoisting motor starts to actually absorb large current, since the power supply side has entered the preparation state in advance, the voltage of the DC bus only appears a small and within the allowed range of down, and then restores stability, avoiding voltage instability that may be caused by response delay; after the random silent waiting period of the trolley traveling motor controller ends, it re-listens to the channel, at this time the channel has returned to silence, and it successfully injects its own characteristic harmonic signature, and the system units respond to its request for the second time; this operation mode converts a resource competition that may cause bus disturbance and information conflict into an orderly and time-sharing cooperative response sequence based on the physical layer channel access rule, thereby realizing the parallel operation of high-power energy transmission and weak intention information transmission on a single DC bus physical medium; during the entire concurrent task, the DC bus voltage of the crane is maintained within the preset working interval, and the main hoisting motor and the trolley traveling motor are both started smoothly, and no controller protective shutdown event caused by voltage fluctuation occurs.

[0033] In order to objectively verify the effect of the foregoing technical solution in suppressing the fluctuation of the DC bus voltage, a hardware-in-the-loop test platform for simulating a multi-motor power supply system of a special vehicle is constructed in Embodiment 2. The platform is composed of a programmable DC power supply simulating a main power supply unit, a high-power programmable electronic load simulating a main hoisting motor, and two motor controllers respectively configured with the method of the present application and the prior art, and a high-speed data acquisition system is used to synchronously monitor the voltage and current of the DC bus. The test aims to quantitatively compare the differences in key performance indicators between the system using the cooperative control method of the present application and the system using the traditional CAN bus communication cooperative method when subjected to the same instantaneous high-power load impact. The key parameters of the test platform are set as follows: the nominal voltage of the DC bus is set to 600 V; the instantaneous load impact is set to linearly increase from the no-load state to a current step of 200 A within 10 ms, which is used to simulate the common process of starting a high-power motor from static to full load, and the value is selected based on the analysis of the commonly used motor starting current curve in this field; for the sample group of the present application, the characteristic harmonic signature used to broadcast the heavy load starting intention is set with a center frequency of 150 kHz, and this frequency is selected to avoid the low-frequency harmonics generated by the main power supply unit and the motor inverter during normal power conversion, so as to obtain a higher communication signal-to-noise ratio.

[0034] The test is divided into two groups, one group is a control group using traditional CAN bus for cooperative control, and the other group is an inventive sample group using the harmonic cooperative power supply control method of the application; in the test of the control group, the programmable DC power supply only compensates the output voltage through its internal regulation loop after monitoring that the bus current actually changes, and its cooperative information depends on the analog CAN bus signal with millisecond-level delay; in the test of the inventive sample group, the controller of the programmable electronic load injects a 150kHz characteristic harmonic signature into the DC bus within a specific time window before performing the current step operation, and the controller of the programmable DC power supply is configured with harmonic signature detection and pre-response capability; under the same load impact condition, if the dynamic processes of the bus voltage in the two groups of tests are compared, significant differences can be observed, the voltage of the control group has a sharp drop with a depth of 58.4V, and the time required for its recovery to 98% of the stable threshold is 125.6ms, which reflects that its cooperative response time is limited by the communication delay of the CAN bus about 1850.5us; in comparison, the voltage of the inventive sample group only has a gentle depression of 11.3V, and the voltage recovery time is 41.5ms, and its cooperative response time is shortened to 85.2us, which is improved because the main power supply unit can receive the power consumption intention through the physically propagated harmonic signature within the microsecond window before the programmable electronic load actually consumes large current, and starts to increase the power output in advance, thereby actively canceling most of the upcoming load impact; the test results show that under the same load impact condition, the drop amplitude and recovery time of the DC bus voltage of the power supply system using the method of the application are reduced compared with the system using the traditional CAN bus cooperation, and this improvement of voltage stability helps to reduce the working stress of power electronic components in the system and improve the operation reliability of the whole vehicle power supply system.

[0035] Embodiment 3: This embodiment combines Figs. 1 to 3 to describe a motor cooperative power supply control method of a special vehicle auxiliary equipment, such as Fig. 1As shown, the process begins with any motor controller receiving a working condition change instruction, then executes a listen-before-talk channel access mechanism, that is, listens to the harmonic communication frequency band, if the channel is detected to be idle, a characteristic harmonic signature is injected to broadcast its working condition intention, if the channel is detected to be occupied, it is re-detected after a delay to avoid information aliasing, at the same time, other controllers in the system continuously monitor the bus signal, and through adaptive noise cancellation and spectral analysis decoding technology, accurately identify this intention signal from the strong interference background, and then realize predictive cooperative response, adjust the working state before the power disturbance occurs, and finally achieve the goal of realizing bus voltage stability and efficient cooperation, in addition, the process also reuses the information interaction mechanism to provide endogenous health status evaluation, which includes shared channel health monitoring and evaluation of individual device state of the shared channel, and the whole process relies on the DC bus as the energy and information physical layer fusion medium.

[0036] As shown in Fig. 2 , the main power supply unit broadcasts the real-time background harmonic characteristics through the CAN bus according to its internal noise model, and each controller connected to the DC bus cooperates, wherein the first motor controller executes 1, channel listening and 2, signature injection after receiving the instruction, while the second device controller and energy storage unit controller continuously monitor the bus, and after receiving the noise template broadcast by the main power supply unit, use an adaptive cancellation filter to purify the signal according to the formula , and then perform characteristic signature detection through FFT spectral analysis, once the signature is detected, a series of actions such as 3, signature detection, 4, pre-response, 5, cooperative control, and finally achieve the purpose of 6, stabilizing the bus, this architecture uses distributed intelligence to upgrade the traditional DC bus to a system with power transmission and high-speed information interaction capabilities.

[0037] As shown in Fig. 3 , in this figure, the horizontal axis is time , the left vertical axis is bus voltage , and the right vertical axis is load current When the load current graph shows a step impact, the bus voltage under the control of the dashed line in the traditional CAN bus method produces a sharp drop, and the recovery process is slow, in contrast, the bus voltage under the control of the solid line in the harmonic communication method of the present application only appears a small amplitude and rapid recovery of the concave, indicating that the present application has a significant technical advantage in suppressing bus voltage fluctuations through predictive cooperative response.

[0038] Example 4: This example is used to illustrate the systematic calibration procedure of the key models and thresholds involved in the foregoing method. To ensure the reliability of the operation of the coordinated power supply control method, a set of standardized offline calibration and online self-calibration procedures need to be performed before a special vehicle is first put into production or after deep maintenance. The procedure first calibrates the noise model of the main power supply unit in a controlled test environment. The unit is passed through a standard working condition cycle program, and is sequentially and stably operated at a plurality of preset discrete load points from idle speed to full load. At each load point, a high-bandwidth spectrum analyzer is used to collect the harmonic ripple data output by the unit to the DC bus, and a plurality of frequency points with significant energy in the harmonic communication frequency band and their corresponding amplitudes are recorded. These load point harmonic characteristic data pairs are stored in the non-volatile memory of the main power supply unit controller in the form of a lookup table, thereby constructing a noise model reflecting the harmonic ripple characteristics of the unit in different working states. Subsequently, the system enters the health state baseline learning stage. When all auxiliary equipment of the vehicle is in a silent state, all controllers jointly analyze the background harmonic spectrum form of the DC bus at this time, and obtain the baseline entropy value through a standardized background harmonic energy entropy calculation process. The process is as follows: the monitored harmonic communication frequency band is divided into equal-width frequency windows, the signal energy in each window is calculated , the energy proportion of each window is calculated by , and finally the baseline entropy value representing the initial health state of the system is obtained by formula . The degradation judgment threshold value associated with the baseline entropy value is set to trigger a warning when the real-time calculated background harmonic energy entropy is less than 80% of for a plurality of consecutive sampling periods.

[0039] The spectrum purity health state threshold for evaluating the health state of the transmitting end is set through another calibration process. In the debugging stage, a controller injects a reference characteristic harmonic signature with a spectral form close to ideal generated by a high-precision signal source into the bus. All receiving controllers quantify the spectral purity of the reference signal at this time, take the average value of multiple measurements as 98.5%, and set 85% of the average value as the health state threshold. Through the above process, each model and threshold mentioned in the previous implementation is given a clear physical meaning and reproducible calibration method. After completing all offline calibration and online self-calibration, the coordinated power supply control system of the special vehicle has a known quantitative initial state, and all subsequent health state monitoring and diagnosis in actual operation will be based on comparison with this initial state.

[0040] Example 5: This embodiment describes the adaptive configuration of the cooperative power supply control method when applied to different vehicle platforms, and the integration verification procedure when new auxiliary equipment is added during the system lifecycle; before deploying the method of the present application on a new model of a special vehicle platform, a basic survey of harmonic channel characteristics and signature set design procedure needs to be performed; this procedure first collects the inherent background harmonic noise spectrum of the DC bus under the vehicle's preset operating conditions, including idle and high load states, and identifies several high-frequency bands with background noise energy below the preset threshold as candidate harmonic communication frequency bands; then, within the selected frequency bands, a set of candidate characteristic harmonic signatures with intervals in center frequency and bandwidth are defined, and cross-correlation analysis is performed through offline simulation to evaluate the probability of any signature being misidentified as another signature under conditions of signal attenuation and phase distortion; finally, a set of characteristic harmonic signatures with the lowest cross-correlation coefficient and highest recognition separation degree in the electrical environment of the specific vehicle platform is selected and solidified as the communication protocol that all controllers on the vehicle platform follow.

[0041] When a vehicle that has deployed the method of the present application needs to add a new auxiliary electrical equipment, in order to maintain the operational integrity of the original harmonic cooperative communication, a field compatibility verification and channel evaluation process needs to be performed; this process runs the new equipment independently while keeping the original vehicle equipment silent, and makes it traverse its main operating modes; during this period, all configured controllers in the vehicle monitor and record whether the harmonic noise generated by the new equipment overlaps with any of the signatures in the solidified characteristic harmonic signature set; if the monitoring result shows that its noise spectrum does not interfere with the existing harmonic communication frequency bands, the device is considered compatible; if it is found that its noise energy exceeds the quiet threshold of a communication frequency point, the system can generate a non-compatibility warning, or in a system with dynamic spectrum allocation capability, the operating condition intention corresponding to the disturbed characteristic harmonic signature is reassigned to an uncontaminated backup harmonic communication frequency point, thus maintaining the operational integrity of the cooperative control system.

[0042] Embodiment 6: This embodiment is intended to make a supplementary description of the optimization selection procedure of the key control parameters in the cooperative control method. To determine the value of the silence threshold in the listen-before-talk mechanism to optimize the balance between the channel utilization rate and the communication reliability, an offline calibration of the receiver operating characteristics needs to be performed. The calibration is performed in a controllable noise environment. First, a background noise signal with a known power spectral density and amplitude is injected into the DC bus to simulate the electrical environment of the vehicle. Subsequently, a reference characteristic harmonic signature signal with a power gradient varying from high to low is injected on the noise background, and the miss detection rate of the reference signal and the false alarm rate of the pure background noise are recorded at the receiving controller side under different silence threshold settings. Through analysis of the two sets of mutually restrictive data, an energy value that can minimize the sum of the miss detection rate and the false alarm rate is finally selected as the silence threshold of the system under the background noise level.

[0043] To set the step size factor of the least mean square algorithm in the adaptive cancellation filtering process so that it has the ability of fast convergence while maintaining the stability of the algorithm, another parameter optimization procedure needs to be performed. The procedure is performed in an offline simulation environment. A background harmonic ripple signal derived from a noise model is superimposed with a standard characteristic harmonic signature signal as the input of the algorithm. Then, the value of the step size factor is adjusted in an iterative manner within a preset interval, and the time required for the root mean square error between the estimated noise signal output by the algorithm and the real background harmonic ripple signal to converge to a steady state is recorded under each value. Finally, the value of that can minimize the convergence time and does not cause oscillation of the filter coefficients is selected as the fixed working parameter of the algorithm. To deal with the sudden strong electromagnetic interference events that may be encountered by the vehicle during operation and that are not derived from the power supply system of the vehicle, the method also includes an online identification and response logic for abnormal noise environments. In addition to calculating the background harmonic energy entropy, all controllers continuously monitor the total energy level of the harmonic communication band during the communication silence period. When the total energy level rises to an abnormally high level that is far beyond the historical baseline and the prediction of the noise model within a short period of time, and its spectral pattern does not match any defined characteristic harmonic signature, the system determines that it has encountered external strong electromagnetic interference. In this state, all controllers will suspend the injection of any new characteristic harmonic signature, and the system will automatically remove the above restrictions and restore the normal cooperative communication mode after the total energy level is restored to the normal range.

[0044] It is obvious to those skilled in the art that the present application is not limited to the details of the above exemplary embodiments, and the present application can be implemented in other specific forms without departing from the spirit or essential characteristics of the present application.

[0045] Finally, it should be noted that the above examples are merely intended to illustrate the technical solutions of the present application and not to limit the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present application.

Claims

1. A method for controlling the coordinated power supply of electric machines of auxiliary equipment of special vehicles, characterized by, The method is applied to a power supply system comprising a DC bus, a main power supply unit and a plurality of motor controllers, and the method comprises: a controller of the main power supply unit determines, according to its own real-time working state, a background harmonic ripple characteristic corresponding to the current state from a noise model pre-established and representing harmonic ripple characteristics of the main power supply unit in different working states, and broadcasts the background harmonic ripple characteristic as noise template information; when a first motor controller receives a working condition change instruction, before executing a power operation corresponding to the working condition change instruction, it first listens to the energy level of a harmonic communication frequency band on the DC bus through spectral analysis, and only when the listened energy level is lower than a silence threshold, it controls its own inverter to inject a characteristic harmonic signature corresponding to the working condition change instruction into the DC bus; at least one second device controller continuously monitors the DC bus signal, and performs adaptive cancellation filtering processing on the monitored DC bus signal according to the received noise template information, and then performs spectral analysis on the filtered signal to detect the characteristic harmonic signature, and when the characteristic harmonic signature is detected, adjusts its own working state before the voltage fluctuation caused by the power operation occurs on the DC bus.

2. The method of claim 1, wherein the method further comprises: The characteristic harmonic signature is a narrow-band harmonic current signal with a uniquely determined center frequency and bandwidth combination, and the frequency of the harmonic communication frequency band is higher than the frequency of the main harmonic generated by power transmission when the power supply system is normally working.

3. The method of claim 1, wherein the method further comprises: When the first motor controller listens to the energy level of the harmonic communication frequency band and finds that it is not lower than the silence threshold, it gives up the current injection operation, and after delaying a time generated by a pseudo-random number generator inside the first motor controller, it re-executes the step of listening to the energy level of the harmonic communication frequency band on the DC bus through spectral analysis.

4. The method of claim 1, wherein, The adaptive cancellation filtering process is realized by an adaptive noise canceller, which takes the noise template information as a reference input, takes the monitored DC bus signal as a main input, and continuously adjusts the internal filter weight coefficients, so that the estimated noise signal output by the adaptive noise canceller approximates the actual shape of the background harmonic ripple in shape. The signal filtered by the adaptive noise canceller is obtained by the following formula: wherein, is the monitored DC bus signal, is the estimated noise signal output by the adaptive noise canceller.

5. The method of claim 1, wherein, The method further comprises the step of evaluating the health status of the transmitting end: the second device controller and other receiving controllers in the system, when detecting the characteristic harmonic signature, quantify the spectral purity by calculating the ratio of the main lobe energy of the characteristic harmonic signature signal to the total energy of the signal; when more than a predetermined number of receiving controllers in the system consistently quantify that the spectral purity of the characteristic harmonic signature originating from the first motor controller is continuously below the health status threshold within a continuous time period, a health status warning for the first motor controller is generated.

6. The method of claim 1, wherein, The method further comprises the step of monitoring the health of the shared channel of the power supply system: during the silence period when there is no characteristic harmonic signature injection on the DC bus, all controllers jointly and continuously obtain the background harmonic spectrum of the DC bus through spectral analysis, and calculate the background harmonic energy entropy representing the degree of disorder of the spectrum; compare the real-time background harmonic energy entropy with the baseline entropy value pre-stored to represent the initial state of the system health, and when the cumulative change trend of the difference between the two exceeds the degradation determination threshold, a health status warning of the power supply system is generated.

7. The method of claim 1, wherein, The second device controller adjusts its own working state, specifically: if the second device controller is the controller of the main power supply unit, it adjusts the excitation current to increase the power output capacity; if the second device controller is the controller of the energy storage unit, it controls the working state of the internal bidirectional converter to enter the pre-charging or pre-discharging preparation mode; if the second device controller is another motor controller, it reduces the switching frequency of the inverter or enters the preset standby mode.

8. The method of claim 1, wherein, The method further comprises the step of channel state self-calibration: a controller in the system is designated as an echo reference point in advance; when the echo reference point detects the characteristic harmonic signature injected by the first motor controller, it immediately controls its own inverter to inject an identical echo harmonic signature into the DC bus; other controllers determine the channel attenuation degree between the first motor controller and itself by calculating the ratio between the signal strength of the characteristic harmonic signature received by itself and the signal strength of the echo harmonic signature, and adjust the signal strength judgment threshold for detecting the characteristic harmonic signature according to the channel attenuation degree.

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