Method and system for detecting abnormal degree of rotating speed of generator for excavator

Abstract

The invention discloses a method and a system for detecting the abnormal degree of the rotating speed of a generator for an excavator, relates to the technical field of engineering machinery testing, and aims to solve the problem of high cost of a method for detecting the abnormal degree of the generator in the prior art. The method comprises the steps of collecting voltage waveform parameters of a generator and the actual rotating speed of the engine in real time after the engine is started; according to the voltage waveform parameters and the engine actual rotating speed, the generator actual rotating speed and the generator theoretical rotating speed are obtained through calculation; if the actual rotating speed of the generator is not zero and the difference value between the theoretical rotating speed of the generator and the actual rotating speed of the generator is not smaller than the maximum difference value allowed by an engine belt, it is judged that the rotating speed of the generator is abnormal, and then the abnormal degree is detected according to the actual current of the generator. The abnormal degree of the generator for the excavator is monitored in real time under the condition that the cost is not additionally increased, and a user is reminded in time when the current of the generator does not meet the load.

Description

Technical Field

[0001] The invention relates to a method and a system for detecting abnormal degree of rotation speed of a generator for an excavator, belonging to the technical field of engineering machinery detection. Background Art

[0002] After the engine is started, the engine belt drags the generator to rotate. The rated output voltage of the generator is higher than the rated voltage of the battery, so the generator can charge the battery while meeting the operation of the vehicle's electrical equipment.

[0003] At present, the main controller detects the controller power supply voltage value to determine whether the charging is abnormal. If the voltage is lower than 24.5V after starting the vehicle, it is determined that the charging voltage is low, and the electronic monitor will alarm for low charging voltage. However, when the generator voltage is normal, if the speed is lower than the normal value due to a fault, the output power of the generator cannot meet the power consumption of the whole vehicle due to insufficient output current, which will consume the battery storage power.

[0004] like Figure 2 As shown in the drawings of a certain brand of generator, when the generator output voltage reaches the rated voltage of 27V, Generator speed N = 1600r / min, then the output current is I = 30A; Generator speed N = 6000r / min, then the output current is I = 70A; After the vehicle is started, the total load current of its electrical components reaches I 总 =50A, if the generator speed is 1600r / min, the generator output current I is less than the total load current I 总 This low speed situation will consume the battery power. Because the voltage meets the requirements, the monitor does not alarm, and the user cannot detect the fault problem, which eventually leads to battery depletion and inability to restart successfully after shutdown.

[0005] To address the above problem, a current sensor can be installed to measure the power generation current of the generator, but this method will increase the cost. Summary of the invention

[0006] The purpose of the present invention is to overcome the deficiencies in the prior art and to provide a method and system for detecting the abnormal degree of rotation speed of an excavator generator, so as to monitor the abnormal degree of the excavator generator in real time without increasing additional costs, so as to promptly remind the user when the generator current no longer meets the load.

[0007] To achieve the above object, the present invention is implemented by adopting the following technical solutions: In one aspect, the present invention provides a method for detecting abnormal degree of rotation speed of a generator for an excavator, comprising: Start the engine, and collect the voltage waveform parameters of the generator and the actual engine speed in real time while the engine drives the generator to rotate and generate electricity; The actual speed of the generator is calculated based on the voltage waveform parameters of the generator; The theoretical speed of the generator is calculated based on the actual speed of the engine; Determine the actual speed of the generator: If the actual generator speed is 0, it is judged that the generator is not rotating at this time and needs to be repaired immediately; If the actual speed of the generator is not 0, the difference between the theoretical speed of the generator and the actual speed of the generator is determined: If the difference between the theoretical speed of the generator and the actual speed of the generator is less than the maximum difference allowed by the engine belt, the generator speed is judged to be normal. If the difference between the theoretical speed of the generator and the actual speed of the generator is not less than the maximum difference allowed by the engine belt, the generator speed is judged to be abnormal.

[0008] Furthermore, the voltage waveform parameters include voltage frequency.

[0009] Furthermore, the expression for calculating the actual speed of the generator according to the voltage waveform parameters is: n1=60f / p Among them, n1 represents the actual speed of the generator, f represents the voltage frequency, and p represents the number of pole pairs; The expression for calculating the theoretical speed of the generator according to the actual speed of the engine is: n2=N×K Among them, n2 represents the theoretical speed of the generator, N represents the actual speed of the engine, and K represents the speed ratio.

[0010] Furthermore, after determining that the generator speed is abnormal, the method further includes: Calculate the actual current of the generator; Compare the actual generator current with the total load current; If the actual current of the generator is less than the total load current, it is judged as a primary fault; If the actual current of the generator is not less than the total load current, it is judged as a secondary fault; The total load current is the maximum load current of the entire electrical equipment in the excavator under all usage conditions.

[0011] Furthermore, the actual current of the generator is calculated by combining the actual speed of the generator with a known characteristic curve between the speed of the generator and the current.

[0012] Furthermore, it also includes issuing a fault alarm of a corresponding level according to the fault level.

[0013] On the other hand, the present invention further provides a system for detecting the abnormal degree of rotation speed of a generator for an excavator, the system being used to implement any of the above-mentioned methods for detecting the abnormal degree of rotation speed of a generator for an excavator, comprising a crankshaft sensor, a vehicle controller and an engine controller, the crankshaft sensor being arranged on the engine and being connected to the engine controller by signal, the crankshaft sensor being used to collect the actual rotation speed of the engine and transmit it to the engine controller, the engine controller being communicatively connected to the vehicle controller, and the engine controller being used to transmit the actual rotation speed of the engine to the vehicle controller; The vehicle controller is provided with an analog input port, which is connected to the generator through a wiring terminal. The vehicle controller is used to calculate the actual speed of the generator, the theoretical speed of the generator and the actual current of the generator, as well as data storage.

[0014] Optionally, the vehicle controller is also electrically connected to an electronic monitor, and the electronic monitor is used to issue a fault alarm of a corresponding level according to a fault level instruction of the vehicle controller.

[0015] Optionally, the generator is a three-phase synchronous AC generator, and one phase of the three-phase synchronous AC generator is connected to the wiring terminal.

[0016] Compared with the prior art, the present invention has the following beneficial effects: The detection method provided by the present invention detects whether the generator is abnormal by judging the actual rotation speed of the generator. The method is simple and quick, and can facilitate the staff to repair the generator immediately when the generator is not rotating. After determining that the generator is abnormal, the present invention also obtains the actual current of the generator based on the actual speed of the generator and the characteristic curve between the known speed and current of the generator, and determines the degree of abnormality of the generator based on the actual current of the generator, so that the staff can implement corresponding maintenance measures in time, effectively avoiding the battery from running out of power and being unable to start, without any additional cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a flow chart of a method for detecting abnormal degree of rotation speed of a generator for an excavator in one embodiment of the present invention; Figure 2 This is a schematic diagram of the characteristic curve between the speed and current of a certain brand of generator; Figure 3 The present invention is a schematic structural diagram of a system for detecting abnormal rotation speed of a generator for an excavator in an embodiment of the present invention. DETAILED DESCRIPTION

[0018] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention. Example 1

[0019] like Figure 1 As shown, an embodiment of the present invention provides a method for detecting abnormal degree of rotation speed of a generator for an excavator, comprising: The engine is started, and the engine drives the generator to rotate through the belt. During this process, the voltage waveform parameters of the generator and the actual speed of the engine are collected in real time. The voltage waveform parameters of the generator include voltage value, voltage cycle, voltage frequency, etc., but in this embodiment, only the voltage frequency is required.

[0020] The actual speed of the generator is calculated by combining the voltage waveform parameters with the number of generator pole pairs, and its expression is: n1=60f / p Among them, n1 represents the actual speed of the generator, f represents the voltage frequency, and p represents the number of pole pairs.

[0021] The actual engine speed is combined with the generator speed ratio to calculate the generator theoretical speed, which is expressed as: n2=N×K Among them, n2 represents the theoretical speed of the generator, N represents the actual speed of the engine, and K represents the speed ratio.

[0022] Determine the actual speed of the generator: If the actual speed of the generator is 0, it is determined that the generator is not rotating and needs to be repaired immediately. Possible reasons for this situation include belt breakage, falling off, or damage to internal components of the generator. If it is winter, the generator may be frozen. At this time, the excavator's power consumption is completely dependent on the power stored in the battery. If the staff does not check and repair the fault immediately, the battery will be unable to restart after shutting down due to low power, causing damage to the battery.

[0023] If the actual speed of the generator is not 0, the difference between the theoretical speed of the generator and the actual speed of the generator is determined: If the difference between the theoretical speed of the generator and the actual speed of the generator is less than the maximum difference allowed by the engine belt, the generator speed is judged to be normal. If the difference between the theoretical speed of the generator and the actual speed of the generator is not less than the maximum difference allowed by the engine belt, the generator speed is judged to be abnormal. It should be noted that the maximum difference allowed by the engine belt is a positive number. Example 2

[0024] Because when the generator is abnormal, there may be belt slippage, belt looseness, etc. The severity of slippage can be divided into two types, one is that immediate maintenance is required, and the other is that the excavator may continue to run for a short time and be repaired when it is idle. Therefore, based on this embodiment 1, this embodiment also includes judging the degree of abnormality after judging that the generator is abnormal, specifically: The actual generator speed is combined with the known characteristic curve between the generator speed and current to calculate the actual generator current. The characteristic curve is as follows: Figure 2 shown.

[0025] The actual current of the generator is compared with the total load current, where the total load current is the maximum value of the load current of the entire electrical equipment in the excavator under all usage conditions.

[0026] If the actual current of the generator is less than the total load current, it is judged as a primary fault. At this time, the actual current I output by the generator no longer meets the use requirements of the entire machine, and immediate maintenance is required. Otherwise, the user continues to use the excavator without knowing that there is a fault, and the generated power cannot meet the power consumption of the electrical components of the entire vehicle, which consumes the power stored in the battery, eventually causing the battery to run out of power and unable to restart after shutdown.

[0027] If the actual current of the generator is not less than the total load current, it is judged as a secondary fault. At this time, although the belt slip speed is low, it can meet the charging requirements of the whole machine. The user can perform maintenance when it is idle within a specified period of time t to prevent the secondary fault from deteriorating into a primary fault, which will eventually lead to battery depletion and inability to restart after shutdown.

[0028] After determining the fault level, a fault alarm of the corresponding level may be issued to draw the attention of the staff. Example 3

[0029] On the basis of Example 2, the embodiment of the present invention further provides a system for detecting the abnormal degree of rotation speed of a generator for an excavator, which is used to implement the method for detecting the abnormal degree of rotation speed of a generator for an excavator in Example 1.

[0030] Combination Figure 3 The system includes a crankshaft sensor, a vehicle controller and an engine controller. The crankshaft sensor is installed on the engine. The actual engine speed can be collected in real time through the crankshaft sensor. The crankshaft sensor is also connected to the engine controller signal, so that the collected actual engine speed can be transmitted to the engine controller.

[0031] The engine controller and the vehicle controller are communicatively connected. In this embodiment, the engine controller and the vehicle controller are connected via a CAN1 communication line to achieve data exchange between the two.

[0032] Generators for excavators usually use three-phase synchronous AC generators. The three-phase AC power is rectified into DC power and then supplied to batteries and electrical devices. The generator is equipped with a voltage stabilizing module to make the generator output a stable DC voltage to prevent the generator from overvoltage and damage to the battery. One phase (W end) of the three-phase synchronous AC generator is connected to the analog input port of the vehicle controller through a wiring terminal, so that the generator can transmit the real-time voltage waveform parameters of the engine to the vehicle controller.

[0033] The vehicle controller itself stores data such as known generator parameters and the characteristic curve between speed and current. By combining the received voltage waveform parameters and the actual engine speed, the actual generator speed, the theoretical generator speed, and the actual generator current can be calculated, and fault judgment can be made based on the calculated data.

[0034] In some embodiments, the vehicle controller is also connected to the electronic monitor via electrical signals, and the electronic monitor is used to issue a fault alarm of a corresponding level according to the fault level instruction of the vehicle controller to alert the staff.

[0035] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for detecting abnormal rotation speed of a generator for an excavator, characterized in that: include: Start the engine, and collect the voltage waveform parameters of the generator and the actual engine speed in real time while the engine drives the generator to rotate and generate electricity; The actual speed of the generator is calculated based on the voltage waveform parameters of the generator; The theoretical speed of the generator is calculated based on the actual speed of the engine; Determine the actual speed of the generator: If the actual generator speed is 0, it is judged that the generator is not rotating at this time and needs to be repaired immediately; If the actual speed of the generator is not 0, the difference between the theoretical speed of the generator and the actual speed of the generator is determined: If the difference between the theoretical speed of the generator and the actual speed of the generator is less than the maximum difference allowed by the engine belt, the generator speed is judged to be normal. If the difference between the theoretical speed of the generator and the actual speed of the generator is not less than the maximum difference allowed by the engine belt, the generator speed is judged to be abnormal.

2. The method for detecting abnormal degree of rotation speed of a generator for an excavator according to claim 1, characterized in that: The voltage waveform parameters include voltage frequency.

3. The method for detecting abnormal degree of rotation speed of a generator for an excavator according to claim 1, characterized in that: The expression for calculating the actual speed of the generator according to the voltage waveform parameters is: n1=60f / p Among them, n1 represents the actual speed of the generator, f represents the voltage frequency, and p represents the number of pole pairs; The expression for calculating the theoretical speed of the generator according to the actual speed of the engine is: n2=N×K Among them, n2 represents the theoretical speed of the generator, N represents the actual speed of the engine, and K represents the speed ratio.

4. The method for detecting abnormal degree of rotation speed of a generator for an excavator according to claim 1, characterized in that: After judging that the generator speed is abnormal, the following steps are also included: Calculate the actual current of the generator; Compare the actual generator current with the total load current; If the actual current of the generator is less than the total load current, it is judged as a primary fault; If the actual current of the generator is not less than the total load current, it is judged as a secondary fault; The total load current is the maximum load current of the entire electrical equipment in the excavator under all usage conditions.

5. The method for detecting abnormal degree of rotation speed of a generator for an excavator according to claim 4, characterized in that: The actual current of the generator is calculated by combining the actual speed of the generator with a known characteristic curve between the speed of the generator and the current.

6. The method for detecting abnormal degree of rotation speed of a generator for an excavator according to claim 4, characterized in that: It also includes issuing a fault alarm of a corresponding level according to the fault level.

7. A generator speed abnormality detection system for an excavator, characterized in that: The system is used to implement the method for detecting abnormal degree of rotation speed of a generator for an excavator according to any one of claims 1 to 6, and comprises a crankshaft sensor, a vehicle controller and an engine controller, wherein the crankshaft sensor is arranged on the engine and is connected to the engine controller signal, the crankshaft sensor is used to collect the actual rotation speed of the engine and transmit it to the engine controller, the engine controller is connected to the vehicle controller for communication, and the engine controller is used to transmit the actual rotation speed of the engine to the vehicle controller; The vehicle controller is provided with an analog input port, which is connected to the generator through a wiring terminal. The vehicle controller is used to calculate the actual speed of the generator, the theoretical speed of the generator, the actual current of the generator, as well as fault judgment and data storage.

8. The excavator generator speed abnormality detection system according to claim 7, characterized in that: The vehicle controller is also connected to an electronic monitor via an electrical signal, and the electronic monitor is used to issue a fault alarm of a corresponding level according to a fault level instruction of the vehicle controller.

9. The excavator generator speed abnormality detection system according to claim 7, characterized in that: The generator is a three-phase synchronous AC generator, and one phase of the three-phase synchronous AC generator is connected to the wiring terminal.

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