Hybrid excitation power generation device and control method

Abstract

The invention relates to the technical field of internal combustion generators, and provides a hybrid excitation power generation device and a control method, and the hybrid excitation power generation device comprises an electric control exciter which is installed on a generator main shaft; the permanent magnet exciter and the electric control exciter are coaxially installed in parallel; wherein direct current of the electric control exciter and direct current of the permanent magnet exciter are output in parallel, and fault isolation is achieved through the isolation part. According to the invention, the double-exciter design is adopted, so that the reliability and redundancy of the system are effectively improved.

Description

Technical Field

[0001] The present invention relates to the field of excitation generators, and in particular to a composite excitation generator and a control method. Background Art

[0002] Brushless generators have been widely used in many fields due to their excellent performance and low cost. However, the excitation system of brushless generators is relatively fragile, especially key components such as rectifier bridges, varistors, and automatic voltage regulators, which are easily damaged when subjected to load shocks, causing the generator to lose voltage output.

[0003] The compound excitation generator, such as Figure 4 As shown in the figure, if the generator is used in critical situations such as emergency rescue, a sudden shutdown of the generator may cause serious accidents. According to the experience of on-site rescue, major accidents can be effectively avoided by ensuring that the lighting on site is not interrupted and the power supply of some power tools is not interrupted. Summary of the invention

[0004] The present invention proposes a composite excitation power generation device and a control method to solve the problem that the excitation system of a brushless generator is relatively fragile, especially key components such as a rectifier bridge, a varistor and an automatic voltage regulator, which are easily damaged when subjected to load impact, causing the generator to lose voltage output. If the generator is used in critical occasions such as emergency rescue and disaster relief, a sudden shutdown of the generator may cause serious accidents.

[0005] In a first aspect, the present application proposes a composite excitation power generation device, comprising: The electrically controlled exciter is installed on the generator main shaft; The permanent magnet exciter is installed coaxially in parallel with the electric control exciter; wherein the DC output ends of the electric control exciter and the permanent magnet exciter are current isolated by an isolation part.

[0006] In combination with the first aspect, the isolation unit includes a first isolation diode and a second isolation diode, and the DC output end of the electric control exciter and the DC output end of the permanent magnet exciter are electrically isolated by the first isolation diode and / or the second isolation diode.

[0007] In combination with the first aspect, the current isolation further includes: When both the first isolation diode and the second isolation diode are not faulty, the first isolation diode and the second isolation diode are both in a forward conduction state; When the excitation circuit to which the first isolation diode belongs is faulty and the excitation circuit to which the second isolation diode belongs is not faulty, the first isolation diode is reversely cut off and the second isolation diode is in a forward conduction state; When the excitation circuit to which the second isolation diode belongs is faulty and the excitation circuit to which the first isolation diode belongs is not faulty, the second isolation diode is reversely cut off and the first isolation diode is in a forward conduction state.

[0008] In combination with the first aspect, the anode of the first isolation diode is connected to a first rectifier bridge and a first varistor; Wherein, the first rectifier bridge and the first varistor are connected in parallel; The excitation power of the permanent magnet exciter shall not be less than 30% of the main excitation; The anode of the second isolation diode is connected to a second rectifier bridge and a second varistor; wherein the second rectifier bridge and the second varistor are connected in parallel; The first rectifier bridge and the first varistor are also connected to the second rectifier bridge and the second varistor.

[0009] In combination with the first aspect, the main shaft of the generator is also connected to a diesel engine via a driving flywheel; The diesel engine is equipped with a diesel engine speed controller and a speed sensor. The diesel engine speed controller is used to control the diesel engine to run at a constant speed, and to receive an undervoltage signal to increase the speed of the permanent magnet exciter for variable speed operation. The speed sensor is used to obtain the real-time speed signal of the driving flywheel and perform closed-loop constant speed control.

[0010] In combination with the first aspect, the excitation brushless generator body further includes an output voltage detector for detecting the real-time output voltage and sending an undervoltage signal to the diesel engine speed controller when the electronically controlled exciter fails and the output voltage drops.

[0011] In combination with the first aspect, the electric controlled exciter further comprises an automatic braking voltage regulator, which is used to detect the real-time output voltage of the generator, and when the real-time output voltage drops, performs voltage compensation and controls the real-time output voltage to be a set voltage.

[0012] In a second aspect, the present application proposes a composite excitation power generation control method, which is applicable to a composite excitation power generation device as described in any one of the above, and the method comprises: Check whether the electric control exciter and permanent magnet exciter are faulty; When both the dual exciters are not faulty, the permanent magnet exciter provides part of the excitation current, and the electric control exciter detects the first real-time output voltage through the automatic voltage regulator, and determines whether the first real-time output voltage decreases; When the generator is loaded and the first real-time output voltage deviates, voltage compensation is performed through the electronically controlled exciter. During voltage compensation, the output voltage and the excitation current are closed-loop automatically regulated to a constant voltage; When the permanent magnet exciter fails, the electric control exciter performs closed-loop regulation of the excitation current and output voltage through the automatic voltage regulator, independently provides excitation current for the magnetic poles of the generator, and realizes constant voltage control; When the electronically controlled exciter fails, the second real-time output voltage is detected by the output voltage detector, an undervoltage signal is generated, and the undervoltage signal is sent to the diesel engine speed controller. The diesel engine speed controller increases the speed of the diesel engine to supplement the voltage until the second real-time output voltage reaches the set voltage.

[0013] In combination with the second aspect, when the electronically controlled exciter fails, the undervoltage signal and the real-time speed signal of the speed sensor constitute a signal superposition, and the superimposed signal is used to control the diesel engine from a constant speed state to a variable speed operation; wherein, the emergency power distribution load when the electronically controlled exciter fails is thirty percent to fifty percent of the rated output of the generator.

[0014] In combination with the second aspect, when there is no fault, the speed sensor obtains the real-time speed of the driving flywheel and feeds it back to the diesel engine speed controller, and the diesel engine is closed-loop controlled to run at a constant speed; wherein, When the generator output voltage is within the normal range, the diesel engine does not perform speed / voltage compensation; When the generator set is in closed-loop speed control, the power generation frequency corresponding to the first real-time output voltage is 50Hz; when the generator set is in variable speed operation, the power generation frequency is greater than the normal operation of 50Hz; wherein, the closed-loop control includes speed closed-loop (constant speed) control, voltage closed-loop (constant voltage) control and speed / voltage closed-loop (constant voltage) control.

[0015] The beneficial effects of the present invention are: The present invention adopts a dual exciter design of electric control and permanent magnet composite, which improves the reliability and redundancy of the power generation equipment. The design not only has the function of self-excitation constant voltage, but also can still generate electricity in an emergency when one of the exciters fails, meeting the toughness requirements of emergency equipment.

[0016] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the written description and the accompanying drawings.

[0017] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention and do not constitute a limitation of the present invention.

[0019] In the attached picture: Figure 1 This is a circuit schematic diagram of a composite excitation power generation device in an embodiment of the present invention; Figure 2 A structural diagram of a composite excitation power generation device in an embodiment of the present invention; Figure 3 A method flow chart of a composite excitation power generation control method according to an embodiment of the present invention; Figure 4 1 is a circuit schematic diagram of a standard excitation power generation device in conventional technology in an embodiment of the present invention. DETAILED DESCRIPTION

[0020] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0021] Embodiment 1: As attached Figure 1 and Figure 2 As shown, the present invention proposes a composite excitation power generation device, comprising: The electrically controlled exciter is installed on the generator main shaft; The permanent magnet exciter is installed coaxially in parallel with the electric control exciter; wherein the DC output ends of the electric control exciter and the permanent magnet exciter are current isolated by an isolation part.

[0022] In the actual implementation process, the rotor of the generator is coaxially installed with standard magnetic poles and two exciters. One of the two exciters is a standard electrically controlled electric exciter, and the other is a permanent magnet exciter with uncontrollable magnetic field strength. Under normal circumstances, the two exciters are mixed and electrically connected in parallel to provide mixed excitation current for the magnetic poles (excitation windings) of the generator; the generator armature contains a stator core, and the generator magnetic poles contain a rotor core and excitation windings. The diesel engine drives the flywheel and the main shaft to rotate, and then drives the entire generator system through the main shaft; the dual exciter (permanent magnet and electric excitation) provides the necessary excitation current for the magnetic poles of the generator, and the magnetic poles produce a rotating magnetic field, so that the main armature (the stator of the generator) generates electrical energy output. For voltage regulation, the output voltage is detected and the excitation current is controlled by the automatic voltage regulator to achieve constant voltage output of the generator. The speed sensor is used to detect the speed information, and the speed of the diesel generator set is adjusted by the speed controller, so that the generator set can run at a constant speed and constant voltage under different loads.

[0023] In the present invention, the magnitude of the excitation current of the permanent magnet exciter is related to the speed at which the armature coil of the permanent magnet exciter cuts the magnetic lines of force of the permanent magnet. First, the magnetic field strength of the permanent magnet is designed to meet the no-load output voltage when the generator is running at the rated speed and meets the power distribution requirements (for example, 380V). Under normal circumstances, the permanent magnet exciter and the electric exciter work in parallel to effectively improve the redundancy of the excitation system; the permanent magnet exciter is designed to provide the magnetic poles (windings) of the generator with 30% to 50% of the rated excitation current. When no-load, when the output voltage of the generator has met the set voltage, the excitation current of the electric exciter is very small, or even automatically shut down. When the load of the generator set increases and the output voltage drops, the voltage regulator of the electric exciter will increase the excitation current in time to make the output voltage of the generator constant.

[0024] When the composite excitation generator is connected to the load, because it is a dual exciter, it can also realize voltage compensation and constant voltage and constant speed operation under fault and normal conditions of the generator. The designed permanent magnet exciter provides about 30%~50% of the excitation power to the main excitation of the generator, and makes the output voltage of the generator under no-load condition not exceed the rated value. The electric control exciter can provide 100% of the excitation power to the main excitation of the generator. When the permanent magnet exciter is operating normally, the automatic voltage regulator adapted to the electric control exciter automatically compensates for the output voltage drop caused by the load of the generator by detecting the output voltage change of the generator, and keeps the output voltage constant at the set voltage. However, when the permanent magnet exciter fails, the excitation output current of the permanent magnet exciter decreases or disappears, and the electric control exciter will fully bear the excitation of the generator. When the electric control exciter fails, the electric control exciter will have no excitation current output. The excitation current of the generator is all provided by the permanent magnet exciter, and the output current of the permanent magnet exciter can only meet the load of the generator output ≥30%, and the output voltage decreases as the load increases. At this time, the generator output voltage detection circuit instructs the diesel engine speed controller to increase the speed of the generator. As the speed increases, the output current of the permanent magnet exciter increases, and the output voltage of the generator rises synchronously. The designed permanent magnet exciter and diesel engine speed regulation realize voltage / speed closed-loop control.

[0025] In the actual implementation of the present invention, the DC output ends of the electric control exciter and the permanent magnet exciter are connected in parallel through isolation diodes to provide excitation current for the magnetic poles of the generator. When one of the exciters fails, the current fault is isolated through the isolation diode isolation part. The other exciter continues to provide excitation current for the magnetic poles of the generator.

[0026] The beneficial effects of the above scheme are: The present invention adopts a dual exciter design of electric control and permanent magnet composite, which improves the reliability and redundancy of the power generation equipment. The design not only has the function of self-excitation constant voltage, but also can still generate electricity in an emergency when one of the exciters fails, meeting the toughness requirements of emergency equipment.

[0027] Embodiment 2: like Figure 1 As shown, as an embodiment of the present invention, the isolation part includes a first isolation diode D1 and a second isolation diode D2, and the DC output end of the electric control exciter and the DC output end of the permanent magnet exciter are current isolated by the first isolation diode D1 and / or the second isolation diode D2.

[0028] The current isolation also includes: When both the excitation circuit to which the first isolation diode D1 belongs and the excitation circuit to which the second isolation diode D2 belongs have no faults, the first isolation diode D1 and the second isolation diode D2 are both in a forward conduction state; When the excitation circuit to which the first isolation diode D1 belongs is faulty and the excitation circuit to which the second isolation diode D2 belongs is not faulty, the first isolation diode D1 is reversely cut off and the second isolation diode D2 is in a forward conduction state; When the excitation circuit to which the second isolation diode D2 belongs is faulty and the excitation circuit to which the first isolation diode D1 belongs is not faulty, the second isolation diode D2 is reversely cut off and the first isolation diode D1 is in a forward conduction state.

[0029] The anode of the first isolation diode is connected to the first rectifier bridge HB1 and the first varistor YR1; Wherein, the first rectifier bridge HB1 and the first varistor YR1 are connected in parallel; The excitation power of the permanent magnet exciter shall not be less than thirty percent of the main excitation.

[0030] In the actual implementation process, in order to enhance reliability, the DC outputs of the permanent magnet exciter and the electric control exciter are isolated by diodes D1 and D2. D1 and D2 can prevent damage to the three-phase rectifier bridge or varistor without affecting the output of the other excitation circuit, ensuring the stability and safety of the excitation system.

[0031] In the actual implementation process: When both the permanent magnet exciter and the electric control exciter are fault-free, the first isolation diode D1 and the second isolation diode D2 are both in the forward conduction state, and the dual exciters are connected in parallel to provide excitation current for the magnetic poles of the generator; When the permanent magnet exciter fails and the electric control exciter is not faulty, the first isolation diode D1 is reversely cut off, the fault of the permanent magnet exciter is isolated, the second isolation diode D2 is in a forward conduction state, and the electric control exciter independently provides excitation current for the magnetic poles of the generator; When the electric control exciter fails and the permanent magnet exciter has no fault, the second isolation diode D2 is reversely cut off, the fault of the electric control exciter is isolated, the first isolation diode D1 is in the forward conduction state, and the permanent magnet exciter independently provides excitation current for the magnetic poles of the generator.

[0032] In actual implementation, the dual exciter parallel design and the unidirectional conduction characteristics of the diode are used to realize the automatic fault isolation and standby switching functions. When any exciter fails, the reverse cutoff characteristics of the isolation diode can quickly cut off the fault circuit to prevent the fault current from spreading to the normal exciter or the generator pole winding, and seamlessly switch to another normal exciter for independent power supply, which significantly improves the reliability of the system and complies with the "importance of rotating diode fault isolation to excitation system protection". Based on the physical characteristics of the diode's unidirectional conduction, the fault isolation process is completely completed independently without relying on complex control logic or protection device triggering. If this solution is adopted, the fault path can be automatically isolated in the event of an exciter burnout accident caused by poor contact, avoiding the risk of manual operation delay. Compared with the "fault-tolerant control based on model prediction" in the prior art, this solution has a faster response speed. Electrical isolation is achieved through diodes, reducing the reliance on additional components such as fuses and overvoltage protection devices. When a single exciter fails, 50% of the excitation capacity can still be maintained, which provides buffer time for fault handling.

[0033] Embodiment 3: The anode of the second isolation diode D2 is connected to the second rectifier bridge HB2 and the second varistor YR2; wherein the second rectifier bridge HB2 and the second varistor YR2 are connected in parallel; In the actual implementation process of the first rectifier bridge HB1 and the second rectifier bridge HB2, in order to enhance reliability, the DC outputs of the permanent magnet exciter and the electric control exciter are isolated by diodes D1 and D2. D1 and D2 can prevent damage to the three-phase rectifier bridge or varistor without affecting the output of the other excitation circuit, ensuring the stability and safety of the excitation system. A varistor YR1 is also connected to the second rectifier bridge HB2 and the second varistor YR2 through an isolation part. The first isolation diode D1 and the second isolation diode D2 also cooperate with the rectifier bridge and varistor of the electric control exciter and the permanent magnet exciter to achieve electrical isolation of their respective exciters.

[0034] In actual implementation, the permanent magnet exciter and the electric control exciter convert three-phase AC to DC through the first rectifier bridge HB1 and the second rectifier bridge HB2 respectively, and the physical isolation of the output channel is achieved through isolation diodes D1 and D2. When any exciter works normally, its corresponding diode is forward-conducted, while the faulty exciter causes the diode to be reverse-cut off due to circuit abnormality, thus achieving automatic isolation; the varistors YR1 and YR2 connected in parallel at both ends of the rectifier bridge constitute an overvoltage protection layer. When a surge voltage appears at the output end of the rectifier bridge, the varistor quickly conducts and shunts through the nonlinear resistance characteristics to avoid high-voltage shocks that damage the rectifier device. The first varistor YR1 is connected to the second rectifier bridge HB2 through an isolation part to form a cross-system protection network. This design can trigger the coordinated action of the protection elements of another system through the isolation part when an overvoltage fault occurs in a single exciter, thereby enhancing the system-level protection capability. The dual exciters are powered by independent rectifier bridges to avoid load coupling effects caused by shared rectifier devices.

[0035] Embodiment 4: In case of failure of the electric control exciter or permanent magnet exciter: When the armature, rectifier bridge or varistor of the permanent magnet exciter is damaged, the permanent magnet exciter has no excitation current output, the D1 diode is reverse-phase cutoff and the fault is isolated, D2 maintains normal electric excitation current output, the permanent magnet exciter does not work, and the electric exciter operates independently according to the principle of standard brushless power generation.

[0036] When the voltage regulator, armature, rectifier bridge or varistor of the electric exciter is damaged, the electric exciter has no excitation current output, the D2 diode is reversed and cut off, D1 maintains the normal permanent magnet excitation current output, and the electric exciter does not work. However, since the magnetic field strength of the permanent magnet of the permanent magnet exciter must take into account the no-load output voltage of the generator and cannot exceed the standard (for example, 380V), the magnetic field strength is limited, so it can only meet the excitation current of the no-load output voltage of the generator.

[0037] Embodiment 5: The main shaft of the generator is also connected to a diesel engine via a driving flywheel; The diesel engine is equipped with a diesel engine speed controller and a speed sensor. The diesel engine speed controller is used to control the diesel engine to run at a constant speed, and to receive an undervoltage signal to increase the speed of the permanent magnet exciter for variable speed operation. The speed sensor is used to obtain the real-time speed signal of the driving flywheel and perform closed-loop constant speed control.

[0038] In the actual implementation process, when the electric exciter fails, the output voltage of the generator is lower than the set value, and the generator output voltage detection circuit instructs the diesel engine speed controller to increase the speed of the generator. When the speed increases, the output current of the permanent magnet exciter increases, and the output voltage of the generator rises synchronously. The speed regulation of the permanent magnet exciter and the diesel engine realizes voltage / speed closed-loop control; When the generator output voltage is within the normal range, the diesel engine does not need speed / voltage compensation.

[0039] The speed control of the diesel engine of the present application adopts a speed and voltage closed-loop controller. When the generator is generating electricity normally, the controller satisfies the constant speed operation of the diesel generator set. When the excitation system of the electric exciter fails and the output voltage of the generator is low, the control signal of the start voltage closed-loop regulation and the speed sensor signal are superimposed on the diesel engine speed controller (the lower the output voltage, the more the speed of the diesel engine is increased). By increasing the speed of the diesel engine, the excitation current of the permanent magnet exciter is increased, and the diesel engine is controlled to increase speed, so that the generator set can automatically compensate for the insufficient output voltage of the generator within a certain output power range.

[0040] Embodiment 6: The excitation brushless generator body also includes an output voltage detector, which is used to detect the real-time output voltage and send an undervoltage signal to the diesel engine speed controller when the electronically controlled exciter fails and the output voltage drops.

[0041] In actual implementation, the speed sensor detects the speed of the diesel engine and feeds back to the diesel engine speed controller in real time to adjust the fuel quantity, and closes the loop to control the diesel engine to run at a constant speed. In addition, the diesel engine speed controller also receives the undervoltage control signal from the output voltage detection device. The control signal of the output voltage detection device is superimposed on the signal of the speed sensor, so that the diesel engine speed controller controls the diesel generator set to change from constant speed to variable speed operation. Since the speed adjustment range of the diesel engine is limited, the current compensation of the permanent magnet exciter by increasing its speed can only meet 30~50% of the rated load of the generator set (in actual implementation, it is set according to the speed range of the diesel engine) The electric control exciter also includes an automatic voltage regulator, which is used to detect the real-time output voltage of the generator, and when the real-time output voltage drops, performs voltage compensation and controls the real-time output voltage to be a set voltage.

[0042] In the actual implementation process, when the permanent magnet exciter operates normally, the automatic voltage regulator adapted to the electric control exciter detects the output voltage change of the generator, automatically compensates for the output voltage drop caused by the load of the generator, and keeps the output voltage constant at the set voltage. However, when the permanent magnet exciter fails, the excitation output current of the permanent magnet exciter decreases or disappears, and the electric control exciter will take full responsibility for the excitation of the generator.

[0043] Embodiment 7: like Figure 3 As shown, a composite excitation power generation control method is applicable to the composite excitation power generation device mentioned above, and the method comprises: Check whether the electric control exciter and permanent magnet exciter are faulty; When both the dual exciters are not faulty, the permanent magnet exciter provides part of the excitation current, and detects the first real-time output voltage through the automatic voltage regulator, and determines whether the first real-time output voltage decreases; When the generator is loaded and the first real-time output voltage deviates, voltage compensation is performed through the electronically controlled exciter. During voltage compensation, the output voltage and the excitation current are closed-loop automatically regulated to a constant voltage; When the permanent magnet exciter fails, the electric control exciter performs closed-loop regulation of the excitation current and output voltage through the automatic voltage regulator, independently provides excitation current for the magnetic poles of the generator, and realizes constant voltage control; When the electronically controlled exciter fails, the second real-time output voltage is detected by the output voltage detector, an undervoltage signal is generated, and the undervoltage signal is sent to the diesel engine speed controller. The diesel engine speed controller increases the speed of the diesel engine to supplement the voltage until the second real-time output voltage reaches the set voltage.

[0044] At this time, the excitation current of the generator is all provided by the permanent magnet exciter, and the output current of the permanent magnet exciter can only meet the load of 30%~50% of the generator output, and the output voltage decreases as the load increases. At this time, the generator output voltage detection circuit instructs the speed controller of the diesel engine to increase the speed of the generator. When the speed increases, the output current of the permanent magnet exciter increases, and the output voltage of the generator rises synchronously. The speed regulation of the permanent magnet exciter and the diesel engine realizes voltage / speed closed-loop control. Since the permanent magnet exciter bears all the excitation power, after the load is connected, the magnetic field of the permanent magnet exciter is not enough, and then the speed must be increased to compensate. Because the magnetic field strength of the permanent magnet is uncontrollable, the output voltage of the generator will decrease after the load is increased. Therefore, the existing technology uses an electrically controlled exciter. At present, there is a hybrid magnetic excitation technology, which is to add a group of permanent magnets to the electrically controlled exciter, mainly to improve the performance of automatic excitation, which is actually an exciter. This application is two exciters, one is a standard electrically controlled exciter, and the other is a permanent magnet exciter. The designed permanent magnet exciter adopts speed increase to compensate for the magnetization of the permanent magnet exciter. The operating dual exciter can effectively improve the reliability and redundancy of the excitation system. When the electric control exciter fails, the permanent magnet exciter in parallel will automatically bear all the excitation power, but as the load of the generator increases, its output voltage drops and cannot meet the standard. The system will increase the speed of the permanent magnet exciter to increase the excitation current output, thereby compensating for the insufficient power generation voltage.

[0045] Embodiment 8: When the electronically controlled exciter fails, the undervoltage signal and the real-time speed signal of the speed sensor constitute a signal superposition, and the superimposed signal is used to control the diesel engine from a constant speed state to a variable speed operation; wherein, the emergency power distribution load when the electronically controlled exciter fails is more than thirty percent of the rated output of the generator.

[0046] In the actual implementation process, the diesel engine speed controller receives the undervoltage control signal from the output voltage detection device at the same time. The control signal of the output voltage detection device is superimposed on the signal of the speed sensor, so that the diesel engine speed controller controls the diesel generator set to change from constant speed to variable speed operation. The emergency power distribution load is 30%~50% of the rated output of the generator.

[0047] Embodiment 9: When there is no fault, the speed sensor obtains the real-time speed of the drive flywheel and feeds it back to the diesel engine speed controller, and the diesel engine is closed-loop controlled to run at a constant speed; wherein, when the output voltage of the generator is within the normal range, the diesel engine does not perform speed / voltage compensation.

[0048] In the actual implementation process, the generator set is in a normal power generation state, and its speed sensor obtains the real-time speed of the drive flywheel and feeds it back to the diesel engine speed controller, which controls the speed of the diesel engine in a closed loop to achieve constant speed regulation of the generator set; the speed sensor is used to obtain the real-time speed information of the drive flywheel to ensure constant speed operation of the generator set under normal conditions. When the output voltage of the generator is within the normal range, the diesel engine does not perform speed / voltage compensation.

[0049] Embodiment 10: When the generator output voltage is within the normal range, the diesel engine does not perform speed / voltage compensation; When the generator set is in closed-loop speed control, the power generation frequency corresponding to the first real-time output voltage is 50Hz; when the generator set is in variable speed operation, the power generation frequency is greater than the normal operation of 50Hz; wherein, the closed-loop control includes speed closed-loop (constant speed) control, voltage closed-loop (constant voltage) control and speed / voltage closed-loop (constant voltage) control.

[0050] In actual implementation, speed closed-loop (constant speed) control is when the system detects that the power generation frequency needs to be stabilized at 50Hz (such as grid-connected operation or fixed load scenarios), the speed sensor provides real-time feedback signals, and the diesel engine throttle opening is adjusted in combination with the control algorithm (PID algorithm) to maintain a constant speed.

[0051] Voltage closed-loop (constant voltage) control is a scenario where the output voltage fluctuates but the frequency is stable (such as independent power supply mode), in which the generator magnetic field strength is adjusted through the excitation regulator to keep the output voltage constant.

[0052] There is also a variable speed operation mode. When the power generation frequency needs to be adjusted dynamically (such as to cope with sudden load changes or participate in grid frequency modulation), the system allows the power generation frequency to be higher than 50Hz, while maintaining the output voltage stability through voltage closed-loop compensation.

[0053] In actual implementation, there are also intelligent compensation triggers, such as: non-intervention strategy when the voltage is normal. When the output voltage is within the set range (such as 380V±5%), the system automatically disables the speed / voltage compensation function to avoid energy loss caused by redundant regulation. Dynamic compensation trigger conditions: when the voltage deviation exceeds the threshold (such as ±5%) or the frequency fluctuates (±0.5Hz), the compensation algorithm is activated immediately. In terms of performance advantages, the device of this application is based on a nested design of dual closed loops to achieve millisecond-level voltage regulation, and can implement a frequency-decoupled voltage control scheme to eliminate the impact of frequency changes on voltage.

[0054] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A composite excitation power generation device, characterized in that: include: The electrically controlled exciter is installed on the generator main shaft; The permanent magnet exciter is installed coaxially in parallel with the electric control exciter; wherein the DC output ends of the electric control exciter and the permanent magnet exciter are current isolated by an isolation part.

2. A composite excitation power generation device as claimed in claim 1, characterized in that: The isolation part includes a first isolation diode D1 and a second isolation diode D2. The DC output end of the electric control exciter and the DC output end of the permanent magnet exciter are current-isolated by the first isolation diode D1 and / or the second isolation diode D2.

3. A composite excitation power generation device as claimed in claim 1, characterized in that: When the current is isolated, it also includes: When both the first isolation diode D1 and the second isolation diode D2 are not faulty, the first isolation diode D1 and the second isolation diode D2 are both in a forward conduction state; When the excitation circuit to which the first isolation diode D1 belongs is faulty and the excitation circuit to which the second isolation diode D2 belongs is not faulty, the first isolation diode D1 is reversely cut off and the second isolation diode D2 is in a forward conduction state; When the excitation circuit to which the second isolation diode D2 belongs is faulty and the excitation circuit to which the first isolation diode D1 belongs is not faulty, the second isolation diode D2 is reversely cut off and the first isolation diode D1 is in a forward conduction state.

4. A composite excitation power generation device as claimed in claim 2, characterized in that: The anode of the first isolation diode D1 is connected to the first rectifier bridge HB1 and the first varistor YR1; Wherein, the first rectifier bridge HB1 and the first varistor YR1 are connected in parallel; The excitation power of the permanent magnet exciter shall not be less than 30% of the main excitation; The anode of the second isolation diode D2 is connected to the second rectifier bridge HB2 and the second varistor YR2; wherein the second rectifier bridge HB2 and the second varistor YR2 are connected in parallel; The first rectifier bridge HB1 and the first varistor YR1 are also connected to the second rectifier bridge HB2 and the second varistor YR2.

5. A composite excitation power generation device as claimed in claim 1, characterized in that: The main shaft of the generator is also connected to a diesel engine via a driving flywheel; The diesel engine is equipped with a diesel engine speed controller and a speed sensor. The diesel engine speed controller is used to control the diesel engine to run at a constant speed, and to receive an undervoltage signal to increase the speed of the permanent magnet exciter for variable speed operation. The speed sensor is used to obtain the real-time speed signal of the driving flywheel and perform closed-loop constant speed control.

6. A composite excitation power generation device as claimed in claim 5, characterized in that: The electric control exciter and the permanent magnet exciter are also connected to an output voltage detector, which is used to detect the real-time output voltage and send an undervoltage signal to the diesel engine speed controller when the electric control exciter fails and the output voltage drops.

7. A composite excitation power generation device as claimed in claim 1, characterized in that: The electric control exciter also includes an automatic voltage regulator, which is used to detect the real-time output voltage of the generator, and when the real-time output voltage drops, performs voltage compensation and controls the real-time output voltage to be a set voltage.

8. A composite excitation power generation control method, applicable to a composite excitation power generation device according to any one of claims 1 to 7, characterized in that: The method comprises: Check whether the electric control exciter and permanent magnet exciter are faulty; When both the dual exciters are not faulty, the permanent magnet exciter provides part of the excitation current, and the electric control exciter detects the first real-time output voltage through the automatic voltage regulator, and determines whether the first real-time output voltage decreases; When the generator is loaded and the first real-time output voltage deviates, voltage compensation is performed through the electronically controlled exciter. During voltage compensation, the output voltage and the excitation current are closed-loop automatically regulated to a constant voltage; When the permanent magnet exciter fails, the electric control exciter performs closed-loop regulation of the excitation current and output voltage through the automatic voltage regulator, independently provides excitation current for the magnetic poles of the generator, and realizes constant voltage control; When the electronically controlled exciter fails, the second real-time output voltage is detected by the output voltage detector, an undervoltage signal is generated, and the undervoltage signal is sent to the diesel engine speed controller. The diesel engine speed controller increases the speed of the diesel engine to supplement the voltage until the second real-time output voltage reaches the set voltage.

9. A compound excitation power generation control method as claimed in claim 8, characterized in that: When the electronically controlled exciter fails, the undervoltage signal and the real-time speed signal of the speed sensor constitute a signal superposition, and the superimposed signal is used to control the diesel engine from a constant speed state to a variable speed operation; wherein, the emergency power distribution load when the electronically controlled exciter fails is 30% to 50% of the rated output of the generator.

10. A compound excitation power generation control method as claimed in claim 8, characterized in that: When there is no fault, the speed sensor obtains the real-time speed of the driving flywheel and feeds it back to the diesel engine speed controller, and the diesel engine is controlled in a closed loop to run at a constant speed; wherein, When the generator output voltage is within the normal range, the diesel engine does not perform speed / voltage compensation; When the generator set speed is closed-loop controlled, the power generation frequency corresponding to the first real-time output voltage is 50Hz; when the generator set speed / voltage variable speed operation is performed, the power generation frequency is greater than the normal operation of 50Hz; wherein the closed-loop control includes speed closed-loop control, voltage closed-loop control and speed / voltage closed-loop control.

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