A composite excitation power generation device and control method

Abstract

The present invention relates to the technical field of internal combustion generators and provides a composite excitation generator and control method. The device comprises an electrically controlled exciter mounted on the generator main shaft and a permanent magnet exciter mounted coaxially in parallel with the electrically controlled exciter. The DC outputs of the electrically controlled exciter and the permanent magnet exciter are connected in parallel, and fault isolation is achieved via an isolation unit. The dual exciter design effectively improves system reliability and redundancy.

Description

Technical Field

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

[0002] Brushless generators (BLGs) are widely used in many fields due to their superior performance and low cost. However, their excitation systems are relatively fragile. Key components, such as the rectifier bridge, varistors, and automatic voltage regulators, are particularly susceptible to damage when subjected to load shocks, resulting in a loss of generator voltage output.

[0003] The compound excitation generator, such as Figure 4 As shown, if a generator is used in critical situations such as disaster relief, a sudden shutdown could result in a serious accident. Experience with on-site rescue efforts suggests that ensuring uninterrupted lighting and power to some power tools can effectively prevent major accidents. Summary of the Invention

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

[0006] The electronically controlled exciter is installed on the generator main shaft;

[0007] The permanent magnet exciter is coaxially installed 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 through an isolation part.

[0008] 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 electronically controlled 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.

[0009] In combination with the first aspect, the current isolation further includes:

[0010] When both the first isolation diode and the second isolation diode are in good condition, the first isolation diode and the second isolation diode are in a forward conduction state;

[0011] 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;

[0012] 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.

[0013] In combination with the first aspect, the anode of the first isolation diode is connected to the first rectifier bridge and the first varistor;

[0014] Wherein, the first rectifier bridge and the first varistor are connected in parallel;

[0015] The excitation power of the permanent magnet exciter shall not be less than 30% of the main excitation;

[0016] The anode of the second isolation diode is connected to the second rectifier bridge and the second varistor; wherein the second rectifier bridge and the second varistor are connected in parallel;

[0017] The first rectifier bridge and the first varistor are further connected to the second rectifier bridge and the second varistor.

[0018] In combination with the first aspect, the generator main shaft is further connected to a diesel engine via a drive flywheel;

[0019] 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.

[0020] The speed sensor is used to obtain the real-time speed signal of the driving flywheel and perform closed-loop constant speed control.

[0021] In combination with the first aspect, the excitation brushless generator body further 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.

[0022] In combination with the first aspect, the electronically controlled exciter further includes 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, perform voltage compensation and control the real-time output voltage to a set voltage.

[0023] In a second aspect, the present application proposes a composite excitation power generation control method, applicable to any composite excitation power generation device described above, the method comprising:

[0024] Check whether there are faults in the electric control exciter and permanent magnet exciter;

[0025] When both exciters are fault-free, the permanent magnet exciter provides partial excitation current, and the electronically controlled exciter detects the first real-time output voltage through the automatic voltage regulator and determines whether the first real-time output voltage drops.

[0026] 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.

[0027] When the permanent magnet exciter fails, the electronically controlled exciter performs closed-loop regulation of the excitation current and output voltage through the automatic voltage regulator, independently provides excitation current to the generator's magnetic poles, and achieves constant voltage control;

[0028] 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.

[0029] 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.

[0030] In combination with the second aspect, 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 closed-loop control of the diesel engine is constant speed operation; wherein,

[0031] When the generator output voltage is within the normal range, the diesel engine does not perform speed / voltage compensation;

[0032] When the generator set is in closed-loop speed control, the generation frequency corresponding to the first real-time output voltage is 50Hz; when the generator set is in variable speed operation with respect to speed / voltage, the generation frequency is greater than the normal operation of 50Hz; among them, 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.

[0033] The beneficial effects of the present invention are:

[0034] This invention utilizes a dual exciter design combining electronic control and permanent magnets, improving the reliability and redundancy of the power generation equipment. This design not only provides self-excitation and constant voltage, but also enables emergency power generation in the event of a failure in one of the exciters, meeting the resilience requirements of emergency equipment.

[0035] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or will be 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.

[0036] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] 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.

[0038] In the attached figure:

[0039] Figure 1 This is a circuit diagram of a composite excitation power generation device according to an embodiment of the present invention;

[0040] Figure 2 This is a structural diagram of a composite excitation power generation device according to an embodiment of the present invention;

[0041] Figure 3 This is a flow chart of a method for controlling a composite excitation power generation according to an embodiment of the present invention;

[0042] Figure 4 1 is a circuit diagram of a standard excitation generator in conventional technology in an embodiment of the present invention. DETAILED DESCRIPTION

[0043] The preferred embodiments of the present invention are described below with reference to 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.

[0044] Example 1:

[0045] As attached Figure 1 and Figure 2 As shown, the present invention proposes a composite excitation power generation device, comprising:

[0046] The electronically controlled exciter is installed on the generator main shaft;

[0047] The permanent magnet exciter is coaxially installed 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 through an isolation part.

[0048] In actual implementation, the generator rotor is coaxially mounted with standard magnetic poles and two exciters. One exciter 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 to the generator's magnetic poles (excitation winding). The generator armature contains the stator core, while the generator poles contain the rotor core and excitation winding. The diesel engine rotates the flywheel and main shaft, which in turn drives the entire generator system. The dual exciters (permanent magnet and electric exciter) provide the necessary excitation current to the generator's magnetic poles, generating a rotating magnetic field that causes the main armature (generator stator) to generate electrical energy. For voltage regulation, an automatic voltage regulator monitors the output voltage and controls the excitation current to achieve constant generator output voltage. A speed sensor detects speed information, and a speed controller adjusts the diesel generator set's speed, enabling constant speed and voltage operation under varying loads.

[0049] In the present invention, the excitation current of the permanent magnet exciter is related to the speed at which the armature coil of the permanent magnet exciter cuts through the magnetic lines of force of the permanent magnet. The magnetic field strength of the permanent magnets is designed to ensure that the no-load output voltage meets power distribution requirements (e.g., 380V) when the generator is operating at rated speed. Under normal circumstances, the permanent magnet exciter and the electric exciter operate in parallel, effectively improving the redundancy of the excitation system. The permanent magnet exciter is designed to provide 30% to 50% of the rated excitation current to the generator's poles (windings). When the generator output voltage reaches the set voltage at no-load, the excitation current of the electric exciter is very low, or even automatically shuts down. However, when the load on the generator set increases and the output voltage drops, the electric exciter's voltage regulator promptly increases the excitation current to maintain a constant output voltage.

[0050] When connected to a load, the dual-exciter design of the compound excitation generator allows for voltage compensation and constant voltage and speed operation, both during fault conditions and under normal operation. The designed permanent magnet exciter provides approximately 30% to 50% of the excitation power for the generator's main excitation, ensuring that the generator's output voltage does not exceed the rated value when no-loaded. The electronically controlled exciter can provide 100% of the excitation power for the generator's main excitation. When the permanent magnet exciter operates normally, the automatic voltage regulator (AVR) integrated with the electronically controlled exciter detects changes in the generator's output voltage, automatically compensates for the output voltage drop caused by load, and maintains the output voltage at the set voltage. However, if the permanent magnet exciter fails, the excitation output current of the permanent magnet exciter decreases or disappears, and the electronically controlled exciter assumes full generator excitation. If the electronically controlled exciter fails, the electronically controlled exciter will no longer output excitation current. The generator's excitation current is entirely provided by the permanent magnet exciter, but its output current can only meet loads exceeding 30% of the generator's output. Furthermore, the output voltage decreases as the load increases. At this point, the generator's output voltage detection circuit instructs the diesel engine's speed controller to increase the generator's speed. This increase in speed increases the permanent magnet exciter's output current, and the generator's output voltage rises synchronously. The designed permanent magnet exciter and diesel engine speed regulators achieve closed-loop voltage / speed control.

[0051] In the actual implementation of the present invention, the DC output terminals of the electric-controlled exciter and the permanent-magnet exciter are connected in parallel through isolation diodes to provide excitation current to the generator's magnetic poles. When one of the exciters fails, the isolation diode isolates the current fault, while the other exciter continues to provide excitation current to the generator's magnetic poles.

[0052] The beneficial effects of the above scheme are:

[0053] This invention utilizes a dual exciter design combining electronic control and permanent magnets, improving the reliability and redundancy of the power generation equipment. This design not only provides self-excitation and constant voltage, but also enables emergency power generation in the event of a failure in one of the exciters, meeting the resilience requirements of emergency equipment.

[0054] Example 2:

[0055] 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.

[0056] The current isolation also includes:

[0057] 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;

[0058] 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;

[0059] 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.

[0060] The anode of the first isolation diode is connected to the first rectifier bridge HB1 and the first varistor YR1;

[0061] Wherein, the first rectifier bridge HB1 and the first varistor YR1 are connected in parallel;

[0062] The excitation power of the permanent magnet exciter shall not be less than thirty percent of the main excitation.

[0063] In the actual implementation process, in order to enhance reliability, the DC outputs of the permanent magnet exciter and the electronically controlled 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.

[0064] In the actual implementation process:

[0065] When both the permanent magnet exciter and the electronically controlled exciter are in good condition, 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;

[0066] When the permanent magnet exciter fails and the electronically controlled 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 the forward conduction state, and the electronically controlled exciter independently provides excitation current for the magnetic poles of the generator;

[0067] When the electric control exciter fails and the permanent magnet exciter is not faulty, 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.

[0068] In practical implementation, the parallel design of dual exciters, combined with the unidirectional conduction characteristics of diodes, achieves automatic fault isolation and backup switchover. If either exciter fails, the reverse-blocking characteristics of the isolation diodes quickly disconnect the fault circuit, preventing the fault current from spreading to the functioning exciter or generator pole windings. Simultaneously, independent power supply is seamlessly switched to the functioning exciter, significantly improving system reliability and embodying the importance of rotating diode fault isolation for excitation system protection. Leveraging the diode's unidirectional conductivity, the fault isolation process is fully autonomous, eliminating the need for complex control logic or protective device triggering. In the event of an exciter burnout due to poor contact, this solution automatically isolates the fault path, eliminating the risk of manual delays. Compared to existing model-based predictive fault-tolerant control, this solution offers faster response times. Electrical isolation achieved through diodes reduces the need for additional components such as fuses and overvoltage protection devices. Even in the event of a single exciter failure, 50% of the excitation capacity can be maintained, providing buffer time for fault resolution.

[0069] Example 3:

[0070] 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;

[0071] To enhance reliability, the first rectifier bridge HB1 and the second rectifier bridge HB2 are implemented with diodes D1 and D2 to isolate the DC outputs of the permanent magnet exciter and the electronically controlled exciter. These diodes 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, via an isolation section. The first and second isolation diodes D1 and D2 also work in conjunction with the rectifier bridges and varistors of the electronically controlled exciter and the permanent magnet exciter to achieve electrical isolation between the respective exciters.

[0072] In practical implementation, the permanent magnet exciter and the electronically controlled exciter convert three-phase AC to DC via the first rectifier bridge HB1 and the second rectifier bridge HB2, respectively. Isolation diodes D1 and D2 physically isolate the output channels. When either exciter is operating normally, its corresponding diode conducts in the forward direction, while the faulty exciter's diode reverses due to a circuit anomaly, achieving automatic isolation. Varistors YR1 and YR2, connected in parallel across the rectifier bridges, form an overvoltage protection layer. When a surge voltage appears at the rectifier bridge output, the varistors quickly conduct and shunt the current through their nonlinear resistance characteristics, preventing damage to the rectifier components from the high-voltage surge. The first varistor YR1 is connected to the second rectifier bridge HB2 via an isolation section, forming a cross-system protection network. This design allows the isolation section to trigger coordinated action of the protection components of the other system when an overvoltage fault occurs in a single exciter, enhancing system-level protection. The dual exciters are powered by independent rectifier bridges, avoiding load coupling effects caused by shared rectifier components.

[0073] Example 4:

[0074] In case of failure of the electric control exciter or permanent magnet exciter:

[0075] 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.

[0076] When the exciter's voltage regulator, armature, rectifier bridge, or varistor is damaged, the exciter will not output excitation current. Diode D2 will be reverse-phase cutoff, and D1 will maintain normal permanent magnet excitation current output, and the exciter will not function. However, since the magnetic field strength of the permanent magnet in the permanent magnet exciter must be within the generator's no-load output voltage (e.g., 380V), the magnetic field strength is limited, so it can only meet the excitation current required for the generator's no-load output voltage.

[0077] Example 5:

[0078] The main shaft of the generator is also connected to the diesel engine via a driving flywheel;

[0079] 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.

[0080] The speed sensor is used to obtain the real-time speed signal of the driving flywheel and perform closed-loop constant speed control.

[0081] In actual implementation, when the electric exciter fails, the generator's output voltage is lower than the set value. The generator output voltage detection circuit instructs the diesel engine's speed controller to increase the generator's speed. As the speed increases, the output current of the permanent magnet exciter increases, and the generator's output voltage rises synchronously. The speed regulation of the permanent magnet exciter and the diesel engine realizes voltage / speed closed-loop control.

[0082] When the generator output voltage is within the normal range, the diesel engine does not need speed / voltage compensation.

[0083] The diesel engine speed control in this application utilizes a speed and voltage closed-loop controller. When the generator is operating normally, the controller ensures constant speed operation of the diesel generator set. However, if a fault in the excitation system of the electric exciter causes the generator output voltage to drop below zero, the control signal for the startup voltage closed-loop regulation is superimposed on the speed sensor signal on the diesel engine speed controller (the lower the output voltage, the greater the increase in diesel engine speed). This increases the diesel engine speed, boosting the excitation current of the permanent magnet exciter and controlling the diesel engine to increase speed, enabling the generator set to automatically compensate for insufficient generator output voltage within a certain output power range.

[0084] Example 6:

[0085] The excitation brushless generator body further comprises 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.

[0086] In actual implementation, the speed sensor detects the speed of the diesel engine and provides real-time feedback to the diesel engine speed controller for fuel quantity adjustment, maintaining closed-loop control over the diesel engine's constant speed operation. Furthermore, the diesel engine speed controller simultaneously receives an undervoltage control signal from the output voltage detection device. The output voltage detection device's control signal is superimposed on the speed sensor's signal, causing the diesel engine speed controller to control the diesel generator set from constant speed to variable speed operation. Due to the limited speed adjustment range of the diesel engine, increasing its speed to compensate for the current of the permanent magnet exciter can only meet 30-50% of the generator set's rated load (in actual implementation, the setting depends on the speed range of the diesel engine).

[0087] The electric controlled exciter further comprises 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, perform voltage compensation and control the real-time output voltage to be a set voltage.

[0088] In actual implementation, when the permanent magnet exciter operates normally, the automatic voltage regulator (AVR) adapted to the electronically controlled exciter detects changes in the generator's output voltage, automatically compensates for the output voltage drop caused by the generator's load, and maintains a constant output voltage at the set voltage. However, if the permanent magnet exciter fails and its excitation output current decreases or disappears, the electronically controlled exciter will assume full responsibility for the generator's excitation.

[0089] Example 7:

[0090] 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 includes:

[0091] Check whether there are faults in the electric control exciter and permanent magnet exciter;

[0092] When both exciters are fault-free, the permanent magnet exciter provides partial excitation current, and detects the first real-time output voltage through the automatic voltage regulator, and determines whether the first real-time output voltage drops;

[0093] 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.

[0094] When the permanent magnet exciter fails, the electronically controlled exciter performs closed-loop regulation of the excitation current and output voltage through the automatic voltage regulator, independently provides excitation current to the generator's magnetic poles, and achieves constant voltage control;

[0095] 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.

[0096] At this point, the generator's excitation current is entirely provided by the permanent magnet exciter, but the exciter's output current can only meet 30%-50% of the generator's output load, and the output voltage decreases as the load increases. At this point, the generator's output voltage detection circuit instructs the diesel engine's speed controller to increase the generator's speed. As the speed increases, the permanent magnet exciter's output current increases, and the generator's output voltage rises synchronously. The speed regulation of the permanent magnet exciter and the diesel engine achieves closed-loop voltage / speed control. Since the permanent magnet exciter bears all the excitation power, when the load is connected, the permanent magnet exciter's magnetic field becomes insufficient, necessitating an increase in speed to compensate. Because the magnetic field strength of the permanent magnets is uncontrollable, the generator's output voltage decreases as the load increases. Therefore, existing technologies typically use electronically controlled exciters. Hybrid excitation technology currently exists, which adds a set of permanent magnets to an electronically controlled exciter, primarily to improve automatic excitation performance. This effectively creates a single exciter. This application utilizes two exciters: a standard electronically controlled exciter and a permanent magnet exciter. The designed permanent magnet exciter uses speed increase to compensate for magnetization. The dual exciter operation effectively improves the reliability and redundancy of the excitation system. If the electronically controlled exciter fails, the parallel permanent magnet exciter automatically assumes full excitation power. However, as the generator load increases, its output voltage drops and falls below the specified voltage. The system then increases the speed of the permanent magnet exciter, boosting the excitation current output and compensating for the insufficient generator voltage.

[0097] Example 8:

[0098] 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, when the electronically controlled exciter fails, the emergency power distribution load is more than 30% of the rated output of the generator.

[0099] In actual operation, the diesel engine speed controller simultaneously receives an undervoltage control signal from the output voltage detection device. This signal is superimposed on the speed sensor signal, causing the diesel engine speed controller to control the diesel generator set from constant speed to variable speed operation. The emergency power distribution load is 30% to 50% of the rated generator output.

[0100] Example 9:

[0101] 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 closed-loop control is used to keep the diesel engine running 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.

[0102] During the actual implementation process, the generator set is in a normal power generation state. Its speed sensor obtains the real-time speed of the driving 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 driving flywheel to ensure that the generator set runs at a constant speed under normal conditions. When the output voltage of the generator is within the normal range, the diesel engine does not perform speed / voltage compensation.

[0103] Example 10:

[0104] When the generator output voltage is within the normal range, the diesel engine does not perform speed / voltage compensation;

[0105] When the generator set is in closed-loop speed control, the generation frequency corresponding to the first real-time output voltage is 50Hz; when the generator set is in variable speed operation with respect to speed / voltage, the generation frequency is greater than the normal operation of 50Hz; among them, 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.

[0106] 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), and uses real-time feedback signals from the speed sensor combined with the control algorithm (PID algorithm) to adjust the diesel engine throttle opening to maintain a constant speed.

[0107] Voltage closed-loop (constant voltage) control is a scenario where the output voltage fluctuates but the frequency is stable (such as in independent power supply mode). The excitation regulator is used to adjust the generator magnetic field strength to keep the output voltage constant.

[0108] There is also a variable speed operation mode. When the power generation frequency needs to be dynamically adjusted (such as to cope with sudden load changes or participate in grid frequency regulation), the system allows the power generation frequency to be higher than 50Hz, while maintaining the output voltage stability through voltage closed-loop compensation.

[0109] In actual implementation, there are also intelligent compensation triggers, such as a 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 adjustment. Dynamic compensation trigger conditions: when the voltage deviation exceeds the threshold (such as ±5%) or the frequency fluctuates (±0.5Hz), the compensation algorithm is immediately activated. In terms of performance advantages, the device of this application is based on a nested dual-closed-loop design, achieving millisecond-level voltage regulation and can implement a frequency-decoupled voltage control scheme to eliminate the impact of frequency changes on voltage.

[0110] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A composite excitation power generation device, characterized in that: include: The electronically controlled exciter is installed on the generator main shaft; A permanent magnet exciter is coaxially installed in parallel with an electric control exciter; wherein the DC output terminals of the electric control exciter and the permanent magnet exciter are electrically isolated by an isolation portion; the isolation portion includes a first isolation diode D1 and a second isolation diode D2, and the DC output terminals of the electric control exciter and the permanent magnet exciter are electrically isolated by the first isolation diode D1 and / or the second isolation diode D2; The current isolation also includes: When both the first isolation diode D1 and the second isolation diode D2 are in good condition, the first isolation diode D1 and the second isolation diode D2 are 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; The main shaft of the generator is also connected to the diesel engine through a drive 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.

2. A composite excitation power generation device according to claim 1, 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 further connected to the second rectifier bridge HB2 and the second varistor YR2.

3. A composite excitation power generation device according to claim 1, characterized in that: The electronically controlled 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 electronically controlled exciter fails and the output voltage drops.

4. A composite excitation power generation device according to claim 1, characterized in that: The electric controlled exciter further comprises 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, perform voltage compensation and control the real-time output voltage to be a set voltage.

5. A composite excitation power generation control method, applicable to a composite excitation power generation device according to any one of claims 1 to 4, characterized in that: The method comprises: Check whether there are faults in the electric control exciter and permanent magnet exciter; When both exciters are fault-free, the permanent magnet exciter provides partial excitation current, and the electronically controlled exciter detects the first real-time output voltage through the automatic voltage regulator and determines whether the first real-time output voltage drops. 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 electronically controlled exciter performs closed-loop regulation of the excitation current and output voltage through the automatic voltage regulator, independently provides excitation current to the generator's magnetic poles, and achieves 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.

6. A compound excitation power generation control method according to claim 5, 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, when the electronically controlled exciter fails, the emergency power distribution load is 30% to 50% of the rated output of the generator.

7. The compound excitation power generation control method according to claim 5, 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 closed-loop control is used to control the diesel engine 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 speed closed-loop control, the power generation frequency corresponding to the first real-time output voltage is 50Hz; when the generator set is in speed / voltage variable operation, the power generation frequency is greater than the normal operation of 50Hz; among them, the closed-loop control includes speed closed-loop control, voltage closed-loop control and speed / voltage closed-loop control.

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