A three-phase six-beat control method for an electrically excited doubly salient generator system

Abstract

A three-phase, six-beat control method for an electrically excited doubly salient pole generator system includes: Based on a control strategy that switches on the upper-arm switch connected to the phase winding of the doubly salient pole generator during the rising phase inductance period, switches on the lower-arm switch connected to the winding during the falling phase inductance period, and disables the switch during the constant phase inductance period, the upper and lower switches are advanced by an angle α, and the upper switch is additionally advanced by an angle δ. The generator operates under rated conditions, and the output power of the generator is recorded for different combinations of advance angles α and δ. A radial basis function neural network is used to establish a model relating the advance angles α and δ to the output power of the doubly salient pole generator system. This model is used to determine the conduction angles α and δ corresponding to maximum power, and the conduction angles α and δ are used to control the doubly salient pole generator according to the operating conditions. This invention can improve the output voltage and power of the doubly salient pole generator system.

Description

Technical Field

[0001] The present invention relates to the field of electrical control technology, and in particular to a three-phase six-beat control method for an electrically excited double-salient-pole power generation system. Background Art

[0002] Electromagnetic doubly salient generators (EDGBs) lack permanent magnets and rotor windings, offering advantages such as simple structure, high reliability, low cost, and ease of fault demagnetization. They are particularly suitable for applications such as aviation power generation systems, which have high requirements for speed, reliability, and environmental adaptability. Traditional EGBs typically use uncontrolled rectifiers to achieve energy conversion. The armature winding current is rectified by an uncontrolled rectifier bridge, resulting in a DC output.

[0003] Because the back EMF of an electrically excited doubly salient generator is neither a sine wave nor a square wave, the space vector pulse width modulation (SVPWM) method widely used in permanent magnet motors is not applicable. Traditional uncontrolled rectification methods offer poor rectification results. Controlled rectification of an electrically excited doubly salient generator is an important technical means of improving the output voltage and power of an electrically excited doubly salient generator system. Among existing control methods, angle position control, a method based on electrical angles, is the most widely used. The key concept of this method is that within each electrical cycle of a simplified model of an electrically excited doubly salient generator, the phase self-inductance can be divided into three 120°-wide regions. These regions are divided into rising, falling, and constant value regions based on the changing trends of the motor's three-phase inductance. In angle position control, β is defined as the turn-off angle. At the start of the rising phase of the inductance of a phase in an electrically excited doubly salient generator, the upper arm connected to that phase's winding conducts and then shuts off after β. At the start of the falling phase of the inductance, the lower arm connected to that phase's winding conducts and then shuts off after β. When the inductance is in the constant range, neither the upper nor lower arms conduct. Because the timing of the upper and lower arms turning on always coincides with the start of the rising and falling phases, this method is called standard angle position control.

[0004] The advanced angle position control method, based on the standard angle position control method, simultaneously turns on the upper and lower bridge switches by an angle α, further improving the output voltage and output power of the electrically excited doubly salient generator. Both of the above controlled rectification methods employ three-phase, three-beat control strategies, as the switches can have three conduction states within a single electrical cycle.

[0005] However, when adopting the two three-phase three-beat control strategies of standard angle position control and advanced angle position control, the existence of dead time limits the improvement of the output performance of the electrically excited double-pole power generation system, which is not conducive to the stable operation of the power generation system. Summary of the Invention

[0006] In order to solve the above technical problems, the present invention proposes a three-phase six-beat control method for an electrically excited doubly salient pole power generation system, which can improve the output voltage and output power of the power generation system.

[0007] To achieve the above object, the technical solution of the present invention is as follows:

[0008] A three-phase six-beat control method for an electrically excited doubly salient generator system is disclosed. The electrically excited doubly salient generator is a three-phase generator. Within one electrical cycle, the switch tube has six conduction states, including:

[0009] S1: In the rising region of the phase winding inductance, the upper bridge arm switch connected to the winding is turned on in advance by α+δ degrees; in the falling region of the phase winding self-inductance, the lower bridge arm switch connected to the winding is turned on in advance by α degrees; in the constant value region of the phase winding, the upper and lower bridge arm switches connected to the winding are not turned on;

[0010] In step S1, the advance conduction angle α acts on both upper and lower bridge arm switches, while the advance conduction angle δ acts only on the upper bridge arm switch based on the advance conduction angle α;

[0011] S2. Under rated operating conditions, set an initial value of α and keep it unchanged, change the value of δ, and measure the output voltage and output power of the electrically excited doubly salient-pole generator system corresponding to different δ angles;

[0012] S3. Under rated operating conditions, select a new α value and repeat S2 to further obtain the output voltage and output power of the power generation system under different α and δ angle combinations;

[0013] S4. Using the output powers corresponding to different angles α and δ obtained in S3 above, an RBF algorithm is used to establish a model of the conduction angles α and δ and the output power of the electrically excited doubly salient-pole generator system;

[0014] S5. Based on the model obtained in S4 above, obtain the combination of advance conduction angles α and δ that maximizes the output power of the power generation system, and perform optimal power control of the electrically excited doubly salient pole power generation system.

[0015] As a further improvement of the present invention, in step S2, the conduction angle δ is taken in the range of 0° to 40°, and no less than 4 sampling points are evenly selected.

[0016] As a further improvement of the present invention, in step S3, the conduction angle α is taken in the range of 0° to 60°, and no less than 5 sampling points are uniformly selected.

[0017] As a further improvement of the present invention, in step S4, an RBF algorithm is used, which is characterized by:

[0018] S41, using the advance angles α and δ and the output power of the electrically excited doubly salient pole generator system as samples, and using the RBF algorithm for training, where the inputs of the training are the advance angles α and δ, and the output of the training is the output power of the electrically excited doubly salient pole generator system;

[0019] S42. After the training is completed, a model of the advance angle and output power of the electrically excited double-salient-pole generator system based on the RBF algorithm is obtained.

[0020] As a further improvement of the present invention, in step S5, the combination of the advance conduction angles α and δ when the generator output power is maximum is obtained using the RBF algorithm.

[0021] As a further improvement of the present invention, the electrically excited doubly salient pole power generation system includes an excitation voltage source, a generator control unit, an electrically excited doubly salient pole generator, a controlled rectifier, a DC side filter capacitor, a DC load, an excitation current sensor, a rotor position sensor, a DC side output current sensor, and a DC side output voltage sensor. The self-inductance of the phase winding of the electrically excited doubly salient pole generator is divided into three equal regions: a rising region, a falling region, and a constant value region. Based on the control strategy of turning on the upper bridge arm switch tube connected to the winding in the rising region of the self-inductance of the phase winding of the electrically excited doubly salient pole generator, turning on the lower bridge arm switch tube connected to the winding in the falling region of the self-inductance, and not turning on the switch tube in the constant value region, the conduction angles of the upper and lower switch tubes are advanced by an angle α, and the conduction angle of the upper switch tube is further advanced by an angle δ. Under the condition that the operating conditions remain unchanged, the output power of the generator under different combinations of conduction angles α and different conduction angles δ is recorded; a radial basis function neural network algorithm is used to establish a model of the conduction angles α, δ and power; and the above model is used to obtain the conduction angles α and δ corresponding to the maximum power.

[0022] The beneficial effects of the present invention are:

[0023] (1) The present invention utilizes the inherent controller and sensor of the electrically excited double-saliency controlled rectifier power generation system, without the need to add any devices, resulting in a simple and effective structure and resource conservation;

[0024] (2) Based on the three-phase three-beat advance angle control, the upper bridge arm switch tube is advanced by a conduction angle δ, thereby avoiding the phase change dead zone time and improving the output voltage and output power.

[0025] (3) The present invention uses an artificial neural network algorithm to achieve rapid modeling of the output power of the power generation system, and obtains the power distribution under a wide range of operating conditions with less experimental testing work, which greatly saves experimental workload, calculation amount and calculation time, and provides a reference for the optimization of other system parameters. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0027] Figure 1 It is a block diagram of the principle of a controlled rectifier circuit of an electrically excited double-salient-pole power generation system;

[0028] Figure 2 It is a schematic diagram of a three-phase six-beat control strategy for an electrically excited doubly salient generator system;

[0029] Figure 3 This is a modeling flow chart of the advance angle and output power model of the electrically excited double-salient-pole generator system based on the RBF algorithm;

[0030] Figure 4 The bus voltage comparison is under the two control methods of three-phase three-beat advance angle control (α = 30°) and three-phase six-beat (α = 30°, δ = 12°) when the generator speed is 5000r / min, the load is 24.3Ω, and the excitation current is 2A.

[0031] Figure 5 The bus current comparison is under three-phase three-beat advance angle control (α = 30°) and three-phase six-beat (α = 30°, δ = 12°) control methods when the generator speed is 5000 r / min, the load is 24.3Ω, and the excitation current is 2A.

[0032] Figure 6 The output power and average torque are compared under three-phase three-beat advance angle control (α=30°) and three-phase six-beat (α=30°, δ=12°) control methods when the generator speed is 5000r / min, the load is 24.3Ω, and the excitation current is 2A. DETAILED DESCRIPTION

[0033] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments:

[0034] Example 1:

[0035] The embodiment of the present invention provides a three-phase six-beat control strategy for an electrically excited doubly salient pole generator system. Figure 1As shown, it includes an excitation voltage source A1, a generator control unit (GCU) A2, an electrically excited doubly salient generator (DSEG) A3, a controlled rectifier A4, a DC side filter capacitor A5, a DC load A6, an excitation current sensor A7, a rotor position sensor A8, a DC side output current sensor A9, and a DC side output voltage sensor A10. Figure 1 Parameter i in f Represents the generator excitation current, I DC Represents the DC side output current of the generator, U DC Represents the DC side output voltage of the generator, C represents the capacitance of the filter capacitor, and R represents the DC side load resistance.

[0036] The controlled rectifier test platform for an electrically excited doubly salient generator in this embodiment includes an electrically excited doubly salient generator, a drive motor for dragging the test platform, a rectifier, a load, a controller, and an excitation power supply; the controller includes a three-phase six-beat control strategy for an electrically excited doubly salient generator system.

[0037] The three-phase six-beat control strategy of the electrically excited doubly salient generator of this embodiment includes the following steps:

[0038] S1. A three-phase, six-beat control strategy program is pre-programmed into the controller. The controller reads the rotor position via the rotor position sensor, thereby determining the current phase winding self-inductance region. In the rising region of the phase winding self-inductance, the upper-arm switch connected to that winding is turned on in advance by an angle of α+δ. In the falling region of the phase winding self-inductance, the lower-arm switch connected to that winding is turned on in advance by an angle of α. In the constant-value region of the phase winding, both upper and lower-arm switches connected to that winding are not conducting.

[0039] S2. Set the initial value of the conduction angle α to 0° and keep it unchanged. Experiment with the conduction angle δ from 0° to 40° at intervals of 10°, and record the output voltage and output power of the power generation system at different δ values;

[0040] S3, keeping the working condition unchanged, repeat S2 with α equal to 10°, 20°, 30°, 40°, 50°, and 60° respectively, to obtain the output voltage and output power values ​​of the power generation system under 7×5 different α and δ angle combinations, a total of 35 groups;

[0041] S4. Using the output powers corresponding to different angles α and δ obtained in S3 above, an RBF algorithm is used to establish a model of the conduction angles α and δ and the output power of the power generation system;

[0042] S5. Based on the model obtained in S4 above, obtain a combination of the advance conduction angles α and δ that maximizes the output power of the power generation system.

[0043] S6. Use the conduction angle obtained in S5 to conduct experiments and compare the effects of three-phase three-beat advance angle control and three-phase six-beat control on output voltage and output power.

[0044] Furthermore, the training method of the RBF algorithm includes:

[0045] S41, using the conduction angles α and δ as input parameters of the RBF algorithm, and using the output power as an output parameter of the RBF algorithm for training;

[0046] S42. After the RBF algorithm is trained, the conduction angles α and δ are input to obtain the output power obtained by regression of the RBF algorithm, that is, a model of conduction angle and output power of the electrically excited double-salient-pole power generation system based on the RBF algorithm is obtained.

[0047] Furthermore, in S6, in the three-phase three-beat advance angle control, the advance angles of the upper and lower switch tubes are set to α; in the three-phase six-beat control, the advance angle of the lower switch tube is α, and the advance angle of the upper switch tube is α+δ.

[0048] Test example:

[0049] Further test results based on the above embodiment are as follows:

[0050] The conduction angle and output power model of the electrically excited double-pole power generation system based on the RBF algorithm is used to obtain the conduction angle combination that optimizes the output power, i.e., α = 30°, δ = 12°, and this conduction angle combination is applied to the three-phase three-beat and three-phase six-beat strategies.

[0051] Figure 4 The following diagram compares the voltages of the three-phase, three-beat advance angle control strategy (α = 30°) and the three-phase, six-beat control strategy (α = 30°, δ = 12°) at a generator speed of 5000 r / min, a load of 24.3Ω, and an excitation current of 2A. It can be seen that when the bus voltage reaches steady state, the three-phase, three-beat control strategy has a bus voltage of 400 V, while the three-phase, six-beat control strategy has a bus voltage of 420 V.

[0052] Figure 5 This is a current comparison chart for a three-phase, three-step advance angle control strategy (α = 30°) and a three-phase, six-step control strategy (α = 30°, δ = 12°) at a generator speed of 5000 r / min, a load of 24.3Ω, and an excitation current of 2A. The results are similar to the voltage comparison chart.

[0053] Figure 6This chart compares the output power and average torque of a three-phase, three-step advance angle control strategy (α = 30°) and a three-phase, six-step control strategy (α = 30°, δ = 12°) at a generator speed of 5000 r / min, a load of 24.3Ω, and an excitation current of 2A. All parameters are expressed with the values ​​for the three-phase, three-state strategy as 100%. It can be seen that the three-phase, six-step control strategy increases the generator's output power and average torque compared to the three-phase, three-state control strategy.

[0054] The above description is merely a preferred embodiment of the present invention and does not constitute any other form of limitation to the present invention. Any modification or equivalent variation based on the technical essence of the present invention shall still fall within the scope of protection claimed by the present invention.

Claims

1. A three-phase six-beat control method for an electrically excited doubly salient power generation system, characterized in that: The electrically excited double-pole generator system includes an excitation voltage source, a generator control unit, an electrically excited double-pole generator, a controlled rectifier, a DC side filter capacitor, a DC load, an excitation current sensor, a rotor position sensor, a DC side output current sensor, and a DC side output voltage sensor. The self-inductance of the phase winding of the electrically excited double-pole generator is divided into three equal regions: a rising region, a falling region, and a constant region. In the rising region of the self-inductance of the phase winding of the electrically excited double-pole generator, the upper bridge arm switch connected to the winding is turned on, and in the falling region of the self-inductance, the lower bridge arm switch connected to the winding is turned on. Based on the control strategy of non-conducting the switch tube in the constant value region, the conduction angles of the upper and lower switch tubes are advanced by an angle α, and the conduction angle of the upper switch tube is also advanced by an angle δ. Under the condition that the operating conditions remain unchanged, the output power of the generator is recorded under different combinations of conduction angles α and δ. A radial basis function neural network algorithm is used to establish a model of conduction angles α, δ and power. The conduction angles α and δ corresponding to the maximum power are obtained using the above model. The electrically excited doubly salient-pole generator is a three-phase generator. Within one electrical cycle, the conduction states of the switch tubes are a total of six, including: S1: In the rising region of the phase winding inductance, the upper bridge arm switch connected to the winding is turned on in advance by α+δ degrees; in the falling region of the phase winding self-inductance, the lower bridge arm switch connected to the winding is turned on in advance by α degrees; in the constant value region of the phase winding, the upper and lower bridge arm switches connected to the winding are not turned on; In step S1, the advance conduction angle α acts on both upper and lower bridge arm switches, while the advance conduction angle δ acts only on the upper bridge arm switch based on the advance conduction angle α. S2. Under rated operating conditions, set an initial value of α and keep it unchanged, change the value of δ, and measure the output voltage and output power of the electrically excited doubly salient-pole generator system corresponding to different δ angles; S3. Under rated operating conditions, select a new α value and repeat S2 to further obtain the output voltage and output power of the power generation system under different α and δ angle combinations; S4. Using the output powers corresponding to different angles α and δ obtained in S3 above, an RBF algorithm is used to establish a model of the conduction angles α and δ and the output power of the electrically excited doubly salient-pole generator system; S5. Based on the model obtained in S4 above, obtain the combination of advance conduction angles α and δ that maximizes the output power of the power generation system, and perform optimal power control of the electrically excited doubly salient pole power generation system.

2. The three-phase six-beat control method of an electrically excited doubly salient power generation system according to claim 1, characterized in that: In step S2, the conduction angle δ is taken in the range of 0° to 40°, and no less than 4 sampling points are uniformly selected.

3. The three-phase six-beat control method for an electrically excited doubly salient power generation system according to claim 1, characterized in that: In step S3, the conduction angle α is taken in the range of 0° to 60°, and no less than 5 sampling points are uniformly selected.

4. The three-phase six-beat control method for an electrically excited doubly salient power generation system according to claim 1, characterized in that: In step S4, the RBF algorithm is used, which is characterized by: S41, using the advance angles α and δ and the output power of the electrically excited doubly salient pole generator system as samples, and using the RBF algorithm for training, where the inputs of the training are the advance angles α and δ, and the output of the training is the output power of the electrically excited doubly salient pole generator system; S42. After the training is completed, a model of the advance angle and output power of the electrically excited double-salient-pole generator system based on the RBF algorithm is obtained.

5. The three-phase six-beat control method of an electrically excited doubly salient power generation system according to claim 4, characterized in that: In step S5, the RBF algorithm is used to obtain a combination of the advance conduction angles α and δ when the generator output power is maximum.

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