CN113890433B - Electro-magnetic doubly salient motor capable of ensuring fault-tolerant power generation power by improving bus voltage - Google Patents

Abstract

The invention discloses an electric excitation doubly salient motor capable of ensuring fault-tolerant power generation by increasing the busbar voltage, and relates to the field of electric excitation doubly salient motors. After the excitation fault occurs, switch to the fault power generation mode, and by increasing the bus voltage, the armature current can quickly reach the current reference value required for the loss-of-excitation fault fault-tolerant power generation operation, so that when the winding is excited, it can have a higher current value. bus voltage, so as to achieve rapid excitation, greatly improve the output power, improve the fault-tolerant power generation of the motor in the case of loss of field failure, and improve the reliability of the electric excitation doubly salient motor in various environments. It is suitable for use in aviation aerospace, automotive and other industries.

Description

Electric excitation doubly salient motor to ensure fault-tolerant power generation by increasing bus voltage

technical field

The invention relates to the field of electric excitation doubly salient motors, in particular to an electric excitation doubly salient motor which ensures fault-tolerant power generation by increasing the busbar voltage.

Background technique

Electric excitation double salient pole motor is a new type of brushless DC motor developed on the basis of switched reluctance motor. The stator is wound with armature windings and excitation windings, and there is no winding on the rotor. The structure is simple and reliable, and the control is flexible. The main difference between it and the switched reluctance motor is that the stator is embedded with an excitation winding. Due to the existence of the excitation magnetic field, the electric excitation doubly salient motor only needs to be connected to an uncontrolled rectifier bridge to generate electricity due to the existence of the excitation magnetic field, so it has good fault tolerance and is suitable for use. At the same time, when the load or speed changes, the output voltage can be maintained constant by adjusting the size of the excitation current, the control is very flexible, and it has broad application prospects in aviation, wind power generation and other fields.

The existence of the field winding enhances the flexibility of the system control on the one hand, but also brings about safety and reliability issues. The aging, moisture, heat, and corrosion of the excitation winding may affect the safe operation of the system. In addition, the excitation power circuit used to control the excitation may also fail due to overcurrent, reverse voltage shock, etc., and in severe cases, the entire system will lose excitation. If the electric excitation doubly salient generator has a loss of field fault during operation, it will cause the entire system to stop running.

At present, there are few researches on the fault-tolerant control strategy for the loss-of-excitation fault of the electrically excited doubly salient motor. Existing technologies include: "Electrical excitation doubly salient motor excitation fault-tolerant power generation system and its control method" (China, authorization date: May 17, 2017, authorization number: CN104579067B) disclosed by Shi Liwei et al. Redundant bridge arms are added to form a three-phase four-bridge converter. By alternately passing positive and negative excitation currents to each phase of the three-phase four-bridge converter, the fault-tolerant power generation function of the motor excitation fault is realized. "A four-phase electric excitation double salient motor loss-of-excitation fault-tolerant power generation method" disclosed by Zhou Xingwei et al. (China, publication date: May 22, 2017, publication number: CN107147339A) by adding a redundant bridge arm to combine the four-phase A new control method is proposed because the self-inductance of the motor changes with the rotor position, so as to realize the fault-tolerant power generation due to the loss of magnetic field. At the same time, the "Electrically Excited Doubly Salient Motor Excitation Fault-tolerant Power Generation System and Its Control Method" published by Wen Tengxiang et al. (China, public date: June 5, 2018, public number: CN108123646A) also proposed the direct use of a three-phase full bridge The converter, by controlling the switching tube of the power converter, provides positive and negative alternating current for each phase to realize the function of power generation due to loss of field failure. This method does not need to add a new bridge arm, the main power circuit has a simple structure, low cost, and the power generation angle Small, low power generation efficiency. Zhao Feng et al. published "Electrically Excited Double Salient Pole Motor Loss of Field Fault Tolerant Power Generation System and Its Control Method" (China, Publication Date: 917, 2019, Publication No.: CN110247597A), which uses a half-bridge for control, resulting in low power generation efficiency. In addition, the "Electrical Excitation Doubly Salient Motor Loss of Field Fault Tolerant Power Generation System and Its Control Method" published by Wang Kaimiao et al. (China, publication date: March 8, 2019, publication number: CN109450340A) proposed the use of an H-bridge converter, This method separates the three-phase windings through 12 switching tubes, and each phase performs excitation and power generation independently, and the efficiency is relatively high.

Although the above-mentioned various loss-of-excitation fault-tolerant power generation control topologies can realize the fault-tolerant control of the loss-of-excitation fault, there is a problem that the generated power cannot reach the generated power before the fault tolerance after the fault tolerance.

SUMMARY OF THE INVENTION

In view of the above problems and technical requirements, the present inventor proposes an electric excitation doubly salient motor that ensures fault-tolerant power generation by increasing the busbar voltage, and further improves the fault-tolerant power generation. The technical scheme of the present invention is as follows:

An electric excitation doubly salient motor that ensures fault-tolerant power generation by increasing the busbar voltage, the electric excitation doubly salient motor includes a controller, a salient pole stator and rotor structure, an excitation circuit, a main power supply, three groups of H-bridge converters, a load R, load energy storage capacitor C1, power main switch S13 and boost capacitor C2;

The excitation circuit is connected to the excitation winding in the salient pole stator and rotor structure, and the middle points of the two bridge arms of each group of H-bridge converters are respectively connected to both ends of the one-phase armature winding in the salient pole stator and rotor structure;

The positive pole of the main power supply is connected to the collector of the upper switch tube of each bridge arm in the three groups of H-bridge converters through the diode D13, and the negative pole of the main power supply is connected to the emitter of the lower switch tube of each bridge arm in the three groups of H-bridge converters ;

The load is connected in parallel with the load energy storage capacitor and is connected to the first end of the power main switch S13, the second end of the power main switch S13 is connected to the collectors of the upper switch tubes of each bridge arm through the diode D14, and each bridge in the three groups of H-bridge converters The emitters of the upper switching tubes of the arms are respectively connected to the second end of the power main switch S13 through a diode, and the lower switching tubes of each bridge arm are respectively connected in reverse parallel with a diode;

The boost capacitor is connected in parallel with the collector of the upper switch tube of each bridge arm and the emitter of the lower switch tube of each bridge arm in the three groups of H-bridge converters;

The controller connects and controls the excitation circuit, the three groups of H-bridge converters and the on-off of the power main switch: when the electric excitation doubly salient motor is working normally, it controls the power main switch S13 to conduct, and the three-phase armature winding passes through the three groups of H The diodes in the bridge converter form an uncontrolled rectifier bridge to generate electricity; when the excitation fault of the electric excitation doubly salient motor is detected, the excitation circuit is disconnected, and the hysteresis control is used to control the on-off of the power main switch S13, so as to boost the voltage The voltage of the capacitor is greater than the load voltage of the load to boost the bus voltage for winding excitation.

The beneficial technical effects of the present invention are:

The present application discloses an electric excitation doubly salient motor that ensures fault-tolerant power generation by increasing the busbar voltage. The electric excitation doubly salient motor generates power in a traditional uncontrolled rectifier power generation method before the excitation fault occurs, and after the excitation fault occurs , switch to the fault power generation mode, by increasing the busbar voltage, the armature current can quickly reach the current reference value required for the demagnetization fault-tolerant power generation operation, so that the winding can have a higher busbar voltage during excitation, so as to achieve fast excitation, greatly It improves the output power of the motor, improves the fault-tolerant power generation of the motor when it runs in a loss of field fault, and improves the reliability of the electric excitation doubly salient motor in various environments. It is suitable for use in aerospace, automotive and other industries.

In addition, the electric excitation doubly salient motor adopts three sets of H-bridge converters, which helps to separate the windings of each phase, there is no problem of current gap that may be caused by the change of the midpoint potential, and the control strategy is more flexible. The motor power generation process does not need to be connected in series with the power-consuming phase, which reduces the loss and improves the efficiency of power generation. In addition to the loss-of-excitation fault fault tolerance function, there is also the possibility of maintaining fault-tolerant operation when the armature winding fails.

Description of drawings

FIG. 1 is a control structure diagram of the electric excitation doubly salient motor of the present application.

FIG. 2 is a schematic diagram of the control logic of the electric excitation doubly salient motor of the present application.

Detailed ways

The specific embodiments of the present invention will be further described below with reference to the accompanying drawings.

The present application discloses an electrically excited doubly salient motor that ensures fault-tolerant power generation by increasing the bus voltage. Please refer to FIG. 1. The electrically excited doubly salient motor includes a controller, a salient pole stator and rotor structure, an excitation circuit, and a main power supply E. , three groups of H-bridge converters, load R, load energy storage capacitor C1, power main switch S13 and boost capacitor C2. The power main switch S13 in this application is implemented by a switch tube.

The salient-pole stator-rotor structure includes a stator and a rotor, and three-phase armature windings and excitation windings L _f are installed on the stator. The excitation circuit is connected to the excitation winding L _f in the salient pole stator and rotor structure. Specifically, the excitation circuit includes an excitation power supply U _f and an H-bridge excitation converter. The excitation-side power supply U _f is connected to the DC side of the H-bridge excitation converter, and the H-bridge excitation The middle point of the two bridge arms of the converter is connected to the outgoing end of the excitation winding L _f .

The middle points of the two bridge arms of each group of H-bridge converters are respectively connected to both ends of the one-phase armature winding in the salient-pole stator-rotor structure. Specifically, the three-phase armature winding includes an A-phase winding La and _a B-phase winding L _b and C-phase winding L _c , the first H-bridge converter is connected to the A-phase winding L _a , the second H-bridge converter is connected to the B-phase winding L _b , and the third H-bridge converter is connected to the C-phase winding L _c .

The positive pole of the main power supply E is connected to the collectors of the upper switch tubes of each bridge arm in the three groups of H-bridge converters through the diode D13, and the negative pole of the main power supply E is connected to the lower switch tubes of each bridge arm in the three sets of H-bridge converters. emitter.

The load R is connected in parallel with the load energy storage capacitor C1 and is connected to the first end of the power main switch S13, and the second end of the power main switch S13 is connected to the collectors of the upper switch tubes of each bridge arm through the diode D14. The emitters of the upper switch tubes of each bridge arm of the three groups of H-bridge converters are respectively connected to the second end of the power main switch S13 through a diode, and the lower switch tubes of each bridge arm are respectively connected in parallel with a diode.

The boost capacitor C2 is connected in parallel with the collector of the upper switch tube of each bridge arm and the emitter of the lower switch tube of each bridge arm in the three groups of H-bridge converters.

The structures of the three groups of H-bridge converters are the same. Each H-bridge converter includes a first bridge arm and a second bridge arm respectively composed of an upper switch tube and a lower switch tube in reverse series connection, and an upper switch tube in the two bridge arms. The collector of the upper switch in the first bridge arm is connected to the second end of the power main switch S13 through a diode and an electronic switch, and the emitter of the upper switch in the second bridge arm is connected through a diode. The second end of the power main switch S13; the two ends of the lower switch tubes in the two bridge arms are respectively connected in reverse parallel with a diode. As shown in FIG. 1 , the first H-bridge converter includes an upper switch S1 and a lower switch S2 on the first bridge arm and an upper switch S3 and a lower switch S4 on the second bridge arm. The second H-bridge converts The converter includes an upper switch tube S5 and a lower switch tube S6 on the first bridge arm and an upper switch tube S7 and a lower switch tube S8 on the second bridge arm. The third H-bridge converter includes an upper switch tube on the first bridge arm S9 and the lower switch S10 and the upper switch S11 and the lower switch S12 on the second bridge arm. The diodes D2, D4, D6, D8, D10 and D12 are connected in parallel to the two ends of the lower switch tubes S2, S4, S6, S8, S10 and S12 respectively, and the anode of the diode is connected to the corresponding emitter and cathode of the lower switch tube. The collector of the lower switch tube. Upper switch S1 is connected to S13 through diode D1 and electronic switch K1, upper switch S5 is connected to S13 through diode D5 and electronic switch K2, and upper switch S9 is connected to S13 through diode D9 and electronic switch K3. The upper switch tubes S3, S7 and S11 are sequentially connected to S13 through diodes D3, D7 and D11, respectively.

The controller connects and controls the on-off of each switch tube in the excitation circuit, each switch tube in the three groups of H-bridge converters and the power main switch S13. In addition, the electric excitation double salient pole motor is also provided with various sensors connected to the controller to obtain various parameter values. Specifically, the position sensor is arranged in the salient pole stator and rotor structure to collect the rotor position signal θ , a current sensor is set at the excitation winding L _f to collect the excitation winding current i _f , the three-phase armature windings are respectively set with a current sensor to use the three-phase phase winding currents _ia , _ib , _ic , and a voltage sensor is set at the load R to The load voltage U ₀ is collected, and the positive electrode of the boost capacitor C2 is set with a voltage sensor to collect the voltage U _c2 of the boost capacitor.

Combined with the structure shown in Figure 1, the working process of the electric excitation doubly salient motor is introduced as follows:

When the electric excitation doubly salient motor is working normally: when the current sensor does not detect the excitation fault, the electric excitation doubly salient motor works in the generator state, the controller controls the main power switch S13 to conduct, and the three-phase armature winding passes through three groups of The diodes in the H-bridge converter form an uncontrolled rectifier bridge to generate electricity. Specifically, in FIG. 1 , the controller controls the main power switch S13 to be turned on continuously, controls all the upper and lower switches S1 to S12 in the three groups of H-bridge converters to be turned off, and controls the three groups of H-bridge converters in the The three electronic switches K1, K2 and K3 are all closed, and the three-phase armature windings form an uncontrolled rectifier bridge to generate electricity through the diodes D1-D12 in the three groups of H-bridge converters.

When the current sensor detects the excitation fault, the controller controls to disconnect the excitation circuit, switch to the fault-tolerant mode operation, and use hysteresis control to control the on-off of the main power switch S13, so that the voltage U _c2 of the boost capacitor is greater than the load voltage of the load U ₀ , preferably U _c2 >1.2U ₀ , so as to increase the busbar voltage for winding excitation, so that the winding excitation can have a higher busbar voltage, thereby realizing rapid excitation and increasing output power. Specifically, in Fig. 1, the controller controls the three electronic switches K1, K2 and K3 in the three groups of H-bridge converters to be turned off, uses hysteresis control to control the on-off of the main power switch S13, and uses the corresponding hysteresis The ring width, the application sets the hysteresis ring width to 0.5V. Then, the states of the corresponding upper switch tubes and/or lower switch tubes in the three groups of H-bridge converters are controlled according to the current electrical angle range of the motor. The specific control strategy is as follows, please refer to the control law shown in Figure 2:

When the electrical angle of the motor is in the range of [0, θ _off -120°), the upper switch S9 of the first bridge arm and the lower switch S12 of the second bridge arm in the third H-bridge converter are turned on, so that the C-phase winding is turned on. in the excitation phase;

When the electrical angle of the motor is in the interval of [θ _off -120°, θ _on ), all switches in the three H-bridge converters are controlled to be disconnected, so that the C-phase winding starts to generate electricity;

When the electrical angle of the motor is in the interval [θ _on , θ _off ), the upper switch S1 of the first bridge arm and the lower switch S4 of the second bridge arm in the first H-bridge converter are turned on, so that the A-phase winding is in excitation stage, the C-phase winding continues to be in the power generation stage;

When the electrical angle of the motor is in the interval of [θ _off , θ _on +120°), all switches in the three H-bridge converters are controlled to be disconnected, so that the A-phase winding starts to generate electricity;

When the electrical angle of the motor is in the interval [θ _on +120°, θ _off +120°), the upper switch S5 of the first bridge arm and the lower switch S8 of the second bridge arm in the second H-bridge converter are turned on, Make the B-phase winding in the excitation stage and the A-phase winding in the power generation stage;

When the electrical angle of the motor is in the interval of [θ _off +120°, θ _on +240°), all switches in the three H-bridge converters are controlled to be disconnected, so that the B-phase winding starts to generate electricity;

When the electrical angle of the motor is in the range of [θ _on +240°, 360°), the upper switch S9 of the first bridge arm and the lower switch S12 of the second bridge arm in the third H-bridge converter are turned on, so that the C-phase is turned on. The winding is in the excitation stage, and the B-phase winding continues to be in the power generation stage;

Among them, θ _on represents the armature winding excitation open angle, θ _off represents the armature winding excitation off angle, 0°<θ _on <120°, 120°<θ _off <240°.

In the process of controlling the state of the switching tubes of the three groups of H-bridge converters, the controller adjusts the error between the output voltage and the given voltage by PI to obtain the given current, and then compares the given current with the currently excited three-phase armature. The current of the winding is adjusted by PI to obtain the corresponding duty cycle. If the output voltage is lower than the given voltage, the controller will increase the duty cycle of the switching tubes of the three groups of H-bridge converters according to the obtained corresponding duty cycle; if If the output voltage is higher than the given voltage, the controller reduces the duty cycle of the switching tubes of the three groups of H-bridge converters according to the obtained corresponding duty cycle, so as to control the current of the three-phase armature winding by chopping. To achieve closed-loop control of the output voltage.

The above descriptions are only preferred embodiments of the present application, and the present invention is not limited to the above embodiments. It can be understood that other improvements and changes directly derived or thought of by those skilled in the art without departing from the spirit and concept of the present invention should be considered to be included within the protection scope of the present invention.

Claims (7)

1. An electric excitation doubly salient motor capable of ensuring fault-tolerant power generation power by improving bus voltage is characterized by comprising a controller, a salient pole stator and rotor structure, an excitation circuit, a main power supply, three groups of H-bridge converters, a load R, a load energy storage capacitor C1, a power main switch S13 and a boost capacitor C2;

The excitation circuit is connected with an excitation winding in the salient pole stator and rotor structure, and the middle points of two bridge arms of each group of H-bridge converters are respectively connected with two ends of one-phase armature winding in the salient pole stator and rotor structure;

the positive pole of the main power supply is connected with the collector of the upper switch tube of each bridge arm in the three groups of H-bridge converters through a diode D13, and the negative pole of the main power supply is connected with the emitter of the lower switch tube of each bridge arm in the three groups of H-bridge converters;

the load is connected with the load energy storage capacitor in parallel and connected with a first end of a power main switch S13, a second end of the power main switch S13 is connected with a collector electrode of an upper switch tube of each bridge arm through a diode D14, an emitter electrode of the upper switch tube of each bridge arm in the three groups of H-bridge converters is connected with a second end of the power main switch S13 through a diode respectively, and a lower switch tube of each bridge arm is connected with a diode in parallel in a reverse direction;

the boost capacitor C2 is connected in parallel at the collector of the upper switch tube of each bridge arm and at the two ends of the emitter of the lower switch tube of each bridge arm in the three groups of H-bridge converters;

the controller is connected with and controls the on-off of the excitation circuit, the three groups of H-bridge converters and the power main switch: when the electro-magnetic doubly salient motor works normally, the power main switch S13 is controlled to be conducted, and a three-phase armature winding forms an uncontrolled rectifier bridge through diodes in three groups of H-bridge converters to generate electricity; when detecting that the double-salient electro-magnetic motor has an excitation fault, disconnecting the excitation circuit, and controlling the on-off of a power main switch S13 by adopting hysteresis loop control, so that the voltage of the boost capacitor is greater than the load voltage of the load to boost the bus voltage for carrying out winding excitation.

2. The doubly salient electro-magnetic machine of claim 1, wherein three groups of H-bridge converters are identical in structure, each H-bridge converter comprises a first bridge arm and a second bridge arm which are respectively formed by connecting an upper switch tube and a lower switch tube in series in an opposite direction, collectors of the upper switch tubes in the two bridge arms are connected, an emitter of the upper switch tube in the first bridge arm is connected with the second end of the main power switch S13 through a diode and an electronic switch, and an emitter of the upper switch tube in the second bridge arm is connected with the second end of the main power switch S13 through a diode; two ends of a lower switching tube in the two bridge arms are respectively connected with a diode in parallel in a reverse direction;

when the doubly salient electro-magnetic motor works normally, the controller controls the power main switch S13 to be continuously conducted, controls all upper switch tubes and lower switch tubes in the three groups of H-bridge converters to be turned off, controls three electronic switches in the three groups of H-bridge converters to be turned on, and controls a three-phase armature winding to form an uncontrolled rectifier bridge through diodes in the three groups of H-bridge converters to generate electricity.

3. The doubly salient electro-magnetic machine of claim 2, wherein when an excitation fault occurs in the doubly salient electro-magnetic machine, the controller controls all three electronic switches in the three groups of H-bridge converters to be switched off, controls the power main switch S13 to be switched on and off by hysteresis control, and controls the states of corresponding upper switch tubes and/or lower switch tubes in the three groups of H-bridge converters according to the current electrical angle interval of the machine.

4. The electrically excited doubly salient machine of claim 3, wherein said three-phase armature windings comprise an A-phase winding, a B-phase winding and a C-phase winding, a first H-bridge converter connecting said A-phase winding, a second H-bridge converter connecting said B-phase winding, a third H-bridge converter connecting said C-phase winding;

controlling the states of corresponding upper switching tubes and/or lower switching tubes in the three groups of H-bridge converters according to the current electrical angle interval of the motor, wherein the states comprise:

when the electrical angle of the motor is at 0, theta_offIn the interval of-120 degrees, an upper switching tube S9 of a first bridge arm and a lower switching tube S12 of a second bridge arm in a third H-bridge converter are switched on, so that a C-phase winding is in an excitation phase;

when the electrical angle of the motor is positioned in [ theta ]_off-120°，θ_on) During interval, all switching tubes in the three H-bridge converters are controlled to be in an off state, so that the C-phase winding starts to generate electricity;

when the electrical angle of the motor is positioned in [ theta ]_on，θ_off) During interval, an upper switch tube S1 of a first bridge arm and a lower switch tube S4 of a second bridge arm in the first H-bridge converter are conducted, so that an A-phase winding is in an excitation stage, and a C-phase winding is continuously in a power generation stage;

when the electrical angle of the motor is positioned in [ theta ]_off，θ_onIn the interval of +120 degrees, all switching tubes in the three H-bridge converters are controlled to be in an off state, so that the A-phase winding starts to generate electricity;

When the electrical angle of the motor is positioned in [ theta ]_on+120°，θ_offIn the +120 DEG interval, the upper switch tube S5 of the first arm and the lower switch tube S8 of the second arm in the second H-bridge converter are conducted, so that the B-phase winding is positioned inIn the excitation stage, the A-phase winding is continuously in the power generation stage;

when the electrical angle of the motor is positioned in [ theta ]_off+120°，θ_onIn the interval of +240 degrees, all switching tubes in the three H-bridge converters are controlled to be in an off state, so that the B-phase winding starts to generate electricity;

when the electrical angle of the motor is positioned in [ theta ]_onIn the interval of +240 degrees and 360 degrees, an upper switching tube S9 of a first bridge arm and a lower switching tube S12 of a second bridge arm in a third H-bridge converter are conducted, so that a C-phase winding is in an excitation phase, and a B-phase winding is continuously in a power generation phase;

wherein, theta_onRepresenting the armature winding field-on angle, θ_offRepresents the excitation off-angle of the armature winding, 0 DEG < theta_on＜120°，120°＜θ_off＜240°。

5. The electrically excited doubly salient motor of claim 1, wherein the controller PI-regulates an error between an output voltage and a given voltage to obtain a given current in a process of controlling states of switching tubes of three groups of H-bridge converters, PI-regulates the given current and a current of a currently excited three-phase armature winding to obtain a corresponding duty ratio, and increases the duty ratio of the switching tubes of the three groups of H-bridge converters according to the obtained corresponding duty ratio if the output voltage is lower than the given voltage; if the output voltage is higher than the given voltage, the controller reduces the duty ratio of the switching tubes of the three groups of H-bridge converters according to the obtained corresponding duty ratio so as to carry out chopping control on the current of the three-phase armature winding and realize closed-loop control on the output voltage.

6. The electrically excited doubly salient machine of claim 1, wherein when hysteresis control is used to control the on/off of the power main switch S13, the hysteresis width is 0.5V.

7. The doubly salient electro-magnetic machine of claim 1, wherein the voltage U of said boost capacitor is taken_c2＞1.2U₀，U₀Is negative of said loadAnd carrying a voltage.

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