A high-speed electrically-excited doubly salient motor drive system based on variable bus voltage converter
By introducing a variable bus voltage converter into the electrically excited doubly salient pole motor drive system, the problem of slow armature current rise was solved, and the motor speed range was widened and torque performance was improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
- Filing Date
- 2022-10-08
- Publication Date
- 2026-05-19
AI Technical Summary
In traditional electrically excited doubly salient pole motor drive systems, the armature current rises slowly and torque loss is significant when running at high speeds, which limits the motor speed.
By introducing a variable bus voltage converter at the front end of the three-phase full-bridge inverter, the capacitor voltage is adjusted by controlling the metal-oxide-semiconductor field-effect transistor, thereby increasing the armature current rise rate and widening the motor speed range.
It accelerates the armature current rise rate, widens the speed range of the electrically excited doubly salient pole motor, and improves the torque performance of the electrically excited doubly salient pole motor.
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Figure CN115514284B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of variable reluctance motor drive control technology, and in particular to a high-speed electrically excited doubly salient pole motor drive system based on a variable bus voltage converter. Background Technology
[0002] With the development of more-electric aircraft technology, integrated starter-generator technology has become an important direction for aviation electrical development. The more-electric engine is the core of this technology, and the high-speed starter-generator is a key technological support for it. The electrically excited doubly salient pole motor, as a type of reluctance motor, has a rotor structure similar to that of a switched reluctance motor. It inherits the advantages of simple structure and high reliability of switched reluctance motors, and is suitable for operation under harsh conditions such as high speed. Therefore, it has significant research value in the starting and generating systems of more-electric aircraft.
[0003] Traditional electrically excited doubly salient pole (ESP) motor drive systems use a constant DC power supply voltage and control the armature current through a power converter in a three-phase full-bridge converter. When the ESP motor operates at low speed, the armature current rises rapidly due to the low speed and back EMF, resulting in minimal torque loss in the rising region. However, under constant DC power supply voltage, as the motor speed gradually increases, the back EMF gradually approaches the DC power supply voltage, the armature current rises slowly, and the torque loss becomes greater, thus limiting the motor speed. Summary of the Invention
[0004] The embodiments of the present invention provide a high-speed electrically excited doubly salient pole motor drive system based on a variable bus voltage converter, which can improve the torque performance of the electrically excited doubly salient pole motor.
[0005] To achieve the above objectives, the embodiments of the present invention adopt the following technical solutions:
[0006] The system comprises: a DC power supply, a variable bus voltage converter, a three-phase full-bridge inverter, and an electrically excited doubly salient pole motor; the positive and negative input terminals of the variable bus voltage converter are both connected to the DC power supply; the output terminal of the variable bus voltage converter is connected to the positive and negative input terminals of the three-phase full-bridge inverter; the variable bus voltage converter includes: a diode connected to the positive input terminal of the variable bus voltage converter, and a capacitor installed at the output terminal of the variable bus voltage converter; the three-phase full-bridge inverter is connected to the electrically excited doubly salient pole motor.
[0007] In the electrically excited doubly salient pole motor, both the excitation winding F and the armature winding are placed in the stator slots, and the rotor has no winding. The armature winding includes the armature windings of phases A, B and C of the electrically excited doubly salient pole motor.
[0008] The three-phase full-bridge inverter includes six metal-oxide-semiconductor field-effect transistors (MOSFETs) Q1, Q2, Q3, Q4, Q5, and Q6, and six diodes D1, D2, D3, D4, D5, and D6. The source of MOSFET Q1 is connected to the anode of diode D1, and the drain of MOSFET Q1 is connected to the cathode of diode D1. The source of MOSFET Q2 is connected to the anode of diode D2, and the drain of MOSFET Q2 is connected to the cathode of diode D2. The source of transistor Q3 is connected to the anode of diode D3; the drain of field-effect transistor Q3 is connected to the cathode of diode D3; the source of field-effect transistor Q4 is connected to the anode of diode D4; the drain of field-effect transistor Q4 is connected to the cathode of diode D4; the source of field-effect transistor Q5 is connected to the anode of diode D5; the drain of field-effect transistor Q5 is connected to the cathode of diode D5; the source of field-effect transistor Q6 is connected to the anode of diode D6; and the drain of field-effect transistor Q6 is connected to... The cathode of diode D6 is connected; the source of field-effect transistor Q1 is connected to the drain of field-effect transistor Q4; the source of field-effect transistor Q3 is connected to the drain of field-effect transistor Q6; and the source of field-effect transistor Q5 is connected to the drain of field-effect transistor Q2. The sources of field-effect transistors Q1, Q3, and Q5 respectively constitute the output of the three-phase full-bridge inverter. The drains of field-effect transistors Q1 and Q3 are respectively connected to the drain of field-effect transistor Q5. The drains of the three-phase full-bridge inverter are connected to form the positive input terminal of the three-phase full-bridge inverter; the sources of field-effect transistors Q4 and Q6 are connected to the sources of field-effect transistors Q2, respectively, to form the negative input terminal of the three-phase full-bridge inverter; the positive input terminal and the negative input terminal of the three-phase full-bridge inverter are connected to the output terminal of the variable bus voltage converter; the output terminal of the three-phase full-bridge inverter is connected to phases A, B, and C of the armature winding of the electrically excited doubly salient pole motor.
[0009] Specifically, the variable bus voltage converter is a controllable variable bus voltage converter, including: inductor L1, large capacitor C1, metal-oxide-semiconductor field-effect transistor Q7, and diode D7; inductor L1 constitutes the positive input terminal of the controllable variable bus voltage converter, and large capacitor C1 constitutes the output terminal of the controllable variable bus voltage converter, and the voltage U of the large capacitor is... C1 Equal to bus voltage U dc Specifically, the voltage U of the large capacitor is adjusted by controlling the on / off state of the metal-oxide-semiconductor field-effect transistor Q7. C1 When the three-phase full-bridge inverter is in the turn-off commutation width angle (0°, α), it charges the large capacitor C1 by feeding back energy from the armature current of the electrically excited doubly salient pole motor, and increases the large capacitor voltage U by controlling the metal-oxide-semiconductor field-effect transistor Q7. C1When the MOSFET Q7 is turned on, the DC power supply charges the inductor L1; when the MOSFET Q7 is turned off, the DC power supply and the inductor L1 together charge the large capacitor C1, causing the capacitor voltage U to... C1 It is greater than the DC power supply voltage U1.
[0010] Optionally, the bus voltage converter is an uncontrolled bus voltage converter, including: a small capacitor C2 and a diode D8, wherein the diode D8 constitutes the positive input terminal of the uncontrolled bus voltage converter, the small capacitor C2 constitutes the output terminal of the uncontrolled bus voltage converter, and the voltage U of the small capacitor is... C2 Equal to bus voltage U dc During the commutation width angle (0°, α) phase of the three-phase full-bridge inverter, the DC power supply charges the small capacitor C2 through diode D8. Simultaneously, the B-phase and C-phase windings of the electrically excited doubly salient pole motor also charge the small capacitor C2 during the commutation phase, so that the capacitor voltage U of the small capacitor C2 can be increased. C2 It is greater than the DC power supply voltage U1.
[0011] This invention provides a high-speed electrically excited doubly salient pole motor drive system based on a variable bus voltage converter. The invention introduces a variable bus voltage converter at the front end of a three-phase full-bridge inverter, proposing a high-speed electrically excited doubly salient pole motor drive system based on this converter. Specifically, there are two types of variable bus voltage converters: a controllable type with a large capacitor whose voltage is controlled by a metal-oxide-semiconductor field-effect transistor (MOSFET); and an uncontrollable type with a small capacitor. Both types of variable bus voltage converters can accelerate the armature current rise rate, widen the motor's speed range, and improve the motor's torque performance. Compared with existing technologies, this invention charges the capacitors, ensuring that the capacitor voltages in the variable bus voltage converter are all greater than the DC power supply voltage, thereby accelerating the armature current rise rate, widening the speed range of the electrically excited doubly salient pole motor, and improving its torque performance. Attached Figure Description
[0012] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0013] Figure 1 This is a schematic diagram of an electrically excited doubly salient pole motor.
[0014] Figure 2A schematic diagram of the standard angle control strategy and three-phase current waveforms for an electrically excited doubly salient pole motor;
[0015] Figure 3 A schematic diagram of a three-phase full-bridge inverter drive system based on a variable bus voltage converter;
[0016] Figure 4 This is a topology diagram of a controllable variable bus voltage converter;
[0017] Figure 5 This is a topology diagram of an uncontrollable variable bus voltage converter;
[0018] Figure 6 This is a schematic diagram of the conduction mode of a three-phase full-bridge inverter based on a controllable variable bus voltage converter when the turn-off commutation width angle is (0°, α).
[0019] Figure 7 This is a schematic diagram of the conduction mode of a three-phase full-bridge inverter based on a controllable variable bus voltage converter when the turn-on width angle is (α,β).
[0020] Figure 8 This is a schematic diagram of the conduction mode of a three-phase full-bridge inverter based on an uncontrollable variable bus voltage converter when the turn-off commutation width angle is (0°, α).
[0021] Figure 9 This is a schematic diagram of the conduction mode of a three-phase full-bridge inverter based on an uncontrollable variable bus voltage converter when the turn-off commutation width angle is (α,β). Detailed Implementation
[0022] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Embodiments of the present invention will be described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. Those skilled in the art will understand that, unless specifically stated otherwise, the singular forms “a,” “an,” “the,” and “the” used herein may also include the plural forms. It should be further understood that the term “comprising” as used in the specification of the present invention means the presence of the stated features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. It should be understood that when we say an element is “connected” or “coupled” to another element, it can be directly connected or coupled to the other element, or there may be intermediate elements. Furthermore, “connected” or “coupled” as used herein can include wireless connections or couplings. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items. It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the meaning consistent with their meaning in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless defined as herein.
[0023] The design concept of this embodiment is as follows: a bus voltage converter is introduced at the front end of the three-phase full-bridge inverter. Specifically, there are two types of bus voltage converters: one is a controllable bus voltage converter, which has a large capacitor value, and the voltage U of the large capacitor is controlled by controlling the MOSFET Q7. C1 Another type is the uncontrolled variable bus voltage converter, which uses smaller capacitors. Both types of variable bus voltage converters can accelerate the armature current rise rate during commutation, improve the motor's torque output performance, and broaden the motor's speed range.
[0024] Specifically, embodiments of the present invention provide a high-speed electrically excited doubly salient pole motor drive system based on a variable bus voltage converter, such as... Figure 3 As shown, the system consists of: a DC power supply, a variable bus voltage converter, a three-phase full-bridge inverter, and an electrically excited doubly salient pole motor.
[0025] The positive and negative input terminals of the variable bus voltage converter are both connected to the DC power supply; the output terminal of the variable bus voltage converter is connected to the positive and negative input terminals of the three-phase full-bridge inverter; the variable bus voltage converter includes: a diode connected to the positive input terminal of the variable bus voltage converter, and a capacitor installed at the output terminal of the variable bus voltage converter; the three-phase full-bridge inverter is connected to the electrically excited doubly salient pole motor.
[0026] The electrically excited doubly salient pole motor in this embodiment is specifically an electrically excited doubly salient pole motor, the structure of which is as follows: Figure 1 As shown, A, B, and C represent phases A, B, and C of the armature winding of an electrically excited doubly salient pole motor, respectively, and F represents the field winding. Both the field winding and armature winding are located in the stator slots, and the rotor has no winding. A+, B+, and C+ represent the current input terminals of the armature windings of phases A, B, and C of the electrically excited doubly salient pole motor, respectively. A-, B-, and C- represent the current output terminals of the armature windings of phases A, B, and C of the electrically excited doubly salient pole motor, respectively. F+ represents the current input terminal of the field winding of the electrically excited doubly salient pole motor, and F- represents the current output terminal of the field winding of the electrically excited doubly salient pole motor. The winding configuration of the phase A armature winding and the field winding F is shown in the figure. Figure 1 The excitation regulator shown in the figure mainly controls the excitation current of the electrically excited doubly salient pole motor, thereby regulating the excitation magnetic field of the electrically excited doubly salient pole motor.
[0027] Figure 2This describes the standard angle control strategy and three-phase current waveforms for an electrically excited doubly salient pole motor. The 0°, 120°, and 240° positions represent the alignment of the stator and rotor poles for phases A, B, and C, respectively, at which the armature winding inductance reaches its maximum value. Furthermore, these three positions divide the armature winding inductance curve into three regions: the inductance rising region, the inductance falling region, and the inductance constant region. The 0° position is the point where the phase current of the A-phase armature winding is turned on, the phase current of the B-phase armature winding is turned off, and the phase current of the C-phase armature winding is reversed. The situations at the 120° and 240° positions are similar. In the standard angle control method, the turning on, reversing, and turning off of the phase current all occur at the stator-rotor pole alignment points, i.e., at the 0°, 120°, and 240° positions. However, since the armature winding of an electrically excited doubly salient pole motor is inductive, the three-phase armature current cannot change abruptly during commutation at the 0°, 120°, and 240° positions. Taking the 0° position as an example, before the 0° position, phases B and C are in a conducting state, and transistors Q5 and Q6 are turned on. At the 0° position, transistors Q5 and Q6 are turned off, and transistors Q1 and Q2 are turned on. Since the 0° position is the point where the phase current of phase A armature winding is turned on, the point where the phase current of phase B armature winding is turned off, and the point where the phase current of phase C armature winding is reversed, and since the three-phase armature current cannot change abruptly, there are three intervals in (0°, 120°): (0°, α), (α, β), and (β, 120°). (0°, α) represents the turn-off commutation width angle. During this stage, the current in phase A is zero, the current in phase B gradually becomes zero, and the current in phase C gradually rises to zero. (α, β) represents the turn-on width angle. During this stage, the current in phase A gradually rises to the positive stable value I. pm The current in phase B is zero, and the current in phase C gradually decreases to the reverse stable value -I. pm (β, 120°) is the stable width angle; during this stage, the current in phase A is the positive stable value I. pm Phase B current is zero, and phase C current is the reverse stable value -I. pm .
[0028] Figure 3This is a three-phase full-bridge inverter drive system based on a variable bus voltage converter. The three-phase full-bridge inverter structure includes six metal-oxide-semiconductor field-effect transistors (MOSFETs) Q1, Q2, Q3, Q4, Q5, and Q6, and six diodes D1, D2, D3, D4, D5, and D6. The source of MOSFET Q1 is connected to the anode of diode D1, and the drain of MOSFET Q1 is connected to the cathode of diode D1. The source of MOSFET Q2 is connected to the anode of diode D2, and the drain of MOSFET Q2 is connected to the cathode of diode D2. The source of MOSFET Q3 is connected to the anode of diode D3, and the drain of MOSFET Q3 is connected to the cathode of diode D3. The source of MOSFET Q4 is connected to the anode of diode D4, and the drain of MOSFET Q4 is connected to the cathode of diode D4. The source of MOSFET Q5 is connected to the anode of diode D6. The anode of transistor Q5 is connected, the drain of transistor Q5 is connected to the cathode of diode D5, the source of transistor Q6 is connected to the anode of diode D6, the drain of transistor Q6 is connected to the cathode of diode D6, the source of transistor Q1 is connected to the drain of transistor Q4, the source of transistor Q3 is connected to the drain of transistor Q6, and the source of transistor Q5 is connected to the drain of transistor Q2. The sources of transistors Q1, Q3, and Q5 respectively constitute the output of the three-phase full-bridge inverter. The drains of field-effect transistors Q1, Q3, and Q5 are connected to form the positive input terminal of the three-phase full-bridge inverter. The sources of field-effect transistors Q4 and Q6 are connected to form the negative input terminal of the three-phase full-bridge inverter. The positive and negative input terminals of the three-phase full-bridge inverter are connected to the output terminal of the bus voltage converter. The output terminal of the three-phase full-bridge inverter is connected to phases A, B, and C of the armature winding of the electrically excited doubly salient pole motor.
[0029] Traditional electrically excited doubly salient pole motor drive systems connect a DC power supply directly to a three-phase full-bridge inverter. The three-phase full-bridge inverter is connected to the A-phase armature winding phase W of the electrically excited doubly salient pole motor. a B-phase armature winding W b C-phase armature winding W c Connected. This invention introduces a variable bus voltage converter at the front end of a three-phase full-bridge inverter, and proposes a high-speed electrically excited doubly salient pole motor drive system based on the variable bus voltage converter. The drive system proposed in this invention increases the bus voltage U by charging the capacitor. dc This allows for an increase in armature current rise rate, widens the motor's speed range, and improves the torque performance of the electrically excited doubly salient pole motor.
[0030] In this embodiment, as Figure 4As shown, the variable bus voltage converter is a controllable variable bus voltage converter, including: inductor L1, large capacitor C1, metal-oxide-semiconductor field-effect transistor Q7 and diode D7; inductor L1 constitutes the positive input terminal of the controllable variable bus voltage converter, large capacitor C1 constitutes the output terminal of the controllable variable bus voltage converter, and the voltage U of the large capacitor is... C1 Equal to bus voltage U dc Specifically, the voltage U of the large capacitor is adjusted by controlling the on / off state of the metal-oxide-semiconductor field-effect transistor Q7. C1 In this embodiment, a large capacitor refers to one that can limit the bus voltage so that the bus voltage will not increase as the bus current increases; a small capacitor refers to one that cannot limit the bus voltage so that the bus voltage will increase as the bus current increases.
[0031] When the electrical angle of the electrically excited doubly salient pole motor is the turn-off commutation width angle (0°, α), the three-phase full-bridge inverter uses the armature current feedback energy of the electrically excited doubly salient pole motor to charge the large capacitor C1, and increases the voltage U of the large capacitor by controlling the metal-oxide-semiconductor field-effect transistor Q7. C1 Here, the turn-off commutation width angle refers to the electrical angle of the electrically excited doubly salient pole motor; when the metal-oxide-semiconductor field-effect transistor Q7 is turned on, the DC power supply charges the inductor L1; when the metal-oxide-semiconductor field-effect transistor Q7 is turned off, the DC power supply and the inductor L1 together charge the large capacitor C1, causing the capacitor voltage U of the large capacitor to increase. C1 It is greater than the DC power supply voltage U1.
[0032] Specifically, such as Figure 6 As shown, the conduction modes of a three-phase full-bridge inverter based on a controllable variable bus voltage converter when the turn-off commutation width angle is (0°, α) are specifically divided into two conduction modes: Q7 on and Q7 off. Figure 6 (a) is the conduction mode when Q7 is turned on, and the DC power supply charges the inductor L1; when the turn-off commutation width angle is (0°, α), the armature current feeds back energy to charge. Figure 6 (b) is the conduction mode when Q7 is off. The DC power supply and inductor L1 together charge the large capacitor C1, and the armature current feedback energy also charges the large capacitor C1, causing the capacitor voltage U to... C1 Greater than the DC power supply voltage U1. α represents the electrical angle at which the A-phase current crosses zero from negative to positive, and β represents the positive steady-state value I of the A-phase current. pm The electrical angle at that time.
[0033] Furthermore, in a traditional electrically excited doubly salient pole motor drive system, which uses a DC power supply and a three-phase full-bridge inverter, the capacitor voltage U... C1 It is equal to the DC power supply voltage U1, while the capacitor voltage U of the three-phase full-bridge inverter based on the controllable variable bus voltage converter is equal to the capacitor voltage U1 during the turn-on width angle (α,β).C1 The voltage is greater than the DC power supply voltage U1. According to formula (2), this increases the current rise rate and the output torque. Specifically, when the electrical angle of the electrically excited doubly salient pole motor is the turn-on width angle (α, β), the large capacitor C1 supplies power to the A-phase armature winding and the C-phase armature winding of the electrically excited doubly salient pole motor. Its circuit mode equation is:
[0034]
[0035] The rate of change of the A-phase and C-phase currents of the electrically excited doubly salient pole motor is:
[0036]
[0037] Among them, E a L represents the back electromotive force of the armature winding of phase A. a E represents the self-inductance of the armature winding in phase A. c L represents the back electromotive force of the C-phase armature winding. c Indicates the self-inductance of the C-phase armature winding, i a Indicates the current of phase A, i c This represents the C-phase current. Specifically, during the turn-off commutation width angle (0°, α) phase, the capacitor voltage U of the large capacitor C1... C1 The voltage is greater than the DC power supply voltage U1, so regardless of whether the MOSFET Q7 is turned on or off, D7 is always off. For example: Figure 7 This refers to the conduction modes of a three-phase full-bridge inverter based on a controllable variable bus voltage converter when the turn-on width angle is (α, β), specifically divided into two conduction modes: Q7 turn-on and Q7 turn-off. However, according to... Figure 6 Analysis shows that, due to the capacitor voltage U C1 Since the voltage is greater than the DC power supply voltage U1, D7 is always off regardless of whether Q7 is on or off.
[0038] In general, a traditional electrically excited doubly salient pole motor drive system connects the DC power supply directly to a three-phase full-bridge inverter, and the DC power supply voltage U1 is equal to the bus voltage U. dc During the turn-on width angle (α, β), a DC power supply is used to power the A-phase and C-phase armature windings of the electrically excited doubly salient pole motor. However, the drive system proposed in this invention uses a large capacitor C1 to power the A-phase and C-phase armature windings of the electrically excited doubly salient pole motor. Because the capacitor voltage U of the large capacitor C1... C1 Equal to bus voltage U dc And it is greater than the DC power supply voltage U1. Therefore, according to formula (2), the three-phase full-bridge inverter based on the controllable bus voltage converter can improve the current change rate of phase A and phase C, so that the current can quickly reach a stable value, thereby widening the speed range of the motor and improving the torque performance of the electrically excited double salient pole motor.
[0039] In this embodiment, in addition to using a controllable variable bus voltage converter, an uncontrollable variable bus voltage converter can also be used, such as... Figure 5 As shown, the uncontrollable bus voltage converter includes a small capacitor C2 and a diode D8. Diode D8 forms the positive input terminal of the bus voltage converter, and the small capacitor C2 forms the output terminal. The positive and negative input terminals of the bus voltage converter are connected to the positive and negative terminals of the DC power supply, respectively. The output terminal of the bus voltage converter is connected to the positive and negative input terminals of the three-phase full-bridge inverter.
[0040] In this embodiment, the bus voltage converter is an uncontrollable bus voltage converter, including a small capacitor C2 and a diode D8. Diode D8 forms the positive input terminal of the uncontrollable bus voltage converter, and the small capacitor C2 forms the output terminal. The voltage across the small capacitor is U. C2 Equal to bus voltage U dc .
[0041] When the three-phase full-bridge inverter is in the commutation width angle (0°, α) phase, the DC power supply charges the small capacitor C2 through diode D8. Simultaneously, the B-phase and C-phase windings of the electrically excited doubly salient pole motor also charge the small capacitor C2 during the commutation phase, so that the capacitor voltage U of the small capacitor C2 can be increased. C2 Greater than the DC power supply voltage U1. For example: Figure 8 This describes the conduction mode of a three-phase full-bridge inverter based on an uncontrollable variable bus voltage converter when the commutation width angle is (0°, α). During this stage, the DC power supply charges the small capacitor C2 through diode D8, and the B-phase and C-phase windings of the electrically excited doubly salient pole motor also charge the small capacitor C2 during the commutation phase. Because capacitor C2 is small, the capacitor voltage U will be affected during the charging phase. C2 It is greater than the DC power supply voltage U1.
[0042] When the three-phase full-bridge inverter is in the turn-on width angle (α, β) phase, the small capacitor C2 supplies power to the A-phase and C-phase armature windings of the electrically excited doubly salient pole motor. Its circuit mode equations are as follows:
[0043]
[0044] The rate of change of the A-phase and C-phase currents of the electrically excited doubly salient pole motor is:
[0045]
[0046] Among them, E a L represents the back electromotive force of the armature winding of phase A. a E represents the self-inductance of the armature winding in phase A.c L represents the back electromotive force of the C-phase armature winding. c This represents the self-inductance of the C-phase armature winding. Specifically, during the turn-off commutation width angle (0°, α), the capacitor voltage U of the small capacitor C2... C2 The voltage is greater than the DC power supply voltage U1, therefore diode D8 is in the off state. For example: Figure 9 This describes the conduction mode of a three-phase full-bridge inverter based on an uncontrollable variable bus voltage converter when the commutation width angle is (α, β). During this stage, due to the capacitor voltage U... C2 When the voltage is greater than the DC power supply voltage U1, diode D8 is in the off state, and small capacitor C2 supplies power to the armature winding of the electrically excited doubly salient pole motor.
[0047] Because the capacitor voltage U of the small capacitor C2 C2 Equal to bus voltage U dc And it is greater than the DC power supply voltage U1. Therefore, according to formula (4), the three-phase full-bridge inverter based on the uncontrollable variable bus voltage converter can also improve the current change rate of phase A and phase C, so that the current quickly reaches a stable value, thereby widening the speed range of the motor and improving the torque performance of the electrically excited doubly salient pole motor. In the stage of the turn-on width angle (α,β) of the three-phase full-bridge inverter based on the uncontrollable variable bus voltage converter, the capacitor voltage U C2 The voltage is greater than the DC power supply voltage U1. According to formula (4), the current rise rate is increased, and the output torque is increased.
[0048] This invention establishes a high-speed electrically excited doubly salient pole motor drive system based on a variable bus voltage converter. This drive system introduces a variable bus voltage converter at the front end of a traditional electrically excited doubly salient pole motor drive system, proposing a high-speed electrically excited doubly salient pole motor drive system based on a variable bus voltage converter. Specifically, the variable bus voltage converter is divided into two types: controllable and uncontrollable. The controllable variable bus voltage converter uses a large capacitor, while the uncontrollable variable bus voltage converter uses a small capacitor. This invention charges the capacitors, making the capacitor voltage in both types of variable bus voltage converters greater than the DC power supply voltage, thereby accelerating the armature current rise rate, widening the speed range of the electrically excited doubly salient pole motor, and improving the torque performance of the electrically excited doubly salient pole motor.
[0049] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on its differences from other embodiments. In particular, the device embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments. The above descriptions are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.
Claims
1. A high-speed electrically excited doubly salient pole motor drive system based on a variable bus voltage converter, characterized in that, The system consists of: a DC power supply, a variable bus voltage converter, a three-phase full-bridge inverter, and an electrically excited doubly salient pole motor; Both the positive and negative input terminals of the bus voltage converter are connected to the DC power supply. The output terminal of the variable bus voltage converter is connected to the positive and negative input terminals of the three-phase full-bridge inverter. The variable bus voltage converter includes: a diode connected to the positive input terminal of the variable bus voltage converter, and a capacitor installed at the output terminal of the variable bus voltage converter; The three-phase full-bridge inverter is connected to the electrically excited doubly salient pole motor. The variable bus voltage converter is a controllable variable bus voltage converter, which includes: inductor L1, large capacitor C1, MOSFET Q7 and diode D7. Inductor L1 forms the positive input terminal of the controllable bus voltage converter, and large capacitor C1 forms the output terminal of the controllable bus voltage converter, with the voltage U of the large capacitor being... C1 Equal to bus voltage U dc ; Specifically, the voltage U of the large capacitor is adjusted by controlling the MOSFET Q7 to turn it on or off. C1 ; Also includes: When the electrical angle of the electrically excited doubly salient pole motor is the turn-off commutation width angle (0°, α), the three-phase full-bridge inverter uses the armature current of the electrically excited doubly salient pole motor to feed energy back to the large capacitor C1, and increases the voltage U of the large capacitor by controlling the MOSFET Q7. C1 The three-phase armature current exists in three intervals within the range of (0°, 120°): (0°, α), (α, β), and (β, 120°). (0°, α) represents the turn-off commutation width angle, during which the A-phase current is zero, the B-phase current gradually decreases to zero, and the C-phase current gradually rises to zero. (α, β) represents the turn-on width angle, during which the A-phase current gradually rises to its positive stable value I. pm The current in phase B is zero, and the current in phase C gradually decreases to the reverse stable value -I. pm (β, 120°) is the stable width angle; during this stage, the current in phase A is the positive stable value I. pm Phase B current is zero, and phase C current is the reverse stable value -I. pm ; When MOSFET Q7 is turned on, the DC power supply charges inductor L1; when MOSFET Q7 is turned off, the DC power supply and inductor L1 together charge the large capacitor C1, causing the capacitor voltage U to... C1 It is greater than the DC power supply voltage U1.
2. The high-speed electrically excited doubly salient pole motor drive system based on a variable bus voltage converter according to claim 1, characterized in that, Also includes: The large capacitor C1 supplies power to the A-phase and C-phase armature windings of the electrically excited doubly salient pole motor. Its circuit mode equations are as follows: The rate of change of the A-phase and C-phase currents of the electrically excited doubly salient pole motor is: E a L represents the back electromotive force of the armature winding of phase A. a E represents the self-inductance of the armature winding in phase A. c L represents the back electromotive force of the C-phase armature winding. c Indicates the self-inductance of the C-phase armature winding, i a Indicates the current of phase A, i c This represents the C-phase current.
3. The high-speed electrically excited doubly salient pole motor drive system based on a variable bus voltage converter according to claim 1, characterized in that, In the electrically excited doubly salient pole motor, both the excitation winding F and the armature winding are placed in the stator slots, and the rotor has no winding. The armature winding includes the armature windings of phases A, B and C of the electrically excited doubly salient pole motor.
4. The high-speed electrically excited doubly salient pole motor drive system based on a variable bus voltage converter according to claim 1, characterized in that, The three-phase full-bridge inverter includes six MOSFETs: Q1, Q2, Q3, Q4, Q5, and Q6, and six diodes: D1, D2, D3, D4, D5, and D6. In this configuration, the source of field-effect transistor Q1 is connected to the anode of diode D1, and the drain of field-effect transistor Q1 is connected to the cathode of diode D1. The source of field-effect transistor Q2 is connected to the anode of diode D2, and the drain of field-effect transistor Q2 is connected to the cathode of diode D2. The source of field-effect transistor Q3 is connected to the anode of diode D3, and the drain of field-effect transistor Q3 is connected to the cathode of diode D3. The source of field-effect transistor Q4 is connected to the anode of diode D4, and the drain of field-effect transistor Q4 is connected to the cathode of diode D4. The source of field-effect transistor Q5 is connected to the cathode of diode D1. The anode of diode D5 is connected, the drain of field-effect transistor Q5 is connected to the cathode of diode D5, the source of field-effect transistor Q6 is connected to the anode of diode D6, the drain of field-effect transistor Q6 is connected to the cathode of diode D6, the source of field-effect transistor Q1 is connected to the drain of field-effect transistor Q4, the source of field-effect transistor Q3 is connected to the drain of field-effect transistor Q6, and the source of field-effect transistor Q5 is connected to the drain of field-effect transistor Q2. The sources of field-effect transistors Q1, Q3, and Q5 respectively constitute the output of the three-phase full-bridge inverter. The drains of field-effect transistors Q1 and Q3 are connected to the drain of field-effect transistor Q5, respectively, and form the positive input terminal of the three-phase full-bridge inverter. The sources of field-effect transistors Q4 and Q6 are connected to the source of field-effect transistor Q2, respectively, and form the negative input terminal of the three-phase full-bridge inverter. The positive input terminal and the negative input terminal of the three-phase full-bridge inverter are connected to the output terminal of the variable bus voltage converter, and the output terminal of the three-phase full-bridge inverter is connected to phases A, B and C of the armature winding of the electrically excited doubly salient pole motor.
5. A high-speed electrically excited doubly salient pole motor drive system based on a variable bus voltage converter, characterized in that, The system consists of: a DC power supply, a variable bus voltage converter, a three-phase full-bridge inverter, and an electrically excited doubly salient pole motor; Both the positive and negative input terminals of the bus voltage converter are connected to the DC power supply. The output terminal of the variable bus voltage converter is connected to the positive and negative input terminals of the three-phase full-bridge inverter. The variable bus voltage converter includes: a diode connected to the positive input terminal of the variable bus voltage converter, and a capacitor installed at the output terminal of the variable bus voltage converter; The three-phase full-bridge inverter is connected to the electrically excited doubly salient pole motor. The bus voltage converter is an uncontrolled type, comprising a small capacitor C2 and a diode D8. Diode D8 forms the positive input terminal of the uncontrolled bus voltage converter, and the small capacitor C2 forms the output terminal. The voltage across the small capacitor is U. C2 Equal to bus voltage U dc ; Also includes: When the three-phase full-bridge inverter is in the commutation width angle (0°, α) phase, the DC power supply charges the small capacitor C2 through diode D8. Simultaneously, the B-phase and C-phase windings of the electrically excited doubly salient pole motor also charge the small capacitor C2 during the commutation phase, so that the capacitor voltage U of the small capacitor C2 can be increased. C2 Greater than the DC power supply voltage U1; The three-phase armature current exists in three intervals within the range (0°, 120°): (0°, α), (α, β), and (β, 120°). (0°, α) represents the turn-off commutation width angle, during which the A-phase current is zero, the B-phase current gradually decreases to zero, and the C-phase current gradually rises to zero. (α, β) represents the turn-on width angle, during which the A-phase current gradually rises to its positive stable value I. pm The current in phase B is zero, and the current in phase C gradually decreases to the reverse stable value -I. pm (β, 120°) is the stable width angle; during this stage, the current in phase A is the positive stable value I. pm Phase B current is zero, and phase C current is the reverse stable value -I. pm .
6. The high-speed electrically excited doubly salient pole motor drive system based on a variable bus voltage converter according to claim 5, characterized in that, Also includes: The three-phase full-bridge inverter has an on-width angle During the initial stage, the small capacitor C2 supplies power to the A-phase and C-phase armature windings of the electrically excited doubly salient pole motor, and its circuit mode equations are as follows: The rate of change of the A-phase and C-phase currents of the electrically excited doubly salient pole motor is: E a L represents the back electromotive force of the armature winding of phase A. a E represents the self-inductance of the armature winding in phase A. c L represents the back electromotive force of the C-phase armature winding. c This indicates the self-inductance of the C-phase armature winding.
7. The high-speed electrically excited doubly salient pole motor drive system based on a variable bus voltage converter according to claim 5, characterized in that, In the electrically excited doubly salient pole motor, both the excitation winding F and the armature winding are placed in the stator slots, and the rotor has no winding. The armature winding includes the armature windings of phases A, B and C of the electrically excited doubly salient pole motor.
8. The high-speed electrically excited doubly salient pole motor drive system based on a variable bus voltage converter according to claim 5, characterized in that, The three-phase full-bridge inverter includes six MOSFETs: Q1, Q2, Q3, Q4, Q5, and Q6, and six diodes: D1, D2, D3, D4, D5, and D6. In this configuration, the source of field-effect transistor Q1 is connected to the anode of diode D1, and the drain of field-effect transistor Q1 is connected to the cathode of diode D1. The source of field-effect transistor Q2 is connected to the anode of diode D2, and the drain of field-effect transistor Q2 is connected to the cathode of diode D2. The source of field-effect transistor Q3 is connected to the anode of diode D3, and the drain of field-effect transistor Q3 is connected to the cathode of diode D3. The source of field-effect transistor Q4 is connected to the anode of diode D4, and the drain of field-effect transistor Q4 is connected to the cathode of diode D4. The source of field-effect transistor Q5 is connected to the cathode of diode D1. The anode of diode D5 is connected, the drain of field-effect transistor Q5 is connected to the cathode of diode D5, the source of field-effect transistor Q6 is connected to the anode of diode D6, the drain of field-effect transistor Q6 is connected to the cathode of diode D6, the source of field-effect transistor Q1 is connected to the drain of field-effect transistor Q4, the source of field-effect transistor Q3 is connected to the drain of field-effect transistor Q6, and the source of field-effect transistor Q5 is connected to the drain of field-effect transistor Q2. The sources of field-effect transistors Q1, Q3, and Q5 respectively constitute the output of the three-phase full-bridge inverter. The drains of field-effect transistors Q1 and Q3 are connected to the drain of field-effect transistor Q5, respectively, and form the positive input terminal of the three-phase full-bridge inverter. The sources of field-effect transistors Q4 and Q6 are connected to the source of field-effect transistor Q2, respectively, and form the negative input terminal of the three-phase full-bridge inverter. The positive input terminal and the negative input terminal of the three-phase full-bridge inverter are connected to the output terminal of the variable bus voltage converter, and the output terminal of the three-phase full-bridge inverter is connected to phases A, B and C of the armature winding of the electrically excited doubly salient pole motor.