Multi-power brushless starter generator system

Abstract

The multi-power-supply brushless starter generator system comprises a multi-phase permanent magnet brushless motor, a rotor position sensor, a control circuit, a driving protection circuit, a plurality of drivers 1-N (N is greater than or equal to 2) and a plurality of current sensors. There is no common point between multiple phases of windings of the permanent magnet brushless motor, the parameters (the number of turns W and the wire diameter) of each phase of winding are not completely the same, and each phase of winding is connected with an independent driver. The control circuit obtains rotor position information of the multi-phase permanent magnet brushless motor through the rotor position sensor and controls on-off of power tubes of the multiple drivers. When the system works in a starting state, the current of each phase winding is controlled to meet W1 * I1 = W2 * I2 =...... = WN * IN, it can be guaranteed that the stator synthesis magnetomotive force amplitudes in each state are the same, and the motor rotor rotates under the rotating electromagnetic force. When the system works in a generator state, the back electromotive force amplitudes of the windings of all phases are not completely the same, and power output of multiple groups of different voltages is achieved. The starting system only needs one motor to realize various (power generation) power supply outputs, and the starting process of the motor is simple to control and low in cost.

Description

Technical Field

[0001] The invention relates to a brushless starter generator system, in particular to a multi-power brushless starter generator system. Background Art

[0002] Starter generators are widely used in systems such as automobiles, ships, drones, aircraft, and backup power supplies. They are usually required to have the characteristics of large torque, rapid starting, high power generation efficiency, small voltage fluctuation, and low operating noise. There are four common starter generator systems: DC brush motor, double-pole motor, permanent magnet brushless motor, auxiliary excitation motor, etc. Among them, DC brush motors have brush sparks, which leads to short system life, large electromagnetic interference, and limited application range; double-pole motors have simple structures and high temperature resistance, but the operating noise is large, suitable for use in extreme environments; auxiliary excitation motors can adjust excitation and have excellent output performance, but the system structure and control algorithm are relatively complex and costly, and are usually used in aircraft; permanent magnet brushless motors have simple structures, low operating noise, high operating efficiency, and long service life. They are the most widely used, but there is a disadvantage that the excitation cannot be adjusted. Although there is a patent that changes the excitation by changing the axial relative position of the stator and the rotor, this structure is very complex and the position accuracy is difficult to guarantee.

[0003] The motor body of the existing permanent magnet brushless starter generator usually adopts star-connected winding or delta-connected winding. There is a common point between the three-phase windings. When one phase winding or the half-bridge inverter connected to it fails, it will affect the normal operation of the other two phase windings, and the fault tolerance performance of the entire motor is poor. The existing three-phase permanent magnet brushless starter generator is powered by one power supply when working in the motor state, and has only one voltage output when working in the power generation state, which is difficult to meet the needs of multi-power application of external equipment; although other power conversion modules can be used to increase the multi-voltage output, it will make the system structure complicated, increase the cost, and reduce the efficiency.

[0004] As the functions of complete equipment become more and more abundant, more and more types of power supplies are required, especially the voltage levels of different power supplies increase, including low voltage, medium voltage, high voltage, etc. In some cases, the complete equipment also requires the frequencies of multiple power supplies to remain the same. It can be seen that traditional permanent magnet brushless starter generators are difficult to meet the application conditions of multiple power supplies. Summary of the invention

[0005] In order to solve the above problems, the present invention provides a multi-power brushless starter generator system, which is mainly used to solve the problem that the whole equipment requires a variety of power supply voltages for the starter generator.

[0006] The present invention is realized by the following technical scheme: a multi-power brushless starter generator system, comprising:

[0007] A multi-phase permanent magnet brushless motor has a stator with N phase windings, no common connection point between the phase windings, and different numbers of turns and wire diameters of the phase windings;

[0008] A rotor position sensor, used to detect the position information of the rotor;

[0009] A control circuit, connected to the rotor position sensor, for obtaining rotor position information and generating N groups of PWM control signals;

[0010] A driving protection circuit receives the PWM control signal and controls the on and off of the power tubes of multiple drivers;

[0011] Multiple drives, each drive is connected to a corresponding phase winding, and the bus voltage of each drive is different;

[0012] Multiple current sensors are used to detect the current of each phase winding.

[0013] As a preferred technical solution, the spatial arrangement of the N phase windings of the multi-phase permanent magnet brushless motor is a symmetrical structure.

[0014] As a preferred technical solution, each of the multiple drivers (1 to N) adopts a full-bridge structure, consisting of four power tubes (VN1 to VN4) and their anti-parallel freewheeling diodes (DN1 to DN4); each driver can also adopt a half-bridge structure, consisting of two power tubes (VN1, VN2) and their anti-parallel freewheeling diodes (DN1, DN2).

[0015] As a preferred technical solution, the bus voltages (U1, U2, ..., UN) of the multiple drivers (1 to N) and the number of turns of the corresponding phase windings (W1, W2, ..., WN) satisfy the following relationship: U1 / W1=U2 / W2=...=UN / WN.

[0016] As a preferred technical solution, when the system works in the motor state, the control circuit adjusts the current of each phase winding (I1, I2, ..., IN) to satisfy W1×I1=W2×I2=…=WN×IN to ensure that the amplitude of the stator synthetic magnetomotive force is the same, thereby generating a circular rotating magnetic field to drive the rotor to rotate.

[0017] As a preferred technical solution, when the system works in the generator state, the external power drives the rotor to rotate, and the back electromotive force amplitude generated by each phase winding is different. Multiple drivers (1 to N) are used as rectifier circuits, and different bus voltages (U1, U2, ..., UN) are output after rectification to achieve multiple groups of power supply outputs with different voltages.

[0018] The control circuit detects the operation signal of each phase winding and the fault signal of the system in real time, and generates N groups of PWM control signals according to the rotor position information and the operation state, and sends them to the drive protection circuit.

[0019] The rotor position sensor is coaxially mounted with the rotor of the multi-phase permanent magnet brushless motor to detect the angular position of the rotor in real time. The position sensor is not necessarily an actual sensor, and the rotor angular position information can also be obtained by converting and processing other signals.

[0020] The beneficial effects of the present invention are as follows: the present invention only requires one starter generator to achieve multiple (power generation) power outputs, eliminating the need for multiple generators or power conversion circuits; at the same time, the motor starting process is simple to control, the structure of the entire system is greatly simplified, the system efficiency is improved, and the cost is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. 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 creative work.

[0022] Figure 1 It is a structural diagram of the multi-power brushless starter generator system of the present invention;

[0023] Figure 2 The back electromotive force and current of the phase winding of the two-power brushless generator system of the present invention;

[0024] Figure 3 is the magnetomotive force vector of the two-power brushless generator system of the present invention;

[0025] Figure 4 The back electromotive force and current of the phase winding of the three-power brushless generator system of the present invention;

[0026] Figure 5 It is the magnetomotive force vector of the three-power brushless generator system of the present invention. DETAILED DESCRIPTION

[0027] All features disclosed in this specification, or steps in all methods or processes disclosed, except mutually exclusive features and / or steps, can be combined in any manner.

[0028] Any feature disclosed in this specification (including any additional claims, abstract and drawings), unless otherwise stated, may be replaced by other equivalent or alternative features with similar purposes. That is, unless otherwise stated, each feature is only an example of a series of equivalent or similar features.

[0029] like Figure 1 As shown, the multi-power brushless starter generator system of the present invention includes main modules such as a multi-phase permanent magnet brushless motor, a rotor position sensor, a control circuit, a drive protection circuit, multiple drivers, and multiple current sensors.

[0030] The multi-phase windings of the multi-phase permanent magnet brushless motor are arranged in a symmetrical structure, but the parameters (number of turns W and wire diameter) of each phase winding are not completely the same. The number of turns of the first, second, third ... Nth phase windings of the motor are W1, W2, W3 ... WN respectively, and the back electromotive force waveform of the phase winding can be a trapezoidal wave or a sine wave.

[0031] The multi-phase winding is connected to a separate driver, and the current I1, I2...IN of each phase winding can be controlled separately, and the driver can control the forward conduction, reverse conduction and shutdown of the motor phase winding. A filter capacitor is connected in parallel to the bus of each driver, and a current sensor and a half fuse are installed on the driver. The bus voltages of the multiple drivers 1 to N are not exactly the same, and the bus voltages of the first, second, third...Nth drivers are U1, U2, U3...UN respectively.

[0032] The number of turns of each phase winding of the multi-phase permanent magnet brushless motor and the corresponding power supply voltage of the H-bridge driver have the following relationship: U1 / W1=U2 / W2=U3 / W3=...=UN / WN.

[0033] The rotor position sensor is coaxially installed with the rotor of the multi-phase permanent magnet brushless motor to detect the angular position of the rotor in real time.

[0034] The control circuit is the computing center of the entire system. On the one hand, it collects the operating information of the motor system, and on the other hand, it sends out PWM control signals. The control circuit obtains the rotor position information of the multi-phase permanent magnet brushless motor through the rotor position sensor, and detects the operating signals of each phase winding and the fault signals of the entire system in real time, sends out PWM control signals to the drive protection circuit, and controls the power tubes of multiple drivers to be turned on and off.

[0035] The drive protection circuit realizes signal transmission between the weak current signal of the control circuit and the power circuit of the driver, and realizes hardware fault protection at the same time.

[0036] The rotor and stator structure of the multi-phase permanent magnet brushless motor are the same as those of the conventional permanent magnet brushless motor, but the multi-phase windings of the permanent magnet brushless motor stator proposed in this patent have no common points, and the back electromotive force waveform of each phase winding can be a trapezoidal wave or a sine wave. The spatial placement of the multi-phase winding is a symmetrical structure, and the parameters of each phase winding (number of turns W and wire diameter) are not exactly the same. The number of turns of the first, second, third...Nth phase windings of the motor are W1, W2, W3...WN respectively. On the one hand, the lack of common points between the multi-phase windings improves the fault tolerance of the motor windings, and on the other hand, the spatial symmetrical structure offsets the asymmetric torque that may be caused by different winding parameters.

[0037] The calculation formula of the phase winding back electromotive force of the permanent magnet brushless motor is:

[0038] e=C e Φ δ n

[0039] Where: Φ δ is the air gap flux; C e is the back EMF constant and n is the motor speed.

[0040] The multi-phase windings of the permanent magnet brushless motor are connected to separate drivers, and each driver can control the forward conduction, reverse conduction and shutdown of the phase winding. The multiple drivers 1~N can adopt a full-bridge structure composed of four power tubes VN1~VN4 and their anti-parallel freewheeling diodes DN1~DN4, or a half-bridge structure composed of two power tubes VN1~VN2 and their anti-parallel freewheeling diodes DN1~DN2. A filter capacitor is connected in parallel to the driver bus, and a current sensor and a half fuse are installed on the driver. The power supply voltages of the multiple drivers 1~N are not exactly the same, and the bus voltages of the first, second, third...Nth H-bridge drivers are U1, U2, U3...UN respectively.

[0041] The number of turns of each phase winding of the multi-phase permanent magnet brushless motor and the power supply voltage of the corresponding driver have the following relationship: U1 / W1=U2 / W2=U3 / W3=…=UN / WN.

[0042] The rotor position sensor is coaxially mounted with the rotor of the multi-phase permanent magnet brushless motor to detect the angular position of the rotor in real time. The rotor position sensor is not a necessary component and the angular position of the rotor can be calculated by a software algorithm.

[0043] The control circuit is the computing center of the entire system. On the one hand, it collects the operating information of the motor system, and on the other hand, it sends out PWM control signals. The control circuit obtains the rotor position information of the multi-phase permanent magnet brushless motor through the rotor position sensor, and detects the operating signals of each phase winding and the fault signals of the entire system in real time, sends out PWM control signals to the drive protection circuit, and controls the power tubes of multiple drivers to be turned on and off.

[0044] The drive protection circuit realizes signal transmission between the control circuit and each driver 1-N, and realizes hardware fault protection at the same time.

[0045] When the multi-power brushless starter generator system works in the motor state, each phase winding is turned on in a certain logical order according to the rotor position, and can be one-phase winding turned on, two-phase winding turned on (one phase winding is forwardly conductive and the other phase winding is reversely conductive), or three-phase winding turned on (one phase winding is forwardly conductive and the other two phase windings are reversely conductive, or one phase winding is reversely conductive and the other two phase windings are forward conductive).

[0046] The phase winding voltage balance equation can be expressed as:

[0047] U0=I x R x +ΔU+e x

[0048] Where: i x 、e x , R x , L x (x=a, b, c) are the winding phase current (A), back electromotive force (V), phase resistance (Ω), and phase inductance (H) of the permanent magnet brushless motor, U0 is the bus voltage (V), and ΔU is the saturated tube voltage drop of the power tube.

[0049] The power supply voltage applied to the driver of each phase winding is not exactly the same. Since the current I1, I2...IN of each phase winding can be controlled individually, it can ensure that the amplitude of the stator synthetic magnetomotive force in each state is the same, that is, W1*I1=W2*I2=...=WN*IN, so that the stator produces a circular rotating magnetic field of equal amplitude, allowing the motor rotor permanent magnet to rotate due to the rotating electromagnetic force.

[0050] When the multi-power brushless starter generator system works in the generator state, the external power drags the motor rotor to rotate, and the back electromotive force amplitudes of the multi-phase windings are not completely the same, but the frequencies are the same. The working state of the driver of each phase winding is a single-phase full-wave controlled rectifier circuit with high rectification efficiency. There is no common point between the multi-phase windings, the interference between the windings is small, and the fault tolerance performance of the system is improved. The bus voltages U1, U2...UN output by the multiple drivers 1~N after rectification are not completely the same, thereby realizing multiple groups of power outputs with different voltages.

[0051] Embodiment 1 Two-power brushless generator system

[0052] The turns of the two-phase windings of the two-power brushless starter generator are W1 and W2 respectively, where W1=0.5*W2. Taking the trapezoidal wave back-EMF phase winding as an example, the principle of the two-power brushless starter generator system is introduced.

[0053] When the two-power brushless starter-generator system works in the motor state, the ideal back electromotive force e and current I of the phase winding of the starter-generator system are as follows: Figure 2 , 4 As shown, when the motor runs stably at a speed n, the back electromotive force of the first and second phase windings of the motor are eA and eB respectively. According to the back electromotive force formula, it can be obtained that eA=0.5*eB.

[0054] The power supply voltages U1 and U2 applied to the driver of the two-phase winding are different. Since the currents I1 and I2 of the two-phase winding can be controlled separately, the phase winding state can be forward conduction, reverse conduction or off. Controlling the two-phase current to satisfy IA = 2*IB can ensure that the amplitude of the phase winding magnetomotive force in each state is the same, that is, satisfying W1*I1 = W2*I2, so that the stator generates a circular rotating magnetic field of equal amplitude, such as Figure 3 As shown, the permanent magnet of the motor rotor is rotated by the rotating electromagnetic force.

[0055] When the two-power brushless starter generator system works in the generator state, the external power drives the motor rotor to rotate, and the back electromotive force amplitude of the two-phase winding is not exactly the same, but the frequency is the same. The working state of the driver of the two-phase winding is a single-phase full-wave controlled rectifier circuit with high rectification efficiency. There is no common point between the two-phase windings, the interference between the windings is small, and the fault tolerance of the system is improved. The bus voltages U1 and U2 output by the two drivers after rectification are different, thereby realizing two sets of power outputs with different voltages.

[0056] Embodiment 2 Three-power brushless generator system

[0057] The turns of the three-phase winding of the three-power brushless starter generator are W1, W2, and W3 respectively, where W1=0.5*W2=2*W3. Taking the trapezoidal wave back-EMF phase winding as an example, the principle of the three-power brushless starter generator system is introduced.

[0058] When the three-power brushless starter generator system works in the motor state, the ideal back electromotive force e and current I of the phase winding of the starter generator system are as follows: Figure 4 As shown, when the motor runs stably at a speed n, the back electromotive force of the first, second and third phase windings of the motor are eA, eB and eC respectively. According to the back electromotive force formula, it can be obtained that eA=0.5*eB=2*eC.

[0059] The power supply voltages U1, U2, and U3 applied to the driver of the three-phase winding are not exactly the same. Since the currents I1, I2, and I3 of the three-phase winding can be controlled separately, the phase winding state can be forward conduction, reverse conduction, or off. Controlling the three-phase current to meet IA = 2*IB = 0.5*IC can ensure that the amplitude of the magnetomotive force of the phase winding in each state is the same, that is, satisfying W1*I1 = W2*I2 = ... = WN*IN, so that the stator generates a circular rotating magnetic field of equal amplitude, such as Figure 5 As shown, the permanent magnet of the motor rotor is rotated by the rotating electromagnetic force.

[0060] When the three-power brushless starter generator system works in the generator state, the external power drags the motor rotor to rotate, and the back electromotive force amplitude of the three-phase winding is not exactly the same, but the frequency is the same. The working state of the driver of the three-phase winding is a single-phase full-wave controlled rectifier circuit with high rectification efficiency. There is no common point between the three-phase windings, the interference between the windings is small, and the fault tolerance of the system is improved. The bus voltages U1, U2, and U3 output by the three drivers after rectification are not exactly the same, thereby realizing three sets of power outputs with different voltages.

[0061] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that are not conceived through creative work should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope defined in the claims.

Claims

1. A multi-power brushless starter generator system, characterized in that: include: A multi-phase permanent magnet brushless motor (6), the stator of which has N phase windings, each phase winding has no common connection point, and each phase winding has a different number of turns and wire diameter; A rotor position sensor (3), used for detecting the position information of the rotor; A control circuit (5) connected to the rotor position sensor (3) for acquiring rotor position information and generating N groups of PWM control signals (8); A driving protection circuit (4) receives the PWM control signal (8) and controls the on and off of the power tubes of the multiple drivers; Multiple drives, each drive is connected to a corresponding phase winding, and the bus voltage of each drive is different; Multiple current sensors are used to detect the current of each phase winding.

2. The multi-power brushless starter generator system according to claim 1, characterized in that: The spatial arrangement of the N phase windings of the multi-phase permanent magnet brushless motor (6) is a symmetrical structure.

3. The multi-power brushless starter generator system according to claim 1, characterized in that: Each of the multiple drivers (1 to N) adopts a full-bridge structure, consisting of four power tubes (VN1 to VN4) and their anti-parallel freewheeling diodes (DN1 to DN4); or each driver adopts a half-bridge structure, consisting of two power tubes (VN1, VN2) and their anti-parallel freewheeling diodes (DN1, DN2).

4. The multi-power brushless starter generator system according to claim 1, characterized in that: The bus voltages (U1, U2, ..., UN) of the multiple drivers (1 to N) and the number of turns (W1, W2, ..., WN) of the corresponding phase windings satisfy the following relationship: U1 / W1=U2 / W2=...=UN / WN.

5. The multi-power brushless starter generator system according to claim 1, characterized in that: When the system is operating in the starting state, the control circuit (5) adjusts the current (I1, I2, ..., IN) of each phase winding to satisfy W1×I1=W2×I2=...=WN×IN to ensure that the amplitude of the stator synthetic magnetomotive force is the same, thereby generating a circular rotating magnetic field, and the motor rotor rotates due to the rotating electromagnetic force.

6. The multi-power brushless starter generator system according to claim 1, characterized in that: When the system works in the generator state, the external power drives the rotor to rotate, and the back electromotive force amplitude generated by each phase winding is different. Multiple drivers (1 to N) are used as rectifier circuits, and different bus voltages (U1, U2, ..., UN) are output after rectification to achieve multiple groups of power supply outputs with different voltages.

7. The multi-power brushless starter generator system according to claim 1, characterized in that: The control circuit (5) detects the operation signal (7) of each phase winding and the fault signal (9) of the system in real time, and generates N groups of PWM control signals (8) according to the rotor position information and the operation state, and sends them to the drive protection circuit (4).

8. The multi-power brushless starter generator system according to claim 1, characterized in that: The rotor position sensor (3) is coaxially mounted with the rotor of the multi-phase permanent magnet brushless motor (6) to detect the angular position of the rotor in real time.

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