A zero-sequence component injection DPWM modulation method for driving a dual Y-shifted 30° six-phase permanent magnet synchronous motor

Abstract

This invention discloses a zero-sequence component injection DPWM modulation method for driving a dual Y-shift 30° six-phase permanent magnet synchronous motor. The method involves superimposing a sinusoidal modulation wave with a zero-sequence component to form a 60° clamping discontinuous modulation wave. The steps include: S1: Obtaining the six-phase voltage modulation wave and its output current; S2: Taking three-phase windings with a 120° phase difference as one group and three-phase windings with a 30° electrical phase difference from the previous group as another group, obtaining the minimum absolute value of the voltage modulation wave and the maximum absolute value of the corresponding output current in each group; S3: Calculating the injected zero-sequence component in each group; S4: Superimposing the zero-sequence component onto the corresponding voltage modulation wave to obtain a DPWM modulation wave that adaptively clamps the maximum conduction current. This invention determines the optimal clamping region by detecting the inverter output current and reference voltage, reducing system switching losses. The zero-sequence component injection method avoids complex vector calculations, demonstrating significant application value.

Description

Technical Field

[0001] This invention relates to the field of power electronics technology, and in particular to a zero-sequence component injection DPWM modulation method for driving a dual Y-shift 30° six-phase permanent magnet synchronous motor. Background Technology

[0002] Compared to traditional three-phase motors, multiphase motor variable frequency speed control systems can reduce torque ripple amplitude, easily achieve high power with low-voltage devices, have multiple control degrees of freedom, enable redundant control, and improve system reliability. The dual Y-shift 30° six-phase permanent magnet synchronous motor combines the advantages of both permanent magnet synchronous motors and multiphase motors, and is widely used in key national development areas such as national defense equipment, marine engineering, electrified transportation, and new energy utilization.

[0003] Due to the non-ideal characteristics of power devices, the switching frequency is severely limited. To ensure the lifespan of power devices and reduce switching losses, the switching frequency of high-voltage, high-power converters is generally below 1kHz. Discontinuous PWM (DPWM) can ensure that the switching transistors do not operate for 1 / 3 of the voltage fundamental cycle. At any given time, only two phases of the three-phase system are switched on, while the third phase is clamped at a specific level. This reduces switching losses, thereby improving power conversion efficiency and power quality.

[0004] Switching losses are proportional to the instantaneous value of the load current. However, traditional DPWM modulation strategies have a fixed range and cannot track the region where the absolute value of the load current is at its maximum in real time, thus failing to minimize switching losses across the entire power factor range. Summary of the Invention

[0005] To address this, the present invention provides a zero-sequence component injection DPWM modulation method for driving a dual Y-shift 30° six-phase permanent magnet synchronous motor, which solves the problems of the inability of the switching clamp position region to track the region where the absolute value of the current is maximum and the large switching loss under the traditional DPWM modulation strategy.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] This invention provides a zero-sequence component injection DPWM modulation method for driving a dual Y-shifted 30° six-phase permanent magnet synchronous motor. The method includes the following steps:

[0008] S1: Obtain the sinusoidal modulation wave of the six-phase reference voltage and the sinusoidal current of the six-phase output;

[0009] S2: Take a set of stator three-phase windings that are 120° out of phase as one group (abc three-phase as one group), and another set of stator three-phase windings that are 30° out of phase with the previous group as one group (uvw three-phase as one group). Perform intra-group comparisons to obtain the minimum absolute value of the sinusoidal modulation wave of the three-phase reference voltage within the group and the maximum absolute value of the corresponding three-phase output sinusoidal current.

[0010] S3: Within the same group, if the phase with the smallest absolute voltage value is not the phase with the largest absolute current value, then the voltage of the phase with the largest absolute current value is taken as the input to calculate the injected zero-sequence component; if the phase with the smallest absolute voltage value is exactly the phase with the largest absolute current value, then the absolute values ​​of the currents of the remaining two phases are compared. If the absolute values ​​of the currents of the remaining two phases are not equal, then the voltage of the phase with the larger absolute current value is taken as the input to calculate the injected zero-sequence component; if the absolute values ​​of the currents of the remaining two phases are equal, then the voltage of any one of the two phases is taken as the input to calculate the injected zero-sequence component.

[0011] S4: The zero-sequence components calculated in each group are superimposed onto the corresponding reference voltage sinusoidal modulation wave to obtain a DPWM modulation wave that can adaptively clamp the maximum conduction current and drive the six-phase full-bridge switching transistors to work.

[0012] Preferably, step S3 specifically involves: for the three phases abc, the input u is determined based on the comparison within the group. i Calculate the zero-sequence components to be injected in the abc three-phase system:

[0013]

[0014] Among them, U dc The inverter DC bus voltage, u 0abc The zero-sequence voltage component that needs to be injected into the three-phase sinusoidal modulation wave abc.

[0015] For the uvw three-phase system, the input u is determined based on the comparison within the group. j Calculate the zero-sequence component to be injected in the uvw three-phase system:

[0016]

[0017] Among them, u 0uvw The zero-sequence voltage component that needs to be injected into the three-phase sinusoidal modulation wave of uvw.

[0018] Preferably, the specific content of step S4 is as follows:

[0019] u a * =u a +u 0abc

[0020] u b* =u b +u 0abc

[0021] u c * =u c +u 0abc

[0022] u u * =u u +u 0uvw

[0023] u v * =u v +u 0uvw

[0024] u w * =u w +u 0uvw

[0025] Among them, u a *,u b *,u c *,u u *,u v *,u w * represents the six-phase voltage modulation wave after zero-sequence component injection.

[0026] Compared with existing technologies, this invention discloses a zero-sequence component injection DPWM modulation method for driving a dual Y-shift 30° six-phase permanent magnet synchronous motor. By detecting the position of the output current relative to the reference AC voltage, it can adaptively clamp the region where the maximum conduction current is located, thereby achieving minimum switching losses. Furthermore, this method is simple to implement and has high application value. Attached Figure Description

[0027] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of 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.

[0028] Figure 1 This is a flowchart of the zero-sequence component injection DPWM modulation method for driving a dual Y-shifted 30° six-phase permanent magnet synchronous motor according to the present invention;

[0029] Figure 2 This is the topology diagram of the drive circuit for a dual Y-shift 30° six-phase permanent magnet synchronous motor.

[0030] Figure 3 The simulated waveforms of the six-phase initial sinusoidal voltage modulation wave after standardization, the injected zero-sequence component, the voltage modulation wave after the injection of the zero-sequence component, and the six-phase output current are shown in this invention.

[0031] Figure 4 The simulated waveforms of the modulated voltage wave of phase a, the output current of phase a, and the pulse of the upper transistor of phase a after standardization in this invention are shown.

[0032] Figure 5 This is a simulation waveform of the electromagnetic torque and mechanical angular velocity output by the six-phase permanent magnet synchronous motor when the load torque suddenly changes from 0 to 50 N·m at 0.2s in this invention. Detailed Implementation

[0033] The present invention will be further described and illustrated below with reference to specific embodiments. The embodiments described are merely examples of the content of this disclosure and do not limit the scope of the invention. The technical features of each embodiment in the present invention can be combined accordingly, provided that there is no mutual conflict.

[0034] 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 this specification means the presence of the stated features, integers, steps, operations, elements, and / or modules, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, modules, and / or groups thereof.

[0035] 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 same meaning as in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless defined as herein.

[0036] To facilitate understanding of the embodiments of the present invention, further explanations and descriptions will be provided below with reference to the accompanying drawings and specific embodiments. These embodiments do not constitute a limitation on the embodiments of the present invention.

[0037] It should be understood by those skilled in the art that the accompanying drawings are merely schematic diagrams of one embodiment, and the components or devices shown in the drawings are not necessarily essential for implementing the present invention.

[0038] This invention provides a zero-sequence component injection DPWM modulation method for driving a dual Y-shift 30° six-phase permanent magnet synchronous motor. The method involves superimposing a sinusoidal modulation wave with a zero-sequence component to form a 60° clamping discontinuous modulation wave. Compared to continuous PWM and traditional DPWM methods, this method exhibits lower switching losses and includes the following steps:

[0039] S1: Obtain the six-phase sinusoidal voltage modulation wave and the six-phase output sinusoidal current;

[0040] S2: Take a set of stator three-phase windings that are 120° out of phase as one group (abc three-phase as one group), and another set of stator three-phase windings that are 30° out of phase with the previous group as one group (uvw three-phase as one group). Perform intra-group comparisons to obtain the minimum absolute value of the three-phase sinusoidal voltage modulation wave and the maximum absolute value of the corresponding three-phase output sinusoidal current within the group.

[0041] S3: Within the same group, if the phase with the smallest absolute voltage value is not the phase with the largest absolute current value, then the voltage of the phase with the largest absolute current value is taken as the input to calculate the injected zero-sequence component; if the phase with the smallest absolute voltage value is exactly the phase with the largest absolute current value, then the absolute values ​​of the currents of the remaining two phases are compared. If the absolute values ​​of the currents of the remaining two phases are not equal, then the voltage of the phase with the larger absolute current value is taken as the input to calculate the injected zero-sequence component; if the absolute values ​​of the currents of the remaining two phases are equal, then the voltage of any one of the two phases is taken as the input to calculate the injected zero-sequence component.

[0042] S4: The zero-sequence components calculated in each group are superimposed onto the corresponding sinusoidal voltage modulation wave to obtain a DPWM modulation wave that can adaptively clamp the maximum conduction current and drive the six-phase full-bridge switching transistors to work.

[0043] The controlled object in this embodiment is a dual Y-shift 30° six-phase permanent magnet synchronous motor, such as... Figure 2 Based on the 6-phase structure of the motor, the inverter consists of two three-phase bridge structures connected in parallel, with each three-phase bridge employing a two-level topology. The inverter contains a total of 6 phases, with each phase bridge arm containing 2 IGBT or MOSFET switching transistors.

[0044] To further implement the above technical solutions, such as Figure 1 The specific content of step S2 is as follows:

[0045] A set of three-phase stator windings with a phase difference of 120° is used as one group (the three phases abc are used as one group), and another set of three-phase stator windings with a phase difference of 30° electrical angle from the previous group is used as one group (the three phases uvw are used as one group).

[0046] |u m |=min(|u a |,|u b |,|u c|)

[0047] |i n |=max(|i a |,|i b |,|i c |)m,n∈{a,b,c}

[0048] |u z |=min(|u u |,|u v |,|u w |)

[0049] |i x |=max(|i u |,|i v |,|i w |)z,x∈{u,v,w}

[0050] Among them, u a ,u b ,u c ,u u ,u v ,u w For the six-phase reference voltage sinusoidal modulation wave, u m For a three-phase sinusoidal modulation wave u a ,u b ,u c The original value corresponding to the absolute minimum, u z For the other three phases of sinusoidal modulation wave u u ,u v ,u w The original value corresponding to the absolute minimum, i a i b i c i u i v i w For the six-phase output current, i n For the three-phase output current i a i b i c The original value corresponding to the absolute minimum, i x For the other three phase output current i u i v i w The original value corresponding to the minimum absolute value.

[0051] To further implement the above technical solution, the specific content of step S3 is as follows: Compare the three phases as a group. For phases a, b, and c, if the phase with the smallest absolute voltage is not the phase with the largest absolute current, then take the voltage of the phase with the largest absolute current as the input u. iIf the phase with the smallest absolute voltage value is the same as the phase with the largest absolute current value, then compare the absolute values ​​of the currents in the remaining two phases. If the absolute values ​​of the currents in the remaining two phases are not equal, then take the voltage of the phase with the larger absolute current value as the input u. i If the absolute values ​​of the currents in the remaining two phases are equal, then the voltage of any one of the two phases can be taken as the input u. i According to the input u i Calculate the zero-sequence components to be injected in the abc three-phase system:

[0052]

[0053] Among them, U dc The inverter DC bus voltage, u 0abc The zero-sequence voltage component that needs to be injected into the three-phase sinusoidal modulation wave abc.

[0054] For a three-phase system (uvw), if the phase with the minimum absolute voltage is not the phase with the maximum absolute current, then the voltage of the phase with the maximum absolute current is taken as the input u. j If the phase with the smallest absolute voltage value is the same as the phase with the largest absolute current value, then compare the absolute values ​​of the currents in the remaining two phases. If the absolute values ​​of the currents in the remaining two phases are not equal, then take the voltage of the phase with the larger absolute current value as the input u. j If the absolute values ​​of the currents in the remaining two phases are equal, then the voltage of any one of the two phases can be taken as the input u. j According to the input u j Calculate the zero-sequence component to be injected in the uvw three-phase system:

[0055]

[0056] Among them, u 0uvw The zero-sequence voltage component that needs to be injected into the three-phase sinusoidal modulation wave of uvw.

[0057] To further implement the above technical solution, the specific content of step S4 is as follows:

[0058] u a * =u a +u 0abc

[0059] u b * =u b +u 0abc

[0060] u c * =u c +u 0abc

[0061] u u * =u u+u 0uvw

[0062] u v * =u v +u 0uvw

[0063] u w * =u w +u 0uvw

[0064] Among them, u a *,u b *,u c *,u u *,u v *,u w * represents the six-phase voltage modulation wave after zero-sequence component injection.

[0065] Figure 3 The simulated waveforms are: the monotonic six-phase initial sinusoidal voltage modulation wave, the injected zero-sequence component calculated by the method of the present invention, the output voltage modulation wave obtained by injecting the zero-sequence component into the six-phase initial sinusoidal voltage modulation wave according to the method of the present invention, and the six-phase output current.

[0066] Figure 4 The simulated waveforms of the phase a voltage modulation wave, phase a output current, and phase a upper transistor pulse after standardization are shown in this invention. It can be seen that the absolute value of the current in the voltage clamping region is also the largest, effectively reducing switching losses.

[0067] Figure 5 This is a simulation waveform of the electromagnetic torque and mechanical angular velocity output by a six-phase permanent magnet synchronous motor when the load torque abruptly changes from 0 to 50 N·m at 0.2 s. During the sudden load application, the motor torque pulsation is small, and the actual speed can promptly track the given speed. Therefore, this invention, by detecting the position of the output current relative to the reference AC voltage and adaptively clamping the region of maximum conduction current, achieves minimal switching losses and has high application value.

[0068] The above-described embodiments are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. Those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A zero-sequence component injection DPWM modulation method for driving a dual Y-shifted 30° six-phase permanent magnet synchronous motor, characterized in that, Includes the following steps: S1: Obtain the sinusoidal modulation wave of the six-phase reference voltage and the sinusoidal current of the six-phase output; S2: Take a set of stator three-phase windings that are 120° out of phase as one group, and another set of stator three-phase windings that are 30° out of phase with the previous group as another group. Compare within each group to obtain the minimum absolute value of the sinusoidal modulation wave of the three-phase reference voltage within the group and the maximum absolute value of the corresponding three-phase output sinusoidal current. S3: Within the same group, if the phase with the smallest absolute voltage value is not the phase with the largest absolute current value, then the voltage of the phase with the largest absolute current value is taken as the input to calculate the injected zero-sequence component; if the phase with the smallest absolute voltage value is exactly the phase with the largest absolute current value, then the absolute values ​​of the currents of the remaining two phases are compared. If the absolute values ​​of the currents of the remaining two phases are not equal, then the voltage of the phase with the larger absolute current value is taken as the input to calculate the injected zero-sequence component; if the absolute values ​​of the currents of the remaining two phases are equal, then the voltage of any one of the two phases is taken as the input to calculate the injected zero-sequence component. S4: The zero-sequence components calculated in each group are superimposed onto the corresponding reference voltage sinusoidal modulation wave to obtain a DPWM modulation wave that can adaptively clamp the maximum conduction current and drive the six-phase full-bridge switching transistors to work.

2. The zero-sequence component injection DPWM modulation method for driving a dual Y-shifted 30° six-phase permanent magnet synchronous motor according to claim 1, characterized in that, Step S2 specifically involves: One set of stator three-phase windings abc, which are 120° out of phase, is considered as one group; and another set of stator three-phase windings uvw, which are 30° out of phase with the first group, is considered as the second group. |u m |=min(|u a |,|u b |,|u c |) |i n |=max(|i a |,|i b |,|i c |)m,n∈{a,b,c} |u z |=min(|u u |,|u v |,|u w |) |i x |=max(|i u |,|i v |,|i w |)z,x∈{u,v,w} Among them, u a ,u b ,u c ,u u ,u v ,u w For the six-phase reference voltage sinusoidal modulation wave, u m For a three-phase sinusoidal modulation wave u a ,u b ,u c The original value corresponding to the absolute minimum, u z For the other three phases of sinusoidal modulation wave u u ,u v ,u w The original value corresponding to the absolute minimum, i a i b i c i u i v i w For the six-phase output current, i n For the three-phase output current i a i b i c The original value corresponding to the absolute minimum, i x For the three-phase output current i u i v i w The original value corresponding to the minimum absolute value.

3. The zero-sequence component injection DPWM modulation method for driving a dual Y-shifted 30° six-phase permanent magnet synchronous motor according to claim 1, characterized in that, Step S3 specifically involves: For the three phases abc, if the phase with the smallest absolute voltage value is not the phase with the largest absolute current value, then the voltage of the phase with the largest absolute current value is taken as the input u. i If the phase with the smallest absolute voltage value is the same as the phase with the largest absolute current value, then compare the absolute values ​​of the currents in the remaining two phases. If the absolute values ​​of the currents in the remaining two phases are not equal, then take the voltage of the phase with the larger absolute current value as the input u. i If the absolute values ​​of the currents in the remaining two phases are equal, then the voltage of any one of the two phases can be taken as the input u. i According to the input u i Calculate the zero-sequence components to be injected in the abc three-phase system: Among them, U dc The inverter DC bus voltage, u 0abc The zero-sequence voltage component that needs to be injected into the abc three-phase modulation wave; For a three-phase system (uvw), if the phase with the minimum absolute voltage is not the phase with the maximum absolute current, then the voltage of the phase with the maximum absolute current is taken as the input u. j If the phase with the smallest absolute voltage value is the same as the phase with the largest absolute current value, then compare the absolute values ​​of the currents in the remaining two phases. If the absolute values ​​of the currents in the remaining two phases are not equal, then take the phase voltage with the larger absolute current value as the input u. j If the absolute values ​​of the currents in the remaining two phases are equal, then the voltage of any one of the two phases can be taken as the input u. j According to the input u j Calculate the zero-sequence component to be injected in the uvw three-phase system: Among them, u 0uvw The zero-sequence voltage component that needs to be injected into the three-phase modulated sine wave of uvw.

4. The zero-sequence component injection DPWM modulation method for driving a dual Y-shifted 30° six-phase permanent magnet synchronous motor according to claim 3, characterized in that, Step S4 specifically involves: in a * =in a +in 0abc in b * =in b +in 0abc in c * =in c +in 0abc in u * =in u +in 0uvw in v * =in v +in 0uvw in w * =in w +in 0uvw Among them, u a *,u b *,u c *,u u *,u v *,u w * represents the six-phase voltage modulation wave after zero-sequence component injection.

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