CN-121618906-B - Zero sequence current suppression method and device for open winding double-two-level inverter

CN121618906BCN 121618906 BCN121618906 BCN 121618906BCN-121618906-B

Abstract

The embodiment of the invention discloses a zero-sequence current suppression method and device for an open-winding double-two-level inverter, which relate to the field of modulation of a common direct current bus type open-winding permanent magnet synchronous motor and comprise the steps of collecting three-phase current to calculate zero-sequence current and zero-sequence voltage; the method comprises the steps of superposing three-phase voltage to form three-phase reference voltage, converting the three-phase reference voltage into a two-phase static coordinate system, dividing a sector according to phase angles, extracting the maximum on-phase voltage corresponding to each unit of the three-phase reference voltage and the zero-sequence voltage, determining the maximum modulation range by combining a preset pulse position offset coefficient k, and calculating the on-off time of a power device to form a driving pulse signal. The current ripple can be counteracted by utilizing the mutual inductance of the motor in one carrier period, the current THD is reduced to inhibit zero sequence current and the current ripple is reduced. The universality of the modulation strategy is strong only by adjusting the k value, the pulse time overflow can be prevented, the control disorder caused by overmodulation is avoided, and the voltage output range and the robustness of the motor system are expanded.

Inventors

GU XIN
ZHAO WENZHUO
ZHANG GUOZHENG
LIU BO
JIN XUEFENG

Assignees

天津工业大学

Dates

Publication Date: 20260508
Application Date: 20260203

Claims (8)

1. The zero sequence current suppression method of the open winding double-two-level inverter is characterized by comprising the following steps of: S101, collecting three-phase current of an open winding motor, calculating zero sequence current, and calculating zero sequence voltage based on proportional resonance adjustment; S102, respectively superposing the zero sequence voltage and the three-phase voltage output by the double closed-loop control of the motor to form a three-phase reference voltage; S103, converting the three-phase reference voltage into a two-phase static coordinate system, dividing the sector of the voltage space according to the phase angle of the three-phase reference voltage, and determining the current sector; s104, carrying out per unit processing on the three-phase reference voltage and the zero sequence voltage, wherein the per unit range is-1, and extracting the phase voltage of the maximum conducting phase corresponding to the per unit from the per unit three-phase reference voltage according to the current belonged sector, wherein the phase voltage of the maximum conducting phase is one phase with the maximum absolute value in the three-phase reference voltage; s105, determining the maximum modulation range according to the extracted phase voltage of the maximum conducting phase, zero sequence voltage and a preset pulse position offset coefficient k, and calculating the on-off time data of the power device to form a driving pulse signal; The maximum modulation range is formulated as Wherein The voltage of the largest conducting phase after per unit is indicated, Comparing the maximum modulation range with a 0-1 interval to judge the overscope, adopting a first formula group to calculate the power device on-off time when the maximum modulation range does not exceed the 0-1 interval, and adopting a second formula group to calculate the power device on-off time when the maximum modulation range exceeds the 0-1 interval so as to form a driving pulse signal; The first formula group is: the second formula set is: Wherein k represents a pulse position deviation coefficient for continuously adjusting the deviation degree of the voltage pulse of the phase voltage of the second conducting phase and the phase voltage of the last conducting phase on the time axis; 、、 The phase voltages of the maximum conducting phase M, the second conducting phase F and the last conducting phase L of the per unit are respectively represented; 、、 respectively represent four key switch time points of three phases, and ; Representing an end time point of one carrier cycle; representing per unit zero sequence voltage; 、 the upper bridge arm power devices of the two inverters respectively, Is the on-time of the slave To the point of , Is the on-time of the slave To the point of And (2) and 。
2. The method according to claim 1, wherein S103 comprises: Converting the three-phase reference voltage into an alpha-beta two-phase static coordinate system based on Clark transformation, and calculating the phase angle theta of the three-phase reference voltage, wherein the phase angle range is 0-2 pi; dividing a voltage space into 6 sectors by taking pi/3 as one sector according to the phase angle theta of the three-phase reference voltage and determining the current sector; According to the sector division result, mapping the three-phase reference voltage to a maximum conducting phase M, a second conducting phase F and a final conducting phase L respectively, wherein the voltage of the maximum conducting phase is one phase with the largest absolute value in the three-phase reference voltage, the second conducting phase and the final conducting phase are determined according to the conducting sequence, and the voltage polarities of the second conducting phase and the final conducting phase are opposite to the maximum conducting phase.
3. The method of claim 1, wherein forming the drive pulse signal based on the power device on-off time comprises: Determining each corresponding power device according to the current sector and the corresponding phase voltage of the maximum conducting phase M, the phase voltage of the second conducting phase F and the phase voltage of the last conducting phase L; And forming a driving pulse signal for driving the corresponding power device to be turned on or turned off according to the power device on-off time and each corresponding power device.
4. The method of claim 1, wherein S105 further comprises: The preset value range of the pulse position offset coefficient k is 0-1, and the value range is determined according to the per unit ratio of the phase mutual inductance coefficient and the phase self-inductance coefficient of the open-winding motor and the expected current ripple suppression degree, and is used for continuously adjusting the offset degree of the voltage pulse of the phase voltage of the second conducting phase F and the phase voltage of the last conducting phase L on a time axis.
5. The method of claim 1, wherein S105 further comprises: The preset driving pulse signal is configured such that in one carrier period, the voltage pulse polarity of the phase voltage of the maximum conducting phase M is controlled to be opposite to the voltage pulse polarity of the phase voltage of the second conducting phase F and the voltage pulse polarity of the phase voltage of the last conducting phase L, and the phase voltage of the second conducting phase F and the voltage pulse of the phase voltage of the last conducting phase L are not overlapped in time or partially overlapped, so that the change rate of the three-phase current is positive or negative at different times.
6. A zero sequence current suppression device of an open winding double two-level inverter, for implementing the zero sequence current suppression method of the open winding double two-level inverter according to any one of claims 1 to 5, comprising: The current acquisition module is used for acquiring three-phase current of the open-winding motor, calculating zero-sequence current and calculating zero-sequence voltage based on proportional resonance adjustment; The reference voltage calculation module is used for superposing the zero sequence voltage and the three-phase voltage to form a three-phase reference voltage; the sector partitioning module is used for converting the three-phase reference voltage into a two-phase static coordinate system, performing sector division of a voltage space according to the phase angle of the three-phase reference voltage and determining the current sector; The voltage per unit module is used for carrying out per unit processing on the three-phase reference voltage and the zero sequence voltage within the range of-1 to 1, and extracting the phase voltage of the maximum conducting phase corresponding to the per unit from the per unit three-phase reference voltage according to the current belonged sector; a driving pulse module for determining the maximum modulation range according to the extracted phase voltage of the maximum conduction phase, zero sequence voltage and preset pulse position offset coefficient k And comparing the maximum modulation range with a 0-1 interval to judge the out-of-range, when the maximum modulation range does not exceed the 0-1 interval, calculating the power device on-off time by adopting a first formula group, and when the maximum modulation range exceeds the 0-1 interval, calculating the power device on-off time data by adopting a second formula group to form a driving pulse signal.
7. An electronic device, the device comprising: One or more processors; Storage means for storing one or more programs, When executed by the one or more processors, causes the one or more processors to implement the method of zero sequence current suppression for an open winding bi-level inverter as recited in any one of claims 1-5.
8. A storage medium containing computer executable instructions which when executed by a computer processor are for performing the zero sequence current suppression method of an open winding bi-level inverter as claimed in any one of claims 1-5.

Description

Zero sequence current suppression method and device for open winding double-two-level inverter Technical Field The invention relates to the technical field of modulation of a common direct current bus type open winding permanent magnet synchronous motor, in particular to a zero sequence current suppression method and device of an open winding double-two-level inverter. Background The open winding motor (open winding motor) is a special cascade power supply mode that star winding neutral points are opened, two ends of the star winding are respectively connected with an inverter, and the star winding motor is driven by the two inverters together, has the characteristics of high flexibility, high fault tolerance, high direct current voltage utilization rate and the like, and is suitable for the fields of new energy electric automobiles, aerospace and the like. The topology structure of the full-control type common direct current bus open winding motor system based on the two-level inverter is shown in figure 1. When the common direct current bus structure is used for supplying power, the two inverters only need to commonly use one power supply, so that a double-two-level system with two sets of two-level inverters is formed, the system structure can be simplified, and the cost can be reduced. However, a disadvantage of this topology is that the direct connection of two inverters that share the same power supply results in the presence of a zero sequence path. When zero sequence voltage appears in the system, zero sequence current is generated, and the zero sequence current can cause serious distortion of three-phase current, so that extra electric energy loss is formed. The motor driven by the inverter simulates the required current through high-speed switching, the switching action can lead the actual current to fluctuate like saw teeth nearby the average value, current ripple is formed, the effective value of the current is further increased, and finally, the motor winding generates serious heat, the motor output torque fluctuation is influenced, and the system performance is deteriorated. Disclosure of Invention The embodiment of the invention provides a zero-sequence current suppression method and device for an open-winding double-two-level inverter, which are used for solving the technical problem that the zero-sequence current of the double-two-level inverter forms current ripple waves under a common direct current bus of an open-winding motor to cause the fluctuation of heating torque of the motor winding. In a first aspect, an embodiment of the present invention provides a zero sequence current suppression method for an open winding dual two-level inverter, including: S101, collecting three-phase current of an open winding motor, calculating zero sequence current, and calculating zero sequence voltage based on proportional resonance adjustment; S102, respectively superposing the zero sequence voltage and the three-phase voltage output by the double closed-loop control of the motor to form a three-phase reference voltage; S103, converting the three-phase reference voltage into a two-phase static coordinate system, dividing the sector of the voltage space according to the phase angle of the three-phase reference voltage, and determining the current sector; S104, carrying out per unit processing on the three-phase reference voltage and the zero sequence voltage, wherein the per unit range is-1, and extracting the corresponding per unit maximum conducting phase voltage from the per unit three-phase reference voltage according to the current belonging sector; S105, determining the maximum modulation range according to the extracted maximum on-phase voltage, zero sequence voltage and a preset pulse position offset coefficient k, and calculating the on-off time data of the power device to form a driving pulse signal. In a second aspect, an embodiment of the present invention provides a zero sequence current suppression device for an open winding dual two-level inverter, including: the current acquisition module is used for acquiring three-phase current of the open-winding motor and calculating zero-sequence current and zero-sequence voltage; The reference voltage calculation module is used for superposing the zero sequence voltage and the three-phase voltage to form a three-phase reference voltage; the sector partitioning module is used for converting the three-phase reference voltage into a two-phase static coordinate system and performing sector division of a voltage space according to the phase angle of the three-phase reference voltage; the voltage per unit module is used for carrying out per unit processing on the three-phase reference voltage and the zero sequence voltage and extracting the maximum conducting phase voltage corresponding to the per unit; And the driving pulse module is used for determining the maximum modulation range according to the extracted maximum on-phase voltage, zero sequence vol