KR-102965076-B1 - APPARATUS AND METHOD FOR DRIVING MOTOR

KR102965076B1KR 102965076 B1KR102965076 B1KR 102965076B1KR-102965076-B1

Abstract

A motor driving device is disclosed comprising: a first inverter including a plurality of first switching elements and connected to a first terminal of each of a plurality of windings corresponding to each of a plurality of phases of a motor; a second inverter including a plurality of second switching elements and connected to a second terminal of each of the plurality of windings; a plurality of switching switches, each having one end connected to a node where the plurality of windings and the plurality of second switching elements are connected and the other end connected to each other; and a controller that drives the motor in one of a first driving mode in which the plurality of second switching elements are kept in an open state and the plurality of first switching elements are controlled by pulse width modulation to drive the motor, and a second driving mode in which the plurality of first switching elements and the plurality of second switching elements are controlled by pulse width modulation to drive the motor, and applies a dead time in which the plurality of second switching elements and the plurality of switching switches are all kept in an off state for a preset time when switching between the first driving mode and the second driving mode.

Inventors

이용재
정강호
임영설
심재훈
하정익

Assignees

현대자동차주식회사
기아 주식회사
서울대학교산학협력단

Dates

Publication Date: 20260513
Application Date: 20210826

Claims (20)

A first inverter comprising a plurality of first switching elements and connected to a first terminal of each of a plurality of windings corresponding to each of the plurality of phases of a motor; A second inverter comprising a plurality of second switching elements and connected to the second terminal of each of the plurality of windings; A plurality of switching switches, each having one end connected to a node where the plurality of windings and the plurality of second switching elements are connected, and the other ends connected to each other; A controller that drives the motor in one of a first driving mode in which the plurality of second switching elements are kept in an open state and the plurality of first switching elements are controlled by pulse width modulation to drive the motor, and a second driving mode in which the plurality of first switching elements and the plurality of second switching elements are controlled by pulse width modulation to drive the motor, and applies a dead time in which the plurality of second switching elements and the plurality of switching switches are all kept in an off state for a preset time when switching between the first driving mode and the second driving mode; Includes, but the above controller, A motor driving device characterized by controlling the plurality of switching switches from an ON state to an OFF state after applying a preset delay when it is determined that the driving mode is switched from the first driving mode to the second driving mode in the first sampling period, and when the second sampling period following the first sampling period has elapsed and the third sampling period following the second sampling period has started.
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In claim 1, the controller is, A motor driving device characterized by performing an operation to execute the second driving mode in the second sampling period, and in the third sampling period, controlling the second inverter with pulse width modulation using the result calculated in the second sampling period.
In claim 1, the controller is, A motor driving device characterized by starting pulse width modulation of the second switching element after the dead time has elapsed following the above plurality of switching switches being turned off.
In claim 4, The sum of the time interval corresponding to the above delay and the time interval corresponding to the above dead time corresponds to the time interval of one sampling period, and A motor driving device characterized in that the controller starts pulse width modulation of the second switching element at the time when the fourth sampling period following the third sampling period begins.
In claim 5, the controller is, A motor driving device characterized by performing an operation to execute the second driving mode in the third sampling period, and in the fourth sampling period, controlling the second inverter with pulse width modulation using the result calculated in the third sampling period.
In claim 1, the controller is, A motor driving device characterized by, when it is determined that the driving mode is switched from the second driving mode to the first driving mode in the first sampling period, controlling the plurality of second switching elements to an off state at the time when the third sampling period begins, and controlling the plurality of switching switches from an off state to an on state after the dead time has elapsed since the plurality of second switching elements became off state.
In claim 7, the controller is, A motor driving device characterized by performing an operation to execute the first driving mode in the second sampling period, and in the third sampling period, controlling the first inverter with pulse width modulation using the result calculated in the second sampling period.
In claim 1, the controller is, A motor driving device characterized by, when it is determined that the driving mode is switched from the second driving mode to the first driving mode in the first sampling period, applying a preset delay at the time when the third sampling period begins, controlling the plurality of second switching elements to an off state, and after the dead time elapses after the plurality of second switching elements have become off, controlling the plurality of switching switches from an off state to an on state.
In claim 9, The sum of the time interval corresponding to the above delay and the time interval corresponding to the above dead time corresponds to the time interval of one sampling period, and A motor driving device characterized by the above controller controlling the plurality of switching switches from an off state to an on state at the time when a fourth sampling period following the third sampling period begins.
In claim 10, the controller is, A motor driving device characterized by performing an operation to execute the first driving mode in the third sampling period, and in the fourth sampling period, controlling the first inverter with pulse width modulation using the result calculated in the third sampling period.
In a motor driving method implemented by the motor driving device of claim 1, The above controller determines that a switch from the first driving mode to the second driving mode is required during the first sampling period; The above controller controls the plurality of switching switches from an ON state to an OFF state during a single sampling period following the first sampling period; A step of starting pulse width modulation of the second switching element after the dead time has elapsed following the above plurality of switching switches becoming off; A motor driving method comprising, wherein the step of controlling to the off state is characterized in that the controller controls the plurality of switching switches from the on state to the off state after applying a preset delay at the time when the third sampling period begins.
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In claim 12, The above controller further includes the step of performing an operation to execute the second driving mode during the second sampling period, and A motor driving method characterized in that the starting step above controls the second inverter with pulse width modulation using the result calculated in the second sampling period in the third sampling period.
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In claim 12, The sum of the time interval corresponding to the above delay and the time interval corresponding to the above dead time corresponds to the time interval of one sampling period, and A motor driving method characterized in that the above-mentioned starting step is a step in which the controller starts pulse width modulation of the second switching element at the time when the fourth sampling period following the third sampling period begins.
In claim 16, The above controller further includes the step of performing an operation to execute the second driving mode in the third sampling period, and A motor driving method characterized in that the starting step above controls the second inverter with pulse width modulation using the result calculated in the third sampling period in the fourth sampling period.
In a motor driving method implemented by the motor driving device of claim 1, The above controller determines that a switch from the second driving mode to the first driving mode is required during the first sampling period; The above controller controls the plurality of second switching elements to an off state during a sampling period following the first sampling period; and A step of controlling the plurality of switching switches from the off state to the on state after the dead time has elapsed following the above plurality of switching switches becoming off; A motor driving method comprising, wherein the step of controlling to an off state is characterized by controlling the plurality of second switching elements to an off state after applying a preset delay at the time when the third sampling period starts.
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In claim 18, The above controller further includes the step of performing an operation to execute the first driving mode during the second sampling period, and A motor driving method characterized in that the step of controlling to the ON state above controls the first inverter pulse width modulation using the result calculated in the second sampling period in the third sampling period.

Description

Apparatus and Method for Driving Motor The present invention relates to a motor driving device and method, and more specifically, to a motor driving device and method capable of suppressing various control shocks that occur when switching between a driving mode using one inverter and a driving mode using two inverters when driving a motor using two inverters connected to each end of the motor winding. Generally, one end of each phase winding included in the motor is connected to a single inverter, and the other ends are connected to each other to form a Y-connection. When driving the motor, the switching element in the inverter is turned on/off by pulse width modulation control, and torque is generated by applying line voltage to the windings of the Y-connected motor to generate alternating current. Since the fuel efficiency (or electric efficiency) of eco-friendly vehicles, such as electric vehicles that utilize torque generated by such motors as power, is determined by the power conversion efficiency between the inverter and the motor, it is important to maximize the power conversion efficiency of the inverter and the efficiency of the motor to improve fuel efficiency. The efficiency of an inverter-motor system is primarily determined by the voltage utilization rate of the inverter; if the vehicle's operating point, determined by the relationship between motor speed and torque, is formed in a range of high voltage utilization, the vehicle's fuel efficiency can be improved. However, increasing the number of windings to boost maximum torque causes the high-voltage utilization region to move further away from the low-torque region, which is the vehicle's primary operating point, potentially leading to poor fuel efficiency. Furthermore, designing the motor to include the primary operating point within the high-voltage utilization region for the sake of fuel efficiency may result in limitations on the motor's maximum torque, which can lead to reduced acceleration performance. To solve this problem, an Open End Winding (OEW) motor driving technique has been proposed in the field of technology, in which two inverters are driven by connecting an inverter to each end of the motor winding instead of short-circuiting one end of the motor winding through a Y connection. The open-end winding motor drive technique has the advantage of being able to increase phase voltage to improve voltage utilization and enable high output compared to the conventional Y-connection motor drive method. A motor drive device capable of selectively using a Y-connection structure motor drive mode and an open-end winding type motor drive mode as described above has also already been developed. A motor drive device applying two motor drive modes is equipped with a plurality of switching switches at one end of the motor windings that can connect the ends of the motor windings to each other. In the motor driving mode of a Y-connection structure, all switching switches are short-circuited so that a motor with a Y-connection formed at one end can be driven by controlling a single inverter, and in the motor driving mode of an open-end winding method, all switching switches are open and the motor can be driven by controlling both inverters connected to each end of the winding inside the motor. In such a motor drive device, when switching between a Y-connection structure motor drive mode and an open-end winding type motor drive mode is required during motor operation, a short circuit in the DC link may occur as an inverter commonly connected to one end of the same motor winding as the switching switch operates while the switching switch is short-circuited. Furthermore, from a software perspective, it is important to ensure that no control shock occurs when switching between the Y-connection motor drive mode and the open-end winding motor drive mode during motor operation. Here, control shock may refer to fluctuations in torque, current, or unintended control variables. The matters described above as background technology are intended only to enhance understanding of the background of the present invention and should not be construed as an acknowledgment that they constitute prior art already known to those skilled in the art. FIG. 1 is a circuit diagram of a motor driving device according to one embodiment of the present invention. FIG. 2 is a timing diagram illustrating an example of a mode switching control technique from a closed-end winding mode to an open-end winding mode performed by a controller in a motor driving device and method according to an embodiment of the present invention. FIG. 3 is a timing diagram illustrating another example of a mode switching control technique from a closed-end winding mode to an open-end winding mode performed by a controller in a motor driving device and method according to an embodiment of the present invention. FIG. 4 is a timing diagram illustrating an example of a mode switching control technique from an