KR-20260067895-A - MOTOR DRVING APPARATUS

KR20260067895AKR 20260067895 AKR20260067895 AKR 20260067895AKR-20260067895-A

Abstract

A motor driving device is introduced, comprising: a motor; an inverter including a plurality of legs connected to a switching element; a gate driver that applies a driving signal determining a switching state to the gate terminal of the switching element; a variable resistor circuit that provides a gate resistance to the gate terminal; and a controller that adjusts the magnitude of the gate resistance by controlling the application of the driving signal based on the switching loss of the inverter in a weak flux region.

Inventors

문태준
최호림
강진욱
우태겸
유태일
박상우

Assignees

현대자동차주식회사
기아 주식회사

Dates

Publication Date: 20260513
Application Date: 20241106

Claims (20)

A motor having multiple windings corresponding to each of the multiple phases; An inverter comprising a plurality of legs, each corresponding to the plurality of phases and having a switching element connected thereto; A gate driver that applies a driving signal determining the switching state of the switching element to the gate terminal of the switching element; A variable resistor circuit connected between the gate terminal and the gate driver to provide a gate resistance to the gate terminal according to the driving signal; and A motor driving device comprising a controller that maintains or changes the magnitude of the gate resistance by controlling the application of a driving signal to the gate driver based on the switching loss of the inverter in a weak flux region where the motor is driven at a speed exceeding a base speed.
In claim 1, The above controller is, A motor driving device characterized by changing the size of the gate resistor when the switching loss according to the current size of the gate resistor exceeds the switching loss according to the size at the time of change.
In claim 2, The above controller is, A motor driving device characterized by determining the switching loss according to the size of the gate resistance based on the energy loss caused by the gate resistance and the number of switching cycles of the switching element.
In claim 3, The above controller is, A motor driving device characterized by determining the number of switching cycles according to the size of the gate resistor based on a switching zero interval in which the switching state is maintained as either turn-on or turn-off within the output fundamental period of the inverter.
In claim 4, The above controller is, The section in which the pole voltage command for the above inverter is greater than or equal to the reference voltage according to the magnitude of the gate resistor is determined as the switching zero section, The above reference voltage is, A motor driving device characterized by being determined based on the dead time and minimum pulse width according to the size of the gate resistance.
In claim 3, The energy loss due to the gate resistance mentioned above is, A motor driving device characterized by being preset according to DC voltage and current commands applied to the above inverter.
In claim 2, The above controller is, A motor driving device characterized by maintaining or changing the size of the gate resistor by further considering whether to enter a non-linear section where the command voltage and output voltage of the inverter are mismatched.
In claim 7, The above controller is, A motor driving device characterized by increasing the size of the gate resistance based on the switching loss in a portion of the above non-linear section.
In claim 7, The above controller is, A motor driving device characterized by determining the section in which the current modulation index determined based on the dq-axis voltage command of the inverter exceeds the reference modulation index determined based on the dead time and minimum pulse width according to the current magnitude of the gate resistor as the non-linear section.
In claim 2, The above controller is, A motor driving device characterized by receiving a rotational speed and torque command of the motor and maintaining or changing the size of the gate resistor by referring to a preset efficiency table to output a resistance value corresponding to the input rotational speed and torque command.
In claim 10, The above efficiency table is, A motor driving device characterized by being pre-set according to the DC voltage input to the above inverter.
In claim 10, The above efficiency table is, A motor driving device characterized by being configured to output a resistance value among a plurality of preset resistance values such that, under the conditions of the input rotational speed and torque command, the energy loss due to the gate resistance and the switching loss according to the number of switching cycles of the switching element become smaller.
In claim 12, The above number of switching cycles is, A motor driving device characterized by being determined for each of the plurality of resistance values based on a switching zero interval in which the switching state is maintained as either turn-on or turn-off within the output fundamental wave period of the inverter.
In claim 13, The above switching zero section is, A motor driving device characterized in that the pole voltage command for the above inverter corresponds to a section greater than a reference voltage determined based on a dead time and a minimum pulse width according to each of the plurality of resistance values.
In claim 12, The above plurality of resistance values are, It includes a first resistance value and a second resistance value greater than the first resistance value, The above efficiency table is, A motor driving device characterized in that the section where the second resistance value is output is set to be included within a non-linear section where the command voltage and output voltage of the inverter are mismatched.
In claim 15, The above non-linear section is, A motor driving device characterized by a section in which a first modulation index determined based on the dq-axis voltage command of the inverter according to the rotational speed and torque command of the motor exceeds a second modulation index determined based on the dead time and minimum pulse width according to the first resistance value.
In claim 1, The above controller is, A motor driving device characterized by controlling the application of a driving signal of the gate driver based on a dead time preset to correspond to the size of the gate resistance.
In claim 1, The above controller is, A motor driving device characterized by maintaining the size of the gate resistance in the MTPA (Maximum Torque per Ampere) region where the motor is driven at a base speed or lower.
In claim 1, The above variable resistor circuit is, A motor driving device comprising a plurality of branches, each having a resistor connected thereto, and characterized by providing the gate resistor to the gate terminal through the branch to which the driving signal is applied among the plurality of branches.
In claim 1, The above variable resistor circuit is, A first resistor portion comprising a first resistor and a second resistor having a resistance value greater than that of the first resistor, and providing the gate resistor to the gate terminal through the first resistor or the second resistor according to a driving signal that controls the switching state to turn-on; and A motor driving device comprising a third resistor and a fourth resistor having a resistance value greater than that of the third resistor, and a second resistor portion that provides the gate resistor to the gate terminal through the third resistor or the fourth resistor according to a driving signal that controls the switching state to turn-off.

Description

Motor Driving Apparatus The present invention relates to a motor driving device capable of improving the driving efficiency of a motor through a variable gate resistor and a control method thereof. An inverter used in devices such as vehicles is a component that converts the DC voltage of a high-voltage battery into AC voltage to drive a motor. To this end, the inverter is equipped with a plurality of switching elements for voltage conversion, and the switching elements equipped in the inverter can be switched by a gate driver. Meanwhile, losses occur during the operation of switching elements, and these losses can be classified into switching losses, which are losses during the turn-on and turn-off periods of the switching elements, and conduction losses, which are losses during the period when current flows constantly. Since such losses of switching elements are directly related to the efficiency of the inverter, it is necessary to mitigate the losses of switching elements in order to improve the efficiency of the inverter. One method for this purpose is to reduce the gate resistance connected to the switching element. This method utilizes the fact that reducing the gate resistance reduces the turn-on/turn-off time of the switching element, thereby shortening the dead time for preventing short circuits, which reduces switching losses and improves the efficiency of the inverter. 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. FIGS. 1 and FIGS. 2 are drawings showing the configuration of a motor driving device according to an embodiment of the present invention. FIG. 3 is a diagram showing the overall control logic of a controller according to one embodiment of the present invention. FIG. 4 is a drawing showing a switching control unit according to the first embodiment of the present invention. FIG. 5 is a flowchart for explaining a control process according to a first embodiment of the present invention. FIG. 6 is a drawing showing a switching control unit according to a second embodiment of the present invention. FIG. 7 is a flowchart for explaining a control process according to a second embodiment of the present invention. Specific structural or functional descriptions of the embodiments of the present invention disclosed in this specification or application are merely illustrative for the purpose of explaining embodiments according to the present invention, and embodiments according to the present invention may be implemented in various forms and should not be interpreted as being limited to the embodiments described in this specification or application. Since embodiments according to the present invention may be subject to various modifications and may take various forms, specific embodiments are illustrated in the drawings and described in detail in this specification or application. However, this is not intended to limit embodiments according to the concept of the present invention to specific disclosed forms, and it should be understood that they include all modifications, equivalents, and substitutions that fall within the spirit and scope of the present invention. Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by those skilled in the art to which the present invention pertains. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an ideal or overly formal sense unless explicitly defined in this specification. Hereinafter, embodiments disclosed in this specification will be described in detail with reference to the attached drawings. Identical or similar components regardless of drawing symbols are given the same reference number, and redundant descriptions thereof will be omitted. In the description of the following embodiments, the term "pre-set" means that the numerical value of a parameter is predetermined when the parameter is used in a process or algorithm. Depending on the embodiment, the numerical value of the parameter may be set when the process or algorithm starts or during the period in which the process or algorithm is executed. The suffixes "module" and "part" used for components in the following description are assigned or used interchangeably solely for the ease of drafting the specification, and do not inherently possess distinct meanings or roles. In describing the embodiments disclosed in this specification, if it is determined that a detailed description of related prior art may obscure the essence of the embodiments disclosed in this specification, such detailed description is omitted. Furthermore, the attached drawings are inten