阅读说明：本技术 电力变换装置 (Power conversion device ) 是由 佐野壮太 佐竹彰 大石洁 横仓勇希 樋渡天次郎 于 2017-12-07 设计创作，主要内容包括：具有：控制量运算部(13),其根据电力变换器(11)的输出电流和通断状态对表示旋转电机(3)的驱动状态的大于或等于两个控制量进行计算；带限幅指令值生成部(15),其以控制量的指令值为基准而生成带限幅指令值；以及通断状态决定部(16),其以使得控制量收敛于带限幅指令值的限幅内的方式决定通断状态,针对至少一个带限幅指令值,使其限幅基于旋转电机(3)的驱动状态随时间变化。(Comprising: a control amount calculation unit (13) that calculates two or more control amounts that represent the driving state of the rotating electrical machine (3) from the output current and the on-off state of the power converter (11); a band-limiting instruction value generation unit (15) that generates a band-limiting instruction value on the basis of the instruction value of the control amount; and an on-off state determination unit (16) that determines the on-off state such that the control amount converges within the slice with slice command value, and for at least one of the command values with slice, changes the slice with time based on the drive state of the rotating electrical machine (3).)

1. A power conversion device, which is a control device for a power converter that supplies electric power for driving a rotating electric machine by on-off operation of a switching element, comprises:

a control amount calculation unit that calculates two or more control amounts indicating a driving state of the rotating electrical machine based on an output current of the power converter and on/off states of switching elements of the power converter;

a band-limiting command value generation unit that generates a band-limiting command value having a limit of a ripple of the control amount, based on the command value of the control amount; and

an on-off state determination unit that determines an on-off state based on the control amount and the band limiter command value such that the control amount converges within the limiter of the band limiter command value,

for at least one of the band limiting instruction values, limiting of the band limiting instruction value is made to vary with time based on a driving state of the rotating electric machine.

2. The power conversion device according to claim 1,

the control amount of the rotating electrical machine is a torque and a stator interlinkage magnetic flux of the rotating electrical machine.

3. The power conversion device according to claim 1,

the control amount of the rotating electrical machine is a current on two-axis orthogonal rotation coordinates of the rotating electrical machine.

4. The power conversion device according to claim 1,

the control amount of the rotating electrical machine is a current on two-axis orthogonal stationary coordinates of the rotating electrical machine.

5. The power conversion device according to any one of claims 1 to 4,

the limiter-equipped command value generation unit calculates a drive state of the rotating electrical machine from a phase of the stator linkage flux as the control amount, and changes the limiter of the limiter-equipped command value with time based on the drive state of the rotating electrical machine.

6. The power conversion device according to any one of claims 1 to 4,

the limiter-equipped command value generation unit calculates the drive state of the rotating electrical machine from the slope of the trajectory of the control amount, and changes the limiter of the limiter-equipped command value over time based on the drive state of the rotating electrical machine.

7. The power conversion device according to any one of claims 1 to 6,

the on-off state determination unit calculates a trajectory and an on-off number of the control amount extending from a sampling point to a slice with the slice command value for each voltage vector corresponding to the on-off state by using a calculation model formula of a rotating electrical machine for the control amount, and determines the on-off state with the largest evaluation value using the length of the trajectory/the on-off number as an evaluation value.

Technical Field

The present invention relates to a direct torque control type power conversion device used for a rotating electric machine, particularly an electric motor.

Background

Conventionally, in drive control of a multiphase ac rotating electrical machine, instantaneous current control is known in which the on/off state of a power conversion device is directly calculated based on the state (current, torque, rotation speed, and the like) of the rotating electrical machine. As one of instantaneous current control, "direct torque control" is known, and a method of determining an on/off state of a power conversion device using an on/off (Switching) table is disclosed (for example, patent document 1).

In this system, the on-off state of the "direct torque control", that is, the on-off loss is determined by the table, but in the case of a complicated operation or a device that drives a plurality of types of rotating electric machines, there is a problem in that the design of the table becomes complicated.

In order to solve this problem, a method is disclosed in which the state of the motor in the case where each on/off state is used is predicted by using model prediction, and an optimum on/off state is determined based on an evaluation function (for example, patent document 2).

In this system, control can be performed without performing table design, and an effect of reducing on-off loss is also expected.

Patent document 1: japanese laid-open patent publication No. H8-33399 (paragraphs [0013] - [0018] and FIG. 1)

Patent document 2: japanese patent laid-open No. 2006 and 174697 (paragraphs [0023] - [0033] and FIGS. 2 and 3)

Disclosure of Invention

Here, in the direct torque control disclosed in patent documents 1 and 2, the control amount is torque or rotor interlinkage magnetic flux of the rotating electric machine. When the model prediction is combined, an output current such as a current on the two-axis orthogonal rotation coordinate may be used as a control amount. The pulsation amount included in these control amounts greatly varies depending on the driving state of the rotating electric machine.

Further, the relationship between the driving state of the rotating electric machine and the fluctuation of the pulsation amount differs for two or more control amounts. In this case, in the direct torque control, a predetermined allowable pulsation width is set for the command value, and on/off control is performed so that the control amount falls within the range.

In general, the wider the ripple tolerance range, the smaller the number of times of switching per unit time, and the switching loss of the switching element can be suppressed. On the other hand, the pulsation of the control amount increases, and thus becomes a cause of torque pulsation and noise of the rotating electric machine. Therefore, the allowable pulsation width is set in consideration of both the on-off loss and the pulsation component of the controlled object, and is in a trade-off relationship.

However, since the pulsation amount included in the controlled variable is not constant, when the pulsation amount of one controlled variable is small, the other controlled variable exceeds the allowable pulsation width. Therefore, the single controlled variable becomes a pulsation that does not satisfy the allowable pulsation width. In this case, the single controlled variable may be close to the upper limit or the lower limit of the allowable range. As a result, the one control amount outputs a value different from the command value.

In addition, if the allowable pulsation width is reduced to avoid this problem, the number of times of on/off operations increases extremely when the pulsation amount of the control amount is large.

The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a power conversion device capable of suppressing an on/off frequency and making a control amount follow a command value.

A power converter according to the present invention is a power converter control device for supplying electric power for driving a rotating electric machine by on-off operation of a switching element, the power converter control device including: a control amount calculation unit that calculates two or more control amounts indicating a driving state of the rotating electrical machine based on an output current of the power converter and on/off states of switching elements of the power converter; a band-limiting command value generation unit that generates a band-limiting command value having a ripple of a control amount, based on a command value of the control amount; and an on-off state determination unit that determines the on-off state based on the control amount and the band-limited command value such that the control amount falls within the limit with the limited command value, and changes the limit with the limited command value over time based on the driving state of the rotating electric machine for at least one band-limited command value.

ADVANTAGEOUS EFFECTS OF INVENTION

The power conversion device according to the present invention includes: a band-limiting command value generation unit that generates a band-limiting command value having a ripple of a control amount with reference to a command value of the control amount; and an on-off state determination unit that determines the on-off state based on the control amount and the band-limited command value such that the control amount falls within the limit with the limited command value, and changes the limit with the limited command value over time based on the driving state of the rotating electric machine for at least one band-limited command value. Therefore, it is possible to suppress the occurrence of an error between the command value and the output value due to a fluctuation in the pulsation amount of the control amount caused by the driving state of the rotating electric machine, and it is possible to suppress an increase in the on-off frequency by avoiding the occurrence of an error without reducing the amplitude of the pulsation.

Drawings

Fig. 1 is a functional block diagram of a power conversion device according to embodiment 1 of the present invention.

Fig. 2 is a hardware configuration diagram of a power conversion device according to embodiment 1 of the present invention.

Fig. 3 is a diagram showing a phase region of stator interlinkage magnetic flux according to the power conversion device of embodiment 1 of the present invention.

Fig. 4 is a diagram showing an example of a band-limited command value with respect to a control amount command value in the power conversion device according to embodiment 1 of the present invention.

Fig. 5 is an internal block diagram of the on/off state determination unit according to the power conversion device of embodiment 1 of the present invention.

Fig. 6 is an explanatory diagram of hysteresis characteristics of the torque comparator of the on/off state determining unit according to the power conversion device of embodiment 1 of the present invention.

Fig. 7 is an explanatory diagram of hysteresis characteristics of the magnetic flux comparator of the on-off state determining unit according to the power conversion device of embodiment 1 of the present invention.

Fig. 8 is an explanatory diagram of an on-off table of the on-off state determination unit according to the power conversion device of embodiment 1 of the present invention.

Fig. 9A is a voltage vector explanatory diagram of the on-off table according to the power conversion device of embodiment 1 of the present invention.

Fig. 9B is a voltage vector explanatory diagram of the on-off table according to the power conversion device of embodiment 1 of the present invention.

Fig. 10 is a functional block diagram of a power conversion device according to embodiment 2 of the present invention.

Fig. 11 is an internal block diagram of the on/off state determination unit according to the power conversion device of embodiment 2 of the present invention.

Fig. 12 is an explanatory diagram of model prediction by the on-off state determination unit in the power conversion device according to embodiment 2 of the present invention.

Fig. 13 is an explanatory diagram of model prediction by the on-off state determination unit in the power conversion device according to embodiment 2 of the present invention.

Fig. 14 is an explanatory diagram of model prediction by the on-off state determination unit according to the power conversion device of embodiment 2 of the present invention.

Fig. 15 is a functional block diagram of a power conversion device according to embodiment 3 of the present invention.

Fig. 16 is an internal block diagram of the on/off state determination unit according to the power conversion device of embodiment 3 of the present invention.

Fig. 17 is another functional block diagram relating to a power conversion device according to embodiment 3 of the present invention.

Fig. 18 is a functional block diagram relating to a power conversion device according to embodiment 4 of the present invention.

Fig. 19 is a diagram showing an example of a band-limited command value with respect to a control amount command value in the power conversion device according to embodiment 4 of the present invention.

Detailed Description