JP2020010481A - Electric motor control device for home appliance device - Google Patents

Abstract

To provide an electric motor control device with low noise for home appliance devices capable of suppressing a large capacity of memory, and suppressing a decrease in performance even in any load state.SOLUTION: An electric motor control device for home appliance devices that performs synchronous PWM control, includes: a carrier wave generation section that generates a carrier wave; a PWM control command generation section that generates a PWM control command for controlling an electric motor on the basis of an input voltage command and the carrier wave; a control section that controls the electric motor on the basis of the PWM control command; and a deviation detection section that detects a voltage phase deviation between the voltage command and a predetermined reference voltage command. The carrier wave generation section that generates the carrier wave on the basis of a voltage phase deviation and an inputted frequency command is configured such that an interval between a time when the voltage phase deviation is detected by the deviation detection section and a time when the voltage phase deviation is not detected becomes constant irrespective of the load of the electric motor.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a motor control device for home electric appliances.

  Conventionally, home appliances such as vacuum cleaners and washing machines have performed asynchronous PWM control.

  However, when the driving frequency is increased, there is a possibility that motor noise as an electric motor is generated. In order to reduce noise, Patent Document 1 discloses performing synchronous PWM control and correcting a voltage command using a carrier synchronization correction map stored in advance.

JP 2013-223308 A

  However, in Patent Literature 1, there is no carrier synchronization correction map for each carrier wave, and depending on the load condition of the motor, the predetermined carrier synchronization correction map may not be sufficiently corrected and performance may be reduced, or When many carrier synchronization correction maps corresponding to all loads are stored in advance, the capacity of the memory is increased.

  SUMMARY OF THE INVENTION It is an object of the present invention to provide a motor controller for a low-noise household electric appliance that can suppress a large capacity of a memory and can suppress a decrease in performance even in any load state.

  SUMMARY OF THE INVENTION The present invention is directed to a motor control device for a household electric appliance that performs synchronous PWM control to solve the above-mentioned problem, and controls a motor based on an input voltage command and a carrier wave to generate a carrier wave. A PWM control command generation unit that generates a PWM control command to be performed, a control unit that controls the electric motor based on the PWM control command, a shift detection unit that detects a voltage phase shift between the voltage command and a predetermined reference voltage command, The carrier wave generation unit generates a carrier wave based on the voltage phase shift and the input frequency command, from a time when the voltage phase shift is detected by the shift detection unit to a time when the voltage phase shift is not detected. Is constant regardless of the load of the motor.

  ADVANTAGE OF THE INVENTION According to this invention, the motor control apparatus for low-noise household appliances which can suppress increase in memory capacity and can suppress the performance fall even in every load state can be provided.

It is a figure showing the control block of the electric motor control device for household appliances concerning the present invention. It is a figure showing the appearance of a vacuum cleaner. It is a figure explaining correction of a voltage phase gap of a motor control device for household appliances of the present invention.

  The present invention relates to a motor control device for a household electric appliance that controls a motor 105 having windings of a plurality of phases. As an embodiment of the present invention, a motor control device of the vacuum cleaner 10 will be described in detail below as an example. The motor will be described below as a permanent magnet synchronous motor.

  FIG. 2 is an external view of the vacuum cleaner 10 according to the present invention. FIG. 1 is a basic configuration diagram of a motor control device according to the present invention.

  In FIG. 1, a shift detecting unit 101 detects a voltage phase shift Δθv based on an input voltage command and a predetermined ideal voltage command during synchronous PWM control. Specifically, the “current voltage phase” is calculated by a predetermined calculation from the input voltage command. A deviation (deviation) between the calculated “current voltage phase θv” and “reference voltage phase θvbase at the time of synchronous PWM” is output as a voltage phase deviation Δθv.

  Next, the carrier wave generation unit 102 calculates the carrier cycle Tc from the voltage phase shift Δθv output from the shift detection unit 101, the input frequency command ω *, and the carrier pulse number Np set based on the frequency command ω *. Determine and generate a carrier wave. The pulse number Np indicates how many times the carrier frequency is greater than the frequency command ω *. In the case of Np = 3 (three pulses), three times the frequency command ω *, that is, three cycles of the carrier wave exist during one cycle of the frequency command. Np is desirably set at an odd multiple of three. That is, in the present embodiment, Np = 3 will be described, but Np = 9 can be set.

  Specifically, the carrier frequency Fc can be calculated as 2π × Np × {(Δθv × Kv) + ω *}. Here, Kv is a preset PLL gain. The carrier cycle Tc is 1 / Fc.

  For example, if the PLL gain Kv is set to 1, (Δθv × 1) [rad / s] will be added to the frequency command ω * [rad / s], and control to correct the deviation of Δθv [rad] in one second Becomes

  Similarly, when the PLL gain Kv is 100, control is performed to correct a deviation of 100 times Δθv [rad] per second, and control is performed to correct the deviation of Δθv [rad] in 10 [ms].

  With respect to the generated voltage phase shift, control (PLL control) for correcting the shift in a fixed time is performed regardless of the magnitude of the voltage phase shift.

Next, the PWM control command generation unit 103 generates an inverter drive signal based on the carrier wave generated by the carrier wave generation unit and the input voltage command v, and sends the signal to the inverter circuit 104 serving as a control unit. Outputs inverter drive signal. Based on the inverter drive signal, the inverter circuit 104 generates a control command for controlling the electric motor 105 to which the fan 106 as a load is attached.
Although the shift detection unit 101, the carrier wave generation unit 102, and the PWM control command generation unit 103 have been described as processing in the microcomputer 100 as a processing unit, processing outside the microcomputer is also possible.

  The voltage command determines the duty to be output to each phase of the electric motor 105, and the carrier wave or the carrier cycle Tc determines the cycle of the duty.

  Next, FIG. 3 shows a relationship between a voltage phase waveform and a carrier wave at the time of voltage phase shift correction when a voltage phase shift occurs due to a load change at the time of three pulses (Np = 3), and control for correcting the voltage phase shift. (PLL (phase locked loop) control) will be described. In the PLL control, the carrier cycle Tc is determined so as to reduce the voltage phase shift Δθv.

  In this process, in order to synchronize the carrier wave and the voltage phase θv obtained from the voltage command, the error (deviation) between the voltage phase θv and the carrier wave is determined in advance with the voltage phase θv at the mountain cycle (calculated at the peak and reflected at the valley). It is calculated from the determined ideal reference voltage phase θvbase.

  In vacuum cleaners, the operation mode is frequently changed such as power ON / OFF, strong operation, and standard operation, and the load of the motor such as a mounted motor fluctuates finely by sucking dust or the like. This load change causes a voltage phase change, and the voltage phase change causes a voltage phase shift Δθv as shown in FIG.

  Before the occurrence of the voltage phase fluctuation 405, since the voltage phase shift Δθv = 0, the reference voltage phase waveform 402 becomes Cosω * t. The voltage phase shift detection point 406, specifically, the current voltage phase waveform point at the peak or valley of the carrier wave (in FIG. 3, the current voltage phase waveform at the valley of the third pulse is set as the detection point. The voltage phase shift Δθv between the current voltage phase waveform 403 and the reference voltage phase waveform 402 is detected at the current voltage phase waveform at the valley as a detection point, and PLL control is started for the voltage phase shift Δθv. The reference voltage phase waveform 404 at the time of the PLL control becomes Cos ｛ω * + (Kv × Δθv)｝ t, and the carrier wave 401 is corrected by the set response time of the PLL gain Kv. The relationship between the reference voltage phase waveform 402, the reference voltage phase waveform 404 during PLL control, and the carrier wave 401 is the same.

  As shown in FIG. 3, when the period of the voltage phase waveform is shortened (FIG. 3 (2), the rotation speed of the motor increases, that is, when the load is light), and when it becomes longer (FIG. 3 (1), the rotation speed of the motor decreases). In other words, there are two patterns, that is, when the load is heavy. Regardless of the magnitude of the fluctuation, the time from the start of the deviation correction to the end of the correction as shown in FIG. 3 is the response time set by the PLL gain Kv. Thus, the carrier wave can be corrected. At this time, the magnitude and the like of the carrier wave are different before and after the voltage phase shift detection point 406. For example, the interval from the time when the voltage phase shift is detected to the time when the voltage phase shift is not detected regardless of the operation mode of the cleaner (strong operation, standard operation, etc.) is constant.

  That is, the voltage phase shift Δθv can be corrected in the same fixed time by the shift detection unit 101 and the carrier wave generation unit 102 of the present invention. Therefore, the interval from the time when the voltage phase shift Δθv is detected by the shift detection unit 101 to the time when the voltage phase shift Δθv is not detected becomes constant regardless of the load of the electric motor 105, and the carrier wave can be accurately corrected. As a result, it is possible to provide a low-noise electric motor control device for a household electrical appliance that can suppress an increase in the capacity of a memory and can suppress a decrease in performance even in any load state.

  Note that, in the above-described embodiment, an example of a vacuum cleaner including an electric motor has been described, but the present invention may be applied to other home electric appliances such as an electric washing machine.

Reference Signs List 10 vacuum cleaner 100 microcomputer 101 displacement detection unit 102 carrier wave generation unit 103 PWM control command generation unit 104 inverter circuit 105 motor 106 fan 401 carrier wave 402 reference voltage phase waveform 403 current voltage phase waveform 404 reference voltage phase in PLL control Waveform 405 Before voltage phase fluctuation occurs 406 Voltage phase shift detection point

Claims (7)

An electric motor control device for home electric appliances that performs synchronous PWM control,
A carrier wave generation unit that generates a carrier wave;
A PWM control command generation unit that generates a PWM control command for controlling the electric motor based on the input voltage command and the carrier wave;
A control unit that controls the electric motor based on the PWM control command;
A deviation detecting unit that detects a voltage phase deviation between the voltage command and a predetermined reference voltage command,
The carrier wave generation unit generates a carrier wave based on the voltage phase shift and the input frequency command, and from a time when the voltage phase shift is detected by the shift detection unit to a time when the voltage phase shift is not detected. An electric motor control device for home electric appliances, wherein an interval is constant irrespective of a load of the electric motor. An electric motor control device for home electric appliances according to claim 1,
An electric motor control device for a home electric appliance, wherein the magnitude of the carrier wave is different before and after the voltage phase deviation is detected by the deviation detection unit. An electric motor control device for home electric appliances according to claim 1,
An electric motor control device for home electric appliances, wherein the electric motor is a permanent magnet synchronous motor. An electric motor control device for home electric appliances according to claim 1,
The electric motor control device for a home appliance, wherein the deviation detecting unit calculates a current voltage phase from a voltage command and outputs a deviation between the calculated voltage phase and the reference voltage command as a voltage phase deviation. An electric motor control device for home electric appliances according to any one of claims 1 to 4,
The electric motor control device for home electric appliances, wherein the electric motor is an electric motor of a vacuum cleaner. An electric motor control device for home electric appliances according to any one of claims 1 to 4,
The electric motor is an electric motor of a vacuum cleaner,
An electric motor control device for home electric appliances, wherein an interval from a time when a voltage phase shift is detected by a shift detection unit to a time when a voltage phase shift is not detected is constant regardless of an operation mode of the vacuum cleaner. An electric motor control device for home electric appliances according to any one of claims 1 to 4, wherein
The electric motor control device for home electric appliances, wherein the electric motor is an electric motor of an electric washing machine.

Images