JP2006333572A - Vehicle power converter and carrier frequency controlling method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To combine a reduction in a noise sound from a PWM-controlled power converter mounted to a vehicle and an improvement in the conversion efficiency. <P>SOLUTION: A power converter includes an inverter 2a driven by a PWM control, a noise level sensor 7 for detecting a noise within the vehicle, and a carrier frequency controlling section 8a for varying a carrier frequency for the PWM control opposite to the noise detected by the noise level sensor 7. When the noise within the vehicle due to a wind noise and a road noise is increased by high-speed running, the carrier frequency is decreased and the power conversion efficiency is enhanced. When the noise within the vehicle is decreased by low-speed running, the carrier frequency is increased and the noise is suppressed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a PWM-controlled vehicle power conversion device used for power feeding of a drive motor and the carrier frequency control method thereof.

  2. Description of the Related Art Conventionally, an electric type vehicle such as an electric vehicle or a train includes a power conversion device including an inverter and a converter.

  These vehicle power converters are driven by so-called PWM control to supply AC or DC power to a drive motor or the like.

  By the way, in this type of power converter, since the PWM controlled triangular wave or the sawtooth carrier frequency is an audible frequency band of about 20 Hz to 20 kHz, an unpleasant noise noise is generated. It is known that it becomes larger as the load becomes higher.

  On the other hand, humans are most sensitive to sounds of 1 kHz to 10 kHz in terms of auditory characteristics, and the sensitivity decreases as the sound gets farther from the frequency band range.

  Then, at high loads where noise noise based on the carrier frequency of the PWM control becomes a problem, noise noise increases when the carrier frequency is lowered. Therefore, conventionally, the noise frequency is increased by increasing the carrier frequency ( (For example, refer to Patent Document 1).

JP-A-5-184182 (paragraphs [0008], [0011], [0020]-[0021], FIGS. 1 and 3)

  Focusing only on noise noise generated by the carrier frequency of the power converter as in the conventional proposal (described in Patent Document 1), the carrier frequency is increased unconditionally at high loads such as during acceleration when the noise noise increases. If the noise noise is reduced (relaxed), the power conversion efficiency will be reduced by increasing the carrier frequency. Therefore, there is a problem that the power supply becomes insufficient when accelerating during high-speed driving, and sufficient acceleration force cannot be obtained. is there.

  In the present invention, when this type of vehicle moves (during running), noise that becomes so-called background noise such as wind noise and road noise is generated in the vehicle, and this noise increases as the vehicle runs at high speed. The noise sound caused by the carrier frequency is noticed that the noise is drowned out, and the noise sound of the PWM-controlled power conversion device mounted on the vehicle is reduced and the conversion efficiency is improved. The purpose is to achieve both.

  In order to achieve the above-described object, a power converter for a vehicle according to the present invention includes an inverter or converter switching unit driven by PWM control, a noise level sensor for detecting vehicle interior noise, and noise detected by the noise level sensor. The carrier frequency control part which changes the carrier frequency of the PWM control of the said switching part is provided on the contrary (Claim 1).

  The vehicle power converter according to the present invention includes an inverter or converter switching unit driven by PWM control, and carrier frequency control for varying the PWM control carrier frequency of the switching unit in reverse of the vehicle speed detected by the vehicle speed sensor. (2).

  Furthermore, the vehicle power conversion device of the present invention is characterized in that the carrier frequency control unit varies the carrier frequency of PWM control of the switching unit by step switching including binary switching (Claim 3). The frequency control unit holds the carrier frequency map of the PWM control of the switching unit that changes inversely to the detected noise or the detected host vehicle speed in the storage unit, and determines the carrier frequency of the PWM control of the switching unit based on the detected noise or the detected vehicle speed. The frequency may be changed to a frequency read from the carrier frequency map.

  Next, a carrier frequency control method for a vehicle power conversion device according to the present invention is characterized in that in-vehicle noise is detected and the carrier frequency of PWM control of the switching unit is varied in reverse to the detected noise. In addition, the carrier frequency of the PWM control of the switching unit is varied in reverse of the detected vehicle speed (Claim 6).

  First, according to the configurations of claims 1 and 5, the vehicle interior noise based on wind noise or road noise generated with the movement of the vehicle is directly detected, and the detected noise is increased to increase the carrier frequency of PWM control. When driving at a high speed where the noise caused by the noise is drowned out by the noise, the carrier frequency is lowered, the power conversion efficiency of the switching unit is improved, the detected noise in the vehicle is reduced, and the carrier is reduced. When the vehicle is traveling at a low speed where the noise noise caused by the frequency is relatively large, the carrier frequency of the switching unit is increased to suppress the noise noise.

  Therefore, the configuration that directly detects the noise in the vehicle accurately changes the noise sound generated by the power converter according to the vehicle noise so that the driver in the vehicle does not care, and during acceleration during high-speed driving For example, it is possible to improve the power conversion efficiency to obtain a sufficient acceleration force and the like, and to achieve both reduction of noise noise and improvement of conversion efficiency.

  According to the second and sixth aspects of the invention, the noise in the vehicle increases as the traveling speed of the vehicle increases. Therefore, instead of detecting the noise in the vehicle, the vehicle speed is detected and the vehicle is detected. In this case, it is unnecessary to detect the noise in the vehicle, and the vehicle speed can be detected by the existing vehicle speed sensor of the vehicle. There is also an effect.

  Next, according to the configuration of the third aspect, step switching including binary (high and low) switching of the carrier frequency based on the detected noise in the vehicle or the detected vehicle speed based on the variable of the PWM control carrier frequency of the switching unit. Can be realized easily.

  According to the fourth aspect of the present invention, the PWM control carrier frequency of the switching unit can be varied by reading the carrier frequency from the carrier frequency map of the storage means based on the detected noise in the vehicle or the detected vehicle speed. In this case, the carrier frequency can be varied with higher accuracy than step switching.

  Next, in order to describe the present invention in more detail, the embodiment will be described in detail with reference to FIGS.

<First Embodiment>
First, a first embodiment for directly detecting vehicle interior noise will be described with reference to FIGS.

  FIG. 1 shows a configuration when applied to a power conversion device for an electric vehicle. A driving motor 1a composed of a three-phase brushless motor or the like is rotated by a three-phase power source that is feedback-controlled from an inverter 2a as a switching unit. Driven.

  The inverter 2a is constituted by a power switching semiconductor three-phase full-bridge circuit such as an IGBT similarly to a known power inverter, and is driven by PWM control according to the drive pulse of each phase of PWM control of the PWM generator 3. Then, the DC power supply of the power supply unit 4a is turned on / off.

  Further, the PWM drive pulse signal of each phase of the PWM generator 3 includes a drive command signal S1 for feedback control of the motor drive command section 3 that varies in level according to the rotational fluctuation of the motor 1a, and a triangular wave ( For example, as shown in FIG. 2, the level portion of the reference wave signal S2 that is equal to or higher than the drive command signal S1 is a signal of a pulse P having an energization (on) level width. The frequency (PWM control carrier frequency) is determined by the frequency of the reference wave signal S2.

  Next, a noise level sensor 7 for detecting vehicle interior noise is provided in the interior of the electric vehicle.

  The sensor 7 is composed of a microphone or the like as well as a known noise level sensor (noise sensor), and is provided on a dashboard or the like, for example, to mainly detect noise in the vicinity of the driver.

  Further, a noise signal detected by the noise level sensor 7 that changes in proportion to the in-vehicle noise is taken into the carrier frequency controller 8a.

  The carrier frequency control unit 8a includes storage means 9a formed by a nonvolatile memory such as an EEPROM, and stores a map of the carrier frequency (frequency of the reference wave signal S2) of PWM control that changes in reverse to the in-vehicle noise in the storage means 9a. Hold.

  The characteristics of this map are set by measuring in advance the carrier frequency that makes noise sound of a degree that passengers such as drivers do not mind using the in-vehicle noise generated under various driving environments as a parameter, for example, Taking into account the reduction effect of noise generated by the inverter 2a and the stability of rotation of the motor 1a, the carrier frequency of PWM control is set to, for example, 20 kHz (in-vehicle noise) for in-vehicle noise in a range generated under various driving environments. The storage means 9a holds the reset level for controlling the carrier frequency, which varies with the above characteristic, in a range of 15 kHz (when the vehicle interior noise is high).

  2 is output from the carrier frequency control unit 8a to the carrier frequency generator 6 based on the detected noise signal of the noise level sensor 7 and changing in accordance with the detected noise every moment.

  The carrier frequency generator 6 forms a triangular wave (sawtooth) signal S2 of a reference frequency set below the lowest frequency of the reference wave signal S2 by free-running oscillation or the like, and the signal S2 reaches the reset level of the signal S3a. Every time it is reset instantaneously, its output falls.

  Therefore, as is clear from FIG. 2, the frequency of the reference wave signal S2 changes in proportion to the reset level, in other words, in reverse to the in-vehicle noise.

  Since the frequency of the PWM drive pulse of each phase of the PWM generator 3 changes according to the change of the frequency of the reference wave signal S2, the inverter 2a increases the in-vehicle noise, and the noise of the inverter 2a drowns out the in-vehicle noise. When the PWM control carrier frequency is lowered, the conversion efficiency is improved, and when the in-vehicle noise is reduced and the noise sound of the inverter 2a is relatively increased, the PWM control carrier frequency is increased and the noise sound is increased. Get smaller.

  Therefore, in the case of the above embodiment, the noise level sensor 7 directly detects in-vehicle noise based on wind noise or road noise generated as the vehicle travels (moves), and the detected noise increases and the inverter 2a increases. During high-speed running where the noise caused by the carrier frequency of PWM control is drowned out by the noise, the carrier frequency is lowered to improve the power conversion efficiency of the inverter 2a, which is sufficient for acceleration. When the vehicle can travel at a low speed when power can be supplied to the motor 1a and the detected noise in the vehicle is reduced and the noise noise caused by the carrier frequency is relatively high, the noise frequency is increased by increasing the carrier frequency of the inverter 2a. Can be suppressed.

  Therefore, with the configuration that directly detects the noise in the vehicle with high accuracy, the noise generated by the inverter 2a is automatically varied according to the vehicle noise so that the driver in the vehicle does not care, and during acceleration during high-speed traveling For example, it is possible to improve the power conversion efficiency to obtain a sufficient acceleration force and the like, and to achieve both reduction of noise noise and improvement of conversion efficiency.

  In addition, the storage means 9a of the carrier frequency control unit 8a holds a map of the characteristics of the carrier frequency of the PWM control with respect to the vehicle interior noise. Based on this map, the carrier frequency of the PWM control is continuously varied, and is detected every moment. It can be changed with very high accuracy according to the noise.

<Second Embodiment>
Next, a second embodiment for detecting vehicle interior noise from the vehicle speed will be described with reference to FIG.

  3 shows a configuration when applied to a power converter for an electric vehicle. In FIG. 3, the same reference numerals as those in FIG. 1 denote the same components, and the difference from FIG. The sensor 7 is omitted, and instead the vehicle speed signal detected by the existing vehicle speed sensor 10 composed of a wheel speed sensor or the like is used as a detection signal for in-vehicle noise. Second, the carrier frequency control unit 8a in FIG. Instead, a carrier frequency control unit 8b provided with a storage means 9b is provided.

  In addition, in this embodiment, the in-vehicle noise is indirectly detected from the signal of the in-vehicle speed detected by the vehicle speed sensor 10 because the in-vehicle noise based on wind noise and road noise increases as the own vehicle speed increases. To detect.

  Further, the storage means 9b formed of a non-volatile memory has a PWM control carrier that changes in reverse of the vehicle speed detected by the vehicle speed sensor 10 instead of the carrier frequency map of the PWM control for the vehicle interior noise of the storage means 9a of FIG. Holds a frequency map.

  This map is formed in the same manner as the map of the storage means 9a, and the variable characteristic of the carrier frequency of the PWM control with respect to the vehicle interior noise detected via the detected vehicle speed is the same as the characteristics of the map of the storage means 9a.

  Then, based on the signal of the detected vehicle speed detected by the vehicle speed sensor 10, a reset similar to the signal S3a of FIG. 1 is made from the carrier frequency control unit 8b to the in-vehicle noise (detected noise) detected via the detected vehicle speed. A level signal S3b is applied to the carrier frequency generator 6.

  Therefore, in the case of this embodiment, the same effect as in the case of the first embodiment can be obtained at low cost by using the existing vehicle speed sensor 10 without newly providing a sensor such as the noise level sensor 7. Can do.

<Third Embodiment>
Next, a third embodiment will be described with reference to FIG.

  FIG. 4 shows a partial configuration when applied to a power converter for an electric vehicle similar to the first and second embodiments. In FIG. 4, 1b, 2b and 4b denote the motor 1a shown in FIGS. The same motor, inverter and power supply unit as the inverter 2a and power supply unit 4a. Reference numerals 11, 12, and 13 are known first generators (or power storage means) of the power supply unit 4b, converters, and second generators (or power storage means) different in generated voltage from the first generator (or power storage means). ) Each.

  When the voltage difference between the first generator (or power storage means) 11 and the second power generator (or power storage means) 13 is adjusted by the converter 12 and power is supplied between them (or in one direction). At the same time, DC power is supplied from the second generator (or power storage means) 13 to the inverter 2b.

  By the way, the inverter 2b and the converter 12 are each a switching unit driven by PWM control, both of which are based on the drive command signal and the reference wave signal corresponding to the signals S1 and S2 in FIGS. It is driven by PWM control with a signal of the same drive pulse as that of the above signal to generate a noise sound of the carrier frequency of PWM control.

  Therefore, in this embodiment, either the inverter 2b or the converter 12 or the converter 12 is configured by using the noise level sensor 7 and the carrier frequency control unit 8a of FIG. 1 or the vehicle speed sensor 10 and the carrier frequency control unit 8b of FIG. Both carrier frequencies are varied opposite to the in-vehicle noise in the same manner as in the first and second embodiments.

  Therefore, in the case of this embodiment, the same effects as those in the first and second embodiments can be obtained with respect to the noise noise of the switching unit formed by the inverter 2b and the converter 12.

  The present invention is not limited to the above-described embodiments. For example, application to a converter installed between a fuel cell of a fuel cell vehicle and a power storage means, other than those described above, without departing from the spirit of the present invention. Various changes can be made.

  For example, in each of the above-described embodiments, a carrier frequency characteristic map with respect to in-vehicle noise or own vehicle speed is held in the storage means 9a, 9b of the carrier frequency control units 8a, 8b, and PWM is generated by signals S3a, S3b formed based on the map. The carrier frequency of the control is continuously varied, but the carrier frequency control unit compares the detected noise, the detected vehicle speed with one or more threshold values, and changes stepwise including a high / low binary change. The reset level signal may be formed, and the carrier frequency of PWM control may be varied by step switching including binary switching.

  In addition, the variable range of the PWM control carrier frequency may be set appropriately based on experiments or the like, and even if the PWM control circuit configuration of the inverters 2a, 2b, etc. is different from those shown in FIGS. Of course it is good.

  Furthermore, for example, each part except the motor 1a, the inverter 2a, and the sensors 7 and 10 in FIGS. 1 and 3 can be formed by a so-called hardware circuit, and of course, formed by software processing of the ECU of the microcomputer. Of course you can.

  The present invention can be applied to power converters for inverters or converters of various vehicles such as automobiles and trains. At that time, the output of the power converter is fed to the motor as in the above embodiments. It doesn't have to be a thing.

It is a block diagram of a 1st embodiment of this invention. It is a wave form diagram for operation | movement description of FIG. It is a block diagram of 2nd Embodiment of this invention. It is a block diagram of 3rd Embodiment of this invention.

Explanation of symbols

2a, 2b Inverter 7 Noise level sensor 8a, 8b Carrier frequency control unit 9a, 9b Storage means 12 Converter

Claims (6)

A switching unit of an inverter or converter driven by PWM control;
A noise level sensor for detecting vehicle interior noise,
A vehicle power conversion device comprising: a carrier frequency control unit configured to vary a carrier frequency of PWM control of the switching unit opposite to noise detected by the noise level sensor. A switching unit of an inverter or converter driven by PWM control;
A vehicle power conversion device comprising: a carrier frequency control unit configured to vary a carrier frequency of PWM control of the switching unit opposite to the vehicle speed detected by the vehicle speed sensor.   The vehicle power conversion device according to claim 1 or 2, wherein the carrier frequency control unit varies the carrier frequency of PWM control of the switching unit by step switching including binary switching.   The carrier frequency control unit holds the carrier frequency map of the PWM control of the switching unit that changes in reverse to the detected noise or the detected vehicle speed in the storage unit, and the carrier frequency of the PWM control of the switching unit based on the detected noise or the detected vehicle speed The vehicle power conversion device according to claim 1, wherein the frequency is changed to a frequency read from the carrier frequency map. A carrier frequency control method for a vehicle power conversion device including a switching unit of an inverter or converter driven by PWM control,
A carrier frequency control method for a power converter for a vehicle, wherein the carrier frequency of PWM control of the switching unit is varied in reverse of the detected noise by detecting in-vehicle noise. A carrier frequency control method for a vehicle power conversion device including a switching unit of an inverter or converter driven by PWM control,
A carrier frequency control method for a vehicle power converter, wherein the carrier frequency of PWM control of the switching unit is varied in reverse of the detected vehicle speed.

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