JP2005341752A - Power converter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To constitute a power converter that suppresses the sound level of a reactor to a prescribed level and that can obtain required output current, without enlarging a cooling device. <P>SOLUTION: In the power converter provided with a power converter main circuit that is connected from a power converter, which is structured with a plurality of switching elements connected to a power source, to a load via a filter and a control circuit, it is configured to be able to operate the converter, by increasing the frequency of a carrier signal outputted from a carrier signal generating circuit to a carrier frequency that keeps the temperature of the power converter to be within the range of temperature specified value, based on the ambient temperature of the installation position of the power converter and the output current. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a power conversion device that converts power with a switching element.

  A configuration of a power converter that converts DC voltage into AC voltage is shown in FIG. 57 of Patent Document 1, for example. In this configuration, an inverter main circuit is connected to a DC power source, a DC voltage is converted into an AC voltage in the inverter main circuit, and a power conversion main circuit connected to a load via an AC filter composed of a reactor and a capacitor; The control circuit controls the power conversion main circuit. The control circuit uses a multiplier to output the AC sine wave reference transmission circuit and the amplitude command generation circuit to the drive circuit that drives the inverter main circuit. An output voltage command Vos is generated by multiplication, a voltage deviation ΔV between the output voltage command Vos and the output voltage Vo is obtained by an adder / subtractor, and an inverter is driven by a voltage control amplifier and a PWM modulation circuit so that the voltage deviation ΔV becomes zero. A signal is generated and input to the drive circuit, and the inverter main circuit is controlled from the drive circuit.

  The power converter using the switching element is configured such that the junction temperature of the switching element is within the allowable temperature range. The switching element has a rated value set so that the junction temperature of the switching element is the temperature obtained by adding the temperature rise due to the operating conditions such as the number of switching and energization current to the ambient temperature, and this junction temperature becomes the allowable temperature. The reactor or the like is configured to have a predetermined noise level.

In the switching element, a switching loss Psn due to the switching operation and an energization loss Pst due to the energizing current are generated, and the sum thereof is an element loss P generated in the switching element.
That is, P = Psn + Pot.
The switching loss Psn is a product of the switching energy Ps per switching and the number of times of switching n, and the energization loss Pot is a product of the ON voltage drop, the energization current Po, and the energization time ratio t.
Since the switching frequency of the switching element is proportional to the frequency of the carrier signal fc, the relationship between the switching loss Psn and the frequency of the carrier signal fc increases as the frequency of the carrier signal fc increases as shown in FIG.
As shown in FIG. 12, the relationship between the output current Io and the switching element loss P increases as the output current Io increases.
The reactor noise is caused by the magnetic distortion of the iron core. Under the condition where the output current Io is constant, the noise level Sn decreases as the frequency of the carrier signal fc increases as shown in FIG.

  Further, since the waveform distortion rate of the output voltage Vo becomes lower as the frequency of the carrier wave signal fc is increased, the frequency of the carrier wave signal fc is determined to be a value considering the waveform distortion rate of the output voltage Vo.

  As described above, in order to keep the reactor noise low, it is necessary to increase the frequency of the carrier wave signal fc, but the switching loss Psn of the switching element increases and the temperature rise increases. As the output current Io increases, the switching element loss P also increases. Therefore, in the power converter, the frequency of the carrier wave signal fc is determined so that the junction temperature of the switching element falls within the allowable temperature, the noise level is suppressed to a predetermined level, and the waveform distortion rate of the output voltage Vo is also equal to or lower than the predetermined value. It has been.

Japanese Patent Laid-Open No. 10-295083

As described above, it is necessary to set the frequency of the carrier signal fc high in order to keep the reactor noise level low, but if the frequency of the carrier signal fc is set high, the switching loss Psn increases. Therefore, there is a problem that the cooling means becomes large.
Further, in order to keep the waveform distortion rate of the output voltage Vo within the specification value, it is necessary to set the carrier frequency fc high. However, since the junction temperature of the semiconductor switch is limited, the output current value is kept low, or There was a problem that the cooling means had to be enlarged in order to improve the cooling.

  The present invention has been made to solve the above-described problems, and the required noise can be obtained by suppressing the reactor noise level to a predetermined level without increasing the size of the cooling device for the power converter. It is an object of the present invention to constitute a power conversion device in which the waveform distortion rate of the output voltage becomes a specification value without increasing the size of the power conversion device or the cooling device.

  The power conversion device according to the present invention is a power conversion main circuit that supplies a conversion output of a power converter composed of a plurality of switching elements connected to a DC power supply to a load via an AC filter composed of a reactor and a capacitor. And a voltage detection means for detecting the output voltage of the power converter circuit, and a control circuit for controlling the power converter. The maximum ambient temperature at the position where the power converter is disposed is set as the set temperature, and the junction temperature of the power converter is The control circuit includes a carrier signal generation circuit that generates a carrier wave signal and a control signal generation circuit that generates a control signal. The control signal generation circuit generates an output voltage command value and an output voltage. The voltage deviation is obtained, the output voltage command value is calculated so that this voltage deviation becomes zero, and the output voltage command value and the carrier signal generated by the carrier signal generation circuit are calculated. In the power converter that controls the power converter from the drive circuit by generating a control signal from the drive circuit, the ambient temperature detection means for detecting the ambient temperature at the position where the power converter is disposed, and the power converter Output current detection means for detecting the output current and carrier wave signal frequency switching means are provided. The carrier wave signal frequency switching means is a carrier wave output from the carrier wave signal generation circuit based on the detected ambient temperature and the output current of the power converter. In this configuration, the frequency of the signal is switched to a frequency at which the temperature of the power converter falls within the temperature specified range.

  According to the present invention, the temperature of the power converter is controlled by the carrier wave signal having a frequency that falls within the specified range of the allowable temperature of the switching element, and the cooling means of the power converter is not increased in size. Thus, a power conversion device in which the noise of the reactor constituting the AC filter is suppressed to a low level can be obtained.

Embodiment 1 FIG.
FIG. 1 is a block diagram showing the configuration of the power conversion apparatus according to the first embodiment. This configuration includes a power converter 2 composed of a plurality of switching elements connected to the DC power source 1, an output current detection means 3 for detecting the output current Ia of the power converter 2, a reactor 5a and a capacitor 5b. The AC filter 5 and the voltage detection means 6 for detecting the output voltage Vo constitute a power conversion main circuit and connected to the load 7.
A control circuit 10 that controls the power conversion main circuit includes a voltage command generation circuit 11 that generates a voltage command Vos, and a subtractor 12 that compares the voltage command Vos and the output voltage Vo of the power conversion main circuit to calculate a voltage deviation ΔV. A voltage command generation circuit 13 for generating a voltage control command Vas based on the voltage deviation ΔV, a carrier signal generation circuit 14 for generating a carrier signal, and a control signal PWM signal for the power converter 2 based on the voltage control command Vas and the carrier signal fc. The control signal generation circuit 15 for generating the power converter 2 and the drive circuit 16 for driving the power converter 2.

  The carrier wave signal generation circuit 14 includes a voltage control type carrier wave oscillator 14a and a carrier wave signal generator 14b, and the carrier wave oscillator 14a has an oscillation frequency that is proportional to the input voltage as shown in FIG. The carrier wave signal generator 14b generates, for example, a triangular carrier wave signal fc based on the carrier wave.

The carrier signal generation circuit 14 is controlled by an ambient temperature detection means 17 that detects the ambient temperature Ta of the power converter 2 and a carrier signal frequency switching circuit 18 that switches the oscillation frequency of the voltage-controlled carrier oscillator 14a. The carrier wave signal frequency switching circuit 18 stores the maximum ambient temperature at the installation position of the power converter 2 as the set temperature To, and can be allowed in consideration of the junction temperature Tj allowable to the power converter 2 under the condition of the set temperature To. The temperature is set to a specified temperature value Tm, and the output current Ia at which the power converter 2 becomes the specified temperature value Tm at the set temperature To is stored as the output current set value Ios. The difference between the detected ambient temperature Ta and the set temperature To and the output From the difference between the current Ia and the output current set value Ios, the frequency of the carrier signal fc in which the temperature of the power converter 2 falls within the temperature specified value Tm is calculated, and the carrier wave generator 14a of the carrier wave signal generation circuit 14 is commanded. Control is performed so as to output a carrier wave signal fc of a frequency commanded from the carrier wave signal generation circuit 14.
As shown in FIG. 2B, the input voltage Vf input to the reference oscillator 14a is three-dimensional with the ambient temperature Ta as the X axis, the output current Ia as the Y axis, and the input voltage Vf applied to the carrier wave oscillator 14a as the Z axis. The oscillator input voltage Vf to be applied to the reference oscillator 14a is calculated from the detected ambient temperature Ta and output current Ia, and the calculated oscillator input voltage Vf is applied to the carrier wave oscillator 14a to obtain a desired frequency. Are output.

  The power converter compares the voltage command Vos of the voltage command generation circuit 11 with the output voltage Vo of the power conversion main circuit by the subtractor 12 to calculate a voltage deviation ΔV, and based on this voltage deviation ΔV, the voltage control command generation circuit 13 generates a voltage control command Vas, and the control signal generation circuit 15 generates a PWM signal for controlling the power converter 2 based on the voltage control command Vas and the carrier signal fc from the carrier signal generation circuit 14. And the power converter 2 is controlled by the drive circuit 16 based on the PWM signal.

  If the power converter 2 is configured in this way, it can be operated with the carrier wave signal fc switched to an allowable frequency according to the situation of the ambient temperature Ta and the output current Ia, and the carrier frequency is set to the allowable temperature of the power converter 2. By operating at a high setting in this range, the power converter 2 can be a power converter that suppresses the noise level of the reactor and the like without increasing the size of the cooling means of the power converter 2.

Embodiment 2. FIG.
FIG. 3 is a block diagram illustrating a configuration of the power conversion device according to the second embodiment. In this configuration, the carrier wave signal generation circuit having the configuration shown in FIG. 1 of the first embodiment is a carrier wave oscillator having a constant oscillation frequency, and the oscillation frequency is divided to output a carrier wave signal fc having an appropriate frequency. is there.
This configuration includes a DC power source 1, a power converter 2, an output current detection unit 3, an AC filter 5, a voltage detection unit 6, a load 7, and a voltage command generation circuit 11 that constitutes a control circuit 10 in the power converter main circuit portion, The subtractor 12, the voltage control command generation circuit 13, the control signal generation circuit 15, the drive circuit 16, and the ambient temperature detection means 17 are the same as those in FIG.
3 includes a carrier wave oscillator 24c having a constant oscillation frequency, a carrier wave signal generator 24b, and a frequency divider 24d disposed between the carrier wave oscillator 24c and the carrier wave signal generator 24b. The carrier wave oscillator 24c oscillates the carrier wave having the highest frequency necessary for control, and the frequency divider 24d divides the carrier wave oscillated by the carrier wave oscillator 24c by the division ratio n to generate a carrier wave having the required frequency. For example, a triangular wave carrier signal fc is generated and output by the carrier signal generator 24b using the divided carrier wave.

The carrier signal frequency switching means 28 for controlling the carrier signal generation circuit 24 stores the maximum ambient temperature at the position where the power converter 2 is disposed as the set temperature To and is allowed to the power converter 2 under the condition of the set temperature To. The allowable temperature considering the possible junction temperature Tj is set as the temperature specified value Tm, the output current Ia at which the power converter 2 becomes the temperature specified value Tm at the set temperature To is stored as the output current set value Ios, and the detected ambient temperature Ta And the set temperature To, and the relationship between the detected output current Ia and the output current set value Ios, the carrier wave output from the carrier oscillator 24c is divided by a predetermined division ratio n shown in FIG. A carrier signal fc is generated by the carrier signal generator 24b using a carrier having an appropriate frequency.
Division ratio n to be _{selected, a 1 <a 2 <a 3 <a} 4 Nookisajun'nisetteishi,Ta<To,Ta> To and Ia <Ios, Ia> division ratio selecting a relationship Ios n The relationship is as shown in FIG. 4. When the output current Ia is large and the ambient temperature Ta is high, the frequency of the carrier signal fc is set to be low. When the output current Ia is small and the ambient temperature Ta is low, The frequency of the carrier wave signal fc is set to be high.

  In this way, the carrier wave signal 24c of the carrier wave signal generation circuit 24 is changed by stepwise switching the frequency of the carrier wave signal to a frequency at which the power converter 2 is allowed according to the ambient temperature Ta and the output current Ia. With a simple configuration, the frequency of the carrier wave signal fc is set stepwise higher within the allowable temperature range of the power converter 2, and the noise level of the reactor and the like is suppressed without increasing the size of the cooling means of the power converter 2. It becomes a power converter.

Embodiment 3 FIG.
FIG. 5 is a block diagram showing the configuration of the power conversion apparatus according to the third embodiment. In the third embodiment, when the waveform distortion rate of the output voltage Vo does not satisfy the specification value, the specification value is satisfied by increasing the frequency of the carrier wave signal fc.
The configuration of FIG. 5 includes a DC power source 1, a power converter 2, an AC filter 5, a voltage detection means 6, a load 7, a voltage command generation circuit 11 that constitutes a control circuit 10, a subtractor 12, and a power converter main circuit portion. Voltage control command generation circuit 13, carrier wave signal generation circuit 14, carrier wave oscillator 14a, carrier wave signal generator 14b, control signal generation circuit 15 and drive circuit 16 are the same as those in FIG.
In this configuration, an output voltage waveform distortion rate detecting means 37 for detecting the waveform distortion rate of the output voltage and a carrier signal frequency switching circuit 38 for switching the carrier frequency of the carrier wave oscillator 14a are connected to the output circuit of the output voltage detecting means 6, The signal frequency switching circuit 38 controls the oscillation frequency of the carrier wave oscillator 14 a of the carrier wave signal generation circuit 14.
The carrier wave signal frequency switching circuit 38 stores the specification value of the waveform distortion rate, compares the waveform distortion rate detected by the output voltage waveform distortion rate detection means 37 with the specification value of the stored waveform distortion rate, and the waveform distortion rate. Is not satisfied with the specification value, a control signal for increasing the carrier frequency is output so that the waveform distortion rate becomes the specification value.
In addition, when the waveform distortion rate is very small even when the specification value is satisfied, the carrier frequency can be switched to be low so that the waveform distortion rate is close to the specification value.

  Thus, since the carrier frequency can be set low so that the waveform distortion rate of the output voltage is satisfied at a value close to the specification value, the power conversion device can be operated with improved efficiency of the power converter 2.

Embodiment 4 FIG.
FIG. 6 is a block diagram showing a configuration of the power conversion device according to the fourth embodiment. In the fourth embodiment, when the waveform distortion rate of the output voltage Vo of the third embodiment does not satisfy the specification value, the carrier signal generation circuit configured to satisfy the specification value by increasing the frequency of the carrier signal fc. A carrier wave oscillator that oscillates a carrier wave with a constant frequency is generated, a carrier wave signal of a predetermined frequency is generated by dividing the frequency of the carrier wave generated by the carrier wave oscillator, and the waveform distortion rate of the output voltage is the specified value. It is the structure which controls to satisfy.
The configuration of FIG. 6 includes a DC power source 1, a power converter 2, an AC filter 5, a voltage detection means 6, a load 7, a voltage command generation circuit 11 that constitutes a control circuit 10, a subtractor 12, and a power converter main circuit portion. The voltage control command generation circuit 13, the carrier wave signal generation circuit 14, the voltage control oscillator 14a, the control signal generation circuit 15, the drive circuit 16, and the output voltage waveform distortion rate detection means 37 are the same as the configuration of FIG. . The carrier wave signal generation circuit 24 has the same reference oscillator 24c, carrier wave signal generator 24b, and frequency divider 24d as those in the second embodiment.

In this configuration, output voltage waveform distortion rate detection means 37 for detecting the waveform distortion rate of output voltage Vo and carrier wave signal frequency switching means 48 are connected to the output circuit of output voltage detection means 6. The specification value of the waveform distortion rate is stored, the division rate n for dividing the carrier frequency is set and stored in stages, and the waveform distortion rate and the waveform distortion rate detected by the output voltage waveform distortion rate detection means 37 are stored. When the waveform distortion rate does not satisfy the specification value, the frequency division ratio close to the specification value is selected and input to the frequency divider 24d of the carrier wave signal generation circuit 24 to compare the specification value with the specification value. Control to raise.
If the waveform distortion rate is very small while satisfying the specification value, a frequency division rate n that becomes a carrier frequency that gives a waveform distortion rate close to the specification value is selected and divided by the frequency divider 24c. Can be switched to lower the carrier frequency.

  Thus, since the carrier frequency can be set low so that the waveform distortion rate of the output voltage is close to the specification value, the power conversion device can be operated with improved efficiency of the power converter 2.

Embodiment 5 FIG.
FIG. 7 is a block diagram showing a configuration of the power conversion apparatus according to the fifth embodiment. In the third and fourth embodiments, the configuration that satisfies the specification value of the waveform distortion rate of the output voltage has been described. In this case, the carrier frequency increases when the waveform distortion factor is strictly required. There is a problem that the loss of the power converter becomes large and the overload resistance is reduced, and the output current of the power converter is limited. In this case, it is necessary to lower the overload detection level of the protection device corresponding to the allowable output current.
In the fifth embodiment, an overload level is output to a protection device for a power conversion device that is separately installed in response to the allowable output current of the power converter 2.
The configuration of FIG. 7 includes a DC power source 1, a power converter 2, an AC filter 5, a voltage detection means 6, a load 7, a voltage command generation circuit 11 that constitutes a control circuit 10, a subtractor 12, and a power converter main circuit portion. Voltage control command generation circuit 13, carrier wave signal generation circuit 14, carrier wave oscillator 14a, carrier wave signal generator 14b, control signal generation circuit 15, and drive circuit 16 are the same as those in FIG. 5 of the third embodiment.
7 is provided with current detection means 3 for detecting the output current Ia on the output side of the power converter 2 with respect to the configuration of the third embodiment, and an overload corresponding to the carrier frequency shown in FIG. An arithmetic circuit for calculating the detection level is provided, and the frequency of the carrier wave signal fc and the output current Ia detected by the current detection means 3 are input from the carrier wave signal generation circuit 14, and the allowable output current Iom is calculated based on the frequency of the carrier wave signal fc. When the detected output current Ia exceeds the allowable output current Iom, an overload level signal is output to the protection device of the power converter that is separately installed.

  In this configuration, the overload of the power conversion device is detected based on the frequency of the carrier wave signal fc and the output current Ia, and the overload level signal is output to protect the waveform distortion rate. A power conversion device capable of stable operation in a satisfied state.

Embodiment 6 FIG.
FIG. 9 is a block diagram showing a configuration of the power conversion apparatus according to the sixth embodiment. This configuration is a power conversion device that controls the output current Ia of each device to be constant according to a current command when a plurality of power conversion devices are operated in parallel.
The configuration of FIG. 9 includes power converter 2 connected to DC power source 1, output current detection means 3 for detecting output current Ia of power converter 2, and AC filter 5 configured with reactor 5a and capacitor 5b. A conversion main circuit is configured and connected to the load 7.
The control circuit 20 that controls the power conversion main circuit includes a current command generation circuit 21 that generates a current command value Ios, and a subtraction that calculates a current deviation ΔI based on the current command value Ios and the output current Ia detected by the output current detection means 3. Control of the power converter 2 by the current control command Ias and the carrier signal fc, the current command generation circuit 23 for generating the current control command Ias by the current deviation ΔI, the carrier signal generation circuit 14 for generating the carrier signal, and the carrier signal fc. The control signal generation circuit 25 generates the signal PWM and the drive circuit 16 drives the power converter 2.

  The carrier wave signal generation circuit 14 includes a voltage control type carrier wave oscillator 14a and a carrier wave signal generator 14b, and the carrier wave oscillator 14a has an oscillation frequency that increases in proportion to the input voltage, as shown in FIG. The carrier signal generator 14b is configured to generate, for example, a triangular wave carrier signal fc based on the carrier wave fos.

The carrier signal generation circuit 14 is controlled by the ambient temperature detection means 17 that detects the ambient temperature Ta of the power converter 2 and the carrier signal frequency switching circuit 58 that switches the oscillation frequency of the voltage-controlled carrier oscillator 14a.
The carrier signal frequency switching circuit 58 stores the maximum ambient temperature at the installation position of the power converter 2 as the set temperature To, and the temperature considering the allowable junction temperature Tj of the power converter 2 under the condition of the set temperature To. The power converter 2 calculates the carrier frequency at which the temperature prescribed value Tm is stored under the condition of the detected ambient temperature Ta and the current command value Ios, and stores it in the carrier oscillator 14a of the carrier signal generation circuit 14 as the temperature prescribed value Tm. In response to the command, a carrier wave having a frequency commanded from the carrier wave signal generation circuit 14 is output. The command to the carrier wave oscillator 14a is generated by applying the input voltage Vf corresponding to the command frequency by the method shown in FIG. 2B of the method described in the first embodiment.

  The power converter compares the current command Ios of the current command generation circuit 21 with the output current Ia of the power converter 2 by the subtractor 12 to calculate a current deviation ΔI, and based on the current deviation ΔI, the current control command generation circuit 23 generates a current control command Ias, and a control signal generation circuit 25 generates a PWM signal for controlling the power converter 2 based on the current control command Ias and the carrier signal fc from the carrier signal generation circuit 14. And the power converter 2 is controlled by the drive circuit 16 based on the PWM signal.

  If the power converter 2 is configured in this way, the carrier signal fc is obtained by switching the carrier frequency fos so that the temperature of the power converter 2 falls within the temperature specified value Tm with respect to the ambient temperature Ta and the current command value Ios. It becomes the structure which can be drive | operated.

  With this configuration, in a situation where a plurality of power converters are operated in parallel, the output current of each power converter is output according to the current command value Ios, and the power is output under the conditions of the ambient temperature Ta and the current command value Ios. The converter 2 is operated in a temperature range of the temperature regulation value Tm, and an operation in which the noise level of the reactor is suppressed without increasing the size of the cooling means of the power converter 2 is possible.

Embodiment 7 FIG.
FIG. 10 is a block diagram illustrating a configuration of the power conversion device according to the second embodiment.
In the seventh embodiment, the carrier wave signal generation circuit having the configuration shown in FIG. 9 of the sixth embodiment is a carrier wave oscillator having a constant oscillation frequency, and the oscillation frequency is divided to output a carrier wave signal fc having an appropriate frequency. It is what.
This configuration includes a DC power source 1, a power converter 2, an output current detection means 3, an AC filter 5, a load 7, a voltage command generation circuit 21 that constitutes a control circuit 30, a subtractor 22, a voltage The control command generation circuit 23, the control signal generation circuit 25, the drive circuit 16, and the ambient temperature detection means 17 are the same as those in FIG.

  The carrier wave signal generation circuit 24 is the same as that shown in FIG. 3 of the second embodiment, and the carrier wave generator 24c, the carrier wave signal generator 24b, the carrier wave oscillator 24c, and the carrier wave signal generator 24b having a constant oscillation frequency. The carrier oscillator 24c oscillates the highest frequency carrier wave necessary for control, and the divider 24d divides the carrier wave oscillated by the carrier oscillator 24c into a frequency division ratio n. To generate a carrier wave having a required frequency, and a carrier wave signal generator 24b generates, for example, a triangular wave carrier signal fc using the divided carrier wave.

  The carrier signal frequency switching means 58 for controlling the carrier signal generation circuit 24 sets the maximum ambient temperature at the position where the power converter 2 is disposed as the set temperature To, and the junction allowable for the power converter 2 under the condition of the set temperature To. The allowable temperature in consideration of the temperature Tj is set as the temperature regulation value Tm, and the frequency division of the reference carrier is set in advance in a plurality of division ratios so that the frequency can be divided to an arbitrary carrier frequency in advance. A predetermined value Tm and a frequency division ratio n for dividing the carrier signal are stored, and the carrier signal fc in which the temperature of the power converter 2 falls within the range of the temperature predetermined value Tm under the conditions of the set temperature To and the current command value Ios. The frequency is calculated, the division ratio is selected so as to be the calculated carrier frequency, the carrier wave oscillator 24c is commanded, and the carrier wave signal generated at the commanded carrier frequency is operated.

  With this configuration, as in the sixth embodiment, in a situation where a plurality of power converters are operated in parallel, the output current of each power converter is output according to the current command value Ios, and the ambient temperature Ta and current Under the condition of the command value Ios, the carrier frequency is increased and the temperature of the power converter 2 is operated in the range of the temperature specified value Tm, and the noise level of the reactor is suppressed without increasing the cooling means of the power converter 2. Operation is possible.

1 is a block diagram illustrating a configuration of a power conversion device according to a first embodiment. It is explanatory drawing of the relationship between the input voltage of a carrier wave oscillator, and an oscillation frequency. It is a block diagram which shows the structure of the power converter device of Embodiment 2. FIG. It is a table | surface which shows the example of a setting of the dividing rate which divides the frequency of a reference carrier wave. FIG. 6 is a block diagram illustrating a configuration of a power conversion device according to a third embodiment. FIG. 10 is a block diagram illustrating a configuration of a power conversion device according to a fourth embodiment. FIG. 10 is a block diagram illustrating a configuration of a power conversion device according to a fifth embodiment. It is explanatory drawing of the overload detection calculating circuit of a power converter device. FIG. 10 is a block diagram illustrating a configuration of a power conversion device according to a sixth embodiment. FIG. 10 is a block diagram illustrating a configuration of a power conversion device according to a seventh embodiment. It is a figure which shows the relationship between the carrier frequency of a power converter, and switching loss. It is a figure which shows the relationship between the output current of a power converter, and a loss. It is a figure which shows the relationship between a carrier wave frequency and the noise level of a reactor.

Explanation of symbols

1 DC power supply, 2 power converter, 3 output current detection means, 5 AC filter,
6 output current detection means, 7 load, 10 control circuit, 11 voltage command generation circuit,
12 subtractor, 13 voltage control command generation circuit, 14 carrier wave signal generation circuit,
15 control signal generation circuit, 16 drive circuit, 17 ambient temperature detection means,
18 carrier wave signal frequency switching means, 24 carrier wave signal generating circuit,
28 carrier wave signal frequency switching means, 37 waveform distortion rate detecting means,
38 carrier wave signal frequency switching means, 35 overload level calculation circuit,
58 carrier wave signal frequency switching means, 68 carrier wave signal frequency switching means.

Claims (7)

A power conversion main circuit that supplies a conversion output of a power converter composed of a plurality of switching elements connected to a DC power supply to a load via an AC filter composed of a reactor and a capacitor, and an output voltage of the power conversion circuit Voltage detecting means for detecting the power converter and a control circuit for controlling the power converter, the maximum ambient temperature at the position where the power converter is disposed is set as a set temperature, and the allowable value of the junction temperature of the power converter is a temperature regulation. The control circuit includes a carrier signal generation circuit that generates a carrier signal and a control signal generation circuit that generates a control signal, and the control signal generation circuit has a voltage deviation between an output voltage command value and the output voltage. The output voltage command value is calculated so that the voltage deviation becomes zero, and the output voltage command value and the carrier signal generated by the carrier signal generation circuit are calculated. In the power conversion device that generates the control signal and inputs it to the drive circuit and controls the power converter from the drive circuit, the ambient temperature detection means for detecting the ambient temperature at the position where the power converter is disposed, and the power conversion Output current detecting means for detecting the output current of the detector, and carrier wave signal frequency switching means, the carrier wave signal frequency switching means, based on the detected ambient temperature and the output current of the power converter, the carrier wave signal A power conversion device, wherein the frequency of a carrier wave signal output from a generation circuit is switched to a frequency at which the temperature of the power converter falls within the temperature specified value range. The carrier signal generation circuit is composed of a carrier oscillator that oscillates a carrier wave of a constant frequency, a frequency divider, and a carrier signal generator, and the carrier signal frequency switching means has a stepwise frequency division ratio for dividing the carrier frequency in advance. The carrier signal frequency switching means is configured to store the temperature of the power converter based on the ambient temperature detected by the ambient temperature detection means and the output current detected by the output current detection means. 2. The power conversion device according to claim 1, wherein the frequency dividing ratio that falls within a range of values is selected. A power conversion main circuit that supplies a conversion output of a power converter composed of a plurality of switching elements connected to a DC power source to a load via an AC filter composed of a reactor and a capacitor, and an output voltage of the power conversion circuit Voltage detecting means for detecting the power converter and a control circuit for controlling the power converter, the maximum ambient temperature at the position where the power converter is disposed is set as a set temperature, and the allowable value of the junction temperature of the power converter is a temperature regulation. The control circuit includes a carrier signal generation circuit that generates a carrier signal and a control signal generation circuit that generates a control signal. The control signal generation circuit generates an output voltage command value and the output voltage. A voltage deviation is obtained, an output voltage command value is calculated so that the voltage deviation becomes zero, and the output voltage command value and the carrier signal generated by the carrier signal generation circuit In the power conversion device that generates a control signal and inputs the control signal to the drive circuit and controls the power converter from the drive circuit, a waveform distortion rate detection unit that detects a waveform distortion rate of the output voltage, and a waveform distortion rate in advance A carrier signal frequency switching means for setting a specification value is provided, and based on the detected waveform distortion rate, the frequency of the carrier signal output from the carrier signal generation circuit is set within the range of the specification value of the preset waveform distortion rate. The power converter characterized by switching to the frequency which becomes. The carrier signal generation circuit is composed of a carrier oscillator that oscillates a carrier wave of a constant frequency, a frequency divider, and a carrier signal generator, and the carrier signal frequency switching means has a frequency division ratio for dividing the frequency of the carrier signal in advance. The carrier signal frequency switching means is configured to select the frequency division ratio in which the temperature of the power converter falls within the range of the temperature specified value based on the detected waveform distortion rate. The power converter according to claim 3, wherein The output current detecting means for detecting the output current of the power converter, the overload tolerance calculation circuit for calculating the allowable output current corresponding to the carrier frequency, and the calculated allowable load current as an overload level are separately installed. 5. The power conversion device according to claim 3, further comprising an overload level calculation circuit including an output circuit that outputs to a protection device of the power conversion device. A power conversion main circuit that supplies a conversion output of a power converter composed of a plurality of switching elements connected to a DC power source to a load via an AC filter composed of a reactor and a capacitor, and controls the power converter A control circuit, wherein the maximum ambient temperature at the position where the power converter is disposed is a set temperature, the allowable value of the junction temperature of the power converter is a specified temperature value, and the control circuit generates a carrier signal. A circuit, current detection means for detecting an output current of the power converter, and a control signal generation circuit for generating a control signal, the control signal generation circuit comprising an output current command value and a current between the output current The deviation is obtained, the current command value is calculated so that the current deviation becomes zero, and control is performed by the current command value and the carrier signal generated by the carrier signal generation circuit. In the power conversion device that generates a signal and inputs it to the drive circuit and controls the power converter from the drive circuit, the ambient temperature detection means for detecting the ambient temperature at the arrangement position of the power converter, and the carrier signal frequency A carrier signal frequency switching means for switching, and the carrier signal frequency switching means converts the frequency of the carrier signal output from the carrier signal generation circuit based on the detected ambient temperature and the output current command value to the power conversion. A power conversion device, wherein the temperature of the vessel is switched to a frequency that falls within the range of the temperature specified value. The carrier signal generation circuit comprises a carrier oscillator that oscillates a carrier wave having a constant frequency, a frequency divider, and a carrier signal generator, and the carrier signal generation frequency switching means divides the frequency of the carrier signal in advance. The carrier signal frequency switching means is configured to store the frequency in which the temperature of the power converter falls within the range of the temperature specified value based on the ambient temperature and the output current command value. The power converter according to claim 6, wherein a rate is selected.

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