JP4633456B2 - DC motor drive filter - Google Patents

Description

  The present invention relates to a DC motor drive filter that suppresses a voltage surge generated when a DC motor is driven by DC chopper control using a switching element such as an IGBT (Insulated Gate Bipolar Transistor) and prevents insulation deterioration of the motor coil. .

  In current elevator systems, large DC motors for driving up and down are hardly newly employed, and three-phase AC induction motors, permanent magnet motors, and the like are exclusively employed. However, there are many properties that use already installed DC motors as they are, and some of them have already been operating for more than 20 years and some of them have become quite aging.

  Therefore, in such an elevator system, renewal is being implemented from now on, but due to problems such as budget, construction period, removal space, etc., the entire system is not renewed, but the DC motor is used as it is, and only the motor drive system is used. The control renewal method to replace is taken.

  On the other hand, in the current elevator system, an AC motor is exclusively employed, and PWM control by a converter and an inverter is mainly used to drive the AC motor. Therefore, in the control renewal method that uses the existing DC motor as it is and renews only the motor drive system, the inverter that constitutes the power converter used in the new motor drive system is made a DC chopper circuit so that the DC motor can be driven. Configuration is adopted.

  FIG. 9 is a block diagram showing a driving device for driving a conventional DC motor. In the figure, 1 is a converter circuit for converting an AC power source of a customer power source into DC power, 2 is a smoothing capacitor for smoothing DC power, and 3 is a serially connected switching element as with the serially connected switching elements 3aa and 3ab. A chopper circuit formed by connecting the elements 3ba and 3bb to the smoothing capacitor 2 in parallel, 4 is a resonance filter circuit, and 5 is an existing DC motor serving as a load. The resonant filter circuit 4 includes a DC reactor 6 that smoothes the DC power converted by the chopper circuit 3, a damping resistor 7, and a filter capacitor 8.

  By the way, in the motor drive device that drives the existing DC motor 5 using the chopper circuit 3, when the chopper control is performed on the switching elements 3aa, 3ab,... Constituting the chopper circuit 3 based on the chopper control signal from the outside, A resonance phenomenon is caused by a snubber circuit (not shown) provided in each set of switching elements (3aa, 3ab), (3ba, 3bb), a wiring impedance between the chopper circuit 3 and the DC motor 5, and an LC resonance circuit based on the stray capacitance. Is generated, and a voltage twice as much as the DC power supply voltage Vpn is generated, and this doubled voltage is applied to a coil (not shown) of the DC motor 5. Further, the frequency of the resonance current due to the resonance phenomenon is high, and the surge voltage appearing between the terminals of the DC motor 5 is steep. Since this steep surge voltage is concentrated and applied between the terminals of the DC motor 5, that is, at the input end of the motor coil, the motor coil on the input end side may cause dielectric breakdown.

  Therefore, the conventional motor driving apparatus is provided with a resonance filter circuit 4 including a DC reactor 6, a damping resistor 7, a filter capacitor 8 and the like on the output side of the chopper circuit 3 as shown in FIG. In addition, the surge voltage is suppressed.

However, the following problems have been pointed out in the electric motor driving apparatus as described above.
(1) In the conventional motor drive device, when the switching elements 3ab, 3ab,... Are chopper controlled at high speed, the noise of the DC motor 5 is attenuated, but the impedance is zero due to the stray capacitance generated between the windings of the DC reactor 6. It becomes a short circuit state against so-called high frequency. As a result, the high-frequency surge voltage passes through the DC reactor 6 as it is, and there is a risk that a coil (not shown) of the DC motor 5 is broken down.

(2) Further, the power regeneration converter circuit 1 normally has a DC voltage of about 650 (V) based on the reception of the customer power supply 200 (V) and a DC voltage 650 based on the reception of the customer power supply 400 (V). (V) The voltage is boosted to around and then applied to the chopper circuit 3. The chopper circuit 3 outputs a chopper voltage of a maximum DC voltage 350 (V) or 650 (V) and applies it to the DC motor 5 by chopper control of the switching elements 3ab, 3ab,.

  However, the DC motor 5 has many rated voltages of 200 (V) to 400 (V), and the insulation voltage of the coil in the motor 5 is about 300 (V) to 600 (V). Moreover, unlike the current insulating material for motor coils, it is not manufactured to be applied to high-frequency switching of switching elements such as IGBTs. As a result, when a voltage exceeding the rated voltage is applied to the DC motor 5, there is a possibility that the deterioration of the insulation of the motor coil is promoted.

(3) Further, when the DC reactor 6 is provided only in one phase (one line) of the motor drive device, the line impedance between the chopper circuit 3 and the motor terminal of the DC motor 5 is different between the P and N lines. A reflection phenomenon occurs at the end of the motor coil, which becomes the circuit end, and the surge voltage becomes higher, which may accelerate the deterioration of the insulation of the motor coil.

  The present invention has been made in view of the above circumstances, and reduces the surge voltage generated at the time of chopper control by a high-speed switching element and the surge voltage due to reflection from the motor coil end serving as the resonance filter circuit end, and the insulation deterioration of the DC motor coil. An object of the present invention is to provide a filter for driving an electric motor that suppresses electrical breakdown and avoids dielectric breakdown in advance.

(1) In order to solve the above-described problem, the present invention provides a motor drive device that performs chopper control of a DC power supply voltage and controls an armature current of a DC motor using a chopper circuit configured by a switching element. A DC reactor connected to one output end of the chopper circuit, and a damping resistor and a smoothing capacitor connected in series between the other end of the DC reactor and the other output end of the chopper circuit, and the chopper control Including a filter circuit that smoothes a rectangular wave chopper voltage output from the chopper circuit, and a chopper voltage that is connected in parallel to a damping resistor and a smoothing capacitor connected in series and smoothed by the filter circuit, Related to the peripheral circuit of the chopper circuit and the wiring from the chopper circuit to the armature coil of the DC motor. This is a DC motor drive filter provided with a high frequency capacitor having a capacity that can be used in a predetermined frequency region that absorbs a high frequency surge voltage generated by the LC resonance phenomenon that occurs and makes a smooth waveform .

  With this configuration, the chopper voltage output from the chopper circuit can be smoothed by the resonance filter circuit, and a high-frequency surge voltage can be absorbed by the high-frequency capacitor, so that the insulation deterioration of the motor coil can be suppressed. Insulation breakdown can be prevented in advance.

(2) In the configuration of the DC motor driving filter as described above, a DC reactor is connected to each phase (each line) wire line at each output end of the chopper circuit, and each phase (each line) wire line By adopting a configuration in which the wire impedances are made equal, the surge voltage reflected from the armature coil end of the DC motor can be reduced.

(3) Further, by applying the configuration of the motor driving filter including the chopper circuit described above to the field coil of the DC motor, it is possible to prevent dielectric breakdown also in the field chopper control.

  According to the present invention, it is possible to reduce the surge voltage generated during chopper control by the high-speed switching element of the chopper circuit and the surge voltage due to reflection from the end of the motor coil, thereby suppressing the insulation deterioration of the DC motor coil and preventing dielectric breakdown in advance. An electric motor drive filter that can be avoided can be provided.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
FIG. 1 is a block diagram showing an embodiment of an electric motor drive device according to the present invention. In the figure, reference numeral 1 denotes, for example, a converter circuit that converts AC power received from a customer power supply (not shown) into DC power, and 2 denotes a smoothing capacitor that smoothes the DC power converted by the converter circuit 1. Reference numeral 3 denotes a chopper circuit that performs chopper control based on a chopper control signal output from a control unit (not shown), and is configured by switching elements 3aa, 3ab, 3ba, 3bb such as IGBTs (Insulated Gate Bipolar Transistors). Specifically, the serially connected switching elements 3aa and 3ab and the switching elements 3ba and 3bb are connected in parallel to the smoothing capacitor 2, respectively. Reference numeral 5 denotes a DC motor to be driven, which becomes an existing DC motor in the control renewal.

  In addition, as a DC motor driving filter according to the present invention, a novel resonance filter circuit 10 is provided between the chopper circuit 3 and the DC motor 5. The resonance filter circuit 10 is connected to one output end side of the chopper circuit 3, a DC reactor 11 that smoothes the chopper voltage output by the chopper operation of the chopper circuit 3, the output end of the DC reactor 11, and the chopper circuit 3 A damping resistor 12 and a filter capacitor 13 are serially connected to the other output terminal. A high frequency capacitor 14 having good high frequency characteristics is connected to the output side of the resonance filter circuit 10. The damping resistor 12 has an effect of reducing the steep voltage amplitude. The filter capacitor 13 smoothes the chopper voltage, and a capacitor of, for example, 5 μF or more that is in a range where resonance does not occur between the damping resistor 12 and the filter capacitor 13 is used. The high-frequency capacitor 14 is a capacitor having a capacity of 1000 PF or more that is relatively easily available and can be used in a use frequency range of 10 MHz to 150 MHz in consideration of a range in which resonance does not occur.

  Next, the operation of the motor driving filter as described above will be described with reference to FIG.

  The AC voltage received from the customer power supply is converted into a DC voltage by the converter circuit 1, smoothed by the smoothing capacitor 2, and applied as a DC power supply voltage for the chopper circuit 3. In this state, when the switching elements 3aa, 3ab,... Constituting the chopper circuit 3 are chopper-controlled from a control unit (not shown), a chopper voltage of a rectangular wave 16 is output as shown in FIG. At this time, when the rectangular wave 16 rises, the snubber circuit (not shown) added to the switching elements (3aa, 3ab) and (3ba, 3bb) constituting the chopper circuit 3 and the P and N lines of the chopper circuit 3 A surge voltage 17 having a steep dv / dt due to the occurrence of a resonance phenomenon based on an LC resonance circuit such as wiring impedance and stray capacitance is included. The rectangular wave 16 including the steep surge voltage 17 suppresses the steep amplitude by the damping resistor 12 constituting the resonance filter circuit 10 and is smoothed by the DC reactor 11 and the filter capacitor 13 as shown in FIG. Such a smooth waveform 18 is obtained. The smooth waveform 18 falls to a value close to the rated voltage of the DC motor 5, but a steep surge voltage 17 of dv / dt still remains, but the steep surge voltage is absorbed by the high frequency capacitor 14 having good high frequency characteristics. Then, after a smooth waveform 19 as shown in FIG. 2 (c) is applied to the DC motor 5.

  Therefore, according to the embodiment as described above, the rectangular wave 16 output by the chopper control of the chopper circuit 3 is smoothed by the DC reactor 12, the filter capacitor 13, and the like, but the chopper circuit included in the rectangular wave 16 is used. 3 The steep surge voltage 17 generated by the resonance phenomenon of the LC resonance circuit based on the peripheral circuit and the output line wiring remains. That is, when the switching elements 3aa, 3ab,... Are switched at high speed, the high-frequency surge voltage 17 exits as it is and enters the DC motor 5 on the basis of the impedance nullification due to the stray capacitance between the windings of the DC reactor 12. There is a possibility, but by absorbing the steep surge voltage 17 by the high frequency capacitor 14, the steep surge voltage 17 is not concentratedly applied to the input end of the motor coil, and the insulation deterioration of the motor coil is prevented. This suppresses the destruction of the motor coil.

(Second Embodiment)
FIG. 3 is a block diagram showing another embodiment of the motor driving filter according to the present invention.
Since the motor drive device has substantially the same configuration as that of FIG. 1, the same parts are denoted by the same reference numerals and the description thereof is omitted, and particularly different filter parts will be described.

  In this embodiment, DC reactors 11p and 11n constituting the resonance filter circuit 10 are respectively connected to the serially connected switching elements 3aa and 3ab constituting the chopper circuit 3 and the output lines P and N of the switching elements 3ba and 3bb. It is the structure connected individually. That is, the resonant filter circuit 10 includes a DC reactor 11p, 11n connected to the P and N lines that are the output terminals of the chopper circuit 3, and a damping resistor connected in series between the output terminals of the DC reactors 11p, 11n. 12 and a filter capacitor 13. In the figure, reference numerals 5a and 5b denote armature coil terminals of the DC motor 5.

  Next, the operation of the motor driving filter as described above will be described with reference to FIGS. FIG. 4 is an equivalent circuit diagram of a filter including a part of the motor drive device according to the first embodiment, and FIG. 5 is an equivalent circuit diagram of a filter including a part of the motor drive device according to the present embodiment.

Now, the voltage at the time of occurrence of reflection by the armature coil end will be analyzed and explained from each equivalent circuit diagram. 4 and 5, 21a is a wire resistance (hereinafter referred to as wires R1 and R2 if necessary), 21b is a wire inductance (hereinafter referred to as wire inductances L1 and L2 if necessary), and 21c is a space between wires. 21d is a stray capacitance between the wires (hereinafter referred to as stray capacitances C1 and C2). Reference numeral 22 denotes a load impedance (hereinafter referred to as Z1) for the DC motor 5. The load impedance Z1 is a constant of resistance Rz: 0.067 (Ω) and inductance Lz: 8.5 × 10 ³ (H).

  By the way, in the circuit shown in FIG. 4, when the attenuation at the time of reflection of the motor coil end is considered, when the P line input end is short-circuited as shown in FIG. 4A, the N line becomes a transmission line, and the inductance of the DC reactor 11 It is a lossless circuit that does not contain. On the other hand, in the circuit of FIG. 5, the P line and the N line have the same impedance, and the PN line resonates at the same period, so that it does not become a lossless circuit.

  Here, specifically, the reflected voltage in the case where it is constituted by one DC reactor 11 shown in FIG. 4 and in the case where it is constituted by two DC reactors 11p and 11n as shown in FIG. Consider comparison.

  In general, in a lossless circuit having no impedance, when a voltage is applied to the lossless circuit, a voltage twice as much as that is generated. Further, when the resonance due to the reflection of the motor coil end or the like is calculated, as shown in FIG. 6, the resonance occurs at a period t of {4 × (propagation distance l) / wave velocity Ws}. The input end shown in FIG. 6 means the output end of the chopper circuit 3, and the output end means the motor coil end. Also, in the figure, the illustrated right arrow described in the upper frame of the solid line is the traveling wave direction, and the illustrated left arrow described in the upper frame of the dotted line is the traveling direction of the reflected wave from the end of the motor coil, etc. The right arrow in the lower frame of the line indicates the traveling direction of the reflected wave reflected again by the output terminal of the chopper circuit 3.

By the way, the wave velocity Ws due to reflection is substantially equal to the light velocity in the lossless circuit. Therefore,
Ws = 1 / √LC = 3 × 10 ⁸ [m / s]
It becomes. L and C for satisfying the above equation are L = 0.1 [μH] and C = 100 [pF], and can be modeled as constants.

Now, for example, when the propagation distance l = 15 [m], the resonance period t due to reflection at this time is
t = 4 l / Ws = (4 × 15) / (3 × 10 ⁸ ) = 20 × 10 ⁻⁸ = 0.2 × 10 ⁻⁶ [s]
= 200 [ns]
It becomes. Therefore, a resonance wave of 5 MHz is generated in the lossless circuit.

  Therefore, in order to calculate the voltage at the time of reflection when one DC reactor 11 which is an equivalent circuit diagram shown in FIG. 4 is provided, the resonance frequency is obtained as follows. Here, assuming that the DC power supply voltage Vpn is 360 [V] and the inductance L of the DC reactor 11 is 1.6 [mH], the reflection period is different between the P line and the N line. An output terminal voltage is generated by superimposing these resonance waveforms. The N line is a lossless circuit.

Now, in the high frequency band, it is assumed that the load impedance Z1 and the inductance Lz in the Z1 are reduced by about 50%, and further, the calculation is performed by approximating L1 + L = L1 because there is a relationship of wire inductance L1 << L ,
Wave velocity Ws1 = 1 / √ {(L1 + L) + C}
= 1 / √ (1.6 × 10 ⁻³ × 0.5 × 100 × 10 ⁻¹² )
= 3.5 × 10 ⁶ [m / s]
Resonance period T1 = 4 l / Ws1 = (4 × 15) / (3.5 × 10 ⁻⁶ ) = 17.1 × 10 ⁻⁶ [μs]
It becomes. Therefore,
Resonance frequency f1 = 58 [KHz]
It becomes. Accordingly, the resonance frequency of one DC reactor 11 is the resonance frequency of the lossless circuit of the N line described above is 5 [MHz], and therefore the resonance of 58 [KHz] of the P line and 5 [MHz] of the N line. It becomes a high frequency waveform on which the frequency is superimposed.

Next, the attenuation rate when the reflected wave is reflected at the end of the motor coil is calculated.
First, characteristic impedance Z ₀ = √ {(R + jωL) / (G + jωC)}
It becomes. If Z ₀ = R ₀ + jX ₀ , R _{0 and} X ₀ can be expressed by the following formula.

Here, the constants of R1, G1, C1, and L1 are modeled as follows.
R1 = 3 × 10 ⁻⁴ [Ω / m], G1 = 1.6 × 10 ⁻⁹ [Ω / m], C1 = 100 × 10 ⁻¹² [F / m], L1 = 0.11 × 10 ⁻⁶ [H / m], and at this time, the relationship of R1 << ωL1, G1 << ωC1 is established.

Therefore, the characteristic impedance Z _{01 at} 58 [KHz] from the above equation is

It becomes. The load impedance Zl _{1 at} 58 [KHz] is
Zl ₁ = 0.067 + j2πfL
= 0.067 + j2π × 58 × 10 ³ [Hz] × 8.5 × 10 ⁻³ [H] × 0.5
= 0.067 + j1548
| Zl ₁ | = 1548
Accordingly, the reflected voltage drop in the circuit portion having the characteristic impedance is {105 / (105 + 1548)} × 360 × 2 = 46 [V].
Therefore, the surge voltage when reflection occurs at the end of the motor coil, etc. is 720−46 = 674 [V].
It becomes. However, [720] in the equation means a voltage twice the DC power supply voltage 360 (V). The reflected voltage drop at 5 [MHz] is small and can be ignored.

Next, in order to calculate the voltage at the time of reflection when the two DC reactors 11p and 11n which are equivalent circuit diagrams shown in FIG. 5 are provided, the resonance frequency is obtained.
Now, assuming that the inductances Lp and Ln of the DC reactors 11p and 11n are 0.8 [mH], since the reflection period has the same impedance for both the P line and the N line, the P and N lines resonate at the same period. The wave velocity Ws2 and period T2 at this time are as follows.

Wave velocity Ws2 == 1 / √ (0.8 × 10 ⁻³ × 0.5 × 100 × 10 ⁻¹² )
= 5.0 × 10 ⁶ [m / s]
Resonance period T2 = 4 l / Ws2 = (4 × 15) / (5 × 10 ⁻⁶ ) = 12 [μs]
It becomes. Therefore,
Resonance frequency f2 = 83 [KHz]
It becomes.

On the other hand, the attenuation factor at the time of reflection is the same impedance for both the P and N lines, and can be calculated by obtaining the characteristic impedance of any line. Since the DC reactors 11p and 11n are added to the wire resistance R2, if the resistance of these reactors 11p and 11n is 0.01 [Ω],
R2 / L2 = {(R1 + 0.01) / (L1 + 0.8 × 10 ⁻³ )} = 25
G2 / C2 = G1 / C1 = 16
It becomes. Here, the characteristic impedance Z ₀₂ at the resonance frequency f2 = 83 [KHz] is
Z ₀₂ = √ {(0.8 × 10 ⁻³ × 0.5) / (100 × 10 ⁻¹² ) {1−j (1 / 2ω)} (25−16)} = √ {(4 × 10 ⁶ )} × (1-j8.6 × 10 ⁻⁶ ) = 2000−j0.017
| Z ₀₂ | = 2000
It becomes. Therefore, the load impedance Zl ₂ at the resonance frequency f2 = 83 [KHz] is
Zl ₂ = 0.067 + j2πf ₂ L2
= 0.067 + j × 2π × 83 × 10 ⁻³ [Hz] × 8.5 × 10 ⁻³ × 0.5 [H]
= 0.067 + j2216
| Zl ₂ | = 2216
Accordingly, the reflected voltage drop in the circuit portion having the characteristic impedance is {2000 / (2000 + 2216)} × 360 × 2 = 342 [V].
Therefore, the surge voltage at the occurrence of reflection at the end of the motor coil is 720-342 = 378 [V].
It becomes.

  Therefore, according to the embodiment as described above, the surge voltage reflected by the reflection is reduced to about 1/2 in the motor driving filter constituted by the two DC reactors 11p and 11n, and the motor coil is reduced. Therefore, the DC motor 5 can be driven stably over a long period of time.

(Third embodiment)
FIG. 7 is a block diagram showing a third embodiment of the motor driving filter according to the present invention.
Since the motor drive device has substantially the same configuration as that shown in FIGS. 1 and 2, the same parts are denoted by the same reference numerals and description thereof is omitted, and particularly different parts will be described.

  In the figure, 31 is a field coil of the DC motor 5, 32 is a field chopper circuit composed of two switching elements connected in parallel between both ends of the smoothing capacitor 2, and the field chopper circuit 32 The chopper output by the chopper control is applied to the field coil 31. A field resonance filter circuit 33 is connected to the field coil 31. The field resonance filter circuit 33 includes a field DC reactor 34 connected to one end of the field coil 31 and a serial connection between the field DC reactor 34 and the other end of the field coil 31. The field damping resistor 35 and the field filter capacitor 36 are connected. Further, a field high-frequency capacitor 37 having good high-frequency characteristics is connected in parallel with the field damping resistor 35 and the field filter capacitor 36.

  In this embodiment, the filter configuration of the armature coil of the electric motor 5 applied in the previous embodiment is applied, but the filter having the same configuration is applied to the field coil 31. Since it is the same as that of 1st and 2nd embodiment, it leaves to description of these embodiment.

  FIG. 8 shows a configuration in which field DC reactors 34p and 34n are connected to both ends of the field coil 31, that is, to each phase (each line), respectively, and the reflection voltage at the circuit end is suppressed. As described in the second embodiment.

  In the above embodiment, when the chopper operation output of the field chopper circuit 32 is applied to the field coil 31 of the DC motor 5, the field series reactor 34 is connected in series to the field coil 31. Since the filter capacitor 36 and the high frequency capacitor 37 are connected in parallel, the rectangular wave 16 (see FIG. 2A) output from the chopper circuit 32 is converted into the field series reactor 34 and the filter capacitor. The steep surge voltage 17 is absorbed by the high-frequency capacitor 37 by applying the smooth waveform 19 smoothed by 36 and suppressing the surge voltage 17 by the high-frequency capacitor 37 to the field coil 31. Is not intensively applied to the input end of the coil, and the insulating material of the field coil 31 is not deteriorated. There is no concern to breakdown, the DC motor 5 can be stably driven for a long time.

  Further, by inserting a filter between the field coil 31 and the field chopper circuit 32, by connecting the DC reactors 34, 34p, 34n to each phase (each line) of the field coil 31, the circuit end is connected. The surge voltage 17 can be reduced by the generated reflection, the insulating material of the field coil 31 in the DC motor 5 is not deteriorated, and there is no fear of destruction, and the DC motor 5 can be driven stably over a long period of time.

  In addition, this invention is not limited to the said embodiment, In the range which does not deviate from the summary, various deformation | transformation can be implemented. For example, in the above embodiment, FIGS. 1 and 3 apply the motor driving filter according to the present invention to the armature coil side of the DC motor 5, and FIGS. 7 and 8 show the armature coil and the DC motor 5 of FIG. Although the motor driving filter according to the present invention is applied to the field coil 31 side, for example, it may be applied only to the field coil 31 side, and the effect of each application can be obtained.

The block diagram which shows one Embodiment of the electric motor drive device incorporating the filter for electric motor drives concerning this invention. The figure explaining the effect | action of the filter with respect to the chopper operation | movement output by the chopper circuit by FIG. The block diagram which shows other embodiment of the motor drive device which used two DC reactors for the filter for motor drive. FIG. 2 is an equivalent circuit diagram on the output side of the chopper circuit shown in FIG. 1. FIG. 4 is an equivalent circuit diagram on the output side of the chopper circuit shown in FIG. 3. The figure which shows the relationship between a reflected wave and a period. The block diagram which shows one Embodiment of the motor drive device which incorporated the filter for motor drive into the field coil side. The block diagram which shows other embodiment of the electric motor drive device using two DC reactors on the field coil side. The block diagram of the motor drive device incorporating the filter for the conventional motor drive.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Converter circuit, 2 ... Smoothing capacitor, 3 ... Chopper circuit, 5 ... DC motor, 10, 33 ... Resonance filter circuit, 11, 11p, 11n, 34, 34p, 34n ... DC reactor, 12, 35 ... Damping resistance, DESCRIPTION OF SYMBOLS 13, 36 ... Filter capacitor, 14, 37 ... High frequency capacitor, 16 ... Rectangular wave, 17 ... Surge voltage, 18, 19 ... Smooth waveform, 31 ... Field coil, 32 ... Field chopper circuit.

Claims (3)

In a motor drive device that uses a chopper circuit composed of switching elements to chopper-control a DC power supply voltage and control an armature current of a DC motor,
A DC reactor connected to one output end of the chopper circuit, and a damping resistor and a smoothing capacitor connected in series between the other end of the DC reactor and the other output end of the chopper circuit, the chopper A filter circuit for smoothing the chopper voltage of the rectangular wave output from the chopper circuit by the control;
The chopper voltage connected in parallel to the damping resistor and the smoothing capacitor connected in series, and included in the chopper voltage smoothed by the filter circuit, reaches the armature coil of the DC motor from the peripheral circuit of the chopper circuit and the chopper circuit. A DC motor drive characterized by comprising a high-frequency capacitor having a capacity usable in a predetermined frequency region that absorbs a high-frequency surge voltage generated by an LC resonance phenomenon generated in connection with wiring and forms a smooth waveform filter. In the DC motor drive filter according to claim 1,
A DC reactor is connected to each phase (each line) wire line at each output end of each chopper circuit, the wire impedance of each phase (each line) wire line is made equal, and from the armature coil end of the DC motor A filter for driving a DC motor, characterized by reducing a reflected surge voltage. The configuration of the motor driving filter including the chopper circuit according to claim 1 or 2 is incorporated into the field coil side of the DC motor, or both the armature coil side and the field coil side. DC motor drive filter.

Images