JPH0630564A - Controller of power converter and controller of electric rolling stock using the same - Google Patents

Abstract

PURPOSE:To suppress the unbalance of the DC components of two DC voltages effectively with simple control, in dipolar modulation method by adjusting the width of the output pulse of one polarity of the output phase voltage of an inverter, according to the DC components of two DC voltage being divided. CONSTITUTION:In case of suppressing the unbalance (for example, Vdp<Vdn) of DC voltages Vdp and Vdn being divided with capacitors 22 and 23, first, the voltage unbalance suppressing means 54 of a modulating means 5 outputs a signal DELTAV geared to the DC component of the differential voltage (Vdp-Vdn) between DC voltages Vdp and Vdn, dividing it into DELTAVp and DELTAVn. Next, a voltage command dividing means 52 outputs a positive voltage command ep* and a negative voltage command en*, based on the signals DELTAVp and DELTAVn. As a result, the width of the positive output pulse of a three-level inverter 3 having the same polarity as that of a fundamental wave voltage command eo* becomes narrow, and a neutral point N current comes to include the positive DC component. This positive DC ingredient becomes the charge current of the capacitor 22 and the discharge current of the discharge current of the capacitor 23, and increases Vdp and decreases Vdn.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention A control device for a power converter that converts a direct current supplied from a series-connected capacitor that divides a direct current voltage into two into an alternating-current phase voltage having three positive, zero, and negative potentials. Regarding

[0002]

2. Description of the Related Art When a load such as an induction motor is driven by a pulse width modulation inverter, it is desirable that the AC output voltage of the inverter contain few harmonic components.

An inverter called a three-level inverter has been proposed as an inverter that satisfies this requirement.

For example, the novel approach to the generalization and optimization
Observed Level PDA Blue Wave Form "A Novel approach to the Generation and O
ptimization of Three-level PWM Wave Forms''(PESC' 8
8 Record. April 1988), pages 1255 to 1262 (hereinafter referred to as literature). As a modulation method suitable for improving the waveform of a three-level inverter and controlling a minute voltage, this document proposes a dipolar modulation method in which positive and negative pulse voltages are alternately output via a zero voltage.

Further, in this dipolar modulation method, since a minute voltage is controlled by using a pulse having a polarity opposite to that of the fundamental wave of the output phase voltage, the voltage utilization rate is reduced. This document also describes a shift to a control system with a high voltage utilization rate, that is, a unipolar modulation system that outputs a plurality of pulse voltages having only the same polarity as the fundamental wave of the output phase voltage.
On the other hand, as a problem peculiar to the three-level inverter, due to the capacity imbalance of the capacitors connected in series that divide the DC voltage into two, and the DC component of the current flowing in and out of the series connection of the capacitors due to the variation of the output pulse of the inverter. ,
There is a phenomenon in which the DC components of the two divided DC voltages are unbalanced. A technique for suppressing this imbalance is disclosed in
2-101969 publication and "Balance control of DC input capacitor voltage of NPC inverter" (The Institute of Electrical Engineers of Japan Material, Semiconductor Power Conversion Workshop SPC-91-37, 1991 /
6), pages 111 to 120 (hereinafter referred to as references).

[0006]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention The technique for suppressing the unbalance of the DC components of two DC voltages disclosed in Japanese Patent Laid-Open No. 2-101969 is a dipolar modulation method of the literature, which uses two sinusoidal modulation waves. Since the amplitude is changed, the shift amount (bias amount) also changes when this technique is used, as described later. In order to restore this, the shift amount is adjusted again in the latter stage of the control, which may complicate the control.

Further, the technique for suppressing the unbalance of the DC components of the two DC voltages disclosed in the literature is based on the unipolar modulation method of the literature, and a signal corresponding to the DC component of the difference voltage between the two DC voltages is applied to the inverter voltage command. Is to be superimposed on.

By the way, for example, when such a three-level inverter is applied to an electric vehicle, since the output voltage is continuously controlled from zero to near the maximum voltage that can be output, its modulation method (modulation mode) is dipolar modulation. It is necessary to shift from the system (modulation mode) to the unipolar modulation system (modulation mode).

At this time, if the technique for suppressing the imbalance of the DC components of the two DC voltages as described above is applied to each of the modulation systems, the circuit configuration and control become complicated. An object of the present invention is to easily control the dipolar modulation method (modulation mode) and effectively suppress the imbalance of the DC components of the two DC voltages.

Another object of the present invention is to suppress unbalance of DC components of two DC voltages in an electric vehicle to which a dipolar modulation system (modulation mode) and another modulation system (modulation mode) are applied. It is to simplify the control.

[0011]

SUMMARY OF THE INVENTION The above-mentioned object is to connect capacitors connected in series for dividing a DC voltage, and to convert DC supplied from these capacitors into an AC phase voltage having three potentials of positive, zero and negative. A power converter and a signal for generating in the phase of the power converter a train of output pulses represented by a train of pulses having a zero potential between positive and negative half-cycles of the fundamental wave of the output phase voltage of the power converter. In a control device for a power converter including a modulation means for supplying to the power converter, either a positive or negative output pulse of the output phase voltage, depending on a DC component of the divided DC differential voltage. This is achieved by providing means for adjusting the width of one of the output pulses.

Another object of the present invention is to connect capacitors connected in series for dividing a DC voltage and convert DC fed from these capacitors into an AC phase voltage having three potentials of positive, zero and negative. In a control device for an electric vehicle including a power converter and an AC electric motor driven by the power converter, an output phase voltage of the power converter based on a voltage command and a frequency command supplied to the power converter. A first modulation mode for supplying to the power converter a signal that causes a phase of the power converter to generate a train of output pulses in which a half cycle of the fundamental wave is represented by alternating positive and negative pulse trains through a zero potential. A second modulation mode for supplying to the power converter a signal that causes a phase of the power converter to generate a train of output pulses different from the train of output pulses in the first modulation mode. And a single DC component unbalance suppression means for suppressing the unbalance of the DC components of the divided DC voltage in the first modulation mode and the second modulation mode. .

[0013]

In the dipolar modulation system, the width of the output pulse of one polarity of the output phase voltage is adjusted according to the DC component of the voltage difference between the two divided DC voltages, so that the series connection point of the capacitors can be improved. Since the DC components of the incoming and outgoing currents are controlled, it is possible to effectively suppress the imbalance of the DC components of the two DC voltages with simple control. Also,
In the electric vehicle to which the dipolar modulation method and the other modulation methods are applied, the control method can be simplified because the means for suppressing the imbalance of the DC components of the two DC voltages is shared regardless of the modulation method. .

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a circuit configuration showing an embodiment of the present invention.

Reference numeral 1 is a DC overhead wire, 21 is a current smoothing reactor, 22 and 23 are voltage _dividing capacitors connected in series for _{dividing the} voltage V _{d of the} DC overhead wire 1 into two DC voltages V _dp and V _dn ,
Reference numeral 3 is a pulse width modulation three-level inverter that converts two DC voltages into three-phase AC voltage, and 4 is an induction motor that is an AC motor driven by the inverter 3.

The inverter 3 has three phases, U phase, V phase and W phase.
It consists of a level switching arm and its U phase (V phase,
The switching arm for the W phase is a switching element capable of self-extinguishing (eg, IGBT, GTO, power transistor, etc.) G1U to G4U (G1V to G4V, G1W to G).
4W), rectifying element (free wheel diode) D1U
To D4U (D1V to D4V, D1W to D4W) and auxiliary rectifying elements (clamp diodes) D5U to D6U (D5
V to D6V, D5W to D6W). Auxiliary rectifiers D5U and D6U, D5V and D6V, and D5W and D for each phase
The connection point of 6W is connected to the series connection point (hereinafter, referred to as a neutral point) N of the voltage dividing capacitors 22 and 23, respectively, and the switching elements G1U to G4U, G1V to G4V, and G1W to G4W of each phase are listed in Table 1. The ON / OFF operation as described above is performed by the output of the modulation means 5, and the output terminals U, V and W of each phase are
And a three-level voltage (phase voltage) of V _dp , 0, and −V _dn is output between the neutral point and the neutral point N.

[0017]

[Table 1]

Next, the structure of the modulation means 5 and the dipolar modulation will be described with reference to FIGS. In the figure, 1
Only the phase components are shown.

The output frequency command F _inv * of the inverter 3 is given by addition / subtraction of the slip frequency obtained based on the deviation between the current command of the motor 4 and the actual current of the motor 4 and the rotation frequency of the motor 4. In the fundamental wave voltage command generating means 51,
The fundamental wave (sin) generation means 511 receives the inverter output frequency command F _inv * and outputs a fundamental sine wave, and the amplitude calculation means 512 outputs the DC overhead wire 1 voltage V _d and the inverter output frequency command F _inv *. Proportional output voltage effective value command E _m *
Then, the fundamental wave voltage amplitude command K is calculated and output, and the fundamental wave voltage amplitude command K and the fundamental sine wave are multiplied by the multiplier 51.
Multiply by 3 to output the instantaneous fundamental wave voltage command e _o * as shown in FIG.

In the voltage command dividing means 52, a signal obtained by halving the fundamental wave voltage command e _o * inputted from the fundamental wave voltage command generating means 51 by the divider 521 is added to the bias setting means 5
Bias amount B set to be larger than K / 2 and smaller than 0.5 at 22 (this range is a condition of dipolar modulation)
Is added and subtracted by the adder 523 and the subtractor 524,
Two sinusoidal divided voltage commands e _op *, e _on * as shown in FIG. 2A are created, and the divided voltage commands e _op * are generated.
And e _on *, the positive side voltage command e _p * as shown in FIG. 2B is output by the polarity discriminating distributors 526p and 526n and the adder 528p.
To the polarity discriminating distributors 527p and 527n and the adder 52.
At 8n, a negative voltage command e _n * as shown in FIG. 2C is created and output.

In the pulse generating means 53, the positive voltage command e _p * and the negative voltage command e _n * inputted from the voltage command dividing means 52 and the output of the carrier wave generating means 531 are shown in FIG.
The comparison means 532 respectively compares the triangular wave as shown in FIG. 2C with the pulse signal G _{p as} shown in FIG. 2D and the pulse signal G _n as shown in FIG.

The pulse signals G _p and G _n serve as gate signals for the switching elements G1 and G4, and the pulse signals G _p and G _n are inverted by inverters 533 and 534, respectively. Signals such as () are gate signals for the switching elements G3 and G2. As a result, the inverter 3 alternately outputs, as an output phase voltage, a positive pulse voltage whose height is the capacitor 22 voltage V _dp and a negative pulse voltage whose height is the capacitor 23 voltage V _dn as shown in FIG. It outputs to zero to zero voltage.

In the dipolar modulation of FIG. 2, when the bias amount B set by the bias setting means 522 becomes larger than the fundamental wave voltage amplitude command K / 2, the divided voltage commands e _op * and e _on * are shown in FIG. B), the positive voltage command e _p * is shown in FIG. 3 (b), and the negative voltage command e _n * is shown in FIG. 3 (c).
become that way. As a result, the inverter 3 has, as an output phase voltage, a period in which positive and negative pulse voltages are alternately output via a zero voltage, and a period in which a pulse voltage having the same polarity as the fundamental wave is output, as shown in FIG. 3D. Output pulse voltage.
This is so-called partial dipolar modulation.

In the dipolar modulation of FIG. 2, when the bias amount B set by the bias setting means 522 becomes zero, the divided voltage commands e _op * and e _on * become as shown in FIG. The side voltage command e _p * is as shown in FIG. 4 (b), and the negative side voltage command e _n * is as shown in FIG. 4 (c). Figure 3 (b),
The voltage command having the same polarity as the fundamental wave voltage command e _o * is distorted as shown in (c) because the voltage having the opposite polarity is output. As a result, the inverter 3 outputs the output phase voltage as shown in FIG.
A pulse voltage with the same polarity as the fundamental wave as in (d) is output. This is so-called unipolar modulation.

In the unipolar modulation of FIG. 4, the amplitude K of the fundamental wave voltage command e _o *, that is, the peak value K of the positive side voltage command e _p * and the negative side voltage command e _n * is shown in FIG. As shown in (b) and (c), when it becomes larger than the peak value (= 1) of the carrier triangular wave, the inverter 3 has the same polarity as the fundamental wave as shown in FIG. It outputs a pulse voltage with a reduced number of pulses in a half cycle of the wave. This is so-called overmodulation.

In the overmodulation of FIG. 5, the fundamental wave voltage command e
Amplitude K of _o *, that is, positive side voltage command e _p * and negative side voltage command e
_When the peak value K of _n * becomes larger than the peak value (= 1) of the carrier triangular wave as shown in (a), (b) and (c) of FIG. 6, the inverter 3 outputs the output phase voltage as shown in FIG. It has the same polarity as the fundamental wave as in (d), and the number of pulses in the half cycle of the fundamental wave is 1
Output the pulse voltage. This is so-called one-pulse modulation.

The shift of the modulation method as described above is performed according to the amplitude K of the fundamental wave voltage command e _o *, for example. Which modulation method is used varies depending on the application in which the electric motor is used, but in the case of the electric vehicle control device, it is desirable to perform power running and brake (regeneration) control in the order described above.

Next, with respect to the currents flowing into and out of the neutral point N when the DC components of the DC voltages V _dp and V _{dn divided} by the capacitors 22 and 23 are balanced, a diagram using a dipolar modulation system as an example 7 will be described.

As described above, two divided voltage commands e _op * and e _on * based on the fundamental wave voltage command e _o * of FIG. 7 (a).
Figure 7 (b) positive voltage command e _p * and Figure 7 (c) created from
The negative voltage command e _n * of is compared with the carrier triangular wave,
The inverter output phase voltage as shown in FIG. 7D is obtained. At this time, if the harmonic component is ignored in the induction motor 4,
As in (e), a sinusoidal current with no DC component flows.

FIG. 7F shows a switching function which expresses the flowing state of the current flowing in and out of the neutral point N by 1 and 0.
Is flowing, this is a period in which the inverter output phase voltage of FIG. Further, in a state where 0 is not flowing, this is a period in which the inverter output phase voltage in FIG. 7D is not 0.

The product of this switching function and the electric current of the motor 4 is the current flowing through the neutral point N of one phase of the inverter 3 as shown in FIG. 7 (g), which is balanced in the positive and negative cycles. DC component is not included.

Therefore, the DC components of the DC voltages V _dp and V _{dn divided} by the capacitors 22 and 23 are maintained in a balanced state.

However, when the capacitors 22 and 23 have an unbalanced capacity or when the output pulse width of the inverter 3 varies due to the ON / OFF operation of the switching element of the inverter 3, the current flowing into and out of the neutral point N is increased. When a DC component is generated in the DC voltage, an imbalance occurs in the DC components of the DC voltages V _dp and V _{dn divided} by the capacitors 22 and 23. As a result, an overvoltage is applied to the switching element of the inverter 3 having the higher DC voltage, which causes damage to the switching element.

As a conventional technique for suppressing the imbalance of the direct current components of the direct current voltages V _dp and V _dn divided by the capacitors 22 and 23, the above-mentioned Japanese Laid-Open Patent Publication No. 2-101969 for the dipolar modulation system and There is the above-mentioned document for the unipolar modulation method. Therefore, the case where the suppression technique shown in the literature is applied to the dipolar modulation method, and
A case where the suppression technique shown in Japanese Patent Publication No. 01969 is applied to a unipolar modulation system will be described.

The suppression technique shown in the literature is a method of adding a signal according to the DC component of the difference voltage between the DC voltages V _dp and V _{dn divided} by the capacitors 22 and 23 to the inverter output voltage command.

This suppression technique is applied to the above-mentioned dipolar modulation method (when an imbalance of V _dp <V _dn occurs in FIG. 7), and the direct current voltages V _dp and V are _added to the fundamental wave voltage command e _o *. the addition of signal ΔV corresponding to the DC component of the differential voltage between _dn (V _dp -V _dn), divided voltage command e _op * and e _on *, the positive side voltage instruction e _p * and negative-side voltage instruction e _n * Indicates from Fig. 7 (a) to (c) to Fig. 8
It changes like (a) to (c). As a result, the inverter output phase voltage becomes as shown in FIG.

At this time, the DC component contained in the inverter output phase voltage is the output line voltage of the inverter 3 (for example, U-
(Between V) is not canceled and does not appear, and the current of the electric motor 4 does not include a DC component. Further, the switching function expressing the flow state of the neutral point N is also as shown in FIG. However, the period of 1 of the switching function is in equilibrium when viewed in the positive and negative cycles of the fundamental wave voltage command e _o *. Therefore, the neutral point N current obtained by multiplying this switching function by the electric motor 4 current in FIG. 8 (e) is balanced in positive and negative cycles as shown in FIG. 8 (g) and does not include a direct current component. The DC components of the DC voltages V _dp and V _dn remain unbalanced. That is, even if the suppression technique shown in the literature is applied to the dipolar modulation method, there is no suppression effect.

The suppression technique disclosed in Japanese Unexamined Patent Publication No. 2-101969 is a DC voltage V _dp divided by capacitors 22 and 23.
And V _dn , the amplitude and shift amount (bias amount) of the two sinusoidal modulated waves are adjusted according to the DC component of the difference voltage.

By applying this suppression technique to the unipolar modulation system, the divided voltage command e _op is generated by the signal ΔV corresponding to the DC component of the difference voltage (V _dp -V _dn ) between the DC voltages V _dp and V _dn.
Even if the amplitudes of * and e _on * are adjusted as shown in FIG. 9 (a), both are added in unipolar modulation, and as a result, the positive side voltage command e _p * and the negative side voltage command e _n * Does not change, Fig. 9 (b)
And (c) are in equilibrium.

Therefore, the suppression technique disclosed in Japanese Patent Application Laid-Open No. 2-101969 cannot suppress the imbalance of the DC components of the DC voltages V _dp and V _{dn in} the unipolar modulation system.

Therefore, in the embodiment shown in FIG.
In order to suppress the imbalance (for example, V _dp <V _dn ) of the DC voltages V _dp and V _dn divided by 2 and 23, the voltage imbalance suppressing means 54 of the modulating means 5 uses the polarity discriminating distributor 542p. 5
At 42n, the polarity of the fundamental sine wave which is the output of the fundamental wave (sin) generating means 511 is discriminated / distributed and outputted at 1 and 0 respectively, and these outputs and the DC voltage V _dp outputted by the differential voltage detecting means 541. (in this case the signal negative, and therefore the V _dp <V _dn) signal ΔV corresponding to the DC component of the differential voltage V _dn (V _dp -V _dn) multiplied by the multiplier 543p and 543n, and the Δ
V is divided into ΔV _p and ΔV _n and output as shown in FIG.

These ΔV _p and ΔV _n are added to the divided voltage commands e _op * and e _on * in FIG. 10A, and adders 525 p and 525 n are added.
In addition, the positive voltage command e _p * of FIG. 10C and the negative voltage command e _n * of FIG. 10D are obtained.

As a result, the inverter output phase voltage is shown in FIG.
It becomes like (e). That is, the width of the positive output pulse of the inverter having the same polarity as the fundamental wave voltage command e _o * becomes narrower,
The width of the negative output pulse of the inverter having the same polarity as the fundamental wave voltage command e _o * becomes wider. At this time, the neutral point period on the positive side increases and the neutral point period on the negative side decreases, so the switching function expressing the flow state of the neutral point N is as shown in FIG. , The period of 1 of the switching function is unbalanced when viewed in the positive and negative cycles of the fundamental wave voltage command e _o *. Therefore, the neutral point N current obtained by multiplying this switching function by the electric motor 4 current in FIG. 10F becomes unbalanced in the positive and negative cycles, as shown in FIG. The DC component is included. The DC component of the positive becomes a charging current of the capacitor 22, also becomes the discharge current of the capacitor 23, increasing the DC voltage V _dp, also reduces the DC voltage V _dn, the DC voltage V _dp and V _dn It acts to suppress the imbalance of the DC component (V _dp <V _dn ). Further, the DC component included in the inverter output phase voltage is not canceled and appears in the output line voltage (for example, between U and V) of the inverter 3, and the electric current of the electric motor 4 does not include the DC component.

As described above, according to the present embodiment, in the dipolar modulation method, the control is simple and the imbalance of the DC components of the DC voltages V _dp and V _dn can be effectively suppressed.

By the way, although FIG. 10 shows the case of the power running mode, in the case of the regenerative mode, the current of the electric motor 4 is as shown in FIG.
Since the polarity is almost opposite to that of (e), the direct current component included in the neutral point N current also has the opposite polarity to the broken line in FIG.
It is necessary to switch ΔV _p and ΔV _n, which distribute the signal ΔV corresponding to the DC component of the difference voltage (V _dp −V _dn ) between the DC voltage V _dp and V _dn , to have opposite polarities to those in FIG. is there.

That is, when the electric vehicle has a regenerative mode other than the power running mode, the voltage imbalance at the neutral point should be suppressed during the regenerative operation. It will be described with reference to FIG.

The voltage imbalance suppressing means 54 of the modulating means 5 is provided with the polarity selecting means 544 and the multiplier 545, and by providing these components, ΔV _p and Δ at power running and regeneration are provided.
The polarity of V _n can be reversed, and the neutral point voltage imbalance can be suppressed at both times.

The polarity selecting means 544 outputs 1 at the time of power running and -1 at the time of power recovery from a power running / regeneration command from a driver's cab (not shown). By the multiplier 545, the polarity selecting means
The output of the fundamental wave generating means 511 is inverted according to the output of 544, and the polarities of ΔV _p and ΔV _n during power running and regeneration are inverted.

Although the present embodiment is configured to respond to the power running / regeneration command from the driver's cab, the power is obtained from the output voltage and the output current, or from the DC voltage and the DC input current, and the polarity of this power is calculated. May correspond to a power running / regeneration command.

Table 2 shows the polarities at the time of power running and regeneration.

[0051]

[Table 2]

As described above, according to the present embodiment, it is possible to always surely suppress the imbalance of the capacitor voltage without depending on the operating state such as power running / regeneration.

As a modification of this embodiment in the dipolar modulation system, as shown in FIG. 10, ΔV _{p is set} to a voltage command e _op *.
, In addition respectively a [Delta] V _n to the voltage command e _on *, rather than adjusting the width of the fundamental wave voltage instruction e _o * the same polarity of the inverter output pulses, as shown in FIG. 11, the voltage command a [Delta] V _p from e _on *, by subtracting respectively the [Delta] V _n from the voltage command e _op *, adjusting the width of the fundamental wave voltage instruction e _o * opposite polarity inverter of the output pulse (time * fundamental wave voltage instruction e _o is positive Even if the pulse width on the negative side is narrowed and the pulse width on the positive side is widened when the pulse width is negative, the same suppression effect can be obtained.
10 and 11, the same suppression effect can be obtained even _if only the pulse width on one side acts, that is, only ΔV _p acts or only ΔV _n acts.

Next, when the bias amount B is set to 0 and the system shifts to the unipolar modulation system, the voltage command e _op * is divided.
And e _on * are as shown in FIG.
The positive-side voltage command e _p * and the negative-side voltage command e _n * to which ΔV _p and ΔV _n of 2 (b) are added are as shown by thick lines in FIGS. 12 (c) and 12 (d). As a result, the inverter output phase voltage is shown in FIG.
It becomes (e). At this time, the DC component included in the inverter output phase voltage is the output line voltage of the inverter 3 (for example, U-
(Between V) is not canceled and does not appear, and the current of the electric motor 4 does not include a DC component.

The switching function expressing the flow state of the neutral point N is also as shown in FIG. 12 (g), and the period of 1 of the switching function is positive and negative of the fundamental wave voltage command e _o *. The cycle will be unbalanced. Therefore, the neutral point N current obtained by multiplying this switching function by the electric motor 4 current in FIG. 12F becomes unbalanced in the positive and negative cycles, as shown in FIG. The DC component is included. The DC component of the positive becomes a charging current of the capacitor 22, also becomes the discharge current of the capacitor 23, increasing the DC voltage V _dp, also reduces the DC voltage V _dn, the DC voltage V _dp and V _dn It acts to suppress the imbalance of the DC component (V _dp <V _dn ).

Further, in the partial dipolar modulation system of FIG. 3, the overmodulation system of FIG. 5 and the one-pulse modulation system of FIG. 6, the imbalance of the DC components of the DC voltages V _dp and V _dn is similarly performed. It can be understood that it can be suppressed.

As described above, according to the present embodiment, by improving the method of suppressing the imbalance of the DC components of the DC voltages V _dp and V _{dn in} the dipolar modulation method, it is possible to apply the modulation method other than the dipolar modulation method. The effect is that it can be applied as it is.

Further, according to the present embodiment, in the electric vehicle control device to which the dipolar modulation method and the other modulation methods are applied, the direct current voltages V _dp and V _dn of the direct current voltages V _dp and V _dn are applied to all the modulation methods used. By sharing the control for suppressing the component imbalance, there is an effect that the suppression control can be simplified.

In the present embodiment, the voltage imbalance suppression means 54 of the modulation means 5 has a signal ΔV corresponding to the DC component of the difference voltage between the DC voltages V _dp and V _dn output by the difference voltage detection means 541.
10 is not divided into square wave-shaped ΔV _p and ΔV _n as shown in FIG. 10B, but also divided into half-wave sinusoidal ΔV _p and ΔV _n as shown in FIG. Needless to say, the above-described suppression effect can be obtained. for that purpose,
In the embodiment of FIG. 1, the polarity discriminating distributors 542p and 542n of the voltage balancing means 54 may be replaced with the polarity discriminating distributors 526p and 527p of the voltage command dividing means 52.

The present invention is based on a dipolar modulation system different from the dipolar modulation system described in FIG. 2, that is, based on the fundamental wave voltage command e _o *, the two half-waves as shown in FIG. The voltage commands e _op * and e _on * in which the sine wave shape is divided are created, and from these voltage commands e _op * and e _on *, the positive side voltage command e _p * of FIG. As shown in FIG. 14D, the negative side voltage command e _n * is created and the width of the output pulse having the opposite polarity to the fundamental wave of the inverter output phase voltage is made constant, and the output pulse of the inverter is positively and negatively alternated to zero voltage. It goes without saying that the present invention can also be applied to a dipolar modulation method that is generated via the.

Further, in the three-level inverter to which the dipolar modulation system and the other modulation systems are applied, the three-level inverters correspond to the respective modulation systems (for example, the dipolar modulation system is disclosed in Japanese Patent Laid-Open No. 2-101969). Using
It goes without saying that the unipolar modulation method may be provided with a means for switching the method of suppressing the imbalance of the DC components of the DC voltages V _dp and V _{dn (} the technique disclosed in the literature).

[0062]

According to the present invention, in the dipolar modulation system, the control is simple and the imbalance of the DC components of the two DC voltages can be effectively suppressed.

Further, in the electric vehicle control device to which the dipolar modulation method and the other modulation methods are applied, the control for suppressing the imbalance of the DC components of the two DC voltages can be simplified.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram showing an embodiment of the present invention.

FIG. 2 is an operation explanatory diagram of dipolar modulation.

FIG. 3 is an operation explanatory diagram of partial dipolar modulation.

FIG. 4 is an operation explanatory diagram of unipolar modulation.

FIG. 5 is an operation explanatory diagram of overmodulation.

FIG. 6 is an operation explanatory diagram of 1-pulse modulation.

FIG. 7 is an operation explanatory diagram of current flowing in and out of a neutral point during dipolar modulation.

FIG. 8 is an operation explanatory diagram when a conventional technique is applied to dipolar modulation.

FIG. 9 is an operation explanatory diagram when a conventional technique is applied to unipolar modulation.

FIG. 10 is an operation explanatory diagram of dipolar modulation according to the present invention.

FIG. 11 is an operation explanatory diagram of another embodiment of the dipolar modulation of the present invention.

FIG. 12 is an operation explanatory diagram of unipolar modulation of the present invention.

FIG. 13 is an explanatory diagram of a signal corresponding to a DC component of a difference voltage between two DC voltages.

14 is an operation explanatory diagram of dipolar modulation different from the dipolar modulation of FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... DC overhead wire, 3 ... 3-level inverter, 4 ... Induction motor, 5 ... Modulation means, 22, 23 ... Voltage dividing capacitors, 51
... fundamental wave voltage command generating means, 52 ... voltage command dividing means,
53 ... Pulse generating means, 54 ... Voltage imbalance suppressing means.

Claims (24)

[Claims] 1. A series-connected capacitor for dividing a direct current voltage, and a direct current supplied from these capacitors are positive,
A power converter for converting into an AC phase voltage having three potentials of zero and negative, and an output expressed by a pulse train having a zero potential between positive and negative pulses in a half cycle of a fundamental wave of an output phase voltage of the power converter. In a control device for a power converter, which comprises a modulating means for supplying a signal for generating a train of pulses to a phase of the power converter to the power converter, the controller according to the DC component of the divided DC differential voltage. And a controller for the power converter, comprising means for adjusting the width of either the positive or negative output pulse of the output phase voltage. 2. The power converter control device according to claim 1, wherein the means for adjusting the width of the output pulse is provided in the modulation means. 3. A series-connected capacitor for dividing a DC voltage and a DC voltage supplied from these capacitors are positive,
A power converter for converting into an AC phase voltage having three potentials of zero and negative, and an output expressed by a pulse train having a zero potential between positive and negative pulses in a half cycle of a fundamental wave of an output phase voltage of the power converter. In a control device for a power converter, which comprises a modulating means for supplying a signal for generating a train of pulses to a phase of the power converter to the power converter, the controller according to the DC component of the divided DC differential voltage. And a controller for the power converter, comprising means for adjusting the width of the output pulse having the same polarity as the fundamental wave of the output phase voltage. 4. The control device for the power converter according to claim 3, wherein the means for adjusting the width of the output pulse is provided in the modulating means. 5. The power converter control device according to claim 3, wherein the means for adjusting the width of the output pulse is means for adjusting the width of the output pulse according to both positive and negative polarities of the fundamental wave of the output phase voltage. . 6. The electric power according to claim 3, wherein the means for adjusting the width of the output pulse is a means for adjusting the width of the output pulse according to either positive or negative polarity of the fundamental wave of the output phase voltage. Converter control unit. 7. A series-connected capacitor for dividing a DC voltage and a DC voltage supplied from these capacitors are positive,
A power converter for converting into an AC phase voltage having three potentials of zero and negative, and an output expressed by a pulse train having a zero potential between positive and negative pulses in a half cycle of a fundamental wave of an output phase voltage of the power converter. In a control device for a power converter, which comprises a modulating means for supplying a signal for generating a train of pulses to a phase of the power converter to the power converter, the controller according to the DC component of the divided DC differential voltage. During powering, adjust the width of the output pulse of the same polarity as the fundamental wave of the output phase voltage,
A control device for a power converter, comprising means for adjusting the width of the output pulse having a polarity opposite to that of the fundamental wave of the output phase voltage during regeneration. 8. The control device for the power converter according to claim 7, wherein the means for adjusting the width of the output pulse is provided in the modulating means. 9. The control device for a power converter according to claim 7, wherein the means for adjusting the width of the output pulse is means for adjusting the width of the output pulse according to both positive and negative polarities of the fundamental wave of the output phase voltage. . 10. The electric power according to claim 7, wherein the means for adjusting the width of the output pulse is a means for adjusting the width of the output pulse with either positive or negative polarity of the fundamental wave of the output phase voltage. Converter control unit. 11. A series-connected capacitor for dividing a DC voltage and a DC voltage supplied from these capacitors are positive,
A power converter for converting into an AC phase voltage having three potentials of zero and negative, and an output expressed by a pulse train having a zero potential between positive and negative pulses in a half cycle of a fundamental wave of an output phase voltage of the power converter. In a control device for a power converter, which comprises a modulating means for supplying a signal for generating a train of pulses to a phase of the power converter to the power converter, the controller according to the DC component of the divided DC differential voltage. And a control device for the power converter, comprising means for adjusting the width of the output pulse having a polarity opposite to that of the fundamental wave of the output phase voltage. 12. The control device for a power converter according to claim 11, wherein the means for adjusting the width of the output pulse is provided in the modulating means. 13. The power converter control device according to claim 11, wherein the means for adjusting the width of the output pulse is means for adjusting the width of the output pulse according to both positive and negative polarities of the fundamental wave of the output phase voltage. . 14. The electric power according to claim 11, wherein the means for adjusting the width of the output pulse is a means for adjusting the width of the output pulse with either positive or negative polarity of the fundamental wave of the output phase voltage. Converter control unit. 15. A series-connected capacitor for dividing a DC voltage, and a DC voltage fed from these capacitors are positive,
In a control device of a power converter including a power converter that converts an AC phase voltage having three potentials of zero and negative, it is created based on an amplitude command and a frequency command of a voltage to be output to the power converter. The fundamental wave voltage command is divided into a positive-side voltage command for generating a positive output pulse and a negative-side voltage command for generating a negative output pulse in the phase of the power converter, and the power converter is controlled based on these voltage commands. Modulating means for creating a signal for controlling ON / OFF of the switching element to be configured, and means for distributing a signal corresponding to the DC component of the divided DC differential voltage in correspondence with the polarity of the fundamental wave voltage command. , A means for superposing the output of the distribution means on the positive side voltage command or the negative side voltage command. 16. The superimposing means according to claim 15,
A control device for a power converter that superimposes the output of the distribution means having the same polarity as the voltage command on the positive voltage command or the negative voltage command. 17. The superimposing means according to claim 15,
A control device for a power converter that superimposes an output of the distribution unit having a polarity opposite to those of the voltage command on the positive side voltage command or the negative side voltage command. 18. A capacitor connected in series for dividing a direct current voltage, and a direct current supplied from these capacitors being positive,
In a control device for an electric vehicle including a power converter that converts an AC phase voltage having three potentials of zero and negative, and an AC electric motor driven by the power converter, a voltage command supplied to the power converter And a signal for generating, in the phase of the power converter, a train of output pulses in which the half cycle of the fundamental wave of the output phase voltage of the power converter is represented by a pulse train of positive and negative alternating through zero potential, based on the frequency command. To the power converter, a first modulation mode for supplying to the power converter, and a signal for generating a train of output pulses different from the train of output pulses in the first modulation mode in the phase of the power converter. A modulation means having a second modulation mode for supplying;
In the first modulation mode and the second modulation mode,
A control device for an electric vehicle, comprising: a single DC component unbalance suppression unit that suppresses the unbalance of DC components of the divided DC voltage. 19. The second modulation mode according to claim 17, wherein a period in which positive and negative pulses appear alternately through a zero potential and a period in which the pulses appear with the same polarity as the fundamental wave of the output phase voltage are included. A mode for performing partial dipolar modulation in which a train of output pulses existing in a half cycle of the fundamental wave of the output phase voltage is output as the phase voltage of the power converter, of an output pulse having the same polarity as the fundamental wave of the output phase voltage. In the column, a mode for performing unipolar modulation for outputting a column of output pulses in which the number of the output pulses included in the half cycle of the fundamental wave of the output phase voltage is plural as the phase voltage of the power converter,
A train of output pulses having the same polarity as the fundamental wave of the output phase voltage, wherein the number of the output pulses included in a half cycle of the fundamental wave of the output phase voltage is the fundamental of the output phase voltage in the unipolar modulation mode. A mode in which overmodulation is performed in which a train of output pulses smaller than the number of output pulses included in a half cycle of a wave is output as a phase voltage of the power converter, or an output pulse of the power converter is the output phase. One pulse modulation for outputting a train of output pulses having the same polarity as the fundamental wave of the voltage and having one output pulse included in the half cycle of the output phase voltage as the phase voltage of the power converter. A control device for an electric vehicle, which is a mode in which at least one of the modes is performed. 20. The direct current component unbalance suppression means according to claim 18, wherein the width of the output pulse having the same polarity as the fundamental wave of the output phase voltage of the power converter is divided into the DC voltage. A control device for an electric vehicle, which is means for adjusting the DC voltage component of the differential voltage of the electric vehicle. 21. The modulating means according to claim 18,
A fundamental voltage command created based on an amplitude command and a frequency command of a voltage to be output to the power converter, a positive side voltage command to generate a positive output pulse in the power converter and a negative voltage command to the power converter. A means for dividing into a negative voltage command for generating an output pulse, a means for giving a bias that changes these voltage commands, and a signal for controlling on / off of a switching element constituting the power converter based on these voltage commands The single DC component unbalance suppression means is a signal corresponding to the DC component of the voltage difference of the divided DC voltage corresponding to the polarity of the fundamental wave voltage command. A control device for an electric vehicle, comprising: a means for distributing, and means for superimposing an output of the distributing means on the divided positive and negative voltage commands. 22. Capacitors connected in series for dividing a DC voltage and a DC voltage fed from these capacitors are positive,
A power converter for converting into an AC phase voltage having three potentials of zero and negative, and a pulse width generated in a phase of the power converter having a polarity opposite to that of the fundamental wave of the output phase voltage are constant, and this power A signal for causing the power converter to generate a train of output pulses in a phase of the power converter represented by a train of pulses in which a half cycle of a fundamental wave of an output phase voltage of the converter has a zero potential between positive and negative pulses. In the control device for the power converter, which comprises a supplying means for supplying, the modulating means superimposes a signal corresponding to a DC component of the divided DC differential voltage on a fundamental wave voltage command of the output phase voltage. A control device for a power converter, comprising: 23. Capacitors connected in series for dividing a DC voltage and a DC voltage fed from these capacitors are positive,
In a control device for a power converter including a power converter that converts an AC phase voltage having three potentials of zero and negative, a half cycle of a fundamental wave of an output phase voltage of the power converter passes through a zero potential. A first modulation mode for supplying to the power converter a signal for generating a train of output pulses represented by alternating positive and negative pulse trains in the phase of the power converter; and a fundamental wave of an output phase voltage of the power converter. Modulating means having a second modulation mode for supplying to the power converter a signal for producing a train of output pulses of the same polarity in the phase of the power converter; and in the first modulation mode, the voltage dividing First suppressing means for suppressing the imbalance of the DC component of the DC voltage, and second suppressing means for suppressing the imbalance of the DC component of the divided DC voltage in the second modulation mode. These suppressing means are the first Converter control apparatus and means for switching in accordance with the modulation mode and the second modulation mode. 24. The power converter according to claim 23, wherein the first suppressing unit is a unit that adjusts the widths of the positive and negative pulses according to the DC component of the divided DC differential voltage. Control device.