JPS58130774A - Controlling method for dc/dc conversion - Google Patents

Abstract

PURPOSE:To obtain an output having small ripple with a small-sized device by combining a current type inverter and a voltage type inverter. CONSTITUTION:A single phase current type inverter is fomed of a circuit having a smothing reactor 31' and controlled rectifiers 11'-14', and a single phase half- bridged voltage type inverter is composed of controlled rectifiers 11'', 12'', feedback rectifiers 21'', 22'' and smoothing condensers 41' 41''. A negative terminal NI and a positive terminal PV are connected in series with each other at the positive terminal PI and negative terminal NI of a current type inverter and at the positive and negative terminals PV, NV of a voltage inverter, and the AC terminals AC'1, AC'2 and the AC terminals AC'3, AC'4 are of the inverters connected through a transformer 6 therebetween. A current flowing through the voltage inverter coil 6b of the transformer 6 becomes zero during the period that the sets of elements 11', 12' and 13', 14' are simultaneously fired, i.e., in the state that the DC voltage of the current inverter is shortcircuited.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a DC-DC conversion method, in particular, a revision of a control method for a so-called ACIJ-equipped DC-DC converter, which has the function of converting a DC to be converted into AC once using an inverter and then converting it into DC. Regarding.

In general, various types of DC-DC converters are in practical use, and chopper-type DC-DC converters that use a chopper circuit include a step-up chopper that obtains a DC voltage higher than the input voltage, and a The step-down chopper shown in FIG. 1 is known as a step-down chopper that obtains a low DC voltage. That is, FIGS. 1(a) and 1(b) show a step-up chopper converter and a step-down chopper converter.
1.1' is a transistor, gate turn-off (GTO)
A controlled rectifying element that closes or opens according to an external control signal, such as a thyristor or a thyristor with a forced commutation circuit, 2 and 2' are rectifying elements, 3 and 3' are smoothing reactors, 4 and 4' are smoothing capacitors, Pi t Nl is an input terminal, p=e N i e P2'e N, p is an output terminal.

It is known that each of these acquaintances has the following advantages and disadvantages.

(1) The step-up chopper converter is (a) capable of only boosting the voltage, and when the input is high-voltage DC like an electric vehicle, the DC output becomes a higher voltage, so there is no flexibility, and (b) the current to the smoothing capacitor 4 is The ripple current is intermittent and the ripple current is large, and (c) the input current has a relatively small ripple. (2) The step-down chopper converter is capable of (a) only step-down and is suitable for electric vehicles. When the fluctuation range of the input voltage is wide, as in the case of the output voltage must be selected below the minimum value of the input voltage, there is no degree of freedom, and (b) the current of the smoothing reactor 3' is considerably larger than that of the external pressure type. This results in an increase in the weight and dimensions of the smooth reactor part, and (
c) The input current from the chopper becomes intermittent, and the pull current becomes quite large, which has an adverse effect on the input power supply.

Also, A with an inverter part and an AC interposed in the middle
The following are known as DC-DC converters with C-links.

Figure 2 shows a conventional DC-DC converter with an AC link, in which 11, 12, 13, and 14 are control U flow elements and H having the same functions as the control rectifiers l and 1', respectively.
, 22, 23, 24, 2s, 26, 27, 28
is a rectifying element, 31 is a smoothing reactor, 41 is a smoothing capacitor, 5 is a transformer, P 11 e Nl 1 is a DC input terminal, AC1e ACz r ACs eAC4 is an AC terminal, and P21 + N21 is a DC output terminal.

Although such a device is commonly used and its detailed explanation will be omitted, a voltage type single-phase bridge inverter is formed from a circuit consisting of control rectifying elements (11 to 14) and rectifying elements (21 to 24). When performing voltage control, the AC output voltage is controlled by pulse width control, and this AC output is converted to DC by a rectifier circuit including rectifying elements (25 to 28) via a transformer 5, and then converted to DC by a smoothing reactor 31. The DC-DC converter with AC link is output as a DC voltage smoothed by a smoothing capacitor 41.The characteristics of the DC-DC converter with an AC link as described above are as follows.

(1) The output voltage can be freely selected by the step-up/step-down action of the transformer 5 disposed in the middle for coupling.

5 (2) While it is common to control the DC output voltage, the DC voltage obtained by rectifying the AC output using pulse width control becomes intermittent, requiring a smoothing reactor 31 and a smoothing capacitor, and the input current also decreases. The intermittent ripple current becomes large. The capacity of the pressure generator 5 must be commensurate with the output capacity.

The present invention focuses on each of the above-mentioned systems, and provides a DC with a mu-C link that utilizes only the advantages of the conventional system.
- Provides a method by which a DC converter can be realized. The present invention will be explained below based on the drawing numbers.

Figure 1s3 is 111141 of an embodiment to which the present invention is applied.
It shows one's power. That is, smooth reactor 31
' and controlled rectifying elements 11', 12', 13',
14' constitutes a single-phase electric illumination type inverter, and control rectifier elements 11" and 12" and feedback rectifier elements (hereinafter simply referred to as rectifiers) connected in antiparallel to these control rectifier elements 21. 22 and smoothing capacitors 41' and 41' constitute a single-phase half-bridge voltage source inverter. The wrinkles are also the positive terminal P of these current source inverters! e
Negative terminal Nl and positive terminal P of the voltage source inverter,
At the negative terminal Nv, the negative terminal NI and the positive terminal P are connected in series, and the AC terminal C1' of each inverter is connected in series.
, AC,' and AC terminal ACs' e AC4' threshold to the transformer!・The above-mentioned current source inverter and voltage source inverter are conventional techniques, and detailed explanation thereof will be omitted. ・Furthermore, the control rectifier elements (11' to 14 ', 11'.

12') may be the same as shown in FIGS. 1 and 2.

The control operation of such an i-path configuration will be explained in detail with reference to FIGS. 4 to 6. First, an example of the basic operation will be explained using the diagram shown in FIG. 4 showing the input of the control signal and the waveforms of each part.

Now, assuming that the voltage between the DC terminals of the voltage source inverter is 2VD, the AC output voltage e□ma of the voltage source inverter is uniquely determined by the control rectifying elements 11' and 12', and is a rectangular wave with a peak value vD. The AC terminals ACI' and AC! of the current source inverter are as shown in the figure. ', if the winding ratio of the transformer is (current source inverter winding 6 m = voltage source inverter 1 5 isb = s:i), the liquid high value sv
During the current period FD, during which the rectangular liquid D is supplied, even the conduction of the control rectifying elements 11' and 14' is caused by the DC voltage ν,
becomes (-8Vn), and during period FD, the polarity of the AC output voltage ·, □ is reversed and the DC voltage -1 becomes (+l&V
D). Furthermore, during the period PD, the control rectifier element 1 becomes
2' and 13' are conductive, so the DC voltage -1 is ←-5v
D), and in period PD4, the polarity of the CI roofing machine is reversed again, so - becomes (+ * Vn) - One cycle of the operating cycle is completed from period PDI to period PD4. The DC voltage ν is, for example, k. Here, when the sum of the average value of this DC voltage #1 and the voltage 2VD between the DC terminals is strong with the input voltage 8 given from the DC power supply (not shown), the converter operation is balanced. and in this case (
1) Iil[#l voltage of the voltage source inverter which is the voltage 2VD, that is, the output of the DC-DC converter, is determined by the value of the control angle r,
It can be seen that by controlling the control angle r with respect to changes in the input voltage B, it is also possible to keep the output voltage of the DC-DC converter constant at 2VD.

Also, looking at the voltages of the controlled rectifying elements 11' and 14', during the periods PD, , FD, they are conductive and the voltage across them is zero, and during the period PD, the controlled rectifying elements 12' and 13'
A reverse voltage of (-SVD) is applied due to the conduction of
A forward voltage of VD) is applied. Similarly, the control rectifying elements 12', 13' are as shown in the figure. In this way, in the advance control method, normal thyristors are used for the control rectifying elements 11', 12', 13', 14'. However, since the application of reverse voltage during periods PD, , pos is guaranteed, commutation is possible without the need for a forced commutation circuit.Furthermore, looking at the power relationship, voltage source inverters with transformer sb<The waveform of the flowing current 'INV is as shown in the figure based on the value ID of the input 9 voltage IL*o.Therefore, the inflow current 'O1eice' from the power source of the smoothing capacitors 41' and 41' is as shown in the figure. The average value of the currents of the smoothing capacitors 41', 41' must be zero, that is, the average value Io of 11 K'C1#'cm becomes the load current as the DC output current.Therefore, this average value Io is shown in the following equation (2). From the above equations (1) and (2), 2 ID = 2VD -Io...
・・・・・・・・・(Achieved) In this way, the load power PL(2VD・Io) becomes the input power pD(g・ID
) is found to be equal to

Another transformer! Considering the apparent power FT, the apparent power P! becomes (VD-buty ID), and from equation (1), (4)
The formula is: IO Here, considering the case where the DC output voltage of 2VD is controlled to be constant, the maximum value -■ and the minimum value BMIN of the controllable input voltage are as follows.

CCte (2VD=1200 volts), (h■=1
800; N volts), (K=1) is obtained from equation (5), and therefore (EMlll=600 volts). This means that if the rated value of the human power voltage E is 1200 volts, the control angle r is (r = K/2) from equation +1), and the apparent power P! of the transformer is calculated from equation (4). is (PT =
PD/2) In other words, it is an envy pressure device! It can be seen that the required capacity is only half of the load power.

In such a device, the input current is continuous, the ripple is small, and the output can be increased or decreased in pH with respect to the input, and furthermore, the transformer portion can be miniaturized.

Next, a method for further reducing the transformer capacity and voltage source inverter capacity 1 of such a device is shown in Fig. S and 6.
This will be explained with reference to the figures.

First, when lowering the DC output voltage from the input DC voltage according to the operation chart shown in FIG. 5, the control rectifier 11'
, 13' with respect to the AC output voltage is fixed to a sufficiently small advance control angle rts as shown in the example, and the control rectifying elements 12' and 14' are set to the advance control angle rma as shown in the figure, with respect to the AC voltage.・Here, the advance control angle r1m is the control rectifier element 1 for the time that can extinguish the control rectifier element if the current source inverter is a separately excited type.
Proceed to apply a reverse voltage to 1' and 13'. In this case, the input/output voltage relationship is as follows: (6) Formula % Lead control angle ru of 12', 14' is fixed at g, and lead control angle r1s of control rectifying elements 11', 13' is controlled. This case is shown in FIG. 6 similar to FIG. 5.

This input/output voltage relationship is Dx4='), then (6
) can be expressed by the formula 0 As shown in FIG. 85 and FIG. 6, the input voltage fluctuation range is exactly the same as that in FIG.
Electricity fIL flowing through the voltage type in/eta windings of transformer q
IK iris V becomes zero during the period when the set of control rectifiers 11', 12' and control rectifiers 13', 14' are fired simultaneously, that is, in the state where the DC voltage of the current source inverter is short-circuited. . Therefore, when the rated value of the input voltage E and the output voltage 2VD are selected to be equal to the rated value of the input voltage E, that is, (from the formula
In the case of ru = π), if the advance control angle 711 is a sufficiently small value, the voltage source inverter winding 116b has a noteworthy point in which almost no current flows. and,
Normally, if the time during which the input voltage B fluctuates greatly is extremely short, the transformer 8a6 can be rated for short 13 hours and can be used without any wrinkles. Additionally, the current flowing through the voltage source inverter is small, which can also reduce wrinkles and reduce circuit loss.In addition, the DC voltage of the current source inverter! It is clear that the smoothing reactor 31' etc. can be downsized by reducing the pull voltage.Although this example is an example in which a half-bridge is used as a voltage source inverter, it is natural that a single-phase pure bridge inverter is used. The applicability is clear.

Furthermore, it is obvious that the same effect can be achieved even if the connection order of the DC terminals of each inverter is reversed from the illustrated example, and the insertion point of the smoothing reactor is not limited to that shown in Fig. Needless to say, it can be anywhere.

As explained above, according to the present invention, it is possible to provide a method for realizing an exceptional device that uses a combination of a current source inverter and a voltage source inverter to take advantage of the individual advantages of conventional systems.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing a conventional DC-DCCa2 power converter 14 park, Fig. 2 is a circuit diagram showing a conventional DC-DC converter with σ) ACl link, and Fig. 3 is a circuit diagram showing a conventional DC-DC converter with Example 1! Circuit diagram showing the configuration of parts, No. 4
5 and 6 are diagrams showing control signal inputs and each part #IL type shown for explaining the control operation of the device shown in FIG. 3. 1 , 1' , 11 , 12 , 13 , 14 , 1
1', 12', 13', 14', 11". 12'... Control rectifier, 2, 2', 21,
22, 23, 24°25, 26, 27, 28,
21", 22# - Rectifying element, 3.3'. 31, 31'... Smoothing reactor, 4, 4
', 41, 41', 41"... Smoothing capacitor, 5.6... Transformer, PI * pv...
・Positive terminal s Nl e NV...-Negative terminal, A
C,,AC,. ACI @ AC4# Act', AC! ', A.C.
s's AC4'... AC terminal 〇 Patent applicant Toyo Denki Seizo Co., Ltd. Representative Doi Atsushi l Monki A +V Do tile--11π-1-- Leaf, 5 Hiichi---π- ^--忽-一一'$b＋月

Claims (1)

[Claims] Separately excited current source inverter means comprising a smoothing reactor and a plurality of controlled rectifying elements, a smoothing capacitor connected between the plurality of controlled rectifying elements, a feedback rectifying amount of the plurality of controlled rectifying elements, and a DC terminal; The DC terminals of the Zeng relaxation current type inverter means and the voltage type inverter means are connected in series for km, and the AC terminals of each of these inverter means are transformed. By providing a period in which the DC terminals are short-circuited with respect to the AC output terminal voltage during the operation phase of the control rectifying element of the passive current type inverter means, the voltage difference of the passive current source inverter means is A DC-DC conversion control method characterized by controlling a DC voltage.