JP3327012B2 - Power converter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power converter for obtaining AC power from a DC power supply, and more particularly to a power converter for obtaining AC power using a switched capacitor.

[0002]

2. Description of the Related Art Conventionally, there is a circuit shown in FIG. 1 as a circuit for obtaining AC power using a switched capacitor, and an operation waveform diagram thereof is shown in FIG.

In this conventional example, a charging unit for charging a plurality of power supply capacitance elements (hereinafter, referred to as capacitance elements) C _j (j = 1 to 5) via an inductance element L ₁ and a plurality of charging units are provided. Capacitance element C _j (j = 1
Together composed of the load circuit power conversion unit for supplying power from 1 to 5), a direct current power supply E by the inductance element L ₁ the charging current control capacitance element C _S charged via the charging current control Capacitance element C
_S and DC power supply E are connected in series to DC power supply E so that they have the same polarity, and switching element S _j1 (j = 1 to 5) is selectively turned on, so that a plurality of switching elements are connected via inductance element L _1. After charging the capacitance elements C _j (j = 1 to 5) of the switching element S
_j2 (j = 1 to 5) is selectively turned on, and the inductance element L is determined by a plurality of capacitance elements _Cj (j = 1 to 5).
By charging and discharging the load capacitance element C _z via the ₂ and supplies a large substantially sinusoidal voltage of an amplitude than the DC power source E across the load Z. Wherein the load circuit 1 is composed of a bridge circuit composed of the load Z at the load capacitance element C _z and a switching element S _z1 to S _z4.

Next, the operation will be briefly described with reference to FIG. First, a plurality of capacitance elements C _j (j = 1 to
The charging operation 5) will be described. It is assumed that the charging current control capacitance element _CS is charged to the power supply voltage E at time t ₀ .

[0005] Time t₀In FIGS. 5 (a) to 5 (c),
As shown, the switching element S_S1, S ₁₁Switch on and switch
Ching element S_S2To turn off the current I_C1To DC power supply E →
Ductance element L₁→ Switching element S₁₁→ Capacity
Cance element C₁→ Capacitance element C for charging current control
_S→ Switching element S_S1→ Flow through the DC power supply E
And the capacitance element C₁Charge. Capacity
Citance element C₁Voltage supplies alternating current to the load
Voltage (setting voltage V_Ten) Charged until
Immediately before (time t₁), Switch as shown in FIG.
Element S_S1To turn off the current I_C1To DC power supply E → Induct
Tance element L₁→ Switching element S₁₁→ Capacitor
Element C₁→ Diode D_S→ Flow through the DC power supply E
From the charging current path to the charging current control capacitor
Element C_SDisconnect. At this time, E <V_C1Is
Then, as shown in FIG._C1Decreases sharply. FIG.
As shown in (a), (c) and (d), I_C1Is zero
Time t_TwoSwitching element S₁₁Off, switching element
Child S_S1, S_{twenty one}Turn on the capacitance element
C₁Is a DC power source E and a capacitance element for controlling a charging current.
Child C_SFrom the set voltage V_TenHold. In addition,
Style I_C2To DC power source E → inductance element L ₁→ Switch
Ching element S_{twenty one}→ Capacitance element C_Two→ Charging current system
Your capacitance element C_S→ Switching element S_S1→
Capacitance element by flowing in the path of DC power supply E
C_TwoCharge. Similarly, at time t_TwoTo time t_TenIn
And each capacitance element C_j(J = 1 to 5)
Pressure V_j0(J = 1 to 5). Time t_TenFrom to
Capacitance element C₁Time t to start charging₁₆Between
And the switching element S_S2To turn on the charge current control key.
Capacitance element C_SVoltage V_CSTo the initial voltage (= E)
To charge.

Next, a plurality of capacitance elements C _j (j =
The operation of supplying power to the load circuit 1 via the switching element S _j2 (j = 1 to 5) and the inductance element L ₂ from 1 to 5) will be described.

Time t₀From time t_TwoDuring the period, FIG.
As shown in (l), the switching element S₁₂~ S₅₂Off
Then, as shown in FIGS. 5 (m) and (n), the switching element S
_z2, S _z4Is turned on, the voltage of the load Z is
Reset to the command level. Time t_TwoTo time t₁₆Among
As shown in FIGS. 5 (m) and (n), the switching element S_z3,
S_z4Off, switching element S_z1, S_z2Turn on and negative
Load Z to load capacitance element C_zConnect to Times of Day
t_TwoSwitching element S₁₂Turn on the capacitance
Element C₁→ Switching element S₁₂→ Inductance element
L_Two→ Load circuit 1 → Capacitance element C₁In the path of
By flowing the current, energy is supplied to the load circuit 1 for a certain period of time.
Then, the voltage of the load Z is boosted resonantly. And when
Time t_FourAnd switching as shown in FIGS. 5 (h) and 5 (i).
Element S₁₂Off, switching element S_{twenty two}To turn on
The capacitance element C₁Load discharge current path
At the same time as disconnecting from the circuit 1, the capacitance element C_Two
More inductance element L_TwoTo the load circuit 1 via the
Supplies lugi. Similarly, at time t_Four~ T_TenDuring the
Capacitance element C_j(J = 2-5)
Lactance element L_TwoSupply energy to the load circuit 1 through the
Pay. Here, the capacitance element C_j(J = 1 ~
5) More resonance operation to supply energy to the load circuit 1
Accordingly, as shown in FIG.
_j(J = 1 to 5)_Cj(J = 1 to 5) decreases
I do. Also, as shown in FIG.
L_TwoCurrent and load voltage V_ZChanges continuously
You.

[0008] At time t _11, by continuing to turn on the switching element S ₅₂ as shown in FIG. 5 (l), a load capacitance element C _z of the load circuit 1 as a power source,
The load circuit 1 → inductance element L ₂ → the capacitance element C ₅ in the path of the capacitance element C ₅ → the load circuit 1
Resonantly back energy, resonantly load voltage V _Z, as shown in FIG. 5 (p) is reduced. At the time t _12, Fig. 5
(K), turns on the switching element S ₄₂ as shown in (l), by turning off the switching element S _52, with disconnecting the charging and discharging current path of the capacitance element C ₅ from the load circuit 1, a load circuit 1 the inductance element It is connected to the capacitance element C ₄ via L ₂ , and returns energy from the load circuit 1 to the capacitance element C ₄ in a resonant manner. Between times t _{12 and} t ₁₆ , energy is similarly supplied from the load circuit 1 to the capacitance element C _j (j = 4-1) in a resonant manner, and as shown in FIG.
_The voltage V _Cj (j = 1 to 5) across _j (j = 1 to 5) slightly increases. Between time t ₁₆ ~t _17, FIG. 5 (m), by turning on the switching element S _z2, S _z4 as shown in (n), dropping the voltage of the load Z to the ground level. Figure 5 (m) at time t _17, the switching element as shown in (n) S _z1, S _z2 off, by turning on the switching element S _z3, S _z4, load Z inverts the polarity of the load Z Connect to capacitance element C _z .

By repeating the above operations, a pulsating current can be supplied to the load circuit 1 and the load Z can be supplied.
Can be supplied with an alternating current.

[0010]

However, in the above conventional example, when a high frequency AC voltage having a higher peak value than the DC power supply E is supplied to the load Z, the DC power supply E and the charging current controlling capacitance element C are provided. _When charging each capacitance element C _j (j = 1 to 5) from the series circuit with _S , the capacitance element with the lower set voltage is charged in order from the capacitance element with the lower set voltage, and the capacitance of the highest set voltage is also charged. In order to charge the element to near the maximum value of the total voltage of the series circuit of the DC power supply E and the charging current control capacitance element C _S , the highest set voltage is set by the voltage drop of the charging current control capacitance element C _S. To make it impossible to charge the capacitance element,
Charging current control capacitance element C _S becomes relatively large capacity is required, the first problem arises.

[0011] When charging the low capacitance element a series circuit of the set voltage of the DC power source E and the charging current control capacitance element C _S, the voltage difference therebetween increases, higher peak charging current This causes a second problem that the circuit efficiency is reduced and noise is increased.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a switch capable of reducing the capacitance of a charging current control capacitance element, improving circuit efficiency, and reducing noise. To provide a power conversion device using a storage capacitor.

[0013]

According to the present invention, a load, a plurality of power supply capacitance elements, a first inductance element connected to a DC power supply, and the first inductance element are provided. Charging means for charging the plurality of power supply capacitance elements to a substantially predetermined voltage via a load, a load capacitance element connected in parallel to the load , and a parallel circuit of the load and the load capacitance element. A second inductance element connected in series, a plurality of switching elements connected in series between the series circuit including the parallel circuit and the second inductance element, and the plurality of power supply capacitance elements; The power supply capacitance element is selectively switched and connected to the series circuit .
The load capacitance via an inductance element
Control means for changing the voltage across the load capacitance element in a substantially pulsating waveform by charging / discharging the element; and a plurality of the power supply capacitance elements connected to a DC power supply via the first inductance element. A charging current control capacitance element that controls a charging current to the power conversion device, and a charging / discharging unit that charges and discharges the charging current control capacitance element, wherein the charging unit includes a charging current control capacitance element. When a substantially predetermined voltage is charged, the charging current control capacitance element and the DC power supply have the same polarity,
The charging current control capacitance element is connected in series in the charging path of the plurality of power supply capacitance elements, and the plurality of power supply capacitance elements are charged in order from the one having a substantially predetermined voltage value that is charged to a higher value. In addition, the charging current control capacitance element has a low capacitance value such that its own voltage is reduced by discharging.

According to the second aspect of the present invention, the charging current controlling capacitance element has an initial voltage value higher than a DC power supply value.

According to the third aspect of the invention, the charging means determines the difference between the total voltage value of the DC power supply and the charging current control capacitance element and a substantially predetermined value of the total voltage of the plurality of power supply capacitance elements. It is characterized in that each power supply capacitance element is charged to a substantially predetermined voltage by making it small.

According to the fourth aspect of the invention, when the plurality of power supply capacitance elements are charged to a substantially predetermined voltage, the voltage applied to the plurality of power supply capacitance elements is reduced to reduce the current. It is characterized by having means for making it zero.

According to the invention described in claim 5, the load is a discharge lamp.

[0018]

According to the first aspect of the present invention, after charging the charging current control capacitance element with a substantially predetermined voltage from the DC power supply via the first inductance element, the charging current control capacitance element and the DC power supply are charged. Are connected in series so as to have the same polarity, and a plurality of capacitance elements for power supply are sequentially charged from the one having a substantially predetermined voltage value higher.

In this case, the charging current control capacitance element discharges its own voltage so that the difference between the total voltage value of the charging current control capacitance element and the DC power supply and the voltage value of the power supply capacitance element becomes small. Decrease.

According to the second aspect of the present invention, the sum of the DC power supply and the energy stored in the first inductance element is charged to the charge current control capacitance element, and then the charge current control capacitance element is used. The DC power supply is connected in series so as to have the same polarity, and a plurality of capacitance elements for power supply are sequentially charged from a power supply having a substantially predetermined voltage value. In this case, the voltage drop of the charging current control capacitance element further increases.

According to the third aspect of the present invention, after charging the charging current control capacitance element with a substantially predetermined voltage from the DC power supply via the first inductance element, the charging current control capacitance element and the DC power supply are charged. Are connected in series so as to have the same polarity, and a series circuit of a plurality of power supply capacitance elements is charged sequentially from the one having a substantially predetermined voltage value higher.

In this case, the charging current control capacitance element discharges itself so that the difference between the total voltage value of the charging current control capacitance element and the DC power supply and the voltage value of the plurality of power supply capacitance elements becomes small. Voltage of the

According to the fourth aspect of the present invention, when the plurality of power supply capacitance elements are charged to a substantially predetermined voltage, the voltage applied to the plurality of power supply capacitance elements is reduced to reduce the plurality of power supply capacitance elements. The current flowing through the power supply capacitance element is set to zero.

According to the fifth aspect of the present invention, the discharge lamp is stably lit by supplying AC high frequency power to the discharge lamp.

[0025]

【Example】

(Embodiment 1) FIG. 2 is an explanatory diagram of the operation of the first embodiment according to the present invention. The circuit configuration is the same as that shown in FIG.

The difference from the operation of the conventional example shown in FIG.
Than the series circuit of the DC power source E and the charging current control capacitance element C _S, the switching element S _j1 (j = 1~
5) via the inductance element L _1, a plurality of capacitance elements C _{j (j} = 1~5) with sequentially charged from the highest setting voltage, the voltage of the charging current control capacitance element C _S is the capacitance elements C _j (j = 1
As drops to follow the set voltage of 5), by setting the capacitance of the charging current control capacitance element C _S, the voltage of the series circuit composed of a DC power source E and the charging current control capacitance element C _S This is to make it possible to reduce the voltage at the time of the summation and the start of charging of each capacitance element.

Next, the operation will be briefly described with reference to FIG. Note that a plurality of capacitance elements C _j (j = 1 to
From 5), the operation of supplying power to the load circuit 1 via the switching element S _j2 (j = 1 to 5) and the inductance element L ₂ is the same as that shown in the conventional example. The charging operation of _j (j = 1 to 5) will be described.

Time t₁From time t₇During the switch
Element S_S2Turn on the capacitor element for charging current control
Child C_STo the initial voltage (= E). Time t₇At
And a switching element as shown in FIGS. 2 (a) and 2 (g).
S_S1, S₅₁Is turned on and the current I_C5To DC power supply E →
Lactance element L₁→ Switching element S₅₁→ Capacitor
Element C_Five→ Capacitance element C for charging current control_S
→ Switching element S _S1→ Flow through the DC power supply E
The capacitance element C_FiveCharge. FIG. 2 (a)
As shown in FIG._FiveIs the set voltage
V₅₀Immediately before charging (time t₈) Switching element
Child S_S1Is turned off and the current I_C5To DC power supply E → Inductor
Element L₁→ Switching element S₅₁→ Capacitance element
Child C_Five→ Diode D_S→ When flowing through the path of DC power supply E
And the charging current control capacitance element C from the current path.
_SE <V_C5Current I_C5Suddenly
Decrease sharply. Here, the charging current control capacitor
Element C_SVoltage V_C5Is the next charged capacitance
Element C_FourSet voltage V₄₀Key so that the voltage drops
Capacitance element C_FiveSet the capacity of. Current I_C5Is
Time t₉2 (a), 2 (f), and 2 (g)
Switching element S₅₁Turn off the switching element
S_S1, S₄₁To turn on the capacitance element C_FiveThe power
From the current I_C4Directly
Power supply E → inductance element L₁→ Switching element
S₄₁→ Capacitance element C_Four→ Charge current control capacity
Citance element C_S→ Switching element S_S1→ DC power supply E
Of the capacitance element C_FourCharge. same
And the capacitance element C_Three~ C₁Charge sequentially
As a result, as shown in FIG.₁₇V in
The value of cs + E is the time t₁It is almost equal to the value at

[0029] By the above such operation, the it is possible to reduce the capacity of the charging current control capacitance element C _S, the sum of the voltage of the DC power source E and the charging current control capacitance element C _S, the capacitance Element C
_{j (j} = _1~5) charging an initial voltage V _Cj (j = 1~5) and reduction of the peak current by reducing the voltage difference between the noise reduction of, thereby improving the circuit efficiency.

(Embodiment 2) FIG. 3 is a diagram illustrating the operation of a second embodiment according to the present invention. The circuit configuration is the same as that shown in FIG.

The difference from the operation of the first embodiment shown in FIG. 1 is that the total sum of the DC power source E and the energy stored in the inductance element L ₁ is between time t ₁ and time t _7. , by charging to the charging current control capacitance element C _S, is to raise the voltage Vcs to the voltage V _m (> 2E), a description by the same reference symbols are affixed to the other of the first embodiment and the same structure Omitted.

[0032] In this way, the so a voltage drop in the charging current control capacitance element C _S can be further increased, it is possible to further reduce the capacity of the charging current control capacitance element C _S, the circuit It is possible to reduce the peak current, reduce noise, and improve circuit efficiency.

(Embodiment 3) A circuit diagram of a third embodiment according to the present invention is shown in FIG. 4, and an operation waveform diagram thereof is shown in FIG.

The difference from the first embodiment shown in FIG. 1 is that, while a plurality of capacitance elements are sequentially charged one by one in the first embodiment, a DC power supply E and a capacitance element C _S for charging current control are used. two or more capacitance element in series circuit by charging in series connection, or to the of the by controlling the capacity of similar charge current control capacitance element C _S shown in example 1, a high set voltage by two or more continue to charge a series circuit of a capacitance element, and the sum of the voltage of the DC power source E and the charging current control capacitance element C _S, a voltage difference between the sum of the voltages of the two or more capacitance element The same components as those of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

In this way, it is possible to reduce the peak current in the circuit, reduce the noise, and improve the circuit efficiency.

[0036]

According to the first aspect of the present invention, it is possible to reduce the capacity of the charging element for controlling the charging current, to reduce the sum of the voltages of the DC power supply and the capacitance element for controlling the charging current, and to supply the electric power. A power converter using a switched capacitor can be provided which can reduce a peak current, reduce noise, and improve circuit efficiency by reducing a voltage difference from an initial charge voltage of a capacitance element for use.

According to the second aspect of the present invention, it is possible to reduce the capacity of the charging current control capacitance element, reduce the peak current in the circuit, reduce the noise, and improve the circuit efficiency. Further, it is possible to provide a power conversion device using a switched capacitor.

According to the third and fourth aspects of the present invention,
It is possible to provide a power converter using a switched capacitor, which can reduce a peak current in a circuit, reduce noise, and improve circuit efficiency.

According to the fifth aspect of the present invention, it is possible to provide a power converter using a switched capacitor capable of reducing peak current in a circuit, reducing noise, improving circuit efficiency, and stably lighting a discharge lamp.

[Brief description of the drawings]

FIG. 1 shows a circuit diagram according to the invention.

FIG. 2 shows an operation waveform diagram of the first embodiment according to the present invention.

FIG. 3 shows an operation waveform diagram of a second embodiment according to the present invention.

FIG. 4 shows a circuit diagram of a third embodiment according to the present invention.

FIG. 5 shows an operation waveform diagram of a conventional example according to the present invention.

[Explanation of symbols]

 C capacitance element I current L inductance element La discharge lamp S switching element V voltage Z load

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H02M 7/48 H02M 3/07 H05B 41/282

Claims (5)

(57) [Claims] 1. A load, a plurality of power supply capacitance elements, a first inductance element connected to a DC power supply, and substantially predetermined power supply capacitance elements via the first inductance element. Charging means for charging the load , a load capacitance element connected in parallel to the load , a second inductance element connected in series to a parallel circuit of the load and the load capacitance element, and the parallel circuit And a plurality of switching elements connected in series between the series circuit including the second inductance element and the plurality of power supply capacitance elements, and alternatively switching the plurality of power supply capacitance elements. the connected in series circuit the
The load capacitor via the inductance element
Control means for changing the voltage across the load capacitance element in a substantially pulsating waveform by charging / discharging the capacitance element; and connecting the plurality of power supply capacitances to the DC power supply via the first inductance element. A power conversion device comprising: a charging current control capacitance element for controlling a charging current to an element; and charging / discharging means for charging / discharging the charging current control capacitance element. The charging means includes the charging current control capacitance element When a predetermined voltage is charged, the charging current control capacitance element and the DC power supply have the same polarity, and the charging current control capacitance element is connected to the charging path of the plurality of power supply capacitance elements. Connected in series and charged to the plurality of power supply capacitance elements at a substantially predetermined voltage. A power conversion device for charging sequentially from a high value, and wherein the charging current control capacitance element has a low capacitance value such that its own voltage is reduced by discharging. 2. The power conversion device according to claim 1, wherein the charging current control capacitance element has an initial voltage value higher than the DC power supply value. 3. The charging means according to claim 1, wherein a difference between a total voltage value of the DC power supply and the charging current control capacitance element and a substantially predetermined value of a total voltage of the plurality of power supply capacitance elements is determined. A power converter, wherein each of said power supply capacitance elements is charged to a substantially predetermined voltage. 4. When the plurality of power supply capacitance elements are charged to a substantially predetermined voltage, the voltage applied to the plurality of power supply capacitance elements is reduced,
The power converter according to any one of claims 1 to 3, further comprising means for setting a current to zero. 5. The power converter according to claim 1, wherein the load is a discharge lamp.