JP2500553B2 - Power system - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high efficiency, low noise power supply system using a non-constant voltage type resonance power supply in a bulk power supply section.

[0002]

2. Description of the Related Art In a power supply system for supplying a DC power supply to a plurality of loads in a distributed manner, an AC (AC) power supply to a primary DC power supply is used.
AC / DC converter for converting to (DC) power supply and its DC
Further, a DC / DC conversion unit corresponding to a load for converting the output into a secondary DC power supply having a desired voltage is required. There are two types of DC / DC converters, an insulated type that is not limited in use and a non-insulated type that pursues economic efficiency. The DC output voltage can take a wide range from positive to negative depending on the final load. AC
The DC / DC converter has sufficient DC for these DC / DC converters.
Power is supplied, and if the primary DC output voltage is high, the current value can be reduced, so that the power feeding loss to the DC / DC converter can be reduced. There are various methods for this AC / DC converter, but recently, the convenience of a modularized converter has been focused on. This AC / DC conversion module is called a bulk, and the primary side and the secondary side are insulated.

[0003]

The distributed power supply system described above is considered to be the mainstream in the future, but a distributed power supply system using an AC / DC converter and a DC / DC converter is
Compared to a centralized power supply system with only an AC / DC converter, total power supply efficiency is poor. That is, the AC / DC converter is also D
If the C / DC converters are both normal switching regulators and the respective conversion efficiencies are 85%, the total conversion efficiency will drop to 72%. In addition, ordinary switching regulators have a lot of noise, and it is difficult to reduce bulk line noise in particular. The present invention
High efficiency in the above-mentioned AC / DC converter (bulk power supply),
By using a low-noise, non-constant voltage type resonance power supply, it is intended to improve conversion efficiency and reduce line noise.

[0004]

In order to achieve the above object, according to the present invention, a switching means having two main switching elements and two main switching elements are alternately turned on with a period for turning off both of them. and timing control means having a drive element of the system, the Sui
In series with the current flowing through the output terminal of the
Current resonance means and the output of the switching means
Voltage resonance hand formed in parallel with the voltage generated at the terminals
And the switching operation of the switching means
Rectifies and smoothes the current flowing to the output side to produce a DC output.
And a DC output means for controlling the resonance action of the current resonance means and the DC output during the ON period of the main switching element.
The rectifying action of the force means causes a half-wave series resonance with respect to the current, and the voltage resonance means causes a parallel resonance with respect to the voltage during the off period of the main switching element , and the on-state. Of the main switching element
Timing is the current flowing through the main switching element.
From the timing when becomes zero by the end of the series resonance
Delaying zero voltage and zero current
And a bulk power supply unit having an AC / DC conversion function for performing primary and secondary insulation to convert the AC input into a non-constant voltage high -voltage DC output, and a DC output of the bulk power supply unit. Isolated or non-isolated DC / D distributed to receive
And a C conversion unit.

[0005]

Since the DC / DC converter has the constant voltage characteristic, the bulk power supply unit (AC / DC converter) does not need the constant voltage function. Therefore, a resonant power supply without a constant voltage function is used for this bulk power supply section. This resonant power supply is advantageous for isolation because there is no primary or secondary feedback, and it has low noise and high efficiency because switching is performed at a perfect zero cross. Furthermore, since a single output is sufficient, the resonance operation is more stable, which can further reduce noise (line noise, radiation noise, etc.) and improve efficiency.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a distributed power supply system according to an embodiment of the present invention. In the figure, 10 is an AC input terminal, 20 is a bulk power supply section having an AC / DC conversion function, and 31, 32 ... are a plurality of DC / DC conversion sections. The bulk power supply unit 20 is an input AC power supply (100V / 200V)
Generates a primary DC voltage of, for example, 24V to 48V.
The DC / DC converters 31 to 35 receive the primary DC voltage and generate secondary DC voltages DC1 to DC5 having arbitrary polarities and voltages.

AC / used as the bulk power supply unit 20
The DC converter is a switching inverter using voltage resonance and current resonance, which has been proposed by the present inventor and filed as Japanese Patent Application No. 3-166383. First,
The principle configuration of this power supply unit will be described with reference to FIG. In the figure, 1 is a DC power supply, 2 is a DC power supply including a main switching element that can be turned on and off at any timing.
Switching means for switching and converting to AC
Reference numeral 3 is a DC output means for full-wave rectifying the supplied AC input and smoothing it with a capacitor to produce a DC output. Reference numeral 4 is a series resonance circuit formed in series with the current flowing through the output terminal of the switching means 2. Is a parallel resonance means formed in parallel with the voltage generated at the output terminal of the switching means 2, 6
Is a timing control means having a drive element for intermittently turning on the switching element of the switching means 2.

FIG. 3 is a basic principle block diagram showing the block of FIG. 2 in a little circuit configuration. The schematic operation will be described with reference to FIG. The main switching elements S1 and S2 are alternately turned on at a constant cycle under the control of the timing control means 6,
Although it is turned off repeatedly, it has a period in which it is turned off at the same time, as shown in FIGS. At this time, the voltage VC1 at the intersection A of both switching elements receives the positive and negative DC power supply voltages + VI and -VI, and the peak value V is as shown in FIG.
It becomes the exchange of I. At this time, the current iD1 or iD2 is
It is rectified by the diodes D1 and D2 through the inductance L2 and the capacitor C2, smoothed by the capacitors C3 and C4, and flows into the load RL. Since the diode D1 is in the forward direction when the switching element S1 is on,
The charge current iD1 shown in (a) of FIG.
Flow to 3. Here, the impedance of the switching element S1 and the diode D1 is sufficiently small, and C3 >> C
If it is set to 2, the above current will be the inductance L2.
And a sinusoidal series resonance current due to the capacitor C2.

[0009] This resonance current does not flow any more because the diode D1 becomes a reverse voltage and turns off when the direction of the current is reversed after half a wave has passed. In other words, the series resonance automatically stops when the resonance current ends in half wave and the current returns to zero. At this time, the electric charge corresponding to the resonant current that has flown is accumulated in the capacitor C2, so that the voltage VC2 at both ends remains as shown in (e) of FIG. This charge is released to the load RL when the switching element S2 is turned on next time, so that no energy loss occurs. Since the energy stored in the inductance is proportional to the current, the energy of the inductance L2 when the resonance is stopped at the zero current is zero. Therefore, the generation of harmful current noise is extremely small.

When the switching element S1 is turned off, the current resonance has ended, so only the current iL1 ((d) in FIG. 4) flowing through the inductance L1 flows through the switching element S1. The value of the inductance L1 can be set independently of the inductance L2 and the capacitor C2 for series resonance. Therefore, by setting L1 >> L2, the value of the current iL1 flowing through the inductance L1 becomes the series resonance current i.
It can be made sufficiently smaller than D1. Therefore, the switching element S1 can be turned off in the state of almost zero current.

On the other hand, the magnetic energy (current) stored in the inductance L1 while the switching element S1 is turned on becomes energy in which the inductance L1 and the capacitor C1 resonate in parallel. As a result, the voltage VC at point A
1 decreases in a sinusoidal manner, and eventually crosses zero and approaches −VI. This is the voltage resonance mode. The potential at point A is -VI
When it is close to the diode D2, the diode D2 is turned on, and the energy (current) remaining in the inductance L1 is transferred to L2, C2, D.
It is discharged to the capacitor C4 through 2. However, since the current of the inductance L1 is set small, it does not change greatly in terms of current, and the potential at the point A maintains a value near -VI. Therefore, the zero voltage operation that turns on the switching element S2 in a state where the voltage across the switching element S2 is very small becomes possible, and the loss at the time of turning on can be extremely small.

When the switching element S2 is turned on, the inductance L2 and the capacitor C2 cause a negative side current resonance, and the charge current iD2 shown in FIG. 4C flows into the capacitor C4 through the diode D2. After that, the above-described operation is repeated according to ON / OFF of the switching elements S1 and S2. In such a resonance type power supply device, since all switching operations of the switching elements are performed at zero voltage or zero current, the switching loss is small and the efficiency of the entire circuit is extremely high. Also, since both the series resonance current and the parallel resonance voltage have a spectrum close to a single frequency, the possibility of causing ringing or overshoot by interfering with the resonance dip of each part of the circuit is reduced, and unnecessary radiation such as harmonics is reduced. Very few.

FIG. 5 is a practical circuit diagram in which the series resonance circuits L2 and C2 and the parallel resonance circuits L1 and C1 are constructed by utilizing the primary side self-inductance L1 and the leakage inductance L2 of the transformer T1. The capacitor C1 (C2) is a capacitor C1 / 2 (C2 / 2) with a capacity of 1/2
It is configured by connecting in series. By doing so, L2 and C2 are included in the voltage resonance loop, but L2 <
Since <L1, C2 >> C1 is satisfied, L is actually
The influence of the presence of 2, C2 on the voltage resonance can be ignored.
A full-wave rectifier circuit 7 composed of four diodes is connected to the secondary side of the transformer T1, and the rectified output is the capacitor C.
It is smoothed by 3 and supplied to the load RL. The DC power supply 1 may be a DC power obtained by rectifying an AC power supply, and in this case, it becomes an AC / DC converter.

The power supply apparatus of FIG. 6 is of this type, and the full-wave rectifier circuit 8 consisting of four diodes full-wave rectifies the AC power supply AC and smoothes it with the capacitors C5 and C6. Therefore, here, the capacitors C5 and C6 serve as the DC power supply 1 of FIG. Two-part capacitor C1 / 2 for parallel resonance
Are connected in parallel to the switching elements S1 and S2. The capacitor C2 for series resonance is not divided and the transformer T1 is not divided.
Are connected in series to the primary winding of the. The configuration of FIG. 6 is AC
It is compatible with both 100V / 200V, and when 100V is selected, the voltage doubler rectification configuration is adopted. The switching control means 6 has two independent drive control circuits 61 and 62 so that the switching elements S1 and S2 can be driven independently.
Is provided. The output stages of the drive control circuits 61 and 62 are drive elements Q1 and Q2. The ON timings of these elements Q1 and Q2 are controlled by the CR time constant circuits 63 and 64, and the OFF timings thereof are the switching elements Q3 and Q4 of the preceding stage. C
It is controlled by R time constant circuits 63 'and 64'.

The AC components induced in the windings U1, U2 of the transformer T1 are positively fed back to the inputs of the time constant circuits 63, 63 ', 64, 64', respectively. Drive control circuits 61, 62
Have the same circuit configuration, but the output stage drive element Q1,
As shown in FIGS. 4F and 4K, Q2 is alternately turned on with a period in which both are turned off. That is, when the element S1 is turned on, the capacitor of the time constant circuit 63 'is charged by the current induced in the winding U1, and eventually the charging voltage rises to turn on the transistor Q3, so that the drive element Q1 is turned off. To do. When the element Q1 is turned off and the element S1 is turned off, the voltage applied to both ends of the primary winding is inverted by the induction of the primary winding of the transformer T1, and the time constant circuits 64, 64 '.
Will start to be charged. Since the time constant of the circuit 64 'is larger than that of the circuit 64, the drive element Q2 is first turned on and the element S2 is turned on. After that, the capacitor of the time constant circuit 64 'is completely charged, the transistor Q4 is turned on, the element Q2 is turned off, and the element S2 is turned off. Next, the element S1 turns on, but the same operation is repeated thereafter. Details of this circuit operation are shown in Japanese Patent Publication No. 3-1914, which was filed and published by the present inventor except for the operations of the time constant circuits 63 and 64.

The resonant power supply shown in FIG. 6 has, in addition to the advantages of high efficiency and low noise, isolation characteristics between the primary and secondary sides by the transformer T1. This resonant power supply does not have a regulation function against load fluctuation. Instead, the voltage and current waveforms can be changed in a sinusoidal manner, and conversion operation with less line noise and radiation noise can be expected. The bulk power supply unit 20 of FIG. 1 has the circuit configuration of FIG. 6, for example.
Therefore, a) there is no primary or secondary feedback, which is advantageous for isolation, and b) low noise and high efficiency because the switching operation is performed at a perfect zero cross, and c) a single output is sufficient. The resonance operation is more stable, and line noise and the like can be further reduced to achieve low noise and high efficiency.

[0017]

As described above, according to the present invention, A
A distributed supply type power supply system in which a primary DC output is generated from an AC input by a C / DC converter, and a secondary DC output for each load is generated by an individual DC / DC converter from the primary DC output Since a high-efficiency, low-noise, non-constant voltage type resonance power supply is used for the AC / DC conversion unit (bulk power supply unit), it is possible to improve the overall conversion efficiency and reduce noise such as line noise.

[Brief description of drawings]

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

FIG. 2 is a principle configuration diagram of a resonance type power supply device.

FIG. 3 is a detailed circuit diagram showing a specific example of the circuit of FIG.

4 is an operation waveform diagram of the circuit of FIG.

5 is a circuit diagram showing a modified example of the circuit of FIG.

FIG. 6 is a circuit diagram showing a specific example of an AC / DC conversion unit in FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... DC power supply, 2 ... Switching means, 3 ... DC output means, 4 ... Series resonance circuit, 5 ... Parallel resonance circuit, 6 ... Timing control means, 10 ... AC power supply, 20 ... Bulk power supply section (AC / DC conversion section) ) 31-35 ... DC / DC converter.

Claims (1)

(57) [Claims] 1. A switching means having two main switching elements and a timing control means having two drive elements which are alternately turned on with a period of turning off both main switching elements interposed therebetween, and the switch.
Formed in series with the current flowing through the output terminal of the
Current resonance means and output terminal of the switching means
Voltage resonance means formed in parallel with the voltage generated in the
And according to the switching operation of the switching means
DC current is output by rectifying and smoothing the current flowing on the output side.
A direct current output means for controlling the resonance action of the current resonance means and the direct current output during the ON period of the main switching element.
Rectifying action of the means causes a half-wave series resonance with respect to the current, and during the off period of the main switching element, the voltage resonance means causes parallel resonance with respect to the voltage , and the on-state of Turning off the main switching element
The timing changes the current flowing through the main switching element.
Than the timing at which the series resonance ends to zero
Delaying zero voltage and zero current switching
A bulk power supply unit having an AC / DC conversion function for performing primary and secondary insulation of an AC input and converting it into a non-constant voltage high-voltage DC output, and a distributed arrangement for receiving the DC output of the bulk power supply unit. And a plurality of isolated or non-insulated DC / DC converters, the distributed supply type power supply system.