JPH07170660A - Power supply device - Google Patents

Abstract

PURPOSE:To provide a power supply device which can supply power to a load by generating a desired high voltage with a simple configuration and adjusting an electrostatic capacitance for accumulating electric charge to a desired value. CONSTITUTION:This device is provided with n capacitor elements CB1-CB4 which are connected serially, a plurality of power supplies S1-S4 for independently charging the corresponding n capacitor elements, a means for detecting each voltage of n capacitor elements, and a means 20 for controlling a plurality of power supplies selectively corresponding to the desired synthetic capacity and output voltage of n capacitor elements. Therefore, by increasing the number of capacitor banks to be charged, a higher output voltage can be obtained. Also, increasing the number of capacitor banks to be charged causes the resultant capacitance to be reduced even if an output voltage is the same. On the contrary, decreasing the number of capacitor banks to be charged causes the resultant capacitance to be increased, thus supplying a desired power to the load.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply device, and more particularly to a power supply device suitable for supplying a desired power to a load.

[0002]

2. Description of the Related Art In order to measure the safety characteristics when an excessive electric power is supplied to a circuit, it is necessary to generate the excessive electric power and measure it in advance. FIG. 3 shows, as an example thereof, a block diagram when an insulated gate bipolar transistor (IGBT) is used as the device under test (DUT) 10 and a short circuit test of the IGBT is performed. In this short-circuit test, a high voltage is supplied between the collector and the emitter of the IGBT 10 and the characteristic of how much the collector and the emitter of the IGBT 10 are short-circuited is measured.
In FIG. 3, 11 is a power supply, 13 is a voltmeter Vm, 15 is an ammeter Im, and 12 is a switch for switching the supply of electric power. Reference numeral 5 is a pulse generator for supplying a pulse for controlling the gate of the IGBT 10 to be turned on and off. Various devices such as a resistor for a large current, a coil of a motor, and the like are conceivable as the device under test 10, and a device that supplies a high voltage is required when measuring the characteristics when a large voltage is supplied to these Becomes

[0003]

The commercial AC power source in Japan is 50/60 Hz, 100V. One method of obtaining a DC voltage source of 100 V or higher is to boost an AC input and charge a smoothing capacitor (capacitance element) with a rectified current. The peak value of the voltage across the smoothing capacitor is equal to the maximum voltage from the charger. In order to increase the peak voltage of this smoothing capacitor, it is necessary to increase the maximum output voltage of the charger. Such a high voltage output charger is expensive, which increases the cost of the device.

Further, in the short circuit test, if the current flowing through the DUT 10 becomes excessive, there is a concern that other related circuit elements may be destroyed or damaged. The total energy W stored in the capacitor depends on the amount of charge Q charged in the capacitor and is represented by W = (1/2) QV. here,
V is the potential difference across the capacitor. The amount of charge Q is
It is proportional to the capacitance C of the capacitor and is represented by Q = CV. When a load R is connected to this capacitor, the time constant representing the discharging speed of the electric charge (that is, the decreasing speed of the discharging current) is expressed by CR. In this case, when the resistance value R of the load is the same, the larger the capacitance C of the capacitor, the larger the amount of charge Q accumulated, and the decrease in the current flowing through the load is delayed. Therefore, the load (DUT) and related elements are damaged. More likely to. That is, in the short circuit test, after reaching the short circuit state,
It is desirable for the current to decay quickly, which is why
It is desirable that the electrostatic capacity C of the power supply is small.

Therefore, an object of the present invention is to supply a desired electric power to a load by making it possible to generate an arbitrary high voltage with a simple structure and adjust an electrostatic capacity for accumulating charges to a desired value. It is to provide a power supply device that can do.

[0006]

In the power supply device of the present invention, n (integer of 2 or more) capacitor banks (capacitance elements) are connected in series, and each of these n capacitor banks corresponds. Each of the capacitor banks is independently charged by a plurality of charging means. Detection means (voltage control circuit) 44
Detects the voltage of each of the n capacitor banks,
The data is transmitted to the control means (CPU) 20 by a known method. The control means 20 selectively controls the plurality of charging means according to the desired combined capacitance and output voltage of the n capacitor banks.

The power supply apparatus of the present invention includes a plurality of capacitive elements each having one end grounded and the other end connected in series to an output end,
Charging means for independently charging each of the plurality of capacitive elements;
Detection means for detecting a voltage across each of the plurality of capacitance elements, connection means for connecting a node between adjacent capacitance elements of the plurality of capacitance elements and the output end, and detection by the detection means The control means controls the charging means according to the applied voltage and generates a desired electric power from the output end according to the total charge amount of the plurality of capacitive elements.

In the connecting means, an anode is connected to a node between adjacent capacitive elements of the plurality of capacitive elements,
The cathode includes a plurality of diodes commonly connected to the other end of the capacitive element, and switch means connected between the commonly connected cathodes of the plurality of diodes and the output end. .

[0009]

1 shows a block diagram of an embodiment of a power supply apparatus of the present invention. Capacitor banks CB1 to CB4 connected in series have corresponding DC power sources S1.
Are capacitive elements (capacitors) that accumulate the charges supplied from S4. For simplification, the case where each of the capacitor banks and the DC power supplies is four is shown, but it is generally composed of n (n is an integer of 2 or more) capacitor banks CB1 to CBn and the DC power supplies S1 to Sn. DC power supply S1 to S
The configuration of 4 will be described later. Semiconductor switch 12
Switches the supply of the charges accumulated in the capacitor banks CB1 to CB4 to the device under test (load) 10. The solid state switch 12 is off when charging the capacitor bank, while it is on when powering the load 10. As the semiconductor switch 12, for example, an insulated gate bipolar transistor (IGBT) capable of switching high power is suitable.

Reference numerals 13 and 15 denote a voltmeter Vm and an ammeter Im for detecting the voltage and current of the load 10. These are converted into digital data by using an analog-digital converter and transmitted to the CPU 20. You may do it. The pulse generator 14 includes a central processing unit (CPU) 20.
A pulse to be supplied to the gate (control) terminal G is generated based on the control of 1 to control the switching of the IGBT 12.
The compensation capacitance element 16 compensates for the inductance of the conductive path which causes noise. The analog-digital converter (A / D) 18 detects the output voltage Vo of the power supply device of the present invention, converts it into digital data, and transmits it to the CPU 20.

In charging each capacitor bank,
DC power supplies S1 to S4 not compatible with the diodes D1 to D3
Prevents the electric charge from flowing into each of the capacitor banks CB1 to CB4. For example, the electric charge supplied from the DC power source S4 does not flow into the capacitor bank CB3 because of the diode D3. That is, due to the presence of the diodes D1 to D3, the capacitor bank C
Each of B1 to CB4 is charged by a corresponding DC power source S1
~ S4 can be done independently. Further, as can be seen from FIG. 1, the reference potential of the DC power supply S4 is the ground potential, but the reference potentials of the DC power supplies S1 to S3 are floating.
The CPU 20 controls the output voltages of the DC power supplies S1 to S4, respectively, so as to control each capacitor bank CB1.
Controlling the charging of ~ CB4 independently controls the output voltage Vo of the power supply and the combined capacitance Cs of the capacitor bank. The power consumption of the capacitive element is (1 /
2) Since it is given by CV ^ 2 (^ 2 means the square), the minimum combined capacitance Cs in consideration of the required output voltage Vo.
If is selected, the amount of accumulated charge Q = CsV is reduced, so that the supplied power can be reduced.

The following Table 1 shows the combined capacitance Cs of the series capacitor banks according to the embodiment of the present invention shown in FIG. 1, in particular, the combined capacitance Cs according to the number of capacitor banks connected in series and the output voltage. The correspondence of Vo is shown. In addition, x indicates that there is no corresponding item.

[0013]

[Table 1]

In this embodiment, the capacitance C of each of the capacitor banks CB1 to CB4 is 2.
The same is assumed at 2 mF. Of course, the capacity of each CB may be different. When n capacitors of the same capacitance C are connected in series, the combined capacitance Cs is given by Cs = C / n. Increase the number of capacitors connected in series,
Charge Q by charging each capacitor bank CB1 to CB4
Is stored, the output voltage Vo is Vo = Q / Cs.
In other words, the output voltage Vo can be controlled by controlling the number of capacitor banks connected in series and the amount of charge charged in each selected capacitor bank.
Conversely, even with the same output voltage, the combined capacitance Cs can be increased by reducing the number of capacitor banks used. That is, since the combined capacitance Cs can be controlled by controlling the allocation of the voltages supplied from the DC power supplies S1 to S4, the time constant CsR for the load R can be controlled, and the attenuation characteristic of the output current can be controlled. Of course, if the number n of capacitor banks is increased, the selection range of the number of capacitors to be charged is expanded, so that the combined capacitance Cs can be set in finer steps.

FIG. 2 is a block diagram showing in more detail one of the plurality of DC power supply S and capacitor bank CB pairs. The voltage from the commercial AC power supply 28 is the transformer 3
It is transformed by 0 and rectified by the rectification circuit 32. Relay 34
Thus, the on / off of the DC power supply S is controlled. The switching circuit 36 switches under the control of the switching control circuit 38 and generates a pulse signal. The coil 40 constitutes a kind of smoothing circuit together with the capacitor bank CB. The discharge circuit 42 is a capacitor bank CB.
If necessary, the electric charge charged in the battery is discharged. This may be composed of, for example, a discharge resistor and a relay, and the relay may be turned on when discharging. Voltage control circuit 44
Detects the voltage across CB under the control of the CPU 20 and controls the switching control circuit 38 and the discharge circuit 42. For example, when the charge exceeds the set value, the discharge circuit 42 discharges the charge. As a result, the DC power supply functions as a programmable power supply. Further, the voltage control circuit 44 has an analog / digital converter. Then, the detected voltage across the CB is converted from analog to digital, converted into digital data and transmitted to the CPU 20 through the interface 50.

The switching control circuit 38 monitors the voltage across the current sense resistor Rs. When the voltage across the current sense resistor Rs exceeds a constant voltage determined based on the capacitance of the transformer 30, the switching control circuit 38
Turns off the switching circuit 36 to stop the supply of the pulse signal. The current sense resistor Rs also has a function of detecting abnormality in the discharge circuit and CB. For example, C
If the current is flowing when the voltage of B should be constant or if the current is not flowing when the battery is to be charged, it is detected that something is wrong. The switching control circuit 38 has an analog / digital converter, and the voltage across the current sense resistor Rs is analog / digital converted and transmitted to the CPU 20 as digital data.
Optimally, optical communication that is not easily affected by electromagnetic interference (EMI) is used for exchanging data between the interface 50 and the CPU 20. Therefore, it is preferable to use the photoelectric conversion circuits 52 and 54 and the optical fiber.

As described above, the DC power source and the capacitor
Each of the circuits in the bank may be floated or grounded to zero potential as necessary, but since all the circuits have the same configuration, the efficiency of designing and manufacturing is good. Since the voltage generated in each capacitor bank is monitored by the CPU 20 via the voltage control circuit 44, there are a plurality of capacitor banks.
Accurate control is possible even if the voltages of the banks are different.

The CPU 20 uses the combined capacity Cs required to supply the desired power to the load, the required number of capacitor banks n = C / Cs, and the output voltage Vo, the voltage Vk to be output by each DC power source. Calculate Vo / n. In this way, the DC power supply to be used is selected, and the required voltage and current are supplied to the corresponding capacitor banks from each to charge them. When it is desired to suppress the power to be supplied to the load, the number n of capacitor banks to be charged is increased so as to reduce the combined capacitance of the capacitors, and in the opposite case, the number of capacitor banks to be charged is decreased. . This makes it possible to properly supply the desired power required for the load.

FIG. 4 is a block diagram showing another preferred embodiment of the switch 12. This is a series of m high-current semiconductor elements such as IGBTs connected in series and n connected in parallel. Here, m and n are arbitrary integers. For simplicity, each element (IGBT) has the same characteristics, and the maximum voltage and maximum current of each element are Vmax and Imax. FIG. 4 shows an example in which m is 2 and n is 3. Each IGBT is indicated by Q. Collector of Q11, Q12 and Q13 and voltage dividing circuit S
The floating power supply Vfl is provided between 11 and S23. The voltage dividing circuits S11 to S23 divide the voltage Vfl and supply a bias voltage to the gates of Q11, Q12 and Q13. This allows Q11, Q12 and Q13
Is always on (operating). Generally, in an array of IGBTs of m rows and n columns, IGs other than a predetermined row that is arbitrarily determined are arranged.
BT is held in the ON state. However, at this stage, no current flows through the entire circuit.

Diodes Db11 to Db23 are often provided between the emitter and collector of the IGBT.
This is usually to protect the IGBT when reverse biased. However, the present invention also functions as a current path for the current flowing from the floating power supply Vfl via the voltage dividing circuit. The voltage dividing circuits S11 to S23 have not only resistors but also capacitors, in order to improve the response of signals. Gate of each IGBT
Zener diode Dt11 provided between the emitters
.About.Dt23 prevent the gate-emitter voltage of each IGBT from exceeding the rated value and prevent the breakdown of the IGBT.

The pulse generator 14 generates a gate signal having a voltage of a predetermined pulse width and supplies it between the gate and emitter of Q21. In this case, Q21, Q22 and Q2
Note that the gates of 3 are tied together, but the emitters are not. Gate of Q21
When a gate signal is supplied between the emitters, Q21 turns on at the rising edge of the gate signal. This allows all I's in the first column
GBT, that is, Q11 and Q21 are turned on. Then,
The other columns also operate to balance the voltage drop caused by the current flowing through the first column. Therefore, the remaining IGBTs in the m-th row, that is, Q22 and Q23 are also turned on. As a result, all the IGBTs forming the array are turned on (operating). Supplying the gate signal only between the gate and the emitter of Q21 is due to the IGBT in the other m-th row.
This is because even if they are supplied in common, they do not always operate with the same characteristics due to variations in their characteristics. According to this configuration, since the elements other than the m-th row IGBT are in the normal operation state, the entire array can be activated in response to the gate signal at high speed. Therefore, by using this circuit, it is possible to perform high-speed switching even with a large current that cannot be handled by one IGBT.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the embodiments described herein, and various modifications and changes can be made as necessary without departing from the gist of the present invention. It will be apparent to those skilled in the art that changes can be made.

[0023]

According to the power supply device of the present invention, it is possible to arbitrarily adjust the number of volts to which each of a plurality of capacitors connected in series can be charged. By setting a desired capacitance, that is, a desired amount of charge for the output voltage value, it is possible to supply a desired power to the load. Moreover, a desired high voltage output can be easily generated with a simple configuration in which the capacitor and the charging circuit are connected in series.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of a power supply device of the present invention.

FIG. 2 is a block diagram showing in more detail the configuration of one embodiment of multiple DC power supplies and capacitor banks.

FIG. 3 is a block diagram when an IGBT is selected as a device to be measured and a short circuit test is performed.

FIG. 4 is a block diagram showing another preferred embodiment of the switch 12.

[Explanation of symbols]

 10 device to be measured (load) 44 detection means S1 to S4 charging means (DC power supply) CB1 to CB4 capacitive element (capacitor bank) D1 to D3 and 12 connection means

Claims (3)

[Claims] 1. An n (integer of 2 or more) number of capacitive elements connected in series, a plurality of charging means for independently charging the corresponding n number of capacitive elements, and a plurality of the n number of capacitive elements. A power supply comprising: a detection unit that detects each voltage; and a control unit that selectively controls the plurality of charging units according to a desired combined capacitance of the n capacitance elements and an output voltage. Supply device. 2. A plurality of capacitive elements having one end grounded and the other end connected in series to an output terminal, charging means for independently charging each of the plurality of capacitive elements, and each of the plurality of capacitive elements. Detecting means for detecting a voltage between both ends, connecting means for connecting between the output terminal and a node between adjacent capacitive elements of the plurality of capacitive elements, and in accordance with the voltage detected by the detecting means, A power supply device, comprising: a control unit configured to control a charging unit and generate desired power from the output end according to a total charge amount of the plurality of capacitive elements. 3. The plurality of diodes, wherein the connecting means has an anode connected to a node between adjacent capacitive elements of the plurality of capacitive elements, and a cathode commonly connected to the other end of the series capacitive element, The power supply apparatus according to claim 2, further comprising switch means connected between the commonly connected cathodes of the plurality of diodes and the output terminal.