JPH0723987U - Output voltage control circuit in step-up chopper circuit with ± DC dual power supply output - Google Patents

Abstract

(57) [Abstract] [Purpose] Balance the + and-side output voltages of ± DC2 power supply outputs with a simple circuit configuration. [Arrangement] An operational amplifier 17 that outputs an ON / OFF signal synchronized with an input AC power supply frequency via an auxiliary power supply transformer 42, an AC voltage signal and a current signal are input via an auxiliary power supply transformer 42 and a current detector 34, and the difference is generated. Dynamic amplifier 4
And the inverting amplifier 3 are used to alternately input the + side output voltage of the output circuit and the negative side output voltage of the output circuit via the differential amplifier 5 based on the output signal of the operational amplifier 17, and the AND gates 18 and 19 are connected. Through the semiconductor switching elements 31 and 3
It is configured by a high power factor control IC 21 that alternately turns on and off.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a control circuit in a converter that constitutes a UPS used in OA equipment, communication equipment and the like.

[0002]

[Prior art]

An output voltage control circuit in a step-up chopper circuit of ± DC dual power source output according to the prior art is as shown in the block diagram of FIG. In FIG. 3, a + side boosting chopper circuit composed of diodes 107 and 108, a semiconductor switching element 109, and a smoothing capacitor 112, and a − side boosting chopper circuit composed of diodes 106 and 111, a semiconductor switching element 110, and a smoothing capacitor 113 are used. A direct current dual power source is configured, and the commercial alternating current power source 101, the capacitor 103, the step-up reactor 105, the current detector 104, and the auxiliary power source transformer 102 are a common circuit on the input side of the ± direct current dual power source. The voltage signal from one of the two secondary coils provided in the auxiliary power supply transformer 102 is input to the operational amplifier 117 through the resistor 114 and the two diodes 115 and 116, and the voltage signal is output from the other secondary coil. The voltage signal is input to the high power factor control IC 121 together with the current signal from the current detector 104. The operational amplifier 117 outputs a signal synchronized with the input frequency from the input AC power supply 101 and inputs it to one terminal of the AND gate 118 and also inputs it to one terminal of the AND gate 119 via the NOT gate 120. Further, the voltage across the positive side output voltage V ₀₁ and the negative side output voltage V ₀₂ is input to the high power factor control IC 121 via the voltage dividing resistors 122 and 123, and the high power factor control IC 121 The output signal is input to the other terminals of the two AND gates 118 and 119.

The high power factor control IC 121, which is an IC dedicated to the boost chopper, ANDs a signal which is a logical product of the output signal and the output signal of the operational amplifier 117 so that the phases of the input voltage signal and the input current signal match. The gates 118 and 119 are alternately output to control ON / OFF of the semiconductor switching elements 109 and 110. Further, the output voltage is adjusted by inputting the voltage across the output circuit and controlling the Dewey ratio of the semiconductor switching elements 109 and 110.

[0004]

[Problems to be solved by the device]

In the conventional ± DC dual power source output boost chopper circuit described above, the high power factor control IC 121 collectively collects (V ₀₁ + V ₀₂ ) which is the voltage across the _positive side output voltage V ₀₁ and the negative side output voltage V _02. Since they are controlled, the + side output voltage V ₀₁ and the − side output voltage V ₀₂ become unbalanced unless the loads in the two output circuits are balanced. To improve this, either use two high power factor control ICs for the + side and-side respectively, or detect the unbalanced amount of the output voltage, and use this detected amount as the input current detected amount. A circuit to add a correction was required, and in any case, the circuit had to be complicated. The present invention has been made in order to solve the above-mentioned drawbacks of the prior art, and uses one high power factor control IC to balance the + side output voltage and the − side output voltage of ± DC2 power source output. The purpose is to propose an output voltage control circuit that can do this.

[0005]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, an operational amplifier that outputs a signal synchronized with an input power supply frequency, a high power factor control IC that controls the phase of a voltage signal and a current signal of the input power source, the operational amplifier and a high power factor control IC. Output voltage control circuit in a ± DC dual power supply output step-up chopper circuit configured by two AND gates that input the IC output signal and alternately turn on and off the semiconductor switching elements in the two step-up chopper circuits , The analog switch 1 that inputs the output voltage detected from the + side of the output circuit via the differential amplifier 4 and the inverting amplifier 3, and the output voltage detected from the-side of the output circuit via the differential amplifier 5. The analog switch 2 for inputting is input and these two analog switches 1 and 2 are alternately turned on / off by the output signal of the operational amplifier. The detected voltage on the + side and-side of the output circuit are alternately fed back to the high power factor control IC by and, and when the semiconductor switching element 31 is on, the analog switch 1 is also turned on and the output voltage on the + side is When the semiconductor switching element 32 is turned on, the analog switch 2 is also turned on to control the minus output voltage to balance the two output circuit voltages.

[0006]

[Action]

 The + and-side output voltages of the ± DC2 power supplies are alternately detected in synchronization with the input AC power supply frequency and fed back to the high power factor control IC 21 to provide a high-performance operational amplifier 17 synchronized with the AC input power supply frequency. The output signals of the power factor control IC 21 are alternately turned on / off to control the Dewey ratios of the semiconductor switching elements 31 and 32 for each half cycle to balance the + and-side output voltages.

[0007]

【Example】

 Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a circuit configuration of an output voltage control circuit in a step-up chopper circuit of ± DC dual power source output according to the present invention. In FIG. 1, a control circuit including two step-up chopper circuits, an auxiliary power supply transformer 42, a current detector 34, an operational amplifier 17, a high power factor control IC 21, two AND gates 18 and 19 and a NOT gate 20 is a circuit in the prior art. Since the configuration is the same, the description is omitted.

The output voltage V ₀₁ between the + side of the output circuit and the common line is applied to the analog switch 1 through the differential operational amplifier 4 including the resistors 8, 9, 10, 11 and the inverting amplifier 3 including the resistors 6 and 7. The output voltage V ₀₂ between the negative side of the output circuit and the common line is input to the analog switch 2 via the differential amplifier 5 including the resistors 12, 13, 14, and 15. The output signal of the operational amplifier 17 is input to one terminal of the AND gate 18 and also to the control terminal of the analog switch 2. The output signal of the operational amplifier 17, the polarity of which is inverted by the NOT gate 20, is input to one terminal of the AND gate 19 and the control terminal of the analog switch 1. The high power factor control IC 21 inputs the voltage signal from the secondary coil of the auxiliary power transformer 42 and the current signal from the current detector 34, and outputs from the analog switches 1 and 2 on the positive and negative sides of the output circuit. The voltage is input and the output signal is output to the other terminals of the two AND gates 18 and 19.

Next, the operation of the output voltage control circuit composed of the operational amplifier 17, the high power factor control IC 21, the analog switches 1 and 2, and the AND gates 18 and 19 will be described with reference to the waveform diagram of FIG. To do. The voltage signal V _1N of the AC power supply 43 input to the operational amplifier 17 via the auxiliary power transformer 42 is as shown in FIG. 2 (a), and the output signal waveform at the output terminal A of the operational amplifier 17 is shown in FIG. 2 (b). As shown in, a square wave that turns on and off every AC power cycle is generated. This output signal is sent to the analog switch 2, but its control terminal has a negative logic, so the analog switch 2 does not operate and remains off, while the operational amplifier 17 whose polarity is inverted by the inverter 20 is used. Output signal is sent to the analog switch 1 to turn on the analog switch 1. Then, when the signal at the output terminal A of the operational amplifier 17 is turned off, the analog switch 2 is turned on and the analog switch 1 is turned off. As shown in FIGS. -Switches 1 and 2 are turned on and off alternately, and the + side output voltage and-side output voltage of the output circuit are input to the high power factor control IC 21.

The output signal from the high power factor control IC 21 to which the + side output voltage and the − side output voltage are input every half cycle in synchronization with the frequency of the AC input power source is output to the AND gate 18 together with the output signal of the operational amplifier 17. The AND gates 18 and 19 alternately output the gate signals for driving the semiconductor switching elements 31 and 32, and the output of each output circuit is adjusted by adjusting the Dewey ratio of the gate signals. Adjust the voltage. That is, the + side output voltage is adjusted during the positive half-wave period of the input frequency, and the-side output voltage is adjusted during the negative half-wave period for each cycle to balance the + and-side output voltages. Is possible.

[0011]

[Effect of device]

 As explained above, the output voltage control circuit in the step-up chopper circuit of the ± DC2 power supply output according to the present invention synchronizes the output voltage on the + side and − side of the ± DC2 power supply with the input frequency. It is input to a high power factor control IC via an amplifier and an analog switch, and the semiconductor switching element that controls the + side output voltage and the semiconductor switching element that controls the − side output voltage are alternately turned on every half cycle. Turn off. Therefore, one high power factor control IC can independently control the + and-side output voltages of the ± DC dual power supplies to balance the output voltages.

By balancing the output voltages of the ± 2 DC power supplies, the input current also has a symmetrical waveform, so that even high frequencies of the input current can be eliminated. Therefore, even when the boost chopper circuit with ± DC dual power supply output according to the present proposal is used as the DC power supply of the half-bridge type inverter, the input current distortion is small, and the symmetry of the output current is especially obtained when the rectifier is loaded. It became an effective means to realize a high power factor converter.

[Brief description of drawings]

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

FIG. 2 is a signal waveform diagram.

FIG. 3 is a block diagram showing a circuit configuration in a conventional technique.

[Explanation of symbols]

 1, 2 Analog switch 4, 5 Differential amplifier 3 Inversion amplifier 17 Operational amplifier 18, 19 AND gate 20 NOT gate 21 High power factor control IC 31, 32 Semiconductor switching element 34 Current detector 35 Boosting reactor 42 Auxiliary power transformer

Claims (1)

[Scope of utility model registration request] 1. An operational amplifier which inputs a voltage signal through an auxiliary power supply transformer provided in an AC power supply circuit and outputs a signal synchronized with an input power supply frequency; and a voltage signal from the auxiliary power supply transformer and the AC power supply circuit. The high power factor control IC for inputting the current signal from the current detector and outputting the signal for adjusting the phase of the two signal waveforms, and the output signals of the operational amplifier and the high power factor control IC are input. In the output voltage control circuit in the step-up chopper circuit of ± DC2 power source output, which is configured by two AND gates that alternately turn on / off the semiconductor switching elements (31) and (32) that form the two step-up chopper circuits, The output voltage between the + side of the output circuit and the common line is detected and input to the analog switch (1) through the differential amplifier (4) and the inverting amplifier (3). The output voltage between the negative side of the output circuit and the common line is detected and input to the analog switch (2) through the differential amplifier (5), and the analog switch (and When 1) and (2) are on / off controlled and output voltage signals detected from the + side and − side of the output circuit are alternately input to the high power factor control IC and boosted by the semiconductor switching element (31). Controls the + side output voltage when the analog switch (1) is turned on, and when the semiconductor switching element (32) boosts the voltage, the analog switch (2) is turned on to control the − side output voltage. An output voltage control circuit in a step-up chopper circuit that outputs ± DC dual power supplies.