CONTROL CIRCUIT FOR REGULATING A DC-TO-DC CONVERTER

• US 3,815,008 A
• Filed: 03/01/1973
• Issued: 06/04/1974
• Est. Priority Date: 03/01/1973
• Status: Expired due to Term

• Current Assignee: BorgWarner Incorporated
• Original Assignee: George H. Studtmann, John K. Overzet
• Inventors: Studtmann, George H., Overzet, John K.
• Primary Examiner(s): Shoop, Jr., William M.
• Application Number:
  US05/337,053
• Time in Patent Office: 460 Days
• Field of Search: 321/43,44
• US Class Current: 363/79
• CPC Class Codes: G05F 5/00 Systems for regulating electric variables by detecting deviations in the electric input to the system and thereby controlling a device within the system to obtain a regulated output
• CPC Class Codes: H02M 3/10 using discharge tubes with control electrode or semiconductor devices with control electrode H02M3/07 takes precedence

Abstract

A first control system includes a chopper (dc-to-dc converter) for passing part of an input voltage Vi through a filter to provide an output voltage Vo for energizing an inverter. A controller regulates the operation of the semiconductor switch in the chopper by providing an output signal which is a function both of a first input signal derived from the input circuit that supplies the input voltage Vi to the chopper, and of a second input signal derived from a reference member. In a second system the reference voltage input to the controller is replaced by an error voltage provided by a comparator. The comparator receives both the reference voltage signal and a second signal related to the output voltage Vo of the chopper-filter combination.

Claims

1. A dc-to-dc conversion system, including a chopper circuit having at least one semiconductor switch, an input circuit for applying an input voltage subject to transient fluctuations to the chopper circuit, an output circuit for passing an output voltage to a load, and a filter including an inductor coupled in series between the chopper circuit and the output circuIt, a controller connected to apply control signals to the chopper circuit to regulate the conduction times of the semi-conductor switch, means for applying to the controller a first input signal which is a function of the chopper circuit input voltage, and means for applying to the controller a second input signal which is a function of a reference voltage, thus preventing saturation of the filter inductor and maintaining the chopper output voltage substantially constant, notwithstanding the transient fluctuations of the input voltage supplied to the chopper circuit.

2. A dc-to-dc conversion circuit as claimed in claim 1, and further comprising a comparator circuit having an output connection coupled to the controller, a first input connection connected to receive the reference voltage, and a second input connection coupled to the output circuit, which comparator provides an error signal which is a function of the algebraic sum of the reference voltage and the output voltage.

3. A dc-to-dc conversion system, including a chopper circuit having at least one semiconductor switch, an input circuit for applying an input voltage subject to transient fluctuations to the chopper circuit, an output circuit for passing an output voltage to a load, a filter including an inductor coupled in series between the chopper circuit and the output circuit, a controller connected to apply control signals to the chopper circuit to regulate the conduction times of the semiconductor switch, means for applying to the controller a first input signal which is a function of the chopper circuit input voltage, a comparator circuit having a first input connection connected to receive a reference voltage, a second input connection coupled to the output circuit, an output connection for providing an error signal which is a function of the algebraic sum of the reference voltage and the output voltage, and means for applying the error signal as a second input signal to the controller, thus preventing saturation of the filter inductor and maintaining the chopper output voltage substantially constant, notwithstanding the transient fluctuations of the input voltage supplied to the chopper circuit.

4. The method of converting an input d-c voltage Vi to an output voltage Vo for energizing a load from the output voltage, including the steps of regulating the on and off times of a switch to correspondingly regulate that portion of the input voltage Vi which appears as the output voltage Vo, and filtering the voltage passed from the switch to become the output voltage through a circuit including a series-connected inductor, which method is characterized by the steps of:

sensing the input voltage Vi, providing a reference voltage, and controlling the on and off times of the switch as a function of both the input voltage Vi and the reference voltage, to effect switching operation such that the volt-time integral when the switch is closed is kept substantially equal to a constant and the volt-time integral when the switch is opened is kept substantially equal to the same constant.

5. The method of converting an input d-c voltage Vi to an output voltage Vo for energizing a load from the output voltage, including the steps of regulating the on and off times of a switch to correspondingly regulate that portion of the input voltage Vi which appears as the output voltage Vo, and filtering the voltage passed from the switch to become the output voltage through a circuit including a series-connected inductor, which method is characterized by the steps of:

sensing the input voltage Vi, sensing the output voltage Vo, providing a reference voltage, comparing the output voltage Vo with the reference voltage to provide an error signal connoting the relationship of the output voltage to the reference voltage, and controlling the on and off times of the Switch as a function of both the input voltage Vi and the error signal, to effect switching operation such that the volt-time integral when the switch is closed is kept substantially equal to a constant and the volt-time integral when the switch is opened is kept substantially euqal to the same constant.

6. A dc-to-dc conversion system, including a chopper circuit having at least one semiconductor switch capable of being switched on and off, an input circuit for applying an input voltage Vi subject to transient fluctuations of the chopper circuit, an output circuit for passing an output voltage Vo toward a load, a filter including an inductor coupled in series between the chopper circuit and the output circuit, and controller connected to apply first and second control signals to the chopper circuit to regulate the on and off times of the semiconductor switch, which controller includes a flip-flop circuit operative in its first state to provide said first control signal for turning said semiconductor switch on and operative in its second state to provide said second control signal for turning said semiconductor switch off, a first charging circuit including a first capacitor connected to regulate the switching of the flip-flop circuit to its first state, a second charging circuit including a second capacitor connected to regulate the switching of said flip-flop circuit to its second state, means including a common conductor for passing a portion of a charging current signal to said first charging circuit and for passing the remainder of said charging current signal toward said second charging circuit, means, coupled between said input circuit and said common conductor, for supplying to the controller said charging current signal which varies as a function of the input voltage Vi, circuit means connected in said second charging circuit for modifying said remainder of the charging current signal passed toward the second capacitor, and means for applying a reference signal to said circuit means, to modify the turn-off signal to the semiconductor switch as a function both of the input voltage Vi and of said reference signal.

7. A dc-to-dc conversion system, including a chopper circuit having at least one semiconductor switch capable of being switched on and off, an input circuit for applying an input voltage Vi subject to transient fluctuations to the chopper circuit, an output circuit for passing an output voltage Vo toward a load, a filter including an inductor coupled in series between the chopper circuit and the output circuit, and a controller connected to apply first and second control signals to the chopper circuit to regulate the on and off times of the semiconductor switch, which controller includes a flip-flop circuit operative in its first state to provide said first control signal for turning said semiconductor switch on and operative in its second state to provide said second control signal for turning said semiconductor switch off, a first charging circuit including a first capacitor connected to regulate the switching of the flip-flop circuit to its first state, a second charging circuit including a second capacitor connected to regulate the switching of said flip-flop circuit to its second state, means including a common conductor for passing a portion of a charging current signal to said first charging circuit and for passing the remainder of said charging current signal toward said second charging circuit, means, coupled between said input circuit and said common conductor, for supplying to the controller said charging current signal which varies as a function of the input voltage Vi, circuit means connected in said second charging circuit for modifying said remainder of the charging signal passed toward the second capacitor, means for providing a reference signal, means coupled to said output circuit for providing a feedback signal which varies as the output voltage Vo, a comparatoR connected to receive both said reference signal and said feedback signal and to provide an output error signal, and means for applying said output error signal to said circuit means, thus to modify the turn-off signal to the semiconductor switch as a function both of the input voltage Vi and of said output error signal.

8. A dc-to-dc conversion system, including a chopper circuit having at least one semiconductor switch which is turned on as a function of a turn-on signal developed by a current Ion and which is turned off by a turn-off signal developed by a current Ioff, an input circuit for applying an input voltage Vi subject to transient fluctuations to the chopper circuit, an output circuit for passing an output voltage Vo a load, a filter including an inductor coupled in series between the chopper circuit and the output circuit, a controller connected to apply control signals to the chopper circuit to regulate the turn-on and turn-off signals supplied to the semiconductor switch in accordance with the current signals Ion and Ioff, means for applying to the controller a first input signal Io which is a function of the chopper circuit input voltage Vi and which is divided to supply the Ion and Ioff current signals, and means for supplying to the controller a second input signal which is a function of the chopper circuit output voltage Vo, characterized in that said controller is connected to regulate the signals Ion and Ioff in accordance with any two of the following three criteria:

Io Alpha Vi Ioff Alpha Vo Ion Alpha (Vi - Vo)

9. A dc-to-dc conversion system, including a chopper circuit having at least one semiconductor switch, an input circuit for applying an input voltage subject to transient fluctuations to the chopper circuit, an output circuit for passing an output voltage to a load, and a filter including an inductor coupled in series between the chopper circuit and the output circuit, a controller connected to apply control signals to the chopper circuit to regulate the conduction times of the semiconductor switch, means for applying to the controller a first input signal which is a function of the chopper circuit input voltage, means for applying to the controller a second input signal which is a function of a reference voltage, and circuit means in said controller, connected to shorten the on time ( Delta ton) during which the one semiconductor switch is closed responsive to an increase in the chopper circuit input voltage, thus maintaining constant the volt-time integral when the semiconductor switch is closed, which circuit means is also connected to maintain the off time ( Delta toff) unchanged so that the volt-time integral when the semiconductor switch is opened is maintained constant and substantially equal to the volt-time integral when the semiconductor switch is closed.

10. A dc-to-dc conversion system, including a chopper circuit having at least one semiconductor switch, an input circuit for applying an input voltage subject to transient fluctuations to the chopper circuit, an output circuit for passing an output voltage to a load, a filter including an inductor coupled in series between the chopper circuit and the output circuit, a controller connected to apply control signals to the chopper circuit to regulate the conduction times of the semiconductor switch, means for applying to the controller a first input signal which is a function of the chopper circuit input voltage, a comparator circuit having a first input connection connected to receive a reference voltage, a second input connection coupled to the output circuit, an output connection for providing an error signal which is a function of the algebraic sum of the reference voltage and the output voltage, and means for applying the error signal as a second input signal to the coNtroller, and circuit means in said controller, connected to shorten the on time ( Delta ton) during which the one semiconductor switch is closed responsive to an increase in the chopper circuit input voltage, thus maintaining constant the volt-time integral when the semiconductor switch is closed, which circuit means is also connected to maintain the off time ( Delta toff) unchanged so that the volt-time integral when the semiconductor switch is opened is maintained constant and substantially equal to the volt-time integral when the semiconductor switch is closed.