Charger circuit for accessory battery

• US 3,938,020 A
• Filed: 02/11/1975
• Issued: 02/10/1976
• Est. Priority Date: 02/11/1975
• Status: Expired due to Term

• Current Assignee: Gould, Inc. (Transdigm Group Incorporated)
• Original Assignee: Gould, Inc. (Transdigm Group Incorporated)
• Inventors: Bourke, Robert F.
• Primary Examiner(s): Miller, J. D.
• Assistant Examiner(s): Hickey, Robert J.
• Application Number:
  US05/548,914
• Time in Patent Office: 364 Days
• Field of Search: 320/2, 320/9, 320/21, 320/57-59, 320/39, 320/40, 321/2, 321/15, 321/18, 321/21, 321/45 R, 321/45 C, 318/139
• US Class Current: 320/139
• CPC Class Codes: H02J 50/001 Energy harvesting or scavenging
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 7/342 The other DC source being a battery actively interacting with the first one, i.e. battery to battery charging with circuits for polarity protection H02J7/0034
• CPC Class Codes: Y10S 320/24 Inductor

Abstract

A charging circuit adapted to harvest excess energy from a resonating power circuit and use that energy for charging a battery. Energy is inductively transferred from the power circuit to the charging circuit allowing such circuits to remain electrically isolated. The charging circuit utilizes gate controlled thyristors for coupling the harvested energy to the battery and includes means for gating the thyristors at the proper time with respect to the resonant cycle in the power circuit.

Claims

1. A circuit for charging a battery and usable with a thyristor controlled resonant circuit, said resonant circuit having a resonating inductance, and a clamping inductance magnetically coupled to the resonating inductance for clamping the voltage across said resonant circuit at a clamping point, said charging circuit comprising in combination, a charging inductance inductively coupled to the resonating inductance, detecting means coupled to the charging inductance and responsive to the signal induced therein by the resonating inductance for detecting a point in said signal immediately before the clamping point, and switch means responsive to said detecting means for coupling the charging inductor to the accessory battery for harvesting the energy from the resonating inductance and providing it to said battery for charging the same.

2. A circuit for charging an accessory battery and usable with thyristor circuits of the type including auxiliary commutating circuits, said commutating circuits having commutating inductances therein, said charging circuit comprising in combination, charging inductance means magnetically coupled to the commutating inductance, a gate controlled switch coupling the charging inductance means to the accessory battery, sample and hold means driven by said charging inductance means for providing a sampled signal related to the peak voltage induced in said charging inductance means, sensing means for producing a sensed signal following the voltage induced in said charging inductance means, means for comparing the sampled signal and the sensed signal for producing a firing signal when said sensed signal reaches a magnitude which is a predetermined proportion of said sampled signal, and means coupling the firing signal to the gate of the gate controlled switch for causing said charging inductance means to take energy from the commutating inductance and couple said energy through said switch to the auxiliary battery.

3. The accessory battery charging circuit as set forth in claim 2, wherein said comparing means comprises a summer having a first resistor coupled to said sample and hold means and a second resistor coupled to the sensed signal, the respective values of said resistors establishing said predetermined proportion.

4. The accessory battery charging circuit as set forth in claim 2, further including regulator means responsive to the terminal voltage of the accessory battery for inhibiting said firing signal when the accessory battery is in a charged condition.

5. The accessory battery charging circuit as set forth in claim 2, further including capacitor means coupled across said accessory battery and located in proximity to the gate controlled switch for capturing the energy taken by said charging inductance means.

6. The accessory battery charging circuit as set forth in claim 2, wherein the firing signal producing means includes switch means responsive to the comparing means, and means coupling said charging inductance means to the gate of the gate controlled switch, said switch means being coupled in disabling relationship to said last mentioned means for allowing gating current to flow from the charging inductance means to the gate of the gate controlled switch only when the comparing means detects said predetermined proportion.

7. In a thyristor circuit including resonant inductance and capacitance means, said thyristor circuit being powered from a main battery, said circuit including a clamping inductance magnetically coupled to the resonant inductance, a diode in series with said clamping inductance, said serially connected diode and clamping inductance being coupled across said main battery and adapted to clamp the resonant voltage in said circuit at a predetermined maximum, a circuit for charging an auxiliary battery with energy taken from said resonant circuit comprising in combination, charging inductance means magnetically coupled to said resonant inductance, a gate controlled switch coupling said charging inductance means to the auxiliary battery, means coupled to said charging inductance means for producing a first signal related to the peak voltage in said thyristor circuit, sensing means for producing a second signal following the resonant voltage in said thyristor circuit, comparison means for comparing the first and second signals in a predetermined proportion to produce an enabling signal immediately before said clamping circuit clamps said resonant voltage, and means responsive to said enabling signal for coupling a gating signal to the gate controlled switch, thereby to couple the energy in the resonant inductance to the auxiliary battery for charging the same.

8. The auxiliary battery charging circuit as set forth in claim 7 wherein the means for coupling the gating signal comprises circuit means joining the charging inductance means to the gate of the gate controlled switch, and switch means responsive to said enabling signal for allowing conduction through said circuit means from said charging inductance means to said gate, thereby to trigger said gate controlled switch with energy taken from the resonant inductance.

9. The accessory battery charging circuit as set forth in claim 8, further including regulator means responsive to the terminal voltage of the accessory battery for providing a disabling signal under conditions when the accessory battery is charged, and means coupling said disabling signal to the switch means for inhibiting the gating of said gate controlled switch thereby to disable the charging circuit.

10. A circuit for charging an auxiliary battery for use with an auxiliary commutating inverter, said inverter comprising a pair of thyristor controlled resonant circuits serially coupled across a main battery, each of said resonant circuits including a resonant inductor, clamp means magnetically coupled to the respective resonant inductors for clamping the resonant voltage in the respective resonant circuits to a predetermined maximum, said auxiliary battery charger comprising in combination, first and second charging inductances magnetically coupled to the respective resonant inductors, first and second gate controlled switches coupling said charging inductors to the auxiliary battery, sample and hold means responsive to the charging inductors for providing a sampled signal related to the peak voltage within said resonant circuits, sensing means coupled to the charging inductor for producing signal following the resonant voltage within said resonant circuits, comparison means coupled to the sample and hold means and the sensing means for comparing said sampled signal to said resonant voltage and for producing an enabling signal at the point immediately before the clamping circuit is activated, circuit means coupling the respective gates of the first and second gate controlled switches to the respective charging inductors, switch means for interrupting the circuit means, and means coupling the comparison means to the switch means for allowing said current path in response to the presence of an enabling signal thereby to trigger the gate controlled switches immediately before activation of the clamping circuit to take the energy from the resonant inductor and couple it to the auxiliary battery for charging the same.

11. In a thyristor inverter circuit, powered from a main battery and including resonant inductance means and clamping inductance means magnetically coupled to said resonant inductance means for clamping the voltage across said inverter at a predetermined maximum wherein sufficient energy is present in said inverter for operation of subsequent resonant cycles, a circuit for charging an electrically isolated accessory battery with energy taken from said inverter circuit, said charging circuit comprising in combination, charging inductance means magnetically coupled to said resonant inductance means, sample and hold means coupled to the charging inductance means for providing a signal related to the peak voltage in said inverter circuit, sensing means for providing a second signal following the voltage in said inverter circuit, comparison means including a summer for comparing the first and second signals in a predetermined proportion thereby to detect the point immediately before said clamping means is activated to clamp the voltage across said thyristor circuit, and switch means coupling the charging inductance means to the accessory battery, said switch means being closed by said comparison means to take the energy from the resonant inductance and couple said energy to the accessory battery immediately before the operation of said clamping means, whereby said charging circuit effectively harvests a portion of the energy from said resonant inductance means while leaving sufficient energy in said resonant circuit for operation of subsequent resonant cycles.

12. A circuit for charging an auxiliary battery and usable with thyristor controlled resonant circuits of the type including a resonating inductance, said charging circuit comprising in combination, charging inductance means inductively coupled to the resonating inductance, switch means coupled to the charging inductance means, means for providing a first signal related to the peak voltage induced in said charging inductance means, means for producing a second signal following the voltage induced in said charging inductance means, means for comparing the first and second signals for producing a firing signal when said second signal reaches a magnitude which is a predetermined proportion of said first signal, and means coupling the firing signal to the switch means for causing said charging inductance means to take energy from the resonating inductance.