Loss reduction circuit for switching power converters

• US 6,341,076 B1
• Filed: 09/30/2000
• Issued: 01/22/2002
• Est. Priority Date: 05/23/2000
• Status: Expired due to Fees

• Current Assignee: Next Power Corporation
• Original Assignee: Next Power Corporation
• Inventors: Kadatskyy, Anatoly F., Karpov, Yevgen V., Soynikov, Vyacheslav Y., Volovets, Naum I.
• Primary Examiner(s): BERHANE, ADOLF D
• Application Number:
  US09/677,717
• Time in Patent Office: 479 Days
• Field of Search: 363/20, 363/21.01, 363/55, 363/56.06, 363/56.09, 363/56.12, 363/131, 323/220, 323/222, 323/223, 323/224
• US Class Current: 363/56.12
• CPC Class Codes: H02M 1/34 Snubber circuits
• CPC Class Codes: H02M 1/342 Active non-dissipative snubbers
• CPC Class Codes: H02M 3/01 Resonant DC/DC converters
• CPC Class Codes: H02M 3/1584 with a plurality of power processing stages connected in parallel
• CPC Class Codes: H03K 17/0814 by measures taken in the output circuit
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

A DC-DC power converter, and, more specifically, an active snubber circuit, method of operation thereof and power converter employing the same, and more specifically, a pulse width modulated DC-DC power converter which processes power from an input DC voltage source and delivers power to a load through an inductive energy storage component being alternatively connected to the input DC power source and to the load via electronic solid state switches.

Claims

1. A family of switching type pulse-width-modulated DC-DC converters for converting the power from the primary power source to an output power draw defined by the load power consumption demands, said converters comprising:

an input means to be connected to said primary power source;

an output means to be connected to said load;

a common return bus to be connected between said primary power source and said load;

a power storage inductor to accumulate the power absorbed from said primary power source and to deliver said power to said load;

a controllable power switch operated in a pulse-width-modulated fashion and alternatively turned into conducting state to provide the power absorption from said primary power source into said power storage inductor and turned into non-conducting state to provide the power release from said power storage inductor into said load;

a power rectifier to disconnect said load from said power storage inductor and from said primary power source while said controllable power switch is conducting and to provide the power release path from said power storage inductor and from said primary power source to said load while said controllable power switch is non-conducting;

an output smoothing filter to store the power delivered to said load and to absorb the ripple component of delivered power;

an active soft-switching conditioner connected through its nodes across said controllable power switch to provide active shaping the operating points trajectories of the switching devices through active developing soft-switching zero-voltage-across/zero-current-through conditions within the time intervals of alternative changing between conducting and non-conducting states;

said active soft-switching conditioner comprising;

an input node connected to the junction point common for said power storage inductor, for said power controllable switch and for said power rectifier;

an output node;

a common node connected to said common return bus;

a separator to separate the networks within said active soft-switching conditioner, said separator comprising at least a rectifier;

first commutator to provide first controllable path for currents within the network of said active soft-switching conditioner, said first commutator comprising a controllable switch connected in parallel with a rectifier;

second commutator to provide second controllable path for currents within the network of said active soft-switching conditioner, said second commutator comprising at least a rectifier;

third commutator to provide third controllable path for currents within the network of said active soft-switching conditioner, said third commutator comprising a rectifier;

fourth commutator to provide fourth controllable path for currents within the network of said active soft-switching conditioner, said fourth commutator comprising at least a rectifier;

first slope-shaper to provide shaping the voltage wave form developed across said controllable power switch during said controllable power switch transition into non-conducting state, therefore creating soft-switching zero-voltage-across condition for said controllable power switch during its transition into non-conducting state such that said controllable power switch transition into non-conducting state does not produce power loss, said first slope-shaper comprising at least a capacitor;

second slope-shaper to provide shaping the voltage wave form developed across said first commutator, therefore creating soft-switching zero-voltage-across/zero-current-through conditions during said first commutator transition into nonconducting state such that said first commutator transition into nonconducting state does not produce power loss, said second slope-shaper comprising at least one capacitor;

damp/resonant choke to provide the prescribed rate-of-change for the current through said power rectifier during its transition into non-conducting state, therefore creating soft-switching close to zero-current-through condition for said power rectifier during its transition into non-conducting state such that said power rectifier transition into non-conducting state does not produce power loss, and to provide the resonant discharge path for the capacitor within said first slope-shaper for shaping the voltage wave form developed across said controllable power switch during said controllable power switch transition into conducting state, therefore creating soft-switching zero-voltage-across/zero-current-through condition for said controllable power switch during its transition into conducting state such that said controllable power switch transition into conducting state does not produce power loss;

damp switch to provide a current path to release the energy magnetically stored within said damp/resonant choke, and to damp the parasitic circulation of energy magnetically stored within said damp/resonant choke, said damp switch comprising at least a rectifier;

said first slope-shaper is connected between said input node and said common node to shunt said controllable power switch;

a series-connection network comprising said separator connected with said damp/resonant choke connected with said first commutator is parallel-connected across said first slope-shaper to shunt said controllable power switch;

a controllable switch within said first commutator is turned into conducting state prior to said controllable power switch transition into conducting state to provide the prescribed rate-of-change for the current through said power rectifier during its transition into non-conducting state, therefore creating soft-switching close to zero-current-through condition for said power rectifier during its transition into nonconducting state such that said power rectifier transition into non-conducting state does not produce power loss, and to provide the resonant discharge path for the capacitor within said first slope-shaper, therefore creating soft-switching zero-voltage-across/zero-current-through condition for said controllable power switch during its transition into conducting state such that said controllable power switch transition into conducting state does not produce power loss;

a series-connection network comprising said second slope-shaper connected with said damp switch is parallel-connected across said damp/resonant choke to shunt said damp/resonant choke and to provide the prescribed shape-of-change for the voltage across said first commutator during its transition into nonconducting state, therefore creating soft-switching zero-voltage-across/zero-current-through condition for said first commutator such that said first commutator transition into non-conducting state does not produce power loss;

a series-connection network comprising said third commutator connected with said second slope-shaper is adapted to limit the voltage level across said second slope-shaper during resonant release of energy magnetically stored within said damp/resonant choke;

a series-connection network comprising said third commutator connected with said second slope-shaper is adapted to provide a discharge path for the capacitor(s) within said second slope-shaper past said controllable power switch transition into nonconducting state; and

a series-connection network comprising said third commutator connected with said second slope-shaper is coupled between said input node and said output node to provide the prescribed rate-of-change for the voltage across said controllable power switch during its transition into nonconducting state, therefore creating soft-switching zero-voltage-across condition for said controllable power witch such that said controllable power switch transition into non-conducting state does not produce power loss.

2. Converters according to claim 1, wherein said separator is connected between said input node and common junction point of said damp/resonant choke connected with said second commutator connected with said fourth commutator to damp the parasitic circulation of energy magnetically stored within said damp/resonant choke, and to limit the rate-of-change of current through said power rectifier during its transition into non-conducting state, therefore creating soft-switching close to zero-current-through condition for said power rectifier during its transition into non-conducting state such that said power rectifier transition into non-conducting state does not produce power loss, and to limit the rate-of-change of voltage developed across said controllable power switch during its transition into non-conducting state, therefore creating soft-switching zero voltage-across condition for said controllable power switch such that said controllable power switch transition into non-conducting state does not produce power loss.

3. Converters according to claim 2, wherein said damp switch comprises a controllable switch connected in parallel with a rectifier, and said controllable switch within said damp switch commutates the damp/resonant choke with magnetically stored energy release circuit such that said damp/resonant choke is disconnected from said magnetically stored energy release circuit as soon as the current through said damp/resonant choke reaches close to zero, therefore eliminating the parasitic circulation of energy magnetically stored within said damp/resonant choke.

4. Converters according to claim 3, wherein said fourth commutator comprises:

a controllable switch connected in parallel with a rectifier;

a series-connection network comprising said separator connected with said fourth commutator connected with said damp/resonant choke connected with said first commutator is parallel-connected across said first slope-shaper to shunt said controllable power switch, said controllable switch within said first commutator and said controllable switch within said fourth commutator both are simultaneously turned into conducting state prior to controllable power switch transition into conducting state to provide the prescribed rate-of-change for the current through said power rectifier during its transition into non-conducting state therefore creating soft-switching close to zero-current-through condition that said power rectifier transition into non-conducting state does not produce power loss, and to provide the resonant discharge path for the capacitor within said first slope-shaper, therefore creating soft-switching zero-voltage-across/zero-current-through condition for said controllable power switch during its transition into conducting state such that said controllable power switch transition into conducting state does not produce power loss;

said second slope-shaper comprises first capacitor and second capacitor, and said first capacitor has first terminal and second terminal, and said second capacitor has first terminal and second terminal, and aid first capacitor and said second capacitor are arranged in parallel such that;

said first terminal of said first capacitor makes first lead of said second slope-shaper, and said first terminal of said second capacitor makes second lead of said second slope-shaper, and said second terminal of said first capacitor and said second terminal of said second capacitor are connected in common junction which makes third lead of said second slope-shaper;

said first lead of said second slope-shaper is connected to the junction point common to said input node connected with said first slope shaper connected with said separator;

said second lead of said second slope-shaper is connected to the junction point common to said separator connected with said fourth commutator;

said third lead of said second slope shaper is connected to the junction point common to said damp switch connected with said third commutator;

a series-connection network comprising said second slope-shaper connected with said damp switch is parallel-connected across said damp/resonant choke connected at one side both with said second commutator and with said fourth commutator, and connected at other side with said first commutator, to shunt said damp/resonant choke and to provide the prescribed shape-of-change for the voltage across said first commutator as soon as its transition into non-conducting state starts and for the voltage across said fourth commutator as soon as its transition into nonconducting state starts, therefore creating soft-switching zero-voltage-across/zero-current-through conditions both for said first commutator transition into non-conducting state and for said fourth commutator transition into non-conducting state such that both said first commutator transition into non-conducting state and said fourth commutator transition into non-conducting state do not produce power losses;

said second commutator and series-connection network comprising said third commutator connected with said damp switch are adapted to provide a current path to release the energy magnetically stored within said damp/resonant choke and to damp the voltage pikes across the damp/resonant choke;

said second commutator and series-connection network comprising said third commutator connected with said second slope-shaper are adapted to limit the voltage level across said second slope-shaper during resonant charging said capacitor(s) within said second slope-shaper with magnetically stored energy being released from said damp/resonant choke;

said first commutator and a series-connection network comprising said fourth commutator connected with said second capacitor within said second slope-shaper through said second lead and with said third commutator are adapted to shunt said damp/resonant choke while damp/resonant choke releases the magnetically stored energy, therefore limiting voltage pikes across said damp/resonant choke;

a series-connection network comprising said second slope-shaper connected with said third commutator is coupled to said power storage inductor to provide the discharge path for said capacitors within said second slope-shaper past said controllable power switch transition into non-conducting state;

a series-connection network comprising said third commutator connected with said second slope-shaper is coupled between said input node and said output node to provide the prescribed rate-of-change for the voltage across said controllable power switch during its transition into non-conducting state, therefore creating soft-switching zero-voltage-across condition for said controllable power switch such that said controllable power switch transition into non-conducting state does not produce power loss.

5. Converters according to claim 4, wherein said output node is connected to the junction point common for said power rectifier and for said load to forward the released energy both from said damp/resonant choke and from said second slope-shaper to said load.

6. Converters according to claim 4, wherein said output node is connected to the junction point common for said primary power source and for said power storage inductor to forward the released energy both from said damp/resonant choke and from said second slope-shaper to said primary power source.

7. Converters according to claim 4, wherein said controllable power switch and all controllable switches within said damp switch, within said first commutator and within said fourth commutator are solid-state semiconductor switches.

8. Converters according to claim 7, wherein all rectifiers connected across said controllable switch within said damp switch, across said controllable switch within said first commutator and across said controllable switch within said fourth commutator are body diodes of said solid-state semiconductor switches.

9. Converters according to claim 4, wherein said capacitor within said first slope-shaper is a stray capacitor of said controllable power switch.

10. A method for converting the power from said primary power source to an output power draw defined by said load power consumption demands, in a family of switching type pulse-width-modulated DC-DC converters comprising:

an input means, an output means, a common return bus;

a power storage inductor, a controllable power switch, a power rectifier, an output smoothing filter, an active soft-switching conditioner connected through its nodes across the power switch, said active soft-switching conditioner comprising;

an input node, an output node, a common node;

a separator comprising at least a rectifier;

first commutator comprising a controllable switch connected in parallel with a rectifier;

second commutator comprising at least a rectifier;

third commutator comprising at least a rectifier;

fourth commutator comprising a controllable switch connected in parallel with a rectifier;

first slope-shaper comprising at least a capacitor;

second slope-shaper comprising at least one capacitor;

damp/resonant choke;

damp switch comprising a controllable switch connected in parallel with a rectifier;

said first slope-shaper is connected between said input node and said common node;

said separator is connected between said input node and common junction point of said damp/resonant choke connected with said second commutator connected with said fourth commutator to damp the parasitic circulation of energy magnetically stored within said damp/resonant choke, and to limit the rate-of-change of current through said power rectifier during its transition into non-conducting state, therefore creating soft-switching close to zero-current-through condition for said power rectifier such that said power rectifier transition into non-conducting state does not produce power loss, and to limit the rate-of-change of voltage developed across said controllable power switch during its transition into non-conducting state, therefore creating soft-switching zero-voltage-across condition for said controllable power switch such that said controllable power switch transition into non-conducting state does not produce power loss;

a series-connection network comprising said separator connected with said fourth commutator connected with said damp/resonant choke connected with said first commutator is parallel-connected across said first slope-shaper to shunt said controllable power switch;

said controllable switch within said first commutator and said controllable switch within said fourth commutator both are simultaneously turned into conducting state prior to controllable power switch transition into conducting state;

said second slope-shaper comprises first capacitor and second capacitor, and said first capacitor and said second capacitor are arranged in parallel such that;

first terminal of said first capacitor makes first lead of said second slope-shaper, and first terminal of said second capacitor makes second lead of said second slope-shaper, and second terminal of said first capacitor and second terminal of said second capacitor are connected in common junction which makes third lead of said second slope-shaper;

said first lead of said second slope-shaper is connected to the junction point common to said input node connected with said first slope-shaper connected with said separator;

said second lead of said second slope-shaper is connected to the junction point common to said separator connected with said fourth commutator;

said third lead of said second slope shaper is connected to the junction point common to said damp switch connected with said third commutator;

a series-connection network comprising said second slope-shaper connected with said damp switch is parallel-connected across said damp/resonant choke connected at one side both with said second commutator and with said fourth commutator, and connected at other side with said first commutator, to shunt said amp/resonant choke;

a series-connection network comprising said third commutator connected with said second slope-shaper is coupled between said input node and said output node to provide the prescribed rate-of-change for the voltage wave forms across said controllable power switch during its transition into non-conducting state, therefore creating soft-switching zero-voltage-across condition for said controllable power switch during its transition into non-conducting state such, that said controllable power switch transition into non-conducting state does not produce power loss;

said controllable switch within said damp switch commutates the damp/resonant choke with magnetically stored energy release circuit such that said damp/resonant choke is disconnected from said magnetically stored energy release circuit as soon as the current through said damp/resonant choke reaches close to zero, therefore eliminating the parasitic circulation of energy magnetically stored within said damp/resonant choke;

to provide soft-switching zero-voltage-across/zero-current-through conditions both for power switching devices within said family of switching type pulse-width-modulated DC-DC converters and for networks commutating devices within said active soft-switching conditioner, and to eliminate power losses resulted from simultaneous overlapping non-zero-voltage-across/non-zero-current-through conditions during switching transitions within said power switching devices and within said networks commutating devices, and to provide an opportunity of power conversion operational frequency increase and hence the power storing components decrease in weight and size, and to improve the power conversion process regulation quality, and to reduce the radiated EMI, said method comprises the steps of;

turning simultaneously into conducting state both said controllable switch within said first commutator and said controllable switch within said fourth commutator prior to said controllable power switch transition into conducting state to provide the prescribed rate-of-change for the current through said power rectifier during its transition into non-conducting state, therefore creating soft-switching close to zero-current-through condition for said power rectifier such that said power rectifier transition into non-conducting state does not produce power loss, and to provide the resonant discharge path for the capacitor within said first slope-shaper, therefore creating soft-switching zero-voltage-across/zero-current-through condition for said controllable power switch such that said controllable power switch transition into conducting state does not produce power loss;

turning said power rectifier into non-conducting state with soft recovery of its reverse resistance under soft-switching close to zero-current-through condition hence losslessly disconnecting said load from said power storage inductor and from said primary power source;

connecting said power storage inductor to said primary power source for power absorption and accumulation through the networks within said active soft-switching conditioner;

turning said controllable power switch into conducting state under soft switching zero-voltage-across/zero-current-through conditions hence connecting said power storage inductor to said primary power source for power absorption and accumulation;

shunting said damp/resonant choke with a series-connection network comprising said second slope-shaper connected with said damp switch to provide the prescribed shape-of-change for the voltage across said first commutator as soon as its transition into non-conducting state starts and for the voltage across said fourth commutator as soon as its transition into non-conducting state starts, therefore creating soft-switching zero-voltage-across/zero-current-through conditions for said first commutator transition into non-conducting state and for said fourth commutator transition into non-conducting state such that said first commutator transition into non-conducting state and said fourth commutator transition into non-conducting state do not produce power losses;

releasing the energy magnetically stored within said damp/resonant choke through forward-biased said second commutator, through forward-biased said separator and through forward-biased said damp switch into said capacitors within said second slope-shaper and further into said output node as soon as past a prescribed time said third commutator becomes forward-biased/conducting;

turning said damp switch into non-conducting state as soon as its carried current decreases close to zero and soft-switching zero-current-through condition occurs, therefore eliminating the parasitic circulation of energy magnetically stored within said damp/resonant choke;

recovering said second commutator reverse resistance under soft-switching close to zero-current-through condition;

absorbing the power from said primary power source into said power storage inductor through said controllable power switch;

turning said controllable power switch into non-conducting state under soft-switching zero-voltage-across condition;

absorbing the power from said primary power source into said power storage inductor through linear charging said first slope-shaper and through linear discharging said second slope-shaper;

connecting said primary power source and said power storage inductor to said load as a result of said power rectifier transition into conducting state and forwarding the absorbed and accumulated power from said power storage inductor to said load and to said output smoothing filter.

11. Method according to claim 10, wherein said second slope-shaper is discharged through said third commutator into said primary power source to provide releasing the magnetically stored energy from said damp/resonant choke.

12. Method according to claim 10, wherein said second slope-shaper is discharged through said third commutator into said load to provide releasing the magnetically stored energy from said damp/resonant choke.